Crystal structure of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoeth­yl}-1H-imidazol-3-ium chloride

Zende, V.; Girase, T.R.; Chrysochos, N.; Kapdi, A.R.; Schulzke, C.

doi:10.1107/S2056989018014792

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ISSN: 2056-9890

Volume 74| Part 11| November 2018| Pages 1665-1668

https://doi.org/10.1107/S2056989018014792

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Crystal structure of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium chloride

Vidya Zende,^a Tejpalsingh Ramsingh Girase,^a Nicolas Chrysochos,^b Anant Ramakant Kapdi ^a and Carola Schulzke ^b ^*

^aDepartment of Chemistry, Institute of Chemical Technology, Nathalal Parekh Road, Matunga, Mumbai 400019, India, and ^bInstitut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17487 Greifswald, Germany
^*Correspondence e-mail: carola.schulzke@uni-greifswald.de

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 11 October 2018; accepted 19 October 2018; online 26 October 2018)

In the cation of the title molecular salt, C₁₈H₂₄N₃O⁺·Cl⁻, an intramolecular C—H⋯O hydrogen bond stabilizes the almost coplanar orientation of the aromatic ring of the indane unit and the amide plane. In the crystal, the packing is dominated by intermolecular C—H⋯Cl hydrogen-bonding interactions that result in the formation of slab-like structures propagating along [010]. The slabs are linked by weak C—H⋯O interactions, forming layers lying parallel to (100). The methylene carbon atom of the indanyl substituent is disordered over two positions with a refined occupancy ratio of 0.84 (2):0.16 (2). The crystal studied was refined as a twin with matrix [1 0 0.9, 0 $[\overline{1}]$ 0, 0 0 $[\overline{1}]$ ]; the resulting BASF value is 0.30.

Keywords: crystal structure; N-heterocyclic carbenes; imidazolium salt; amido-functionalization; electron-rich ligand; sigma donor acetamide; hydrogen bonding.

CCDC reference: 1832439

1. Chemical context

N-Heterocyclic carbenes (NHCs) are neutral compounds in which a 6e⁻-containing divalent carbon atom is placed between two hetero atoms. They are typically derived from their parent imidazolium salts by deprotonation of the carbon atom located in between the two nitrogen atoms (Bhatia et al., 2013 ). The high reactivity in the case of carbenes can be attributed to the presence of an incomplete octet resulting in a strong electron-donating ability (Hopkinson et al., 2014 ). Arduengo was the first to successfully isolate a free carbene and characterize it by obtaining a single crystal X-ray structure for the same. This study opened a new era in organic chemistry allowing the investigation of the so-called NHCs as ligands (Arduengo et al., 1991 ). To date, a tremendous amount of research on NHCs has enhanced the popularity of these carbene compounds in organic synthesis, organometallic chemistry, organocatalysis, medicinal and pharmaceutical applications and essentially every discipline of modern day science. Over the past two decades, N-heterocyclic carbene (NHC) ligands have been among the most exploited in organic synthesis. They can be considered superior to phosphine ligands as their electronic and steric properties can be easily fine-tuned by simple variations in their structures (Díez-González et al., 2009 ; Hermann, 2002 ; Froese et al., 2017 ). Attempts have been made to tune or modify the electronic and steric properties of NHCs by changing the substituent at one or both nitrogen centres. These changes in electronics and steric properties may further provide subtle information about the mechanism of catalytic transformations (Huynh, 2018 ; Peris, 2018 ). Although the term hemilability for a coordinated ligand was first introduced in 1979 (Jeffrey & Rauchfuss, 1979 ), the first hemilabile NHC ligand was developed some twenty years later (McGuinness & Cavell, 2000 ). The presence of hemilabile coordination sites in a ligand system plays a crucial role in catalysis as well as in biological sciences (cytotoxicity). The modular electronic and steric properties of the hemilabile ligand systems provide extra stability to transition metal complexes (Peris, 2018; Normand & Cavell, 2008 ). Herein we present the synthesis and crystal structure of the chloride salt of the potentially hemilabile amido-functionalized NHC ligand precursor, 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium.

2. Structural commentary

The title compound, consists of a chloride anion and an N-substituted imidazolium cation, combining the NHC precursor moiety with a amide (–NH–C(O)–CH₂–) moiety. The amide group is linked to one nitrogen of the imidazolium ring, N2, by a methylene group, and bears on its opposite side a indanyl substituent bound to the amide nitrogen atom N1. The other (non-amidic) substituent on the second nitrogen atom, N3, of the imidazolium ring is an extended n-butyl chain, whose mean plane (C15–C18) is inclined to the plane of the imidazolium ring (N2/N3/C12–C14) by 73.2 (6)°. The central –CH₂– C atom, C1, of the indanyl substituent is disordered over two positions with a refined occupancy ratio of C1:C1′ = 0.84 (2):0.16 (2). Atom C1 resides 0.393 (12) Å below the plane (on the opposite side of the imidazolium moiety) of the four planar C atoms of the pentene ring (C2–C5), while atom C1′ is 0.40 (4) Å above this plane (i.e. on the same side as the imidazolium moiety).

Crystallographic data of NHC precursor cations substituted by CH₂–C(O)–NH functional groups (amides) are relatively scarce. A search of the Cambridge Structural Database (CSD, version 3.59, August 2018; Groom et al., 2016 ) yielded only 16 hits. Compared to published values of imidazolium salts with amide substituents, the geometrical parameters of the title compound are decidedly unexceptional, falling within the reported ranges. Only the C—C bond between methylene atom C11 and the carbonyl carbon C10 is relatively short [C10—C11 = 1.506 (6) Å] and thereby close to the shortest such bond reported to date, i.e. 1.502 Å for a related compound with no substituent on the amide and a dodecyl chain on the other side of the imidazolium cation (Lee et al., 2003a ). In general, all bond lengths of the two moieties and the methylene linker are in rather close ranges with the largest differences observed being those which lead to further substituents. These are the N—C bond of the amide to its substituent on N ranging from ca 1.409 Å for a phenyl (Samantaray et al., 2007 ) to 1.482 Å for a t-butyl (Ray et al., 2007 ), and the N—C bond of the imidazolium ring to the second substituent ranging from ca 1.422 Å for a pyrimidyl (Lee et al., 2009 ) to 1.483 Å for a rather bulky 3,5-di-tert-butyl-2-hydroxybenzyl (Wan & Zhang, 2016 ). Given the variety of the substituents on both sides in published structures, this observation is not surprising as the potential extension of the π system beyond the imidazolium and amide moieties would be expected to have a considerable influence on these bond lengths. Strictly within the imidazolium and amide moieties, the strongest deviation is found for the amide C(O)—N bond [here C10—N1 = 1.339 (6) Å] ranging from ca 1.301 Å for an unsubstituted amide, i.e. –C(O)–NH₂, (Lee et al., 2003b ) to 1.355 Å for a phenyl-substituted amide (Lee & Zeng, 2012 ). A shorter C10—N1 bond is indicative of a strong tautomeric effect, i.e. C=O double-bond delocalization towards a C=N double bond. In the title compound, the nitrogen atom of the amide is bound to an indanyl group and the C10—N1 bond length of 1.339 (6) Å comprises a rather average value for a –C(O)–NH– bond. A value that often varies in such compounds is the angle at which the plane of the amide moiety [–CH₂–C(O)–NH, calculated without H-atom positions] is arranged with respect to the imidazolium ring plane (C₃N₂). Here the dihedral angles range from ca 42.64° (Lee et al., 2003b) to 85.95° (Lee et al., 2012 ). In the title compound, this dihedral angle is 71.9 (3)°. At this angle, resonance between the two moieties (amide and imidazolium) can clearly be excluded. In contrast, the angle between the amide moiety and the aromatic ring of the indanyl substituent is only 18.1 (2)°, suggesting together with the N1—C8 bond length of only 1.427 (6) Å, that the resonance of the aromatic ring extends to the amide moiety and/or vice versa. This relative orientation of the two aromatic systems is probably supported by a weak intramolecular C—H⋯O hydrogen bond, between the amide oxygen atom (O1) and the aromatic carbon atom C9 (Table 1 and Fig. 1).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C9—H9⋯O1	0.95	2.35	2.915 (6)	118
N1—H1⋯Cl1	0.87 (5)	2.32 (5)	3.177 (4)	167 (4)
C11—H11A⋯Cl1	0.99	2.75	3.541 (4)	137
C12—H12⋯Cl1ⁱ	0.95	2.73	3.530 (4)	143
C15—H15B⋯Cl1ⁱ	0.99	2.71	3.493 (5)	136
C11—H11B⋯Cl1ⁱⁱ	0.99	2.54	3.432 (5)	150
C13—H13⋯O1ⁱⁱⁱ	0.95	2.54	3.066 (5)	115
Symmetry codes: (i) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z]$ ; (ii) x, y+1, z; (iii) $[-x+{\script{1\over 2}}, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]$ .

Figure 1
Molecular structure of the title molecular salt, with the atom labelling and displacement ellipsoids drawn at the 50% probability level. In this and subsequent figures, only the major component of the disordered atom C1 is shown. The hydrogen bonds (Table 1

) are shown as blue dashed lines.

3. Supramolecular features

The comparably large unit cell of the crystal structure with Z = 8 is rather thin with a short b axis of 5.3986 (11) Å, and the eight imidazolium cations are arranged in a single layer within the cell. The chloride anions and imidazolium cations form symmetric pairs, two-by-two, supported by C—H⋯Cl hydrogen bonds involving hydrogen atoms of an n-butyl methylene C atom (C15—H15B), an imidazolium C atom (C12—H12), the amide N atom (N1—H1) and a C atom of the methylene linker (C11—H11A), and the chloride anion Cl1 (Table 1 and Fig. 2). In the crystal, these two-by-two units are linked by C11—H11B⋯Cl1ⁱⁱ hydrogen bonds, forming slab-like structures propagating along the b-axis direction (Table 1 and Fig. 3). Weak C13—H13⋯O1ⁱⁱⁱ interactions link the slabs to form layers lying parallel to the bc plane (Table 1 and Fig. 3)

Figure 2
A view of the two-by-two hydrogen-bonded unit (dashed lines; see Table 1

for details). Only the H atoms (grey balls) involved in the intra- and intermolecular interactions have been included. The unlabelled atoms are related to the labelled atoms by the symmetry operation −x + $[{1\over 2}]$ , −y + $[{3\over 2}]$ , −z.

Figure 3
Crystal packing of the title molecular salt, viewed along the b axis, showing the various hydrogen bonds as dashed lines (see Table 1

for details). Only the H atoms (grey balls) involved in these interactions have been included.

4. Synthesis and crystallization

The title compound, was synthesized by the simple reaction of n-butyl imidazole with 2-chloro-N-(indan-5-yl)acetamide in dry acetonitrile as solvent. All reagents and solvents required for the synthesis were purchased commercially and used without any further purification.

Synthesis of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium chloride: The synthesis of the imidazolium salt was carried out under a nitrogen atmosphere. An oven-dried Schlenk tube was charged with a stirring bar, 1.00 mmol of 2-chloro-N-(indan-5-yl)acetamide, 1.5 mmol of n-butyl imidazole, and 2 ml of dry acetonitrile. The reaction mixture was stirred for 12 h at 353 K. After the reaction mixture was allowed to cool to r.t., diethyl ether was added to the reaction mixture upon which the product precipitated leading already to sufficient separation. The precipitate was isolated by carefully decanting off the solvent, then washed with acetone (2 × 5ml) and hexane (2 × 5 ml), and dried under vacuum. The product was obtained as a colourless (white) solid; yield: 94%. Colourless prismatic crystals suitable for X-ray diffraction analysis were obtained by slow evaporation of a solution in ethanol.

¹H NMR (400 MHz, DMSO-d₆): δ 10.99 (s, 1H), 9.26 (s, 1H), 7.79 (d, J = 10.5 Hz, 2H), 7.50 (s, 1H), 7.34 (d, J = 9.1 Hz, 1H), 7.11 (d, J = 8.1 Hz, 1H), 5.24 (s, 2H), 4.20 (t, J = 7.1 Hz, 2H), 2.77 (q, J = 7.7 Hz, 4H), 1.95 (qui, J = 7.4 Hz, 2H), 1.79–1.70 (m, 2H), 1.28–1.18 (m, 2H), 0.87 (t, J = 7.4 Hz, 3H). ¹³C NMR (101 MHz, DMSO-d₆): δ 163.8, 144.6, 139.3, 137.8, 137.1, 124.7, 124.4, 122.1, 117.6, 115.7, 51.7, 49.0, 32.9, 32.1, 31.7, 25.5, 19.1, 13.7. Analysis calculated for C₁₇H₂₄ClN₃O: C, 64.76; H, 7.25; N, 12.59. Found: C, 64.59; H, 7.12; N, 12.68. IR: C=O Stretching 1700.23 cm⁻¹.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The N-bound hydrogen atom (H1) was located in a difference-Fourier map and freely refined. The C-bound H atoms were placed in calculated positions and treated as riding: C—H = 0.95-0.99 Å with U_iso(H) = 1.5U_eq(C-methyl) and 1.2U_eq(C) for other H atoms.

Table 2
Experimental details

Crystal data
Chemical formula	C₁₈H₂₄N₃O⁺·Cl⁻
M_r	333.85
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	170
a, b, c (Å)	36.270 (7), 5.3986 (11), 18.620 (4)
β (°)	103.34 (3)
V (Å³)	3547.6 (13)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	0.22
Crystal size (mm)	0.35 × 0.27 × 0.13

Data collection
Diffractometer	Stoe IPDS2T
Absorption correction	Numerical (X-RED32 and X-SHAPE; Stoe & Cie, 2010 )
T_min, T_max	0.561, 0.968
No. of measured, independent and observed [I > 2σ(I)] reflections	12392, 3134, 1953
R_int	0.119
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.066, 0.199, 1.05
No. of reflections	3134
No. of parameters	224
No. of restraints	36
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.44, −0.40
Computer programs: X-AREA (Stoe & Cie, 2010), X-RED32 (Stoe & Cie, 2010), SHELXT2018 (Sheldrick, 2015a ), XP (Sheldrick, 2008 ), Mercury (Macrae et al., 2008 ), SHELXL2018 (Sheldrick, 2015b ), WinGX (Farrugia, 2012 ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

The methylene carbon atom C1 of the indanyl substituent is disordered over two positions with a refined occupancy ratio of 0.84 (2):0.16 (2). This disorder was modelled with constraints (SADI for all C-C bonds involving C1, SIMU and DELU). The crystal studied was refined as a twin with matrix [1 0 0.9, 0 $[\overline{1}]$ 0, 0 0 $[\overline{1}]$ ]; the resulting BASF value is 0.30.

Supporting information

CCDC reference: 1832439

Crystal structure: contains datablocks I, Global. DOI: https://doi.org/10.1107/S2056989018014792/su5456sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018014792/su5456Isup2.hkl

checkCIF report

Computing details top

Data collection: X-AREA (Stoe & Cie, 2010); cell refinement: X-AREA (Stoe & Cie, 2010); data reduction: X-RED32 (Stoe & Cie, 2010); program(s) used to solve structure: SHELXT2018 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: XP (Sheldrick, 2008) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2018 (Sheldrick, 2015b), WinGX (Farrugia, 2012), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

1-Butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium chloride top

Crystal data top

C₁₈H₂₄N₃O⁺·Cl⁻	F(000) = 1424
M_r = 333.85	D_x = 1.250 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 36.270 (7) Å	Cell parameters from 19866 reflections
b = 5.3986 (11) Å	θ = 6.6–59.3°
c = 18.620 (4) Å	µ = 0.22 mm⁻¹
β = 103.34 (3)°	T = 170 K
V = 3547.6 (13) Å³	Prism, colourless
Z = 8	0.35 × 0.27 × 0.13 mm

Data collection top

Stoe IPDS2T diffractometer	3134 independent reflections
Radiation source: fine-focus sealed tube	1953 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	R_int = 0.119
ω scans	θ_max = 25.0°, θ_min = 3.5°
Absorption correction: numerical (X-Red32 and X-Shape; Stoe & Cie, 2010)	h = −37→42
T_min = 0.561, T_max = 0.968	k = −6→6
12392 measured reflections	l = −21→22

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.066	Hydrogen site location: mixed
wR(F²) = 0.199	H atoms treated by a mixture of independent and constrained refinement
S = 1.05	w = 1/[σ²(F_o²) + (0.1126P)² + 0.3489P] where P = (F_o² + 2F_c²)/3
3134 reflections	(Δ/σ)_max < 0.001
224 parameters	Δρ_max = 0.44 e Å⁻³
36 restraints	Δρ_min = −0.40 e Å⁻³

Special details top

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. Refined as a 2-component twin.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
N1	0.16282 (10)	0.4778 (7)	0.0721 (2)	0.0366 (9)
N2	0.25866 (10)	0.7006 (6)	0.13822 (19)	0.0336 (8)
N3	0.31102 (11)	0.8875 (6)	0.1857 (2)	0.0358 (8)
O1	0.18710 (10)	0.7509 (6)	0.16419 (18)	0.0477 (8)
C1	0.0069 (2)	0.6310 (17)	0.1297 (7)	0.065 (3)	0.84 (2)
H1A	−0.005777	0.746242	0.090345	0.078*	0.84 (2)
H1B	−0.008010	0.623539	0.167931	0.078*	0.84 (2)
C1'	0.0140 (11)	0.538 (7)	0.163 (2)	0.056 (9)	0.16 (2)
H1'1	0.019558	0.439312	0.209509	0.067*	0.16 (2)
H1'2	−0.009825	0.630514	0.160560	0.067*	0.16 (2)
C2	0.01033 (15)	0.3703 (9)	0.0973 (4)	0.0588 (15)
H2A	0.007424	0.238929	0.132728	0.071*
H2B	−0.008830	0.345562	0.050560	0.071*
C3	0.05004 (14)	0.3727 (9)	0.0845 (3)	0.0479 (12)
C4	0.07030 (15)	0.5732 (8)	0.1194 (3)	0.0464 (12)
C5	0.04634 (15)	0.7158 (10)	0.1626 (4)	0.0629 (16)
H5A	0.053825	0.675188	0.215787	0.075*
H5B	0.048800	0.896697	0.156268	0.075*
C6	0.06731 (15)	0.2103 (10)	0.0450 (3)	0.0539 (13)
H6	0.053560	0.074806	0.019341	0.065*
C7	0.10502 (14)	0.2478 (8)	0.0434 (3)	0.0489 (12)
H7	0.117384	0.133484	0.018010	0.059*
C8	0.12457 (12)	0.4493 (8)	0.0782 (2)	0.0361 (10)
C9	0.10734 (13)	0.6165 (8)	0.1167 (3)	0.0404 (10)
H9	0.120702	0.756550	0.140374	0.048*
C10	0.19013 (13)	0.6220 (7)	0.1116 (2)	0.0351 (10)
C11	0.22575 (12)	0.6170 (8)	0.0831 (2)	0.0366 (10)
H11A	0.230239	0.446019	0.067916	0.044*
H11B	0.222334	0.724566	0.038996	0.044*
C12	0.28154 (12)	0.8823 (7)	0.1286 (2)	0.0337 (10)
H12	0.277478	0.991130	0.087397	0.040*
C13	0.30716 (14)	0.7024 (8)	0.2339 (3)	0.0404 (11)
H13	0.324273	0.664753	0.279459	0.048*
C14	0.27447 (12)	0.5842 (7)	0.2044 (2)	0.0346 (10)
H14	0.264207	0.446855	0.225054	0.042*
C15	0.34367 (14)	1.0541 (8)	0.1924 (3)	0.0448 (11)
H15A	0.355727	1.079649	0.245245	0.054*
H15B	0.334866	1.217060	0.170671	0.054*
C16	0.37271 (15)	0.9480 (10)	0.1533 (4)	0.0598 (15)
H16A	0.359918	0.915740	0.101139	0.072*
H16B	0.392405	1.075129	0.153460	0.072*
C17	0.39176 (17)	0.7154 (11)	0.1855 (4)	0.0678 (17)
H17A	0.372720	0.581383	0.180888	0.081*
H17B	0.403047	0.741053	0.238706	0.081*
C18	0.42267 (19)	0.6376 (13)	0.1468 (5)	0.089 (2)
H18A	0.411994	0.626255	0.093572	0.133*
H18B	0.432805	0.475814	0.165602	0.133*
H18C	0.443086	0.760623	0.156499	0.133*
H1	0.1675 (12)	0.378 (8)	0.039 (3)	0.029 (11)*
Cl1	0.19326 (3)	0.10403 (18)	−0.03275 (7)	0.0429 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
N1	0.036 (2)	0.037 (2)	0.038 (2)	0.0015 (16)	0.0122 (17)	−0.0060 (18)
N2	0.042 (2)	0.0261 (17)	0.035 (2)	0.0016 (15)	0.0149 (17)	−0.0008 (15)
N3	0.044 (2)	0.0271 (17)	0.040 (2)	−0.0053 (16)	0.0163 (17)	−0.0018 (15)
O1	0.052 (2)	0.0487 (18)	0.047 (2)	−0.0017 (15)	0.0207 (16)	−0.0168 (16)
C1	0.052 (4)	0.058 (5)	0.091 (7)	0.015 (3)	0.027 (4)	−0.003 (5)
C1'	0.043 (15)	0.046 (17)	0.091 (19)	0.016 (14)	0.042 (14)	0.001 (15)
C2	0.049 (3)	0.054 (3)	0.079 (4)	0.001 (2)	0.026 (3)	0.003 (3)
C3	0.044 (3)	0.046 (3)	0.056 (3)	0.002 (2)	0.016 (2)	0.003 (2)
C4	0.055 (3)	0.041 (2)	0.046 (3)	0.009 (2)	0.018 (2)	0.002 (2)
C5	0.055 (3)	0.053 (3)	0.091 (4)	0.010 (3)	0.037 (3)	−0.002 (3)
C6	0.047 (3)	0.048 (3)	0.069 (4)	−0.004 (2)	0.017 (3)	−0.009 (3)
C7	0.051 (3)	0.040 (3)	0.057 (3)	0.000 (2)	0.015 (3)	−0.010 (2)
C8	0.040 (2)	0.036 (2)	0.033 (2)	0.0031 (18)	0.0089 (19)	0.0037 (18)
C9	0.044 (3)	0.037 (2)	0.042 (3)	0.004 (2)	0.014 (2)	−0.001 (2)
C10	0.044 (3)	0.028 (2)	0.036 (2)	0.0026 (19)	0.015 (2)	−0.0012 (19)
C11	0.042 (2)	0.032 (2)	0.036 (2)	−0.0015 (19)	0.0079 (19)	−0.0058 (19)
C12	0.045 (3)	0.0210 (19)	0.037 (2)	−0.0004 (18)	0.012 (2)	−0.0011 (17)
C13	0.054 (3)	0.031 (2)	0.040 (3)	0.003 (2)	0.018 (2)	0.0033 (19)
C14	0.043 (2)	0.031 (2)	0.031 (2)	0.0051 (19)	0.0115 (19)	0.0088 (18)
C15	0.050 (3)	0.033 (2)	0.053 (3)	−0.008 (2)	0.014 (2)	−0.003 (2)
C16	0.052 (3)	0.051 (3)	0.079 (4)	−0.014 (2)	0.019 (3)	−0.003 (3)
C17	0.060 (4)	0.051 (3)	0.097 (5)	−0.005 (3)	0.027 (3)	−0.014 (3)
C18	0.071 (4)	0.074 (4)	0.136 (7)	−0.005 (3)	0.055 (5)	−0.026 (4)
Cl1	0.0575 (7)	0.0305 (5)	0.0449 (7)	0.0024 (5)	0.0200 (5)	−0.0028 (5)

Geometric parameters (Å, º) top

N1—C10	1.339 (6)	C2—C3	1.514 (7)
N1—C8	1.427 (6)	C3—C4	1.383 (7)
N2—C12	1.324 (5)	C3—C6	1.384 (7)
N2—C14	1.384 (5)	C4—C9	1.376 (7)
N2—C11	1.455 (6)	C4—C5	1.522 (7)
N3—C12	1.323 (6)	C6—C7	1.390 (7)
N3—C13	1.372 (5)	C7—C8	1.376 (6)
N3—C15	1.469 (6)	C8—C9	1.388 (6)
O1—C10	1.227 (5)	C10—C11	1.506 (6)
C1—C5	1.491 (8)	C13—C14	1.347 (7)
C1—C2	1.547 (8)	C15—C16	1.524 (7)
C1'—C2	1.508 (16)	C16—C17	1.491 (8)
C1'—C5	1.518 (16)	C17—C18	1.525 (8)

C10—N1—C8	129.0 (4)	C1'—C5—C4	102.8 (11)
C12—N2—C14	108.3 (4)	C3—C6—C7	119.2 (5)
C12—N2—C11	124.9 (4)	C8—C7—C6	120.5 (4)
C14—N2—C11	126.2 (3)	C7—C8—C9	120.9 (4)
C12—N3—C13	109.0 (4)	C7—C8—N1	116.9 (4)
C12—N3—C15	124.5 (4)	C9—C8—N1	122.2 (4)
C13—N3—C15	126.3 (4)	C4—C9—C8	117.9 (4)
C5—C1—C2	106.5 (5)	O1—C10—N1	125.3 (4)
C2—C1'—C5	107.1 (13)	O1—C10—C11	122.2 (4)
C1'—C2—C3	102.4 (11)	N1—C10—C11	112.5 (4)
C3—C2—C1	102.6 (5)	N2—C11—C10	112.1 (4)
C4—C3—C6	119.3 (5)	N3—C12—N2	108.8 (4)
C4—C3—C2	110.8 (4)	C14—C13—N3	106.9 (4)
C6—C3—C2	130.0 (5)	C13—C14—N2	107.1 (4)
C9—C4—C3	122.2 (4)	N3—C15—C16	111.2 (4)
C9—C4—C5	128.0 (5)	C17—C16—C15	115.5 (5)
C3—C4—C5	109.7 (4)	C16—C17—C18	111.4 (6)
C1—C5—C4	103.8 (5)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C9—H9···O1	0.95	2.35	2.915 (6)	118
N1—H1···Cl1	0.87 (5)	2.32 (5)	3.177 (4)	167 (4)
C11—H11A···Cl1	0.99	2.75	3.541 (4)	137
C12—H12···Cl1ⁱ	0.95	2.73	3.530 (4)	143
C15—H15B···Cl1ⁱ	0.99	2.71	3.493 (5)	136
C11—H11B···Cl1ⁱⁱ	0.99	2.54	3.432 (5)	150
C13—H13···O1ⁱⁱⁱ	0.95	2.54	3.066 (5)	115

Symmetry codes: (i) −x+1/2, −y+3/2, −z; (ii) x, y+1, z; (iii) −x+1/2, y−1/2, −z+1/2.

Acknowledgements

ARK and CS acknowledge `The Alexander von Humboldt Foundation' for the research cooperation programme, which is also thanked for an equipment grant to ARK. Funding from the ERC for the project MocoModels is gratefully acknowledged by CS.

Funding information

Funding for this research was provided by: Alexander von Humboldt-Stiftung (grant No. 3.4-IP-DEU/1131213 to A. R. Kapdi, C. Schulzke); FP7 Ideas: European Research Council (grant No. 281257 to C. Schulzke).

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