3,4-Bis-O-propargyl-1,2:5,6-di-O-iso­propyl­­idene-D-mannitol: a study of multiple weak hydrogen bonds in the solid state

The title homochiral com­pound, C₁₈H₂₆O₆, 1, was examined by single-crystal X-ray crystallography in order to understand its potential as a synthetic building block, particularly in inter- and intra­molecular cyclo­condensation reactions. It has also proven to be an excellent model for understanding multiple weak donor–acceptor D—H⋯A inter­actions involving terminal acetyl­enes as donors and as acceptors. The asymmetric unit of 1 com­prises three almost identical independent mol­ecules, each with the mannitol 2R,3R,4R,5R con­figuration and different con­formations. Like independent mol­ecules align in strands through acetyl­enic donor C—H⋯O contacts with equivalent dioxolanyl acceptor groups. Two of the strands are aligned unidirectionally, in parallel, while the third strand aligns perpendicular to the first two, to give inter­woven layers in the supra­molecular structure. A detailed study of the inter­digitation of the second propargyl group from each independent mol­ecule between strands, and of other short inter­strand C—H⋯O contacts, provides new insight into the application of weak hydrogen-bond theory within the context of a con­formationally flexible symmetrical mol­ecule. Analyses of the Cambridge Structural Database using Crystal Packing Features and ConQuest search motifs support the importance of the D⋯A distance parameter, demonstrate the different influences of donor and acceptor types, and reveal the inter­play between H⋯A and D⋯A contributions in different contact types.

1. Introduction

Propargyl groups are small and can serve as protection for alcohols that can be selectively removed in the presence of acetonides (1,3-dioxolanyls), methoxymethyl (MOM), benzyl and tert-butyldimethylsilyl (TBS) ethers (Manabe et al., 2008; Rambabu et al., 2013), and provide subtle enhancement of di­astereoselectivity in the synthesis of β-manno­pyran­osylated disaccharides (Crich et al., 2006). Proparg­yloxy groups can also undergo a variety of useful transformations in their own right. One of us recently described the synthesis of 3,4-bis-O-propargyl-1,2:5,6-di-O-iso­propyl­idene-D-mannitol, 1, and its use in Cu^I-catalyzed dipolar cyclo­addition reactions with n-alkyl azides to generate model com­pounds for potential new gemini surfactants (Mohammed et al., 2012), and extended this study in a collaborative effort to O-propargyl derivatives of glucose and galactose sugars and their reactions with polyfluoro­alkyl azides as a route to novel fluorous surfactants (Ahmed et al., 2020). Related sugar-derived oligo-propargyl ethers have participated in intra­molecular 1,3-dipolar nitrone addition (Ghorai et al., 2005) and been used as versatile building blocks in diversity-oriented synthesis of macrocycles (Maurya & Rana, 2017), while oligo-propargylated sugars and other polyols have been used with oligoazides in a modular approach to neoglycoconjugates (Perez-Baldaras et al., 2009). Similar vicinal propargyl ethers derived from furfural have found use in conversion to bis­phenols (Hashmi et al., 2007). Furthermore, dipropargyl malonate and terephthalate esters generate di- and tetra­nuclear clusters with cobalt, molybdenum and ruthenium metal ions (Zhang et al., 2001). In more tangential, although not exclusive, applications, cyclo­addition reactions of bridged di­acetyl­enic com­pounds have been used to generate a wide range of benzenoid substances, including fluoranthenes and indeno­corannulenes (Wu et al., 2006), and propargylic enediyne alcohols have shown participation in nucleophilic cyclo­aromatization (Poloukhtine et al., 2010) akin to the important Bergman cyclization (Bergman, 1973). Relevant to these topics has been the lengthy and sometimes vexed discourse in the literature over the nature of C—H⋯O hydrogen bonds in crystals (Bernstein, 2013), where often the donor inter­actions of terminal acetyl­enic groups have been quoted. Matters of contention have been the acid strength and linearity of C—H⋯O hydrogen bonds (Desiraju, 1990, 1991), the distinction between weak attractive hydrogen bonds versus repulsive van der Waals inter­actions (Steiner & Desiraju, 1998, 1999; Schwalbe, 2012) and the attribution of contacts to electrostatics com­pared with van der Waals inter­actions (Steiner, 2002; Desiraju, 2002). Controversy over such matters has subsided (Bernstein, 2013), with an acceptance that in the solid state there is a continuum of these factors in play, and the best measure of weak donor–acceptor D—H⋯A contact effectiveness is the D⋯A distance (D). Such considerations have influenced subsequent applications of weak hydrogen bonds to mol­ecular recognition in organic crystals (Dunitz & Gavezzotti, 2005), virtual screening in drug design (Desiraju, 2005; Jones et al., 2012) and crystal engineering (Desiraju, 2013, Baillargeon et al., 2014).

As a homochiral vicinal bis-propargyl ether, substance 1 [Fig. 1(a)] therefore has potential to serve as a precursor for a wide range of intriguing materials whose function would depend largely upon tertiary structure and inter­molecular inter­actions. Its solid-state structure also holds inter­est because of the close proximity of two notionally equivalent terminal acetyl­enic groups in the presence of two ethereal oxygen types (proparg­yloxy and dioxolan­yl) as acceptors. The mol­ecule was reprepared here and examined for the first time by single-crystal X-ray diffraction to ascertain a baseline for these structural features in the solid state.

Figure 1 (a) The mol­ecular structure of title com­pound 1, showing the mannitol 2R,3R,4R,5R con­figuration. (b) The mol­ecular structure of mol­ecule A, showing the crystallographic atom-numbering scheme used throughout the remainder of the discussion, with displacement ellipsoids drawn with Mercury CSD (Version 3.0; Macrae et al., 2020) at the 40% probability level and H atoms shown as small spheres of arbitrary radius. (c) Overlay of mol­ecules A (green), B (blue) and C (red) from the unit cell of com­pound 1 represented in capped sticks format, showing good overlap in the O1/O2 dioxolanyl portion (head) and significant variation, especially by mol­ecule A, in the O5/O6 dioxolanyl portion (tail).

2. Experimental

2.1. Synthesis

The synthesis of 3,4-bis-O-propargyl-1,2:5,6-di-O-iso­pro­pyl­idene-D-mannitol, 1 {systematic name: (1R,2R)-1,2-bis­[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-1,2-bis­(prop-2-yn-1-yl­oxy)ethane}, has been reported (Mohammed et al., 2012) and the X-ray diffraction sample crystallized from EtOAc/n-hexane as colourless prisms (m.p. 50–52 °C).

2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The H atoms were not located in the difference Fourier map. Instead, the H atoms were placed geometrically and constrained according to their environment.

Table 1
Experimental details

Crystal data
Chemical formula	C18H26O6
Mr	338.39
Crystal system, space group	Triclinic, P1
Temperature (K)	150
a, b, c (Å)	9.4726 (4), 10.3000 (5), 15.3583 (7)
α, β, γ (°)	73.378 (2), 88.382 (2), 86.400 (2)
V (Å^3)	1432.94 (11)
Z	3
Radiation type	Mo Kα
μ (mm^−1)	0.09
Crystal size (mm)	0.24 × 0.21 × 0.19
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Bruker, 2016)
Tmin, Tmax	0.679, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	25389, 8343, 8134
Rint	0.028
(sin θ/λ)max (Å^−1)	0.595
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.026, 0.065, 1.02
No. of reflections	8343
No. of parameters	661
No. of restraints	3
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å^−3)	0.21, −0.15
Absolute structure	Flack x determined using 3228 quotients [(I^+) − (I^−)]/[(I^+) + (I^−)] (Parsons et al., 2013)
Absolute structure parameter	0.04 (17)
Computer programs: APEX3 (Bruker, 2016), SAINT (Bruker, 2016), SHELXT (Sheldrick, 2015a), SHELXL (Sheldrick, 2015b) and OLEX2 (Dolomanov et al., 2009).

2.3. Analyses of the Cambridge Structural Database (CSD)

2.3.1. Searches of the CSD based on Mercury Crystal Packing Features (PFF)

A total of 33 individual searches of the Cambridge Structural Database (CSD; Groom et al., 2016) for Crystal Packing Features (referred to here as PFFs) and illustrated in Fig. S1 (see supporting information) were carried out on 11 unique sets of donor D (A1, A2, B, C and D) and acceptor A (E, F, G, H, I and J) propargylic contacts that were recognised within the crystal structure of com­pound 1 (Fig. S2). Search criteria specified consideration of `Cyclicity' and were given a `Low' setting tolerance `Level of Geometric Similarity'. Where bifurcation was evident, individual PFF searches were performed for each partner pair and then for the two inter­actions together. The output of each search was recorded with a Positive result (a numerical and itemized list of known structures, with structure codes, that fell within the Low Level of Geometric Similarity), and a Negative result (included a corresponding numerical and itemized list of known structures containing the com­ponents of the search query, but where the geometric tolerances were not met). The reference codes of structures regarded as Positive and Negative hits under each PFF search result, and their total numbers and percentages, were com­piled into Microsoft Excel spreadsheets. A spreadsheet of the results with matching Positive and Negative structure codes aligned (with the exception of search B1.2) was constructed (Table S2), and the numerical data summarized in graphical form (see Section 3.4.2).

2.3.2. Searches based on liberally defined structural motifs using the ConQuest search tool

Loosely constrained structural motifs derived from those shown in Fig. S2 were established in the ConQuest search tool for propargylic donor inter­actions: CSM_A1, CSM_A2, CSM1_R1, CSM1-R2, CSM1_R3 and CSM1_R4; and acceptor inter­actions: CSM1_R5 and CSM1_R6 (Fig. S3). Relevant distance parameters, D1 (H⋯A, Å) and D2 (D⋯A, Å), were liberally defined as within the sum of the van der Waals radii plus 1.0 Å, and the angular measurements, ANG (D—H⋯A, °), limited to within 60–180°. Where multiple contacts were recorded for a single com­pound, sometimes within the same category, these were included for com­pleteness. The values for D1, D2 and ANG for all matching contacts found in the CSD were recorded and the results displayed as scatterplots against `Identity Number' in Fig. S3 and discussed more fully in Section 3.4.3.

3. Results and discussion

3.1. Mol­ecules in the unit cell

The asymmetric unit com­prises three independent mol­ecules (represented as A-green, B-blue and C-red), each with the mannitol 2R,3R,4R,5R con­figuration [Fig. 1(b), randomly selected mol­ecule A] and differing only in the con­formation of the mol­ecule. This establishes asymmetry in each mol­ecule. Hence, in future, and for ease of reference, the terms `head' and `tail' sections will be used for each mol­ecule, based on lower and higher crystallographic element numbers, respectively [Fig. 1(c)].

3.1.1. Conformations of mol­ecules A–C

Based on torsion angles (Table 2), there are marginal differences in the con­formation about the central mannitol core (Entries 1–3), with mol­ecule A the most notable. Marginal differences are also observed in torsions associated with the orientation of the dioxolanyl groups relative to the core (Table 2, Entries 4–15), but most notably in mol­ecule A and to the largest extent in the tail portion of the mol­ecules. In contrast, puckering of the dioxolanyl group, as reflected in the C1/14—O3/10—C3/16—C6/10 torsion angles (Table 2, Entries 16–21), was most varied in the head section, and to the most significant extent (moderately) in mol­ecule C; con­figurations in the tails of mol­ecules A–C were highly consistent. The proparg­yloxy substituents potentially have three sources of con­formational freedom. Marginal differences are observed in the torsions associated with their attachment to the mannitol core in both head and tail sections (Table 2, Entries 22–27), but most noticeably in mol­ecule A. From this point, the orientation of the propargyl groups in com­parison with the mannitol core are relatively conserved in the heads and tails of all three mol­ecules (Table 2, Entries 28–33). However, significant differences are then observed in the orientations of the terminal acetyl­enic groups in the head and tail sections relative to the mannitol fragment (Table 2, Entries 34–39), with the most extreme difference appearing through atom O3 in the head of mol­ecule A and atom O4 in the tail of mol­ecule B.

Table 2
Selected torsion data for the alignment of head and tail dioxolanyl and proparg­yloxy groups, with each other and independently relative to the central mannitol chain of each of the crystallographically independent mol­ecules A–C in the unit cell of com­pound 1, showing individual torsion angles (φ), mean values within each head and tail group, and observed deviations from the means^a

Entry	Position	Torsions	Angle, φ (°)	A–C Mean, φ (°) (±deviation)
1	central	C3A—C6A—C10A—C16A	−176.7 (2)	180.0 (2.3)^b
2	central	C3B—C6B—C10B—C16B	175.2 (2)	180.0 (−4.8)^b
3	central	C3C—C6C—C10C—C16C	175.5 (2)	180.0 (−4.8)^b
		C—C3/16—C6/10—C	Dioxolan­yl(C)—C relative to core(C)
4	head	C2A—C3A—C6A—C10A	76.6 (2)	78.7 (−2.1)
5	head	C2B—C3B—C6B—C10B	80.6 (2)	78.7 (1.9)
6	head	C2C—C3C—C6C—C10C	78.9 (2)	78.7 (0.2)
7	tail	C6A—C10A—C16A—C15A	85.0 (2)	77.4 (7.6)
8	tail	C6B—C10B—C16B—C15B	73.8 (2)	77.4 (−3.6)
9	tail	C6C—C10C—C16C—C15C	73.3 (2)	77.4 (−4.1)
		O—C3/16—C6/10—C	Dioxolan­yl(O)—C relative to core(C)
10	head	O2A—C3A—C6A—C10A	−167.1 (2)	−165.0 (−2.1)
11	head	O2B—C3B—C6B—C10B	−163.4 (2)	−165.0 (1.6)
12	head	O2C—C3C—C6C—C10C	−164.4 (2)	−165.0 (0.6)
13	tail	C6A—C10A—C16A—O5A	−159.5 (2)	−166.8 (7.3)
14	tail	C6B—C10B—C16B—O5B	−170.2 (2)	−166.8 (−3.4)
15	tail	C6C—C10C—C16C—O5C	−170.6 (2)	−166.8 (−3.8)
		C—O2/5—C3/16—C	Dioxolan­yl(C)—O relative to core(C)
16	head	C1A—O2A—C3A—C6A	−152.2 (2)	−148.2 (−4.0)
17	head	C1B—O2B—C3B—C6B	−149.9 (2)	−148.2 (−1.7)
18	head	C1C—O2C—C3C—C6C	−142.4 (2)	−148.2 (5.3)
19	tail	C14A—O5A—C16A—C10A	−137.4 (2)	−137.9 (0.5)
20	tail	C14B—O5B—C16B—C10B	−139.2 (2)	−137.9 (−1.3)
21	tail	C14C—O5C—C16C—C10C	−137.0 (2)	−137.9 (0.9)
		O—C6/10—C10/6—C	Proparg­yl(O) relative to core(C)
22	head	O3A—C6A—C10A—C16A	−52.4 (2)	−58.2 (5.8)
23	head	O3B—C6B—C10B—C16B	−61.4 (2)	−58.2 (−3.2)
24	head	O3C—C6C—C10C—C16C	−60.8 (2)	−58.2 (−2.6)
25	tail	C3A—C6A—C10A—O4A	−54.4 (2)	−58.7 (4.3)
26	tail	C3B—C6B—C10B—O4B	−61.0 (2)	−58.7 (−2.3)
27	tail	C3C—C6C—C10C—O4C	−60.7 (2)	−58.7 (−2.0)
		C—O3/4—C6/10—C	Proparg­yl(C)—O relative to core(C)
28	head	C7A—O3A—C6A—C10A	148.0 (2)	148.1 (−0.1)
29	head	C7B—O3B—C6B—C10B	149.0 (2)	148.1 (0.9)
30	head	C7C—O3C—C6C—C10C	147.4 (2)	148.1 (−0.7)
31	tail	C11A—O4A—C10A—C6A	142.6 (2)	140.3 (2.3)
32	tail	C11B—O4B—C10B—C6B	138.2 (2)	140.3 (−2.1)
33	tail	C11C—O4C—C10C—C6C	140.1 (2)	140.3 (−0.2)
		C—O3/4—C7/11—C	Proparg­yl(C)—C relative to core(C)
34	head	C6A—O3A—C7A—C8A	−58.5 (2)	−68.9 (10.4)
35	head	C6B—O3B—C7B—C8B	−72.9 (2)	−68.9 (−4.0)
36	head	C6C—O3C—C7C—C8C	−75.3 (2)	−68.9 (−6.4)
37	tail	C10A—O4A—C11A—C12A	−86.2 (2)	−79.4 (−6.8)
38	tail	C10B—O4B—C11B—C12B	−63.2 (2)	−79.4 (15.2)
39	tail	C10C—O4C—C11C—C12C	−88.7 (2)	−79.4 (−9.3)
Notes: (a) the colours highlight the torsions of most difference within each triplet: red 2–7°, green 7–12° and blue >12°. (b) Deviation from the ideal angle of 180°.

3.2. Strand and sheet assemblies

3.2.1. Recognition of the like mol­ecular strand construct

More detailed analysis reveals that, in the crystal, the three independent species (A-green, B-blue and C-red) align in strands, each with matching identical mol­ecules A, B and C. Mol­ecules in each strand engage through unique tail-to-tail inter­actions. The differences in each case appear to arise because of subtle differences in the con­formations of each mol­ecule. Such individual strands all occur through C13—H13⋯O6 contacts and are represented and viewed along the a axis in Fig. 2(a) and along the c axis in Fig. 2(b). Thus, the contacts for mol­ecules A (green) and B (blue) occur in a unidirectional sense along the b axis, with identical symmetry codes, namely (x + 1, y, z), while strands of mol­ecules C (red) are oriented perpendicular, along the a axis [consider Figs. 2(a) and 2(b)], through a different symmetry code, (x, y − 1, z). As is also evident, particularly in Fig. 2(b) and the positions of atoms C5 and C9, the mol­ecules in strands A and B are flipped relative to each other by approximately 180° about the length of the two strands. This feature permits near coincidence of the C13—H13⋯O6 alignments, with unidirectionality of the overall strands, while accommodating the steric demands of the remaining portions of the mol­ecules.

Figure 2 Individual crystal packing of mol­ecules A, B and C in com­pound 1. (a) View slightly off-set from the a axis, showing the near linear (θ = 167.8°) alignment of tail-to-tail C13C—H13C⋯O6C intra­strand contacts and inter­digitation inter­actions through inter­strand donor propargylic H9A (green) and H9B (blue) atoms with acceptor dioxolanyl atoms O6C (red) and ether atoms O3C (red), respectively; measurement of very weak engagement between inter­strand donor proparygyl H9C (red) and acceptor propargylic ether atoms O2A (green) is not shown here, but discussed in Section 3.2.3. (b) View along the c axis showing the parallel, unidirectional and tail-to-tail arrangements of strands of outstretched mol­ecules A (green) and B (blue), and the orthogonal tail-to-tail arrangement of strands of mol­ecules C (red), all with acetyl­enic donor C13—H13⋯O6 dioxolanyl acceptor contacts; the positions of atoms C5 and H9 are also shown for reference purposes. Generic atom labels without symmetry codes have been used.

3.2.2. Homogeneous mol­ecular strands and sheets

3.2.2.1. Intra­strand contacts between like mol­ecules. Significant advances have been made towards estimating the H-atom positions of small organic mol­ecules from X-ray crystallographic data (Jayatilaka & Dittrich, 2008; Capelli et al., 2014; Woińska et al., 2016). These have achieved results that are within the accuracy of neutron diffraction. However, a very limited number of examples have been described. As a consequence, contact data for short intra- and inter­strand inter­actions between like mol­ecules of each type have been summarized in Table 3 using parameters that have become accepted more widely as good indicators of strength and efficiency in the field for weak hydrogen bonds (Desiraju, 2005). The values include the accurately measured D⋯A distance (D, Å), the estimated D—H bond length using the previously utilized predicted position of the H atom for each type of weak acid species [CH (acetyl­enic) = 0.95 Å, CH (methine at sp³ carbon) = 1.00 Å, CH₂ (methyl­ene) = 0.99 Å and CH₃ (meth­yl) = 0.98 Å], without any additional normalization, and the resulting H⋯A distance (Å). Common to each of the strands are the aforementioned intra­strand tail-to-tail C13—H13⋯O6 contacts (Table 3; Entries 1, 4 and 12). All three achieve short D⋯A distances with near-linear D—H⋯A contact angles (A 158.3, B 164.7 and C 167.8°). Observed values are consistent with acetyl­enic groups with pK_a (Me₂SO) ∼ 24.9 (Pedireddi & Desiraju, 1992). These intra­strand associations stand alone for mol­ecule A, but are reinforced within the strands from mol­ecule B by additional more distant C13—H13B⋯C14B, C13—H13B⋯C17B and C17B—H17D⋯H13B contacts (Table 3, Entries 5–7), and within those from mol­ecule C by an equally distant head-to-head C4C—H4CB⋯C9C contact (Table 3, Entry 13) (see also Fig. 3). Those involving mol­ecule B are exceptionally weak, as assessed by D⋯A distance measurements. They stem from additional engagement by the C13B—H13B group as a donor in a trifurcated contact with quaternary atom C14B and its neighbouring bonded methyl C17B and H17D atoms. The additional intra­strand contact involving mol­ecules C is remarkable because it occurs between highly remote groups that ordinarily are weak donors and acceptors.

Table 3
Short intra­strand and inter­strand contacts between like mol­ecules from each of strands A–C

Strand/Entry	Intra/inter strand	D⋯A positions	D—H⋯A	D—H	H⋯A	D⋯A	Contact angle, θ
A
1	intra	tail–tail	C13A—H13A⋯O6A^i	0.95	2.34	3.247 (3)	158.3
2	inter	head–tail	C5A—H5AA⋯C13A^ii	0.98	3.39	3.466 (4)	86.1
3	inter	tail–head	C17A—H17B⋯C8A^ii	0.98	2.98	3.652 (3)	127.1
B
4	intra	tail–tail	C13B—H13B⋯O6B^i	0.95	2.21	3.138 (2)	164.7
5	intra	tail–tail	C13B—H13B⋯C14B^i	0.95	2.98	3.884 (3)	159.5
6	intra	tail–tail	C13B—H13B⋯C17B^i	0.95	3.04	3.827 (4)	141.2
7	intra	tail–tail	C17B—H17D⋯H13B^i	0.98	2.57	3.04	109.5
8	inter	head–tail	C5B—H5BB⋯C12B^ii	0.98	3.10	3.612 (3)	114.4
9	inter	tail–head	C17B—H17E⋯C7B^ii	0.98	3.09	3.919 (4)	143.0
10	inter	tail–head	C17B—H17E⋯C8B^ii	0.98	3.06	3.812 (4)	134.1
11	inter	tail–head	C18B—H18E⋯C9B^ii	0.98	3.05	3.861 (5)	141.1
C
12	intra	tail–tail	C13C—H13C⋯O6C^ii	0.95	2.34	3.278 (3)	167.8
13	intra	head–head	C4C—H4CB⋯C9C^ii	0.98	3.02	3.456 (4)	108.3
14	inter	head–tail	C4C—H4CC⋯C18C^iii	0.98	2.92	3.867 (4)	162.5
Symmetry codes: (i) x − 1, y, z; (ii) x, y − 1, z; (iii) x − 1, y + 1, z.

Figure 3 Inter- and intra­strand contacts between like mol­ecules of strands A, B and C, as seen from directly above the mean planes of the A, B and C sheets, with unit cells indicated, as well as closeup views with labels and distance measurements included.

3.2.2.2. Inter­strand contacts between like mol­ecules. Inter­strand contacts are also observed between like mol­ecular strands (Table 3 and Fig. 3). These vary between parallel strands of mol­ecules A, B and C with inter­strand spacings, as measured by C13⋯C13′ distances of 10.300 (5), 10.300 (5) and 9.473 (4) Å, respectively, to create planar sheets of singular mol­ecular type (Fig. 3). Donors in each case com­prise normally weak dioxolanyl methyl groups, in which those between strands of A and B resemble each other, and those between strands C engage differently. For example, those from mol­ecule A include a noticeably moderate C5A⋯C13A contact [D⋯A = 3.466 (4) Å] (Table 3, Entry 2) orthogonal to the aforementioned C13A—H13A⋯O6A inter­action, while those from mol­ecule B include a similar but specific C5B—H5BB⋯C12B contact [D⋯A = 3.612 (3) Å] (Table 3, Entry 8), neither of which are observed between the strands of mol­ecule C. Similarly, mol­ecule A participates in a weaker C17A—H17B⋯C8A contact with a propargylic acceptor (Table 3, Entry 3), while the equivalent donor group in mol­ecule B, namely, C17B—H17E, engages in a bifurcated hydrogen-donor arrangement with the propargylic C7B—C8B bond (Table 3, Entries 9 and 10), neither of which are evident in the strands of mol­ecule C. Mol­ecule B is also involved in a separate propargylic H18E⋯C9B inter­action (Table 3, Entry 11), which is absent in the strands of A, but is observed indirectly in those of mol­ecule C (Fig. 3). Thus, mol­ecule C shows a weak inter­strand donor C4C—H4CC⋯C18C contact [D⋯A = 3.867 (4) Å], as well as the medium-strength intra­strand C4C—H4CB⋯C9C contact [D⋯A = 3.456 (4) Å] (Table 3, Entries 14 and 13, respectively).

A consequence of these analyses is that, despite the orthogonal alignment of strands of mol­ecules C relative to those of mol­ecules A and B, the two-dimensional array of short contacts between like mol­ecules in com­pound 1 is found to result in the formation of homogenous sheets of each mol­ecular type.

3.2.3. Cross-strand/cross-sheet inter­actions

Separate mol­ecular inter­actions occur between, rather than within, the sheets of mol­ecules A–C. The noncon­forming orientation of the C strand com­pared with the A and B strands, in particular, led us to examine even more closely this aspect of the supra­molecular structure. In addition, the inter­molecular inter­actions involving the propargylic C9—H9 acetyl­ene donor functional groups in the head moieties were of inter­est. Contact data for these cross-strand/cross-sheet contacts (contacts between donors and acceptors from different mol­ecular types A–C), almost all of which are ostensibly stronger C—H⋯O contacts, are summarized in Table 4. Contact angle (θ, °), as well as distance measurements, are given for added depth of analyses. Values for intra­strand acetyl­enic C13—H13⋯O6 contacts are included for com­parison (Table 4, Entries 1–3). As with the earlier analyses, it is acknowledged that the resulting data are derived from a single-crystal X-ray crystallographic study and not a com­prehensive crystallographic database search. However, the observations and conclusions drawn from them are based on com­parisons from well debated past literature.

Table 4
Short-contact donor (D) acetyl­enic (Entries 1–8) and non-acetyl­enic (Entries 9–18) H⋯acceptor (A) inter­actions, initially defined automatically within the limits of van der Waals radius −0.05 to 0.30 Å, and measured in Angstroms (Å), for mol­ecules A–C in the crystal lattice of com­pound 1, as well as D—H⋯A contact angles (θ, °), where A = oxygen (O) in most cases, and relevant carbon (C) and hydrogen (H) close contacts in other cases, with relevant head and tail denominations for participating groups, useful for indicating the nature of their alignment

Entry	D⋯A positions	D—H⋯A	D—H	H⋯A	D⋯A	Contact angle, θ
1	tail–tail*	C13A—H13A⋯O6A^i	0.95	2.34	3.247 (3)	158.3
2	tail–tail*	C13B—H13B⋯O6B^i	0.95	2.21	3.138 (2)	164.7
3	tail–tail*	C13C—H13C⋯O6C^ii	0.95	2.34	3.278 (3)	167.8
4	head–tail	C9A—H9A⋯O6C^iii	0.95	2.58	3.376 (4)	140.8
5	head–head	C9B—H9B⋯O3C	0.95	2.19	3.122 (3)	167.1
6	head–head^a	[C9C—H9C⋯O2A^iv	0.95	2.71	3.541 (3)	146.6]
7	head–head	C9B—H9B⋯C2C	0.95	3.21^b	3.676 (3)	112.1
8	head–head	C9B—H9B⋯H2CB	0.95	2.35	2.78	107.4
9	head–head^b	C2C—H2CB⋯C9B	0.99	2.78	3.676 (3)	145.4
10	head–head^b	C2C—H2CB⋯H9B	0.99	2.35	3.21^c	150.3
11	head–head	C7A—H7AA⋯O1B^v	0.99	2.55	3.393 (2)	142.5
12	head–head	C7B—H7BA⋯O1A^ii	0.99	2.29	3.261 (2)	165.8
13	tail–head	C11C—H11E⋯O2B^vi	0.99	2.38	3.372 (3)	176.9
14	tail–head	C11C—H11E⋯C3B^vi	0.99	2.82	3.687 (4)	146.7
15	head–tail	C6C—H6C⋯O5A^vii	1.00	2.67	3.457 (2)	135.6
16	tail–head	C16B—H16B⋯O1C	1.00	2.69	3.584 (3)	149.1
17	head–head	C4C—H4CB⋯O2A^vii	0.98	2.57	3.535 (3)	169.1
18	head–head	C5B—H5BA⋯O3A^v	0.98	2.59	3.525 (3)	160.0
19	tail–tail	C18A—H18B⋯O5C^v	0.98	2.62	3.581 (3)	168.1
Symmetry codes: (i) x − 1, y, z; (ii) x, y − 1, z; (iii) x, y − 1, z − 1; (iv) x, y + 1, z + 1; (v) x − 1, y − 1, z; (vi) x + 1, y, z; (vii) x, y, z − 1. Notes: (a) Not visible in Fig. 4. (b) Non-acetyl­enic donor (D) and acetyl­enic acceptor (A) (see Fig. 6). (c) The C2C⋯H9B contact distance falls outside the constraints set for others and the value was obtained by targeted measurement. (*) Denotes an intra­strand inter­action.

Cross-strand acetyl­enic C9—H9 donor inter­actions occur from mol­ecules A, B and C (Table 4, Entries 4–6). Superficially, those from mol­ecules A (green) and B (blue) engage in unique finger-like intrusions, that are almost perpendicular to the axis of the parent strand, into separate strands of mol­ecules C (red) [Fig. 2(b)], yet each one of the three contacts is different in detail. Readers will find Fig. 4 helpful in providing a pictorial view of the short contacts within the unit cell, as expressed in Table 4.

Figure 4 The unit cell of compound 1 viewed down the crystallographic b axis after rotating by 135° about the vertical axis, showing molecules A (green), B (blue) and C (red) with selected atom labels of close contacts as defined automatically within the limits of van der Waals radius −0.05 to 0.30 Å, within the crystal lattice, and an enlarged inset with details of the linear and orthogonal contacts involving C9B—H9B and C2C—H2CB with additional enforced distance measurements to C2C indicated. Note that the C9C—H9C⋯O2A contact was not detected under the conditions set for close contacts.

3.2.3.1. Cross-strand inter­actions from the standpoint of donor elements. Inter­strand inter­actions are grouped in Table 4 according to notional donor acid strength, as defined by calculated D—H bond lengths, which are based on donor-atom electronegativity. This classification does not correlate directly with the understood mark of contact strength, namely, D⋯A distance, even when contact angle (θ) is considered. The inter­actions in Table 4 are therefore discussed in this order, but within the context of three inter­action types: singlet, pivot and couplet (see Fig. 5).

Figure 5 Major types of oxygen-acceptor-centred short inter­strand contacts in the X-ray crystal structure of com­pound 1, with key atomic labels and bond angles, as recorded by Mercury (Version 2020.3.0; Macrae et al., 2020), for mol­ecules A (green), B (blue) and C (red).

Mol­ecules A (green) provide a modest cross-strand C9A—H9A acetyl­enic donor inter­action with the tail dioxolanyl O6C atom in addition to the strong intra­strand, C13C—H13C donor contact with the same acceptor (Table 4, Entries 3 and 4). Because the acceptor O6C serves as a fulcrum in bringing together adjacent A and C mol­ecules, the contact is called here a `pivot' inter­action [Fig. 5(a)]. The short-to-medium C9A—H9A⋯O6C contact distance [D = 3.376 (4) Å] is consistent with a slightly weaker acid than the acetyl­enic C13—H13 groups (Pedireddi & Desiraju, 1992). Its contact angle (140.8°) (Table 4, Entry 4) is far from the near linear alignment of its partner (167.8°; Table 4, Entry 3) but within the range of other contacts from weak acids where inter­actions have been attributed to electrostatics (Desiraju, 1990; Pedireddi & Desiraju, 1992). However, in this pivot case, where both donors are of the same chemical type, the different D⋯A distances is most likely a reflection of the different contact angles, with the linear contact being more dominant.

In a separate pivot inter­action [Fig. 5(e)], mol­ecules C (red) demonstrate a somewhat longer [D = 3.541 (2) Å] acetyl­enic donor contact (C9C—H9C⋯O2A; Table 4, Entry 6), identified only by a directed measurement (therefore not visible in Fig. 4) with the head dioxolanyl group of an A mol­ecule. The inter­action is associated with another nonlinear contact angle (146.6°), but in this case made with a near linear contact (169.1°) with its pivot donor partner C4C—H4CB (Table 4, Entry 17). The donor in this portion of the pivot is derived from a dioxolanyl methyl group, which would normally be a much less acidic proton source than a terminal acetyl­ene group (com­pare the estimated D—H bond lengths of 0.98 versus 0.95 Å). The observed D⋯A distances for the two inter­actions are indicative of the anti­cipated donor strengths, but closer in magnitude than one might expect. One explanation for their similarity is the acute angle of the first, which would diminish the donor effectiveness from pK_a, and linearity of the latter, which would enhance effectiveness from pK_a for the methyl H atoms that are already the most acidic of those attached to sp³ C atoms in com­pound 1.

Contrasting these dioxolanyl contacts, mol­ecules B (blue) participate in extremely short donor acetyl­enic C9B—H9B inter­actions [D = 3.121 (3) Å] with the head O3C propargylic ether O atom of mol­ecules C (red) (see Fig. 4 and enlargement), with an accordingly near-linear contact angle (167.1°) (Table 4, Entry 5). The acetyl­enic C9B—H9B bond is also engaged in a secondary near-orthogonal contact with the nearby C2C—H2C bond (Fig. 4). This geometry is supported by the H9B—C9B⋯C2C—H2CB torsion angle (φ = 83.8°; not recorded in Table 2) and small contact angles associated when the D—H group is considered C9B—H9B (107.4 and 112.1°; Table 4, Entries 7–8). However, the widely differing contact distance measurements (Table 4, Entries 7–10) for H⋯A (D = 2.35–2.78 Å) and D⋯A [D = 2.78–3.676 (3) Å] reflect a highly distorted orthogonal cluster. The closer contact between participants H2CB⋯C9B (2.78 Å) than H9B⋯C2C (3.21 Å) and larger contact angle values with C2C—H2CB as the D—H group (145.5 and 150.3°) (Table 4, Entries 9–10) are most consistent with C2C—H2CB⋯C9B being the main contact. This secondary inter­action is suggestive of a bifurcated H2CB (Desiraju, 1991), which probably contributes to the extreme shortness of the C9B⋯O3C distance.

These contacts, together, contribute to another type of co-operative set of contacts, called here a `couplet', that include in this example the non-acetyl­enic dioxolanyl methine C16B—H16B⋯O1C contact [Table 4, Entry 16; Fig. 5(d)]. This is one of three couplet inter­actions [Figs. 5(b)–(d)] observed in the crystals of com­pound 1 that, by definition, bring together two inter­strand partners through two independent D⋯A contacts. In this example, the bifurcated H-atom donor from C2C—H2CB and its contact with the acetyl­enic C9B as an acceptor contribute to a `symmetrical' (donor and acceptor in each mol­ecular contributor) 11-membered ring of couplet atoms. Alternatively, the bifurcated H atom can be considered as contributing to a wider 15-membered `unsymmetrical' couplet involving the C9B—H9B⋯O3C contact; in this situation, the two donor com­ponents participate from B mol­ecules while the acceptors are located in C mol­ecules in an unsymmetrical alliance. Couplets of either type can limit con­formational flexibility and distort normal contact angles or, through their attractive nature, force contacts closer together. In the case of the methine C16B—H16B⋯O1C inter­action, the D⋯A contact distance [D = 3.584 (3) Å] (Table 4, Entry 16) is somewhat longer than for the only other methine contact, C6C—H6C⋯O5A (Entry 15), for which the contact angle is smaller. However, it is nearly identical to those of the pivot partners around O2A (Table 4, Entries 6 and 17), wherein contact angles are unequal. It is also very similar to those of methyl donor contacts C5B—H5B⋯O3A and C18A—H18B⋯O5C (Entries 18 and 19) with more linear contact angles. The medium-to-large D⋯A distance in the case of C16B—H16B⋯O1C is possibly the result of it being part of a reasonably large couplet of atoms, and its contact angle the result of con­finement of the donor C16B—H16B bond as part of the tail dioxolanyl ring system in mol­ecule B.

Three non-acetyl­enic donor types of C—H⋯O close contacts are recognisable within the distance range initially defined, and all are cross-strand (see Fig. 3). Those recorded as Entries 11–14 in Table 4 are considered in the first category because they involve similarly weakly acidic D—H participants (note the longer estimated D—H distances for Entries 9–14 com­pared with those for the acetyl­enic donor examples in Entries 1–8). They proceed from the methyl­ene groups at atoms C7 and C11 in the head and tail proparg­yloxy substituents, respectively, but their inter­actions are in turn each different.

Mol­ecules A and B make reciprocal head-group methyl­ene contacts with the dioxolanyl O1 acceptor from the partner mol­ecule. Notably, the donor from mol­ecule B (Entry 12) makes a `singlet' contact with O1A [Fig. 5(g)], that is, a contact without the involvement of any other partner. The singlet C7B—H7BA⋯O1B contact is closer [D = 3.261 (2) Å] and more linear (165.8°) than the C7A—H7AA⋯O1B contact from mol­ecule A [Entry 11; D = 3.393 (2) Å, θ = 142.5°], which is part of another symmetrical seven-membered couplet [Fig. 5(c)] with the donor methyl C5B—H5BA⋯O3A inter­action [Entry 18, D = 3.525 (3) Å, θ = 160.0°]. The smaller ring size of this tight couplet appears to impart a more acute angle to the C7A—H7AA⋯O1B contact and thereby must reduce the D⋯A distance. In contrast, only C11C—H11E participates as donor from the equivalent methyl­ene group of mol­ecule C, but the same donor makes contact with two quite different acceptors, namely, dioxolanyl O2B and C3B, with very different D⋯A distances. However, these acceptors reside at adjacent positions in the same mol­ecule B (Table 3, Entries 13 and 14), and largely for this reason the contact is defined here as a `singlet' inter­action [Fig. 5(f)]. As expected, because the acceptor O2B has two frontier orbitals, each with lone pairs of electrons, contact with O2B is much shorter and more linear [Entry 13, D = 3.372 (3) Å, θ = 176.9°] with respect to the predicted C11C—H11E bond than it is with the adjacent methine C3B acceptor [Entry 14, D = 3.687 (4) Å, θ = 146.7°], with no free bonding electron pairs. The fact that atom H11E is bifurcated probably accounts for the slightly longer C11C⋯O2B contact com­pared with the C7B⋯O1A contact, but with a distance that is tempered by the near perfect alignment of the former.

The second type of non-acetyl­enic donor close contacts exhibit methine donor contributions from C6C—H6C and C16B—H16B, respectively (Table 4, Entries 15 and 16). Contacts occur with inter­strand dioxolanyl oxygen partners, but with only moderate D⋯A distances (D) and contact bond angles (θ). Both C atoms are derived from the mannitol skeleton, the first bearing a proparg­yloxy substituent and the other an oxygen substituent that is part of the tail dioxolanyl group. It is possibly significant that none of mol­ecules A–C exhibit close contacts involving donor C—H bonds from either of the symmetry-equivalent atoms C10 and C3, respectively, of these positions. However, it is worth recalling that C3B does participate in a contact with donor C11C—H11E (Table 4, Entry 14), but only as a weak acceptor, and then with limited efficiency. Donor C16B—H16B was also mentioned earlier as a close contact with O1C within the first couplet com­plex [Fig. 5(d)], with C9B—H9B⋯O3C. The remaining methine donor contact, C6C—H6C⋯O5A (Table 4, Entry 15), participates in an unsymmetrical nine-membered couplet with a tail–tail methyl donor contact, C18B—H18B⋯O5C [Table 4, Entry 19; Fig. 5(b)]. Perhaps because of its slightly different methine donor character, the C6C—H6C⋯O5A contact has a measurably shorter D⋯A distance [D = 3.457 (2) Å] than the C16B—H16B⋯O1C contact [D = 3.584 (3) Å] (Table 4, Entries 15 and 16). Equally, the difference in D⋯A contact distances might arise from the smaller contact angle for C6C—H6C⋯O5A brought about by constraints of its smaller ring couplet than those of the larger one involving C16B—H16B⋯O1C. Finally, the three remaining non-acetyl­enic donor contacts emanate from a C—H bond in one of the slightly more acidic, axial or equatorial geminal methyl groups attached to the dioxolanyl groups (Table 4, Entries 17–19). The three donors inter­act either head–head or tail–tail with a dioxolanyl O-atom acceptor and have com­parable D⋯A distances (D) with near-linear contact angles (θ). All three contacts have been discussed above within the context of other inter­actions (Table 4, Entries 6, 15, and 16).

Between them, this com­plex array of contacts affords stability to the observed alternating layered sheets of A (green)–C (red)–B (blue) mol­ecules (Fig. 6). The arrangement leaves no inter­digitation of propargyl groups between layers of mol­ecules of type A (green) and B (blue). However, there are alternative A⋯B reciprocal C—H⋯O contacts (Table 4, Entries 11–12 and 18), of which the head-to-head propargylic C7B—H7B⋯O1A contact and nonpropargylic C5B—H5BA⋯O3A contact are most important.

Figure 6 Close up of com­pound 1, viewed along the a axis, with a slight offset showing differing inter­digitation of C9—H9⋯O inter­actions between layers of independent mol­ecules A (green), B (blue) and C (red), represented with non-H atoms as ellipsoids for clarity; key C—H donor partners are shown in darker colours.

With this improved understanding of contacts from the perspective of C—H donors, a brief study was made of the geometry about the most important cross-strand contact acceptors in com­pound 1, the relevant dioxolanyl and proparg­yloxy ether O atoms.

3.2.3.2. Cross-strand inter­actions from the standpoint of O-atom acceptors. Data derived from measurements of individual bond and contact angles associated with covalently bound O atoms and their close inter­molecular donor C—H contacts are summarized in Table 5. This process was initiated on the questionable premise that acceptor inter­actions would take place through O-atom lone pairs of electrons (Taylor & Kennard, 1982, 1984; Steiner & Desiraju, 1998) and with the intention of providing better insight into the geometry at the acceptor sites.

Table 5
Analysis of the geometry of close inter­molecular contacts, as defined as shorter than the sum of the van der Waals radii minus 0.01 Å, through measurement of triplet com­ponent angles at each of the key O-atom acceptor atoms^a in mol­ecules A–C of com­pound 1, the arithmetic sum of the individual angles and resulting assignment of con­figuration, and duplicate records of relevant D⋯A distances (Å) and C—H⋯O contact angles, θ (°), with the contact type

Triplet	D⋯A	Component angles	Angle (°)	Angle sum (°)	Contact type
Entry	positions			Con­figuration^b	C—H⋯O
				D⋯A (Å)	Angle (°)
1		C14A—O6A—C15A	106.41 (15)	328.9 (2)
		C14A—O6A⋯C13A	110.9 (1)	pyramidal	singlet-O6A
	tail–tail	C15A—O6A⋯C13A	111.6 (1)	3.247 (3)	158.3
2		C14B—O6B—C15B	106.73 (14)	341.8 (2)
		C14B—O6B⋯C13B	111.0 (1)	pyramidal	singlet-O6B
	tail–tail	C15B—O6B⋯C13B	124.1 (1)	3.138 (2)	164.7
3		C14C—O6C—C15C	106.49 (14)	358.8 (2)
		C14C—O6C⋯C13C	116.9 (1)	planar	pivot-O6C
	tail–tail	C15C—O6C⋯C13C	135.4 (1)	3.278 (3)	167.8
4		C14C—O6C—C15C	106.49 (14)	320.5 (13)
		C14C—O6C⋯C9A	114.8 (1)	pyramidal	pivot-O6C
	head–tail*	C15C—O6C⋯C9A	99.2 (1)	3.376 (4)	140.8
5		C14A—O5A—C16A	108.14 (1)	346.2 (1)
		C14A—O5A⋯C6C	143.1 (1)	planar	couplet-9
	head–tail*	C16A—O5A⋯C6C	95.0 (1)	3.457 (2)	135.6
6		C14C—O5C—C16C	109.83 (15)	337.8 (2)
		C14C—O5C⋯C18A	137.0 (1)	pyramidal	couplet-9
	tail–tail*	C16C—O5C⋯C18A	91.0 (1)	3.581 (3)	168.1
7		C6A—O3A—C7A	115.53 (14)	350.5 (1)
		C6A—O3A⋯C5B	141.0 (1)	planar	couplet-7
	head–head*	C7A—O3A⋯C5B	94.0 (1)	3.525 (3)	160.0
8		C6C—O3C—C7C	114.70 (16)	352.3 (2)
		C6C—O3C⋯C9B	131.0 (1)	planar	couplet-11
	head–head*	C7C—O3C⋯C9B	106.6 (1)	3.122 (3)	167.1
9		C1A—O2A—C3A	106.52 (15)	359.6 (2)
		C1A—O2A⋯C9C	107.1 (1)	planar	pivot-O2A
	head–head*	C3A—O2A⋯C9C	146.0 (1)	3.541 (3)	146.6
10		C1A—O2A—C3A	106.52 (15)	341.5 (2)
		C1A—O2A⋯C4C	135.3 (1)	pyramidal	pivot-O2A
	head–head*	C3A—O2A⋯C4C	99.7 (1)	3.535 (3)	169.1
11		C1B—O2B—C3B	106.77 (15)	334.1 (2)	singlet-O2B
		C1B—O2B⋯C11C	136.4 (1)	pyramidal	(146.7)^c
	tail–head*	C3B—O2B⋯C11C	90.9 (1)	3.372 (3)	176.9
12		C1A—O1A—C2A	107.92 (17)	354.2 (2)
		C1A—O1A⋯C7B	111.1 (1)	planar	singlet-O1A
	head–head*	C2A—O1A⋯C7B	135.2 (1)	3.261 (2)	165.8
13		C1B—O1B—C2B	107.75 (16)	356.1 (2)
		C1B—O1B⋯C7A	107.6 (1)	planar	couplet-7
	head–head*	C2B—O1B⋯C7A	140.7 (1)	3.393 (2)	142.5
14		C1C—O1C—C2C	107.30 (16)	352.9 (2)
		C1C—O1C⋯C16B	147.7 (1)	planar	couplet-11
	tail–head*	C2C—O1C⋯C16B	97.9 (1)	3.584 (3)	149.1
Notes: (a) atoms O2C, O3B, O4A–O4C and O5B showed no close contacts. (b) Configuration assigned arbitrarily based on the magnitude of the angle sum: pyramidal <344° and planar >344°. (c) The C11C—H11C⋯C3B angle.

The method used acknowledges that the O atoms in mol­ecule 1 are all ethers and should have an electron-pair geometry that is approximately tetra­hedral with coordinate angles of 109.5°. Accordingly, the sum of the triplet of bond and contact angles surrounding each relevant acceptor O atom has been calculated and the geometry arbitrarily assessed as `pyramidal' (trigonal pyramidal) or `planar', depending on whether the angle sum is less or more, respectively, than 344°, midway between the ideal for tetra­hedral (328.5°) and planar (360°). In this study, close donor–acceptor (D⋯A) contacts are limited to those shorter than the sum of the van der Waals radii minus 0.01 Å. Under these conditions, atoms O2C, O3B, O4A–O4C and O5B showed no close contacts. In Table 5, the values of the D⋯A distance (D, Å) and contact angle (θ, °) of each observed C—H⋯O short contact are repeated from Table 4 and the contact types from Fig. 5 are added, all for reference purposes and as an aid to inter­pretation.

Surprisingly, only six of the 14 contacts with O atoms can be classified as pyramidal in their geometry. While all these are associated with dioxolanyl O atoms, not all the dioxolanyl O-atom contacts can be classified in this way. As partly discussed in the context of donors, in two of the six cases, dioxolanyl atoms O6C (tail) and O2A (head) each makes pivot contacts with two C—H donors (Table 4, Entries 3/4 and 6/17, respectively). This gives the inter­actions a degree of com­plexity, but with some hope of understanding differences in the geometry at the fulcrum, which is their O atom. In the first case [Table 5, Entries 3 and 4; Fig. 5(a)], two of the angular com­ponents used to evaluate the pyramidal or planar geometry about O6C are nearly identical, but the C15C—O6A⋯D angle differs markedly, i.e. 135.4 (1)° when D = C13C and 99.2 (1)° when D = C9A. The rendition of these contacts in Fig. 5(a) gives insight into the com­petition by donors C13C—H13C and C9A—H9A for access to O6C. It also gives an understanding as to how the closer more linear contact resulting from the former might have arisen through an overall planar geometry with O6C, with a splaying of the C15C—O6A⋯C13C angle, and a slightly weaker more apical contact at O6C through an acute angular inter­action (probably electrostatic) by C9A—H9A. In the second pivot example [Table 5, Entries 9 and 10; Fig. 5(e)], a similar inter­play appears to be involved, but the less acidic donor partner, C4C—H4CB, exerts a closer than expected near-linear contact with acceptor O2A at an angle sum [341.5 (2)°] that is close to being defined as that for a planar contact. As a result, the C1A—O2A⋯C4C and C3A—O2A⋯C9C com­ponent angles are increased and the C9C—H9C⋯O2A contact weakened concomitantly with a decrease in the observed contact angle to 146.6°.

Analyses of observed geometries around each of the O-atom acceptors in the three sets of couplet inter­actions reported in Table 5 (Entries 5–8 and 13–14) reveal that the observations are consistent with similar com­promises in individual contributing angular com­ponents, contact distances and contact angles, but with additional consideration of the nature and size of the couplet. For example, in the symmetrical nine-membered couplet involving O5A and O5C [Fig. 5(b)], the unequal length of the carbon bridge between the donor and acceptor in mol­ecule A (four atoms) and mol­ecule C (five atoms) causes a severe enlargement of the inter­nal C14A—O5A⋯C6C angle [143.1 (1)°] at the expense of the C16A—O5A⋯C6C angle [95.0 (1)°]. At the same time, the connectivity of the two D⋯A systems imposes the reverse distortion of the corresponding individual angles around O5C, with a com­pression of the inter­nal C16C—O5C⋯C18A angle [91.0 (1)°] at the expense of the C14C—O5C⋯C18A angle [137.0 (1)°]. The resulting shorter D⋯A contact for the former [D = 3.457 (2) Å] takes place through an acute D—H⋯A angle (135.6°) and planar though angularly distorted inter­action with O5A. This result occurs despite the more linear (168.1°) contact of the normally more acidic methyl donor C18A—H18B with its couplet partner O5C. Analysis of the seven-membered couplet [Table 5, Entries 7 and 13; Fig. 5(c)] provides a similarly satisfying explanation for angular distortions around the O1B and O3A acceptors and indicates a more convincing dominance of one contact, the C7A—H7AA⋯O1B inter­action, over the other.

The situation in the 11-membered couplet [Table 5, Entries 8 and 14; Fig. 5(d)] is more com­plex because of the participation of the orthogonal donor arrangement of the bifurcated H2C atom, but it is clear that equally explicable distortions of contributing angles around key acceptor com­ponents O1C, C9B and O3C do take place as a result of the couplet arrangement of the two partner com­ponents. Equally, tolerated distortions around the O2B and O1A acceptor O atoms in the two singlet cases [Table 5, Entries 11 and 12; Figs. 5(f) and 5(g)] are explicable for the simple reasons of neighbouring-atom participation and crystallographic dislocation of participants.

3.3. Crystal packing

A review of the crystallographic data to this point highlights a number of noteworthy features about com­pound 1. The three independent mol­ecules A–C that make up the unit cell differ subtly in con­formation, but significantly at two of their ether sites. They each assemble into unique linear strands of like mol­ecules, primarily through C13—H13⋯O6 contacts, but supported by intra­molecular and intra­strand inter­actions. Furthermore, the assemblies are unidirectional, with the strands of A and B aligned in close proximity, head-to-tail, along the crystallographic a axis and those of C aligned orthogonal along the b axis. Additional inter­strand inter­actions between like mol­ecules establish a two-dimensional sheet array of like parallel strands. However, a network of donor–acceptor contacts occur between strands/sheets of unlike mol­ecular type.

3.3.1. Mol­ecular strand and sheet planes

Initial examination of the crystal packing reveals a repeat layering of the three mol­ecular types in the order A (green)–B (blue)–C (red), when viewed along the a and b axes (Fig. 7). Analysis of the mean planes of each mol­ecule across three separate strands con­firms their parallel arrangement, which is most convincing in Fig. 7(a). Such layering is consistent with the establishment of sheets (Section 3.2.2.2).

Figure 7 Crystal packing diagrams for com­pound 1, showing the distinct layering of independent mol­ecules A (green), B (blue) and C (red), as viewed in (a) along the a axis and in (b) along the b axis; the propargylic group in the `tail' moiety of each mol­ecule is circled in its respective colour to highlight the orthogonal directionality of the C (red) com­pared with the A (green) and B (blue) groups. Void spaces observed in the space-filling models are illustrated in cartoon form by dark-grey shapes with relative sizes drawn approximately to scale.

Further analysis of the mean planes of the A, B and C mol­ecules in their respective strands across a span of five mol­ecules in each strand reveals tilts of 6.28, 12.51 and 23.52°, respectively, from the mean planes of the sheets of each mol­ecular type, which are themselves separated unequally by A⋯B = 4.934 Å, B⋯C = 4.866 Å and C⋯A = 5.012 Å (Fig. 8).

Figure 8 Mean planes of mol­ecules A (green), B (blue) and C (red), as viewed slightly offset along the crystallographic b axis and recorded (a) in pale shades for individual mol­ecular strands showing nonparallel but like planes for A and B, which are orthogonal to the angular plane of C strands, and (b) in dark shades for mean planes over five strands of each type, showing parallel but unequally spaced layers, which are repeated in the same order throughout.

In Fig. 7, the C13—H13-bearing propargyl group in each mol­ecule is highlighted by encircling the group. Collectively the orientations of the encircled groups reinforce their orthogonality in the A and B strands relative to those in the C strands. The intrusion of the equivalent C9—H9-bearing propargyl groups from mol­ecules A and B into the strands of mol­ecule C and reciprocal angular intrusion of the group from mol­ecule C only into strands of mol­ecule A is noticeable in Fig. 7(a), and accounts for the minor differences in inter-sheet spacings. This leaves very little inter­action between mol­ecules A and B, as is evident in Fig. 7(b) and as was discussed in Section 3.2.3.1. Minor void spaces are visible, especially in Fig. 7(b), but these are too small for any mol­ecular inclusions.

3.4. CSD searches based on Mercury Crystal Packing Features and ConQuest search motifs involving donor and acceptor acetyl­enic contacts observed in com­pound 1.

3.4.1. Background

In the preceding diffraction studies of com­pound 1, intra- and inter­molecular contacts were observed in which acetyl­enic com­ponents of the two propargyl groups participated in various situations as C—H donors and as C—H acceptors. Two principal searches of the Cambridge Structural Database (CSD; Groom et al., 2016) were carried out in order to ascertain the prevalence of these inter­actions and their scope in crystal engineering. These com­prised firstly a Mercury-based study using highly constrained contact motifs derived from its Crystal Packing Feature (PFF) (Fig. S1) using measurements taken directly from com­pound 1 (Fig. S2). The second study utilized the ConQuest search tool and more loosely defined motifs (CSM) (Fig. S3) that, while artificial in their construct, were again based on general inter­pretations of the observed contacts (Fig. S2). The outcomes of these searches are discussed separately.

3.4.2. Analysis of Mercury Crystal Packing Feature (PFF) search results

As a general observation from the results summarized in Fig. 9 and Table S2, the propargylic group gave more positive matches when it participated as a donor through its terminal acetyl­enic proton than when the group served as a proton acceptor (Fig. 9). An analysis of findings from each contact type is described in detail in the supporting information, and summarized in the following sections.

Figure 9 A bar graph and table of the number of Positive (blue) and Negative (red) PFF results from each of the PFF searches.

3.4.2.1. Propargyl group as donor. There were considerable differences when the propargyl group served as a donor. Searches C and D were the more populous in terms of positive and negative results, while search B was extremely variable, especially with respect to negative results. Searches were dependent upon D⋯A distances, with the observed shorter distances of stand-alone strand-forming contacts in group A being less common than equivalent inter­strand contact distances or distances involving shared contacts with adjacent acceptor atoms. This dependence showed strong variation with the nature of the acceptor atom and with the number and extent of prescription, including Cyclicity, in the atoms/groups associated with the acceptor atom.

3.4.2.2. Propargyl group as acceptor. Despite many fewer positive results from motifs E–J than from motifs A–D, the number of negative results from searches remained in excess of 70 in cases E–I3, and there was less scope than in the A–D cases for varying attached groups to either D or A atoms. Cases G1.1 and H1.1 provided situations with equivalent D and A types where minor differences in numbers of positive results (1 versus 3, respectively, perfectly counterbalanced by the differences in negative results, 75 versus 73) were observed. It was not possible to determine if these resulted intrinsically from very slightly higher D⋯A contact distances, or ultimately by the significantly different D—H⋯A bond angles brought about by inter­molecular intra­strand (G1.1) com­pared with inter­strand (H1.1) contacts (Fig. 3 and Table 4). This situation was helped marginally when the E1.1, F1.1 and F2.1 inter­actions were considered as a whole (Fig S1 and Table 3). The E1.1 and F2.1 features showed a similarity not evident in F1.1; the bond to the distal C atom to which their donor methyl groups are attached is nearly unidirectional to the axis of the methyl C atom to acetyl­enic C atom trajectory, while in F1.1 it is at an acute angle (Fig. S1). Despite this observation, individual analyses showed that the more accurately measureable D⋯A distances increased in the order F2.1 ≤ E1.1 << F1.1, which was not the same as the order of the H⋯A distances (F2.1 ≤ F1.1 << E1.1) or the D—H⋯A angles (E1.1 < F2.1 << F1.1). On the other hand, for E1.1 there were no positive results but 71 negative results, and for F1.1 and F2.1, both recorded 76 results, with four and three, respectively, recorded as positive.

It was concluded from the lack of direct correlation between any of these trends, including intra­stand and inter­strand inter­actions, and the observed number of positive results, that the E1.1, F1.1 and F2.1 features are equally common to those in G, H and I, in the solid state. Again, the D⋯A distances encountered in the crystal structure of com­pound 1 must impose tight limitations that are not commonly met in structures within the CSD.

3.4.2.3. Analysis of structure codes for negative search results. Analysis of the breakdown of structure codes from each search (Table S2) showed relatively good coherence in the structure codes in the negative results for categories A1, A2 and C–I, but not for B1.1–B1.3. This outcome appears to mark a change from cyclic to acyclic O-atom acceptors. A similar lack of coherence was observed, albeit to a less dramatic extent because of fewer overall search results, for PFF J1.2–J1.4. Here it was noted that the donor H atom was part of a cyclic methyl­ene group rather than from an exocyclic methyl group. Such factors were therefore important in inter­preting the negative search results.

3.4.2.4. Analysis of structure codes for positive search results. As for positive results, there was a degree of coherence between structure codes within each of the search PFFs A1.1–A1.4, A2.1–A2.4, B1.1–B1.3 and C1.1–C1.4. The differences that were observed were readily attributable to variations in the attachments to the common acceptor atom in each set. In contrast, there was no overall coherence in the codes in the positive results between the first three categories, i.e. A1, A2 and B1 (Table S2). Initial thoughts of donor type or D⋯A distance as the cause were ruled out. Instead, a much more subtle feature appeared to be at play, namely, a different type of O-atom acceptor (Fig. S2), the influence of which was not as evident in the negative results. The similarities in positive result structure codes between A2, C and D results could then be explained by H⋯C inter­actions in PFF C and D that were strongly influenced by the presence of the corresponding dioxolanyl-derived O—CH₂ attachment to the formal quaternary C-atom acceptors.

3.4.3. Analysis of loosely constrained ConQuest structural motif (CSM) search results

Despite the predominance of positive propargylic donor over acceptor inter­actions in strand assemblies in the crystal structure of com­pound 1, the absolute sum of positive and negative donor inter­actions in each category from the study in Section 3.4.2 remained remarkably small. This prompted a more general search of the CSD for less constrained structural motifs (Fig. S3) that encom­passed the main features of those already examined but focused on H⋯A (D1) and D⋯A (D2) contact distances, and D—H⋯A (ANG) angles.

3.4.3.1. CSD Index Numbers versus contact distances and angles. Simple scatterplots of the individual D1, D2 and ANG values versus the CSD Index Numbers, with their respective search structure motifs (Fig. S3), revealed different cluster patterns in the distances, and to some degree contact angles, of each category, but no direct correlations, particularly between cases of multiple independent contacts within the one structure.

3.4.3.2. Contact distances and distance differences versus contact angles. Far more useful patterns emerged when scatterplots were constructed of D1 and D2 distances versus D—H⋯A (ANG) contact angles for the most populous donor acetyl­enic contacts to O (CSM1_R1) and C (CSM1_R4) acceptor atoms on the one hand, and acceptor acetyl­enic contacts at terminal C atoms (CSM1_R5) and C atoms adjacent to the terminal C atoms (CSM1_R6) by sp³ C—H donors on the other [Fig. 10(a)].

Figure 10 (a) ConQuest search motifs (CSMs) used to define searches of propargylic donor and acceptor inter­actions using loosely constrained distances (D1 and D2) and D—H⋯A angles (ANG). (b) Scatterplots of D1 (blue), D2 (green) and D2–D1 (black)(Å) values versus ANG (°) values for inter­actions in mol­ecules satisfying criteria for ConQuest search motifs CSM1-R1, CSM1-R4, CSM1-R5 and CSM1-R6, including lines of best fit for the D1 and D2 results. (c) Overlay of the four scatterplots of D2–D1 values versus contact angle (ANG) from Fig. 10(b) (with changed marker shapes and colours), as well as related data points (in red) for relevant contacts in com­pound 1.

All searches gave noticeable differences between D1 and D2 that became larger with increasing contact angles [upper portions of each plot in Fig. 10(b)]. Initial observations were codified by additionally recording scatterplots of D2–D1 values against contact angles for each contact motif [lower portions of each plot in Fig. 10(b)]. These showed a nonlinear progression of larger D2–D1 values with increasing contact angle. However, calculated trend lines for each set of the D1 and D2 distance curves unmasked stark differences for each search category in the contributions of D1 and D2. For example, at the two extremes, the CSM1_R1 inter­actions involved a relatively constant D2 (D⋯A) distance and decreasing D1 (H⋯A) distances, while those of the CSM1_R4 and CSM1_R6 inter­actions showed the opposite, with relatively constant D1 and decreasing D2 distances. In CSM1_R5, the D2 (D⋯A) distances increased marginally, while the D1 (H⋯A) distances decreased noticeably, with increasing D—H⋯A angle, indicating that both parameters contributed. Neither absolute magnitudes of D1 and D2 in each search category, which fell in the order CSM1_R1 < CSM1_R4 < CSM1_R5 ≃ CSM1_R6, nor reported contact angles, which fell within four different ranges, could account for these observations. Instead, it was concluded that the type of acceptor atom (O versus C and terminal versus nonterminal acetyl­enic C) was probably responsible.

Despite these anomalies, when the scatterplots of the numerical difference (D2–D1) in contact distances versus contact angle in each category were plotted together, the correlation curves were virtually superposable [Fig. 10(c)]. Modelling studies revealed that very minor variations in the correlation curves were attributable to the different fixed C—H donor bond lengths (0.95–1.00 Å) embedded in each data set. Of the seven data points that could be regarded as outliers from these acknowledged trends, six were attributable to features in the CSD structures for just one com­pound, WUJWAC {(R)-1-[(4S,5R)-5-(hy­droxy­meth­yl)-2,2-dimethyl-1,3-dioxolan-4-yl]but-3-yn-1-ol} (Heinrich et al., 2020) (1 × CSM1_R1, 1 × CSM1_R4, 3 × CSM1_R5 and 1 × CSM1_R6), and one attributable to one other com­pound, EHAKAZ [N-((1R,2S)-2-hy­droxy-1-{(4S,4′R,5S)-2,2,2′,2′-tetra­methyl-[4,4′-bi(1,3-dioxolan)]-5-yl}pent-4-yn-1-yl)acetamide] (Liu et al., 2002) (CSM1_R5) (Fig. S4). Capture of the outliers was due to the liberal contact criteria inherent in the searches. The origins of their outlier properties could not be ascertained, although both mol­ecules possess chirality and contain acetonide (dioxolan­yl) and alcohol groups with multiple opportunities for additional com­peting inter- and intra­molecular contacts. In particular, the hydroxyl groups of diol WUJWAC participitate in numerous strong hydrogen-bond inter­actions in the crystal, which probably drive the very com­plex array of weaker close contacts.

Relevant to the present study, an overlay of the corresponding measured data for representatives of contacts from the three crystallographic mol­ecules A–C from com­pound 1 showed perfect superposition, with marker points [Fig. 10(c)] in red that were dispersed within the normal scatter across the full angular range of the data from the CDS searches.

To our knowledge, the type of com­parisons just described have not been reported previously. They support the notion that acetyl­enic groups, particularly those originating in propargylic substituents, can participate in a wide range of weak but highly influential donor and acceptor inter­actions that are important in establishing crystal packing. These contacts can be mediated over a large range of contact angles, even within crystals of the one com­pound. It is valuable to recognize the high consistency of the correlations participated in by the terminal acetyl­enic com­ponent of the propargyl group, both as donor and as acceptor. As a corollary, rare departures from this norm can be an indication of additional powerful influences that might be present.

4. Summary and conclusion

A com­prehensive single-crystal X-ray crystallographic analy­sis of 3,4-bis-O-propargyl-1,2:5,6-di-O-iso­propyl­idene-D-man­ni­tol, 1, has revealed the presence of three independent mol­ecules A–C in the unit cell, each differing in con­formation. The mol­ecules form a close-packed layered structure aligned in the a and b axes, with each layer com­prising a well-ordered homogeneous array of like mol­ecules. Tail-to-tail acetyl­enic C13—H13 donor and dioxolanyl O6 acceptor contacts are associated with strand-like substructures in each layer. Multiple, much weaker, inter­strand contacts are associated with the packing of parallel strands in each sheet. Strands derived from mol­ecules A and B align co-operatively with minimal contact, along the crystallographic a axis, while those from C align orthogonally along the b axis. A thorough systematic analysis of intra- and inter­molecular inter­actions, including an examination of the geometric parameters associated with the observed close contacts, and consideration of the crystallographic planes, allows identification of the key inter­actions and provides strong support for the current under­standing of weak hydrogen bonds and their description as a continuum of van der Waals contacts and electrostatic inter­actions. The evidence supports the notion that contact strength is best assessed in a D—H⋯A system from the D⋯A distance (D, Å), with a considerable flexibility in the D—H⋯A contact angle and the geometry about the acceptor, at least when A is oxygen or carbon.

Two secondary studies of the Cambridge Structural Database (CSD) using Mercury Crystal Packing Features (PFF) and ConQuest structural motifs, based on features identified in the crystals of com­pound 1 involving the propargyl group, add further insight into the value of 1 as a model for the study of weak inter­actions in the solid state. They give mathematical credence to the close correlation that exists in these D—H⋯A systems between the difference in distance between D⋯A and H⋯A, and the D—H⋯A angle, but point to different contributions that the D⋯A and H⋯A parameters can have in this correlation, depending upon the particular structural motif involved.

Overall, the studies described here provide new insight into factors involved in weak acetyl­enic H⋯A inter­actions and might well prove useful in guiding the design of chemoselective applications of such functional groups, especially where these are propagated in or close to the solid state.

Supporting information

Computing details

Data collection: APEX3 (Bruker, 2016); cell refinement: SAINT (Bruker, 2016); data reduction: SAINT (Bruker, 2016); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL (Sheldrick, 2015b); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).

(1R,2R)-1,2-Bis[(R)-2,2-dimethyl-1,3-dioxolan-4-yl]-1,2-bis(prop-2-yn-1-yloxy)ethane

Crystal data

C18H26O6	Z = 3
Mr = 338.39	F(000) = 546
Triclinic, P1	Dx = 1.176 Mg m^−3
a = 9.4726 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 10.3000 (5) Å	Cell parameters from 9994 reflections
c = 15.3583 (7) Å	θ = 2.6–30.4°
α = 73.378 (2)°	µ = 0.09 mm^−1
β = 88.382 (2)°	T = 150 K
γ = 86.400 (2)°	Block, colourless
V = 1432.94 (11) Å^3	0.24 × 0.21 × 0.19 mm

Data collection

Bruker APEXII CCD diffractometer	8134 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
φ and ω scans	θmax = 25.0°, θmin = 2.6°
Absorption correction: multi-scan (SADABS; Bruker, 2016)	h = −11→11
Tmin = 0.679, Tmax = 0.746	k = −12→12
25389 measured reflections	l = −16→18
8343 independent reflections

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.026	w = 1/[σ^2(Fo^2) + (0.032P)^2 + 0.2227P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.065	(Δ/σ)max < 0.001
S = 1.02	Δρmax = 0.21 e Å^−3
8343 reflections	Δρmin = −0.15 e Å^−3
661 parameters	Absolute structure: Flack x determined using 3228 quotients [(I+)-(I-)]/[(I+)+(I-)] (Parsons et al., 2013)
3 restraints	Absolute structure parameter: 0.04 (17)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. A colourless block-like crystal of 1 with the dimensions 0.19 × 0.21 × 0.24 mm, selected under a polarizing microscope (Leica M165Z), was picked up on a MicroMount (MiTeGen, USA) consisting of a thin polymer tip with a wicking aperture. The X-ray diffraction measurements were carried out on a Bruker kappa-II CCD diffractometer at 150 K using IµS Incoatec Microfocus Source with Mo-Kα radiation (λ = 0.710723 Å). The single crystal, mounted on the goniometer using a cryo loop for intensity measurements, was coated with immersion oil type NVH and then quickly transferred to the cold nitrogen stream generated by an Oxford Cryostream 700 series. Symmetry-related absorption corrections using the program SADABS (Bruker, 2016) were applied and the data were corrected for Lorentz and polarisation effects using Bruker APEX3 software (Bruker, 2016). The structure was solved by program SHELXT (Sheldrick, 2015a) (with intrinsic phasing) and the full-matrix least-square refinements were carried out using SHELXL (Sheldrick, 2015b) through the OLEX2 (Dolomanov, 2009) software platform. Details of the experimental crystallographic data collected for compound 1 are summarized in Table 1. The non-hydrogen atoms were refined anisotropically.

The H atoms were not located in the difference Fourier map. Instead, the H atoms were placed geometrically and constrained according to their environment using different AFIX commands available in SHELXL (Sheldrick, 2015b) operating via the OLEX2 (Dolomanov, 2009) platform.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1A	0.5767 (2)	0.36428 (16)	0.40439 (11)	0.0489 (4)
O2A	0.54541 (15)	0.41366 (14)	0.25379 (10)	0.0330 (3)
O3A	0.24531 (14)	0.50233 (13)	0.28189 (9)	0.0290 (3)
O4A	0.32743 (15)	0.73829 (14)	0.32764 (10)	0.0317 (3)
O5A	0.15270 (14)	0.92079 (13)	0.17358 (10)	0.0289 (3)
O6A	−0.00610 (14)	0.85925 (14)	0.28710 (10)	0.0335 (3)
C1A	0.6383 (2)	0.3393 (2)	0.32429 (16)	0.0368 (5)
C2A	0.5095 (2)	0.4969 (2)	0.37928 (14)	0.0332 (5)
H2AA	0.565949	0.561019	0.398912	0.040*
H2AB	0.413939	0.496536	0.407191	0.040*
C3A	0.5001 (2)	0.5369 (2)	0.27551 (14)	0.0279 (4)
H3A	0.568748	0.607920	0.248585	0.034*
C4A	0.7862 (3)	0.3876 (3)	0.3084 (3)	0.0639 (8)
H4AA	0.822356	0.377996	0.250032	0.096*
H4AB	0.847564	0.333064	0.357378	0.096*
H4AC	0.784989	0.483173	0.307554	0.096*
C5A	0.6321 (3)	0.1904 (2)	0.33391 (19)	0.0485 (6)
H5AA	0.533783	0.164730	0.343942	0.073*
H5AB	0.689372	0.138090	0.385720	0.073*
H5AC	0.669065	0.171312	0.278332	0.073*
C6A	0.3554 (2)	0.58493 (18)	0.23527 (13)	0.0247 (4)
H6A	0.357882	0.582720	0.170576	0.030*
C7A	0.2188 (2)	0.3889 (2)	0.24967 (15)	0.0342 (5)
H7AA	0.141175	0.338975	0.286288	0.041*
H7AB	0.304508	0.326512	0.258799	0.041*
C8A	0.1808 (3)	0.4275 (2)	0.15384 (17)	0.0414 (6)
C9A	0.1549 (3)	0.4568 (3)	0.0760 (2)	0.0646 (8)
H9A	0.133910	0.480487	0.013034	0.078*
C10A	0.31561 (19)	0.73038 (19)	0.23687 (13)	0.0242 (4)
H10A	0.383700	0.792082	0.197112	0.029*
C11A	0.3807 (2)	0.8610 (2)	0.33579 (19)	0.0416 (6)
H11A	0.343471	0.878119	0.392624	0.050*
H11B	0.346433	0.937705	0.284276	0.050*
C12A	0.5352 (2)	0.8555 (2)	0.33670 (16)	0.0368 (5)
C13A	0.6594 (3)	0.8510 (3)	0.3393 (2)	0.0530 (7)
H13A	0.759777	0.847379	0.341310	0.064*
C14A	0.0180 (2)	0.9615 (2)	0.20448 (14)	0.0293 (4)
C15A	0.0487 (2)	0.7341 (2)	0.27351 (16)	0.0334 (5)
H15A	−0.025790	0.688674	0.251278	0.040*
H15B	0.087237	0.672175	0.330696	0.040*
C16A	0.1668 (2)	0.77518 (19)	0.20149 (14)	0.0261 (4)
H16A	0.149377	0.739783	0.148767	0.031*
C17A	0.0309 (3)	1.0948 (2)	0.22541 (18)	0.0429 (6)
H17A	−0.058732	1.120802	0.251044	0.064*
H17B	0.053129	1.164970	0.169404	0.064*
H17C	0.106602	1.085024	0.269395	0.064*
C18A	−0.0953 (2)	0.9680 (3)	0.13585 (18)	0.0456 (6)
H18A	−0.100003	0.878701	0.125695	0.068*
H18B	−0.072469	1.035035	0.078440	0.068*
H18C	−0.186838	0.994524	0.158902	0.068*
O1B	1.0876 (2)	1.16915 (16)	0.43913 (11)	0.0492 (4)
O2B	1.05781 (15)	1.13024 (14)	0.58974 (10)	0.0332 (3)
O3B	0.76846 (14)	1.04616 (13)	0.56368 (9)	0.0283 (3)
O4B	0.86447 (14)	0.79556 (13)	0.53706 (9)	0.0279 (3)
O5B	0.72215 (14)	0.62521 (13)	0.69482 (10)	0.0317 (3)
O6B	0.49602 (15)	0.71009 (15)	0.66106 (12)	0.0405 (4)
C1B	1.1431 (3)	1.1998 (2)	0.51572 (16)	0.0395 (5)
C2B	1.0363 (2)	1.0364 (2)	0.46958 (14)	0.0324 (5)
H2BA	1.102525	0.969835	0.451963	0.039*
H2BB	0.942460	1.034333	0.443360	0.039*
C3B	1.0256 (2)	1.0047 (2)	0.57313 (14)	0.0277 (4)
H3B	1.099290	0.932365	0.601679	0.033*
C4B	1.2967 (3)	1.1509 (3)	0.5300 (3)	0.0691 (9)
H4BA	1.306375	1.053342	0.536337	0.104*
H4BB	1.330406	1.168030	0.585202	0.104*
H4BC	1.352965	1.199614	0.477656	0.104*
C5B	1.1180 (3)	1.3501 (2)	0.50326 (19)	0.0525 (7)
H5BA	1.171484	1.400440	0.450053	0.079*
H5BB	1.149366	1.371919	0.557434	0.079*
H5BC	1.016911	1.375531	0.494201	0.079*
C6B	0.88139 (19)	0.96487 (18)	0.61587 (13)	0.0237 (4)
H6B	0.877626	0.978483	0.677820	0.028*
C7B	0.7308 (2)	1.1699 (2)	0.58671 (15)	0.0337 (5)
H7BA	0.670065	1.230020	0.538455	0.040*
H7BB	0.817704	1.217179	0.589249	0.040*
C8B	0.6558 (3)	1.1457 (2)	0.67389 (16)	0.0386 (5)
C9B	0.5940 (4)	1.1288 (3)	0.7426 (2)	0.0641 (9)
H9B	0.543620	1.115047	0.798606	0.077*
C10B	0.8592 (2)	0.81606 (19)	0.62558 (13)	0.0234 (4)
H10B	0.939195	0.760120	0.661727	0.028*
C11B	0.9412 (2)	0.6735 (2)	0.53223 (16)	0.0348 (5)
H11C	0.933231	0.664014	0.470227	0.042*
H11D	0.898297	0.594684	0.575257	0.042*
C12B	1.0903 (2)	0.6724 (2)	0.55378 (18)	0.0400 (5)
C13B	1.2085 (3)	0.6769 (3)	0.5753 (2)	0.0593 (8)
H13B	1.303346	0.680435	0.592636	0.071*
C14B	0.5836 (2)	0.5878 (2)	0.67922 (15)	0.0315 (5)
C15B	0.5864 (2)	0.8195 (2)	0.62337 (17)	0.0354 (5)
H15C	0.546644	0.905085	0.633850	0.042*
H15D	0.601566	0.833704	0.557340	0.042*
C16B	0.7218 (2)	0.77049 (19)	0.67517 (14)	0.0274 (4)
H16B	0.716709	0.795885	0.733386	0.033*
C17B	0.5916 (3)	0.5305 (3)	0.59954 (18)	0.0465 (6)
H17D	0.499693	0.496962	0.591521	0.070*
H17E	0.664017	0.455561	0.610530	0.070*
H17F	0.616309	0.601554	0.544548	0.070*
C18B	0.5279 (3)	0.4917 (3)	0.76485 (18)	0.0493 (6)
H18D	0.534131	0.531499	0.815363	0.074*
H18E	0.584436	0.405460	0.778480	0.074*
H18F	0.428998	0.475763	0.756414	0.074*
O1C	0.61167 (17)	0.75408 (17)	0.90309 (11)	0.0440 (4)
O2C	0.52196 (16)	0.76013 (14)	1.03885 (10)	0.0351 (3)
O3C	0.46869 (14)	1.05261 (14)	0.93971 (9)	0.0297 (3)
O4C	0.22924 (16)	1.01405 (14)	0.84581 (10)	0.0341 (3)
O5C	0.02811 (15)	1.17539 (14)	0.92172 (10)	0.0333 (3)
O6C	0.13492 (16)	1.37538 (13)	0.87903 (11)	0.0353 (3)
C1C	0.6185 (2)	0.6827 (2)	0.99641 (16)	0.0382 (5)
C2C	0.4691 (2)	0.8041 (2)	0.88441 (15)	0.0357 (5)
H2CA	0.415918	0.740689	0.861936	0.043*
H2CB	0.464849	0.894014	0.838436	0.043*
C3C	0.4087 (2)	0.81503 (19)	0.97665 (14)	0.0285 (4)
H3C	0.326164	0.756654	0.994319	0.034*
C4C	0.5704 (3)	0.5399 (2)	1.01459 (18)	0.0485 (6)
H4CA	0.473775	0.543536	0.992547	0.073*
H4CB	0.572606	0.494752	1.080061	0.073*
H4CC	0.633761	0.489083	0.982932	0.073*
C5C	0.7649 (3)	0.6880 (4)	1.0296 (2)	0.0662 (9)
H5CA	0.831584	0.633648	1.002461	0.099*
H5CB	0.766659	0.651628	1.095927	0.099*
H5CC	0.792168	0.782340	1.012066	0.099*
C6C	0.3656 (2)	0.95786 (19)	0.98242 (13)	0.0252 (4)
H6C	0.358711	0.954767	1.048069	0.030*
C7C	0.5798 (2)	1.0640 (2)	0.99815 (18)	0.0417 (6)
H7CA	0.659208	1.108934	0.960535	0.050*
H7CB	0.615105	0.971922	1.033336	0.050*
C8C	0.5331 (3)	1.1412 (2)	1.06105 (18)	0.0433 (6)
C9C	0.4966 (3)	1.2044 (3)	1.1112 (2)	0.0629 (8)
H9C	0.467075	1.255470	1.151724	0.075*
C10C	0.2229 (2)	1.00907 (19)	0.93945 (13)	0.0254 (4)
H10C	0.152132	0.942138	0.969985	0.031*
C11C	0.1055 (3)	0.9711 (2)	0.81240 (18)	0.0456 (6)
H11E	0.094424	1.020118	0.747139	0.055*
H11F	0.021046	0.995301	0.845263	0.055*
C12C	0.1132 (3)	0.8240 (2)	0.82386 (16)	0.0403 (5)
C13C	0.1198 (3)	0.7073 (3)	0.82963 (19)	0.0513 (6)
H13C	0.125184	0.613195	0.834289	0.062*
C14C	0.0083 (2)	1.3140 (2)	0.86833 (16)	0.0342 (5)
C15C	0.2465 (2)	1.27019 (19)	0.89366 (15)	0.0318 (5)
H15E	0.326336	1.291148	0.926667	0.038*
H15F	0.281872	1.256345	0.835503	0.038*
C16C	0.1723 (2)	1.14708 (19)	0.95107 (14)	0.0269 (4)
H16C	0.177314	1.143658	1.016649	0.032*
C17C	−0.0137 (3)	1.3202 (3)	0.77021 (18)	0.0522 (7)
H17G	0.069566	1.278060	0.747436	0.078*
H17H	−0.027508	1.415097	0.733914	0.078*
H17I	−0.097373	1.271299	0.765590	0.078*
C18C	−0.1132 (3)	1.3816 (3)	0.9080 (2)	0.0507 (6)
H18G	−0.200268	1.336462	0.905159	0.076*
H18H	−0.124911	1.477420	0.873184	0.076*
H18I	−0.093160	1.374728	0.971496	0.076*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1A	0.0747 (12)	0.0358 (9)	0.0325 (9)	0.0204 (8)	−0.0159 (8)	−0.0075 (7)
O2A	0.0375 (8)	0.0324 (8)	0.0288 (8)	0.0122 (6)	−0.0072 (6)	−0.0106 (6)
O3A	0.0346 (8)	0.0255 (7)	0.0274 (8)	−0.0074 (6)	0.0032 (6)	−0.0075 (6)
O4A	0.0343 (8)	0.0333 (8)	0.0312 (8)	−0.0004 (6)	−0.0042 (6)	−0.0150 (6)
O5A	0.0255 (7)	0.0239 (7)	0.0336 (8)	0.0025 (5)	0.0026 (6)	−0.0033 (6)
O6A	0.0278 (7)	0.0356 (8)	0.0326 (8)	0.0039 (6)	0.0045 (6)	−0.0042 (6)
C1A	0.0398 (12)	0.0343 (11)	0.0354 (12)	0.0114 (9)	−0.0134 (10)	−0.0101 (10)
C2A	0.0425 (12)	0.0278 (10)	0.0281 (11)	0.0067 (9)	−0.0107 (9)	−0.0071 (9)
C3A	0.0315 (11)	0.0247 (10)	0.0267 (11)	0.0028 (8)	−0.0029 (9)	−0.0066 (8)
C4A	0.0430 (15)	0.0520 (16)	0.093 (2)	0.0077 (12)	−0.0194 (15)	−0.0144 (16)
C5A	0.0562 (15)	0.0371 (13)	0.0508 (16)	0.0146 (11)	−0.0137 (13)	−0.0126 (12)
C6A	0.0288 (10)	0.0247 (10)	0.0190 (10)	−0.0003 (8)	0.0018 (8)	−0.0040 (8)
C7A	0.0399 (12)	0.0274 (11)	0.0366 (12)	−0.0057 (9)	−0.0024 (10)	−0.0101 (9)
C8A	0.0444 (13)	0.0408 (13)	0.0435 (15)	−0.0112 (10)	−0.0040 (11)	−0.0171 (11)
C9A	0.075 (2)	0.083 (2)	0.0406 (17)	−0.0277 (17)	−0.0117 (15)	−0.0193 (15)
C10A	0.0230 (10)	0.0241 (9)	0.0248 (10)	−0.0015 (7)	0.0016 (8)	−0.0062 (8)
C11A	0.0340 (12)	0.0390 (12)	0.0618 (16)	0.0053 (9)	−0.0117 (11)	−0.0309 (12)
C12A	0.0390 (13)	0.0278 (11)	0.0447 (14)	−0.0017 (9)	−0.0056 (10)	−0.0114 (10)
C13A	0.0352 (14)	0.0353 (13)	0.082 (2)	−0.0049 (10)	−0.0050 (13)	−0.0056 (13)
C14A	0.0242 (10)	0.0312 (10)	0.0296 (11)	0.0043 (8)	−0.0005 (8)	−0.0053 (9)
C15A	0.0257 (10)	0.0307 (11)	0.0403 (13)	−0.0019 (8)	0.0013 (9)	−0.0046 (9)
C16A	0.0275 (10)	0.0238 (10)	0.0262 (11)	−0.0016 (8)	−0.0008 (8)	−0.0055 (8)
C17A	0.0479 (14)	0.0345 (12)	0.0462 (14)	0.0075 (10)	0.0031 (11)	−0.0138 (11)
C18A	0.0346 (13)	0.0530 (15)	0.0448 (14)	0.0010 (10)	−0.0101 (11)	−0.0069 (12)
O1B	0.0763 (12)	0.0408 (9)	0.0311 (9)	−0.0230 (8)	0.0103 (9)	−0.0082 (7)
O2B	0.0403 (8)	0.0304 (7)	0.0300 (8)	−0.0115 (6)	0.0011 (7)	−0.0088 (6)
O3B	0.0317 (7)	0.0284 (7)	0.0229 (7)	0.0074 (6)	−0.0044 (6)	−0.0058 (6)
O4B	0.0285 (7)	0.0328 (7)	0.0248 (7)	0.0034 (6)	−0.0034 (6)	−0.0127 (6)
O5B	0.0290 (7)	0.0242 (7)	0.0412 (9)	−0.0035 (6)	−0.0046 (6)	−0.0074 (6)
O6B	0.0249 (7)	0.0372 (8)	0.0595 (11)	−0.0051 (6)	0.0014 (7)	−0.0138 (8)
C1B	0.0464 (13)	0.0377 (12)	0.0339 (12)	−0.0159 (10)	0.0074 (10)	−0.0070 (10)
C2B	0.0366 (11)	0.0319 (11)	0.0284 (11)	−0.0061 (9)	0.0054 (9)	−0.0077 (9)
C3B	0.0301 (10)	0.0247 (10)	0.0286 (11)	−0.0038 (8)	−0.0035 (9)	−0.0073 (8)
C4B	0.0400 (15)	0.071 (2)	0.093 (3)	−0.0154 (14)	0.0089 (16)	−0.0174 (18)
C5B	0.0757 (18)	0.0349 (13)	0.0469 (15)	−0.0200 (12)	0.0114 (14)	−0.0095 (11)
C6B	0.0266 (10)	0.0246 (9)	0.0186 (10)	0.0025 (8)	−0.0048 (8)	−0.0047 (8)
C7B	0.0415 (12)	0.0228 (10)	0.0322 (12)	0.0048 (8)	0.0054 (10)	−0.0025 (9)
C8B	0.0521 (14)	0.0247 (11)	0.0388 (13)	−0.0036 (10)	0.0081 (12)	−0.0091 (10)
C9B	0.099 (2)	0.0447 (15)	0.0530 (18)	−0.0189 (15)	0.0390 (18)	−0.0221 (13)
C10B	0.0235 (9)	0.0259 (9)	0.0211 (10)	0.0012 (7)	−0.0053 (8)	−0.0071 (8)
C11B	0.0307 (11)	0.0381 (12)	0.0418 (13)	0.0004 (9)	0.0010 (10)	−0.0218 (10)
C12B	0.0329 (13)	0.0333 (11)	0.0561 (15)	0.0033 (9)	0.0039 (11)	−0.0176 (11)
C13B	0.0287 (14)	0.0454 (15)	0.105 (3)	0.0034 (10)	−0.0077 (14)	−0.0237 (15)
C14B	0.0264 (10)	0.0310 (11)	0.0383 (12)	−0.0048 (8)	0.0004 (9)	−0.0112 (9)
C15B	0.0237 (10)	0.0289 (11)	0.0530 (15)	0.0005 (8)	−0.0030 (10)	−0.0110 (10)
C16B	0.0289 (10)	0.0242 (10)	0.0295 (11)	−0.0013 (8)	0.0005 (9)	−0.0086 (8)
C17B	0.0446 (14)	0.0544 (15)	0.0473 (15)	−0.0084 (11)	−0.0028 (12)	−0.0242 (13)
C18B	0.0512 (15)	0.0502 (15)	0.0462 (15)	−0.0180 (12)	0.0085 (12)	−0.0108 (12)
O1C	0.0450 (10)	0.0533 (10)	0.0343 (9)	0.0033 (8)	0.0074 (8)	−0.0155 (8)
O2C	0.0427 (8)	0.0354 (8)	0.0274 (8)	0.0150 (6)	−0.0067 (7)	−0.0123 (6)
O3C	0.0303 (7)	0.0322 (7)	0.0280 (8)	−0.0051 (6)	0.0008 (6)	−0.0101 (6)
O4C	0.0501 (9)	0.0298 (7)	0.0241 (7)	−0.0007 (7)	−0.0121 (7)	−0.0095 (6)
O5C	0.0305 (8)	0.0260 (7)	0.0391 (9)	0.0024 (6)	−0.0080 (6)	−0.0027 (6)
O6C	0.0409 (8)	0.0206 (7)	0.0436 (9)	0.0025 (6)	−0.0083 (7)	−0.0083 (6)
C1C	0.0404 (13)	0.0441 (13)	0.0321 (13)	0.0120 (10)	−0.0018 (10)	−0.0170 (10)
C2C	0.0470 (13)	0.0326 (11)	0.0291 (12)	0.0058 (9)	−0.0024 (10)	−0.0125 (10)
C3C	0.0337 (11)	0.0263 (10)	0.0244 (11)	0.0030 (8)	−0.0028 (9)	−0.0059 (8)
C4C	0.0623 (16)	0.0388 (13)	0.0438 (15)	0.0168 (11)	0.0012 (12)	−0.0153 (11)
C5C	0.0460 (16)	0.086 (2)	0.079 (2)	0.0208 (14)	−0.0141 (15)	−0.0476 (19)
C6C	0.0318 (10)	0.0254 (10)	0.0184 (9)	−0.0018 (8)	0.0011 (8)	−0.0061 (8)
C7C	0.0331 (12)	0.0444 (13)	0.0535 (15)	−0.0027 (10)	−0.0076 (11)	−0.0227 (12)
C8C	0.0467 (13)	0.0387 (13)	0.0458 (14)	0.0014 (10)	−0.0174 (11)	−0.0132 (12)
C9C	0.079 (2)	0.0647 (18)	0.0543 (17)	0.0127 (15)	−0.0203 (15)	−0.0341 (15)
C10C	0.0316 (10)	0.0217 (9)	0.0217 (10)	−0.0025 (8)	−0.0037 (8)	−0.0037 (8)
C11C	0.0631 (16)	0.0322 (12)	0.0450 (14)	0.0044 (11)	−0.0307 (12)	−0.0154 (11)
C12C	0.0513 (14)	0.0345 (13)	0.0360 (13)	−0.0007 (10)	−0.0168 (11)	−0.0104 (10)
C13C	0.0646 (17)	0.0323 (13)	0.0586 (17)	−0.0040 (11)	−0.0202 (14)	−0.0133 (12)
C14C	0.0403 (12)	0.0233 (10)	0.0375 (12)	0.0031 (9)	−0.0108 (10)	−0.0065 (9)
C15C	0.0345 (11)	0.0217 (10)	0.0379 (12)	0.0001 (8)	−0.0049 (9)	−0.0063 (9)
C16C	0.0287 (10)	0.0263 (10)	0.0248 (10)	0.0006 (8)	−0.0045 (8)	−0.0059 (8)
C17C	0.0766 (19)	0.0367 (13)	0.0420 (15)	0.0062 (12)	−0.0240 (14)	−0.0088 (11)
C18C	0.0444 (14)	0.0398 (13)	0.0703 (19)	0.0097 (11)	−0.0086 (13)	−0.0213 (13)

Geometric parameters (Å, º)

O1A—C1A	1.429 (3)	C6B—C10B	1.524 (2)
O1A—C2A	1.423 (3)	C7B—H7BA	0.9900
O2A—C1A	1.424 (3)	C7B—H7BB	0.9900
O2A—C3A	1.440 (2)	C7B—C8B	1.462 (3)
O3A—C6A	1.430 (2)	C8B—C9B	1.166 (3)
O3A—C7A	1.431 (2)	C9B—H9B	0.9500
O4A—C10A	1.427 (2)	C10B—H10B	1.0000
O4A—C11A	1.429 (2)	C10B—C16B	1.520 (3)
O5A—C14A	1.429 (2)	C11B—H11C	0.9900
O5A—C16A	1.436 (2)	C11B—H11D	0.9900
O6A—C14A	1.422 (3)	C11B—C12B	1.458 (3)
O6A—C15A	1.428 (2)	C12B—C13B	1.184 (4)
C1A—C4A	1.506 (4)	C13B—H13B	0.9500
C1A—C5A	1.503 (3)	C14B—C17B	1.502 (3)
C2A—H2AA	0.9900	C14B—C18B	1.506 (3)
C2A—H2AB	0.9900	C15B—H15C	0.9900
C2A—C3A	1.532 (3)	C15B—H15D	0.9900
C3A—H3A	1.0000	C15B—C16B	1.510 (3)
C3A—C6A	1.514 (3)	C16B—H16B	1.0000
C4A—H4AA	0.9800	C17B—H17D	0.9800
C4A—H4AB	0.9800	C17B—H17E	0.9800
C4A—H4AC	0.9800	C17B—H17F	0.9800
C5A—H5AA	0.9800	C18B—H18D	0.9800
C5A—H5AB	0.9800	C18B—H18E	0.9800
C5A—H5AC	0.9800	C18B—H18F	0.9800
C6A—H6A	1.0000	O1C—C1C	1.413 (3)
C6A—C10A	1.529 (2)	O1C—C2C	1.422 (3)
C7A—H7AA	0.9900	O2C—C1C	1.439 (2)
C7A—H7AB	0.9900	O2C—C3C	1.434 (3)
C7A—C8A	1.460 (3)	O3C—C6C	1.433 (2)
C8A—C9A	1.176 (4)	O3C—C7C	1.434 (3)
C9A—H9A	0.9500	O4C—C10C	1.424 (2)
C10A—H10A	1.0000	O4C—C11C	1.436 (3)
C10A—C16A	1.521 (3)	O5C—C14C	1.432 (3)
C11A—H11A	0.9900	O5C—C16C	1.436 (2)
C11A—H11B	0.9900	O6C—C14C	1.425 (3)
C11A—C12A	1.461 (3)	O6C—C15C	1.440 (3)
C12A—C13A	1.176 (3)	C1C—C4C	1.513 (3)
C13A—H13A	0.9500	C1C—C5C	1.500 (4)
C14A—C17A	1.509 (3)	C2C—H2CA	0.9900
C14A—C18A	1.510 (3)	C2C—H2CB	0.9900
C15A—H15A	0.9900	C2C—C3C	1.544 (3)
C15A—H15B	0.9900	C3C—H3C	1.0000
C15A—C16A	1.541 (3)	C3C—C6C	1.528 (3)
C16A—H16A	1.0000	C4C—H4CA	0.9800
C17A—H17A	0.9800	C4C—H4CB	0.9800
C17A—H17B	0.9800	C4C—H4CC	0.9800
C17A—H17C	0.9800	C5C—H5CA	0.9800
C18A—H18A	0.9800	C5C—H5CB	0.9800
C18A—H18B	0.9800	C5C—H5CC	0.9800
C18A—H18C	0.9800	C6C—H6C	1.0000
O1B—C1B	1.424 (3)	C6C—C10C	1.518 (3)
O1B—C2B	1.424 (2)	C7C—H7CA	0.9900
O2B—C1B	1.419 (2)	C7C—H7CB	0.9900
O2B—C3B	1.439 (2)	C7C—C8C	1.460 (3)
O3B—C6B	1.428 (2)	C8C—C9C	1.174 (4)
O3B—C7B	1.439 (2)	C9C—H9C	0.9500
O4B—C10B	1.433 (2)	C10C—H10C	1.0000
O4B—C11B	1.432 (2)	C10C—C16C	1.529 (3)
O5B—C14B	1.436 (2)	C11C—H11E	0.9900
O5B—C16B	1.439 (2)	C11C—H11F	0.9900
O6B—C14B	1.426 (3)	C11C—C12C	1.472 (3)
O6B—C15B	1.435 (3)	C12C—C13C	1.177 (3)
C1B—C4B	1.510 (4)	C13C—H13C	0.9500
C1B—C5B	1.509 (3)	C14C—C17C	1.510 (3)
C2B—H2BA	0.9900	C14C—C18C	1.511 (3)
C2B—H2BB	0.9900	C15C—H15E	0.9900
C2B—C3B	1.531 (3)	C15C—H15F	0.9900
C3B—H3B	1.0000	C15C—C16C	1.522 (3)
C3B—C6B	1.527 (3)	C16C—H16C	1.0000
C4B—H4BA	0.9800	C17C—H17G	0.9800
C4B—H4BB	0.9800	C17C—H17H	0.9800
C4B—H4BC	0.9800	C17C—H17I	0.9800
C5B—H5BA	0.9800	C18C—H18G	0.9800
C5B—H5BB	0.9800	C18C—H18H	0.9800
C5B—H5BC	0.9800	C18C—H18I	0.9800
C6B—H6B	1.0000
C2A—O1A—C1A	107.92 (17)	C8B—C7B—H7BB	109.1
C1A—O2A—C3A	106.52 (15)	C9B—C8B—C7B	178.5 (3)
C6A—O3A—C7A	115.53 (14)	C8B—C9B—H9B	180.0
C10A—O4A—C11A	115.33 (16)	O4B—C10B—C6B	108.79 (15)
C14A—O5A—C16A	108.14 (13)	O4B—C10B—H10B	108.1
C14A—O6A—C15A	106.41 (15)	O4B—C10B—C16B	111.48 (15)
O1A—C1A—C4A	111.1 (2)	C6B—C10B—H10B	108.1
O1A—C1A—C5A	107.81 (19)	C16B—C10B—C6B	112.16 (15)
O2A—C1A—O1A	103.83 (16)	C16B—C10B—H10B	108.1
O2A—C1A—C4A	111.7 (2)	O4B—C11B—H11C	109.2
O2A—C1A—C5A	108.97 (18)	O4B—C11B—H11D	109.2
C5A—C1A—C4A	113.0 (2)	O4B—C11B—C12B	112.20 (16)
O1A—C2A—H2AA	110.7	H11C—C11B—H11D	107.9
O1A—C2A—H2AB	110.7	C12B—C11B—H11C	109.2
O1A—C2A—C3A	105.18 (16)	C12B—C11B—H11D	109.2
H2AA—C2A—H2AB	108.8	C13B—C12B—C11B	175.3 (2)
C3A—C2A—H2AA	110.7	C12B—C13B—H13B	180.0
C3A—C2A—H2AB	110.7	O5B—C14B—C17B	108.60 (16)
O2A—C3A—C2A	103.38 (16)	O5B—C14B—C18B	109.72 (19)
O2A—C3A—H3A	109.3	O6B—C14B—O5B	105.49 (15)
O2A—C3A—C6A	108.86 (16)	O6B—C14B—C17B	111.8 (2)
C2A—C3A—H3A	109.3	O6B—C14B—C18B	107.34 (17)
C6A—C3A—C2A	116.55 (16)	C17B—C14B—C18B	113.59 (19)
C6A—C3A—H3A	109.3	O6B—C15B—H15C	111.3
C1A—C4A—H4AA	109.5	O6B—C15B—H15D	111.3
C1A—C4A—H4AB	109.5	O6B—C15B—C16B	102.53 (17)
C1A—C4A—H4AC	109.5	H15C—C15B—H15D	109.2
H4AA—C4A—H4AB	109.5	C16B—C15B—H15C	111.3
H4AA—C4A—H4AC	109.5	C16B—C15B—H15D	111.3
H4AB—C4A—H4AC	109.5	O5B—C16B—C10B	107.92 (15)
C1A—C5A—H5AA	109.5	O5B—C16B—C15B	103.46 (15)
C1A—C5A—H5AB	109.5	O5B—C16B—H16B	109.4
C1A—C5A—H5AC	109.5	C10B—C16B—H16B	109.4
H5AA—C5A—H5AB	109.5	C15B—C16B—C10B	117.00 (18)
H5AA—C5A—H5AC	109.5	C15B—C16B—H16B	109.4
H5AB—C5A—H5AC	109.5	C14B—C17B—H17D	109.5
O3A—C6A—C3A	113.10 (16)	C14B—C17B—H17E	109.5
O3A—C6A—H6A	108.3	C14B—C17B—H17F	109.5
O3A—C6A—C10A	107.26 (14)	H17D—C17B—H17E	109.5
C3A—C6A—H6A	108.3	H17D—C17B—H17F	109.5
C3A—C6A—C10A	111.46 (16)	H17E—C17B—H17F	109.5
C10A—C6A—H6A	108.3	C14B—C18B—H18D	109.5
O3A—C7A—H7AA	108.9	C14B—C18B—H18E	109.5
O3A—C7A—H7AB	108.9	C14B—C18B—H18F	109.5
O3A—C7A—C8A	113.23 (18)	H18D—C18B—H18E	109.5
H7AA—C7A—H7AB	107.7	H18D—C18B—H18F	109.5
C8A—C7A—H7AA	108.9	H18E—C18B—H18F	109.5
C8A—C7A—H7AB	108.9	C1C—O1C—C2C	107.30 (16)
C9A—C8A—C7A	177.6 (3)	C3C—O2C—C1C	107.38 (15)
C8A—C9A—H9A	180.0	C6C—O3C—C7C	114.70 (16)
O4A—C10A—C6A	108.87 (16)	C10C—O4C—C11C	114.88 (17)
O4A—C10A—H10A	108.7	C14C—O5C—C16C	109.83 (15)
O4A—C10A—C16A	110.70 (14)	C14C—O6C—C15C	106.49 (14)
C6A—C10A—H10A	108.7	O1C—C1C—O2C	103.88 (17)
C16A—C10A—C6A	111.23 (15)	O1C—C1C—C4C	111.61 (19)
C16A—C10A—H10A	108.7	O1C—C1C—C5C	109.0 (2)
O4A—C11A—H11A	109.2	O2C—C1C—C4C	109.82 (18)
O4A—C11A—H11B	109.2	O2C—C1C—C5C	108.56 (18)
O4A—C11A—C12A	112.26 (17)	C5C—C1C—C4C	113.5 (2)
H11A—C11A—H11B	107.9	O1C—C2C—H2CA	110.9
C12A—C11A—H11A	109.2	O1C—C2C—H2CB	110.9
C12A—C11A—H11B	109.2	O1C—C2C—C3C	104.41 (18)
C13A—C12A—C11A	178.6 (3)	H2CA—C2C—H2CB	108.9
C12A—C13A—H13A	180.0	C3C—C2C—H2CA	110.9
O5A—C14A—C17A	108.41 (16)	C3C—C2C—H2CB	110.9
O5A—C14A—C18A	110.89 (17)	O2C—C3C—C2C	103.92 (16)
O6A—C14A—O5A	103.97 (15)	O2C—C3C—H3C	109.3
O6A—C14A—C17A	108.75 (17)	O2C—C3C—C6C	108.41 (15)
O6A—C14A—C18A	111.37 (17)	C2C—C3C—H3C	109.3
C17A—C14A—C18A	113.02 (19)	C6C—C3C—C2C	116.41 (17)
O6A—C15A—H15A	110.9	C6C—C3C—H3C	109.3
O6A—C15A—H15B	110.9	C1C—C4C—H4CA	109.5
O6A—C15A—C16A	104.47 (15)	C1C—C4C—H4CB	109.5
H15A—C15A—H15B	108.9	C1C—C4C—H4CC	109.5
C16A—C15A—H15A	110.9	H4CA—C4C—H4CB	109.5
C16A—C15A—H15B	110.9	H4CA—C4C—H4CC	109.5
O5A—C16A—C10A	108.88 (15)	H4CB—C4C—H4CC	109.5
O5A—C16A—C15A	103.72 (15)	C1C—C5C—H5CA	109.5
O5A—C16A—H16A	109.9	C1C—C5C—H5CB	109.5
C10A—C16A—C15A	114.47 (17)	C1C—C5C—H5CC	109.5
C10A—C16A—H16A	109.9	H5CA—C5C—H5CB	109.5
C15A—C16A—H16A	109.9	H5CA—C5C—H5CC	109.5
C14A—C17A—H17A	109.5	H5CB—C5C—H5CC	109.5
C14A—C17A—H17B	109.5	O3C—C6C—C3C	111.51 (15)
C14A—C17A—H17C	109.5	O3C—C6C—H6C	108.1
H17A—C17A—H17B	109.5	O3C—C6C—C10C	108.76 (15)
H17A—C17A—H17C	109.5	C3C—C6C—H6C	108.1
H17B—C17A—H17C	109.5	C10C—C6C—C3C	112.04 (16)
C14A—C18A—H18A	109.5	C10C—C6C—H6C	108.1
C14A—C18A—H18B	109.5	O3C—C7C—H7CA	109.1
C14A—C18A—H18C	109.5	O3C—C7C—H7CB	109.1
H18A—C18A—H18B	109.5	O3C—C7C—C8C	112.40 (19)
H18A—C18A—H18C	109.5	H7CA—C7C—H7CB	107.9
H18B—C18A—H18C	109.5	C8C—C7C—H7CA	109.1
C1B—O1B—C2B	107.75 (16)	C8C—C7C—H7CB	109.1
C1B—O2B—C3B	106.77 (15)	C9C—C8C—C7C	179.2 (3)
C6B—O3B—C7B	114.46 (15)	C8C—C9C—H9C	180.0
C11B—O4B—C10B	114.60 (16)	O4C—C10C—C6C	109.45 (15)
C14B—O5B—C16B	109.25 (15)	O4C—C10C—H10C	107.8
C14B—O6B—C15B	106.73 (14)	O4C—C10C—C16C	110.75 (16)
O1B—C1B—C4B	111.2 (2)	C6C—C10C—H10C	107.8
O1B—C1B—C5B	108.4 (2)	C6C—C10C—C16C	112.93 (16)
O2B—C1B—O1B	104.31 (16)	C16C—C10C—H10C	107.8
O2B—C1B—C4B	111.1 (2)	O4C—C11C—H11E	109.2
O2B—C1B—C5B	108.03 (18)	O4C—C11C—H11F	109.2
C5B—C1B—C4B	113.3 (2)	O4C—C11C—C12C	112.1 (2)
O1B—C2B—H2BA	110.7	H11E—C11C—H11F	107.9
O1B—C2B—H2BB	110.7	C12C—C11C—H11E	109.2
O1B—C2B—C3B	105.13 (16)	C12C—C11C—H11F	109.2
H2BA—C2B—H2BB	108.8	C13C—C12C—C11C	177.6 (3)
C3B—C2B—H2BA	110.7	C12C—C13C—H13C	180.0
C3B—C2B—H2BB	110.7	O5C—C14C—C17C	109.69 (17)
O2B—C3B—C2B	103.53 (15)	O5C—C14C—C18C	109.09 (19)
O2B—C3B—H3B	109.5	O6C—C14C—O5C	105.14 (17)
O2B—C3B—C6B	108.31 (15)	O6C—C14C—C17C	111.3 (2)
C2B—C3B—H3B	109.5	O6C—C14C—C18C	108.26 (17)
C6B—C3B—C2B	116.29 (17)	C17C—C14C—C18C	113.0 (2)
C6B—C3B—H3B	109.5	O6C—C15C—H15E	111.3
C1B—C4B—H4BA	109.5	O6C—C15C—H15F	111.3
C1B—C4B—H4BB	109.5	O6C—C15C—C16C	102.10 (16)
C1B—C4B—H4BC	109.5	H15E—C15C—H15F	109.2
H4BA—C4B—H4BB	109.5	C16C—C15C—H15E	111.3
H4BA—C4B—H4BC	109.5	C16C—C15C—H15F	111.3
H4BB—C4B—H4BC	109.5	O5C—C16C—C10C	108.28 (15)
C1B—C5B—H5BA	109.5	O5C—C16C—C15C	103.24 (16)
C1B—C5B—H5BB	109.5	O5C—C16C—H16C	109.4
C1B—C5B—H5BC	109.5	C10C—C16C—H16C	109.4
H5BA—C5B—H5BB	109.5	C15C—C16C—C10C	116.94 (16)
H5BA—C5B—H5BC	109.5	C15C—C16C—H16C	109.4
H5BB—C5B—H5BC	109.5	C14C—C17C—H17G	109.5
O3B—C6B—C3B	111.80 (15)	C14C—C17C—H17H	109.5
O3B—C6B—H6B	108.4	C14C—C17C—H17I	109.5
O3B—C6B—C10B	108.72 (15)	H17G—C17C—H17H	109.5
C3B—C6B—H6B	108.4	H17G—C17C—H17I	109.5
C10B—C6B—C3B	111.05 (15)	H17H—C17C—H17I	109.5
C10B—C6B—H6B	108.4	C14C—C18C—H18G	109.5
O3B—C7B—H7BA	109.1	C14C—C18C—H18H	109.5
O3B—C7B—H7BB	109.1	C14C—C18C—H18I	109.5
O3B—C7B—C8B	112.38 (16)	H18G—C18C—H18H	109.5
H7BA—C7B—H7BB	107.9	H18G—C18C—H18I	109.5
C8B—C7B—H7BA	109.1	H18H—C18C—H18I	109.5
O1A—C2A—C3A—O2A	8.0 (2)	C3B—O2B—C1B—C5B	151.4 (2)
O1A—C2A—C3A—C6A	127.32 (18)	C3B—C6B—C10B—O4B	−61.0 (2)
O2A—C3A—C6A—O3A	71.97 (19)	C3B—C6B—C10B—C16B	175.18 (16)
O2A—C3A—C6A—C10A	−167.08 (14)	C6B—O3B—C7B—C8B	−72.8 (2)
O3A—C6A—C10A—O4A	69.86 (18)	C6B—C10B—C16B—O5B	−170.17 (16)
O3A—C6A—C10A—C16A	−52.4 (2)	C6B—C10B—C16B—C15B	73.8 (2)
O4A—C10A—C16A—O5A	79.35 (18)	C7B—O3B—C6B—C3B	−88.03 (18)
O4A—C10A—C16A—C15A	−36.2 (2)	C7B—O3B—C6B—C10B	149.01 (15)
O6A—C15A—C16A—O5A	−7.5 (2)	C10B—O4B—C11B—C12B	−63.2 (2)
O6A—C15A—C16A—C10A	111.01 (18)	C11B—O4B—C10B—C6B	138.17 (16)
C1A—O1A—C2A—C3A	14.6 (2)	C11B—O4B—C10B—C16B	−97.64 (19)
C1A—O2A—C3A—C2A	−27.7 (2)	C14B—O5B—C16B—C10B	−139.19 (17)
C1A—O2A—C3A—C6A	−152.24 (16)	C14B—O5B—C16B—C15B	−14.6 (2)
C2A—O1A—C1A—O2A	−31.9 (2)	C14B—O6B—C15B—C16B	−35.9 (2)
C2A—O1A—C1A—C4A	88.2 (2)	C15B—O6B—C14B—O5B	27.4 (2)
C2A—O1A—C1A—C5A	−147.4 (2)	C15B—O6B—C14B—C17B	−90.5 (2)
C2A—C3A—C6A—O3A	−44.4 (2)	C15B—O6B—C14B—C18B	144.34 (19)
C2A—C3A—C6A—C10A	76.6 (2)	C16B—O5B—C14B—O6B	−7.0 (2)
C3A—O2A—C1A—O1A	37.2 (2)	C16B—O5B—C14B—C17B	112.93 (19)
C3A—O2A—C1A—C4A	−82.5 (2)	C16B—O5B—C14B—C18B	−122.38 (18)
C3A—O2A—C1A—C5A	151.93 (18)	O1C—C2C—C3C—O2C	−4.1 (2)
C3A—C6A—C10A—O4A	−54.44 (19)	O1C—C2C—C3C—C6C	115.03 (19)
C3A—C6A—C10A—C16A	−176.68 (15)	O2C—C3C—C6C—O3C	73.42 (19)
C6A—O3A—C7A—C8A	−58.6 (2)	O2C—C3C—C6C—C10C	−164.40 (15)
C6A—C10A—C16A—O5A	−159.48 (15)	O3C—C6C—C10C—O4C	63.06 (18)
C6A—C10A—C16A—C15A	85.0 (2)	O3C—C6C—C10C—C16C	−60.82 (19)
C7A—O3A—C6A—C3A	−88.7 (2)	O4C—C10C—C16C—O5C	66.19 (19)
C7A—O3A—C6A—C10A	148.04 (17)	O4C—C10C—C16C—C15C	−49.8 (2)
C10A—O4A—C11A—C12A	−86.2 (2)	O6C—C15C—C16C—O5C	29.57 (19)
C11A—O4A—C10A—C6A	142.53 (16)	O6C—C15C—C16C—C10C	148.32 (17)
C11A—O4A—C10A—C16A	−94.91 (19)	C1C—O1C—C2C—C3C	25.1 (2)
C14A—O5A—C16A—C10A	−137.44 (16)	C1C—O2C—C3C—C2C	−17.9 (2)
C14A—O5A—C16A—C15A	−15.2 (2)	C1C—O2C—C3C—C6C	−142.36 (16)
C14A—O6A—C15A—C16A	27.5 (2)	C2C—O1C—C1C—O2C	−36.6 (2)
C15A—O6A—C14A—O5A	−37.32 (19)	C2C—O1C—C1C—C4C	81.6 (2)
C15A—O6A—C14A—C17A	−152.68 (17)	C2C—O1C—C1C—C5C	−152.21 (18)
C15A—O6A—C14A—C18A	82.1 (2)	C2C—C3C—C6C—O3C	−43.2 (2)
C16A—O5A—C14A—O6A	32.5 (2)	C2C—C3C—C6C—C10C	79.0 (2)
C16A—O5A—C14A—C17A	148.07 (17)	C3C—O2C—C1C—O1C	33.7 (2)
C16A—O5A—C14A—C18A	−87.3 (2)	C3C—O2C—C1C—C4C	−85.8 (2)
O1B—C2B—C3B—O2B	6.1 (2)	C3C—O2C—C1C—C5C	149.6 (2)
O1B—C2B—C3B—C6B	124.74 (18)	C3C—C6C—C10C—O4C	−60.68 (19)
O2B—C3B—C6B—O3B	74.95 (19)	C3C—C6C—C10C—C16C	175.45 (15)
O2B—C3B—C6B—C10B	−163.43 (16)	C6C—O3C—C7C—C8C	−75.3 (2)
O3B—C6B—C10B—O4B	62.37 (18)	C6C—C10C—C16C—O5C	−170.65 (15)
O3B—C6B—C10B—C16B	−61.4 (2)	C6C—C10C—C16C—C15C	73.3 (2)
O4B—C10B—C16B—O5B	67.6 (2)	C7C—O3C—C6C—C3C	−88.57 (19)
O4B—C10B—C16B—C15B	−48.5 (2)	C7C—O3C—C6C—C10C	147.38 (16)
O6B—C15B—C16B—O5B	30.37 (19)	C10C—O4C—C11C—C12C	−88.7 (2)
O6B—C15B—C16B—C10B	148.86 (16)	C11C—O4C—C10C—C6C	140.16 (17)
C1B—O1B—C2B—C3B	15.7 (2)	C11C—O4C—C10C—C16C	−94.69 (19)
C1B—O2B—C3B—C2B	−25.8 (2)	C14C—O5C—C16C—C10C	−136.98 (16)
C1B—O2B—C3B—C6B	−149.86 (18)	C14C—O5C—C16C—C15C	−12.4 (2)
C2B—O1B—C1B—O2B	−32.1 (2)	C14C—O6C—C15C—C16C	−36.9 (2)
C2B—O1B—C1B—C4B	87.8 (2)	C15C—O6C—C14C—O5C	29.9 (2)
C2B—O1B—C1B—C5B	−146.99 (19)	C15C—O6C—C14C—C17C	−88.8 (2)
C2B—C3B—C6B—O3B	−41.0 (2)	C15C—O6C—C14C—C18C	146.37 (19)
C2B—C3B—C6B—C10B	80.6 (2)	C16C—O5C—C14C—O6C	−10.0 (2)
C3B—O2B—C1B—O1B	36.2 (2)	C16C—O5C—C14C—C17C	109.8 (2)
C3B—O2B—C1B—C4B	−83.7 (2)	C16C—O5C—C14C—C18C	−125.87 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C7A—H7AA···O1B^i	0.99	2.55	3.393 (3)	143
C9A—H9A···O6C^ii	0.95	2.58	3.375 (3)	141
C13A—H13A···O6A^iii	0.95	2.34	3.246 (3)	158
C18A—H18B···O5C^iv	0.98	2.62	3.581 (3)	168
C5B—H5BA···O3A^v	0.98	2.59	3.525 (3)	160
C9B—H9B···O3C	0.95	2.19	3.121 (3)	167
C13B—H13B···O6B^iii	0.95	2.21	3.138 (3)	165
C16B—H16B···O1C	1.00	2.69	3.584 (2)	149
C4C—H4CB···O2A^vi	0.98	2.57	3.536 (3)	169
C6C—H6C···O5A^vi	1.00	2.67	3.458 (2)	136
C9C—H9C···O2A^vii	0.95	2.71	3.542 (3)	147
C11C—H11E···O2B^viii	0.99	2.38	3.372 (3)	177
C13C—H13C···O6C^ix	0.95	2.34	3.278 (3)	168

Symmetry codes: (i) x−1, y−1, z; (ii) x, y−1, z−1; (iii) x+1, y, z; (iv) x, y, z−1; (v) x+1, y+1, z; (vi) x, y, z+1; (vii) x, y+1, z+1; (viii) x−1, y, z; (ix) x, y−1, z.