Norbornane-exo-cis-2,3-diyl 1′,2′-phenyl­ene orthocarbonate

Betz, R.; Klüfers, P.

doi:10.1107/S1600536807063660

organic compounds

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Volume 64| Part 2| February 2008| Page o399

doi:10.1107/S1600536807063660

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Norbornane-exo-cis-2,3-diyl 1′,2′-phenylene orthocarbonate

Richard Betz ^a and Peter Klüfers ^a ^*

^aLudwig-Maximilians-Universität, Department Chemie und Biochemie, Butenandtstrasse 5–13, 81377 München, Germany
^*Correspondence e-mail: kluef@cup.uni-muenchen.de

(Received 3 October 2007; accepted 27 November 2007; online 9 January 2008)

The title compound (systematic name: 4,7-methano-2,2′-spirobi[1,3-benzodioxole]), C₁₄H₁₄O₄, is an asymmetric spiro ester of orthocarbonic acid and two diols, viz. the aromatic benzene-1,2-diol and the aliphatic vicinal norbornane-exo-cis-2,3-diol. The orthocarbonate molecule is close to having non-crystallographic C_s symmetry. The five-membered ring stemming from the aliphatic diol has an envelope conformation. C—O bonds including the spiro-C atom span an approximately 0.07 Å range, but are within 0.02 Å of the respective distances in a density functional theory calculation, i.e. the distance difference is not caused by packing forces. Accordingly, the crystal packing is characterized by weak C—H⋯O and C—H⋯π interactions.

Related literature

For the synthesis of the title compound, see: Komatsu et al. (1992 ). For related compounds, see: Betz & Klüfers (2007a ,b ,c ); Betz et al. (2007 ). Density functional theory calculations were performed by Betz & Klüfers (2008 ).

Experimental

Crystal data

C₁₄H₁₄O₄
M_r = 246.25
Monoclinic, P 2₁ /n
a = 7.9125 (3) Å
b = 9.5545 (5) Å
c = 15.2813 (6) Å
β = 101.490 (3)°
V = 1132.11 (9) Å³
Z = 4
Mo Kα radiation
μ = 0.11 mm⁻¹
T = 200 (2) K
0.30 × 0.25 × 0.16 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: none
8399 measured reflections
2582 independent reflections
1716 reflections with I > 2σ(I)
R_int = 0.054

Refinement

R[F² > 2σ(F²)] = 0.044
wR(F²) = 0.119
S = 1.05
2582 reflections
164 parameters
Only H-atom displacement parameters refined
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.19 e Å⁻³

Table 1
Selected bond lengths (Å)

O1—C1	1.367 (2)
O2—C1	1.370 (2)
O3—C1	1.412 (2)
O4—C1	1.435 (2)

Table 2
Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C9–C14 phenylene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3⋯O4ⁱ	1.00	2.71	3.623 (2)	151
C7—H7A⋯O4ⁱ	0.99	2.76	3.663 (2)	151
C14—H14⋯O2ⁱⁱ	0.95	2.61	3.501 (2)	156
C14—H14⋯O4ⁱⁱ	0.95	2.88	3.514 (2)	125
C2—H2⋯Cgⁱⁱⁱ	1.00	2.86	3.563 (2)	128
C5—H5⋯Cg^iv	1.00	2.66	3.568 (2)	152
Symmetry codes: (i) -x+1, -y, -z+1; (ii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[x-{\script{1\over 2}}, -y-{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (iv) x+1, y, z.

Data collection: COLLECT (Nonius, 2004 ); cell refinement: SCALEPACK (Otwinowski & Minor 1997 ); data reduction: DENZO (Otwinowski & Minor 1997) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997 ); software used to prepare material for publication: PLATON (Spek, 2003 ; 2006 version).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536807063660/lx2027sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536807063660/lx2027Isup2.hkl

checkCIF report

Comment top

The title compound was prepared in order to compare its NMR-spectroscopic data with those of related silicon compounds.

In the molecule, a central carbon atom is chelated by a phenylene-1,2-dioxy and a norbornylene-exo-cis-2,3-dioxy moiety. The C—O bond lengths differ markedly (1.37 to 1.44 Å). About the same bond-length values were computed for the isolated molecule on the B3LYP/6–31+G(d,p) level of theory thus ruling out packing forces as the origin of the bond-length differences. The five-membered chelate ring stemming from the aliphatic diol adopts an envelope conformation on the spiro center C1 (puckering parameters: Q₂ = 0.1274 (16) Å, ϕ₂ = 42.6 (7)° for the O1—C1—O2—C4—C3 ring).

Accordingly, the crystal packing is characterized by weak C—H···X interactions whose H···X distances are close to the sum of the van-der-Waals radii (vdWr). In terms of the vdWr criterion, the shortest tabulated hydrogen-bond, the C14—H14···O2 interaction, is 0.11 \&A shorter than the radii sum. The weak interactions in (I) are thus less significant than those in the related 1-(ylomethyl)cyclopentyl 1',2'-phenylene orthocarbonate, where C—H···O bonds are observed at the radii sum minus 0.35 Å (Betz & Klüfers, 2007c). Fig. 2 shows this interaction as well as the shortest C—H···π bond which has one of the norbornane-bridgehead C—H functions as the donor. The other bridgehead methylidyne function acts as a donor in a still weaker bond. Moreover, another weak C—H···O bond may be recognized with a diol-CH function as the donor (see the hydrogen bond table).

Related literature top

For the synthesis of the title compound, see: Komatsu et al. (1992). For related compounds, see: Betz & Klüfers (2007a,b,c); Betz et al. (2007). For density functional theory calculations, see: [Please provide reference]

Experimental top

The title compound was prepared based on a published procedure (Komatsu et al., 1992) upon reaction of norbornane-exo-cis-2,3-diol with 2,2-dichlorobenzo[1.3]dioxol in dichloromethane in the presence of pyridine. Crystals suitable for X-ray analysis were obtained after recrystallization from boiling ethyl acetate.

Computing details top

Data collection: COLLECT (Nonius, 2004); cell refinement: SCALEPACK (Otwinowski & Minor 1997); data reduction: DENZO (Otwinowski & Minor 1997) and SCALEPACK (Otwinowski & Minor 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 2003; 2006 version).

Figures top

	Fig. 1. The molecular structure of the title compound, showing displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. The crystal packing viewed along [0 1 0]. Green arrows: the strongest C—H···O interaction in terms of the H···O distance (C14—H14···O2). Green dotted lines: the strongest C—H···π interaction (C5—H5—Cg, Cg is the centroid of the phenylene residue).

4,7-methano-2,2'-spirobi[1,3-benzodioxole] top

Crystal data top

C₁₄H₁₄O₄	F(000) = 520
M_r = 246.25	D_x = 1.445 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 14429 reflections
a = 7.9125 (3) Å	θ = 2.7–27.5°
b = 9.5545 (5) Å	µ = 0.11 mm⁻¹
c = 15.2813 (6) Å	T = 200 K
β = 101.490 (3)°	Block, colourless
V = 1132.11 (9) Å³	0.30 × 0.25 × 0.16 mm
Z = 4

Data collection top

Nonius KappaCCD diffractometer	1716 reflections with I > 2σ(I)
Radiation source: rotating anode	R_int = 0.054
MONTEL, graded multilayered X-ray optics monochromator	θ_max = 27.5°, θ_min = 3.2°
CCD; rotation images; thick slices scans	h = −9→10
8399 measured reflections	k = −12→11
2582 independent reflections	l = −19→19

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)] = 0.044	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.119	Only H-atom displacement parameters refined
S = 1.05	w = 1/[σ²(F_o²) + (0.0569P)² + 0.1349P] where P = (F_o² + 2F_c²)/3
2582 reflections	(Δ/σ)_max = 0.001
164 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.19 e Å⁻³

Crystal data top

C₁₄H₁₄O₄	V = 1132.11 (9) Å³
M_r = 246.25	Z = 4
Monoclinic, P2₁/n	Mo Kα radiation
a = 7.9125 (3) Å	µ = 0.11 mm⁻¹
b = 9.5545 (5) Å	T = 200 K
c = 15.2813 (6) Å	0.30 × 0.25 × 0.16 mm
β = 101.490 (3)°

Data collection top

Nonius KappaCCD diffractometer	1716 reflections with I > 2σ(I)
8399 measured reflections	R_int = 0.054
2582 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.044	0 restraints
wR(F²) = 0.119	Only H-atom displacement parameters refined
S = 1.05	Δρ_max = 0.21 e Å⁻³
2582 reflections	Δρ_min = −0.19 e Å⁻³
164 parameters

Special details top

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

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq
O1	0.39573 (14)	0.24072 (14)	0.47478 (7)	0.0460 (3)
O2	0.51722 (14)	0.20489 (14)	0.35623 (7)	0.0463 (3)
O3	0.27667 (13)	0.34038 (12)	0.34119 (7)	0.0408 (3)
O4	0.25466 (14)	0.10405 (11)	0.35921 (8)	0.0441 (3)
C1	0.3646 (2)	0.22289 (18)	0.38424 (11)	0.0384 (4)
C2	0.67414 (19)	0.32183 (17)	0.56079 (10)	0.0333 (4)
H2	0.6161	0.3766	0.6022	0.0490 (13)*
C3	0.56971 (19)	0.20081 (17)	0.51341 (10)	0.0342 (4)
H3	0.5742	0.1165	0.5526	0.0490 (13)*
C4	0.65286 (19)	0.17354 (18)	0.43193 (10)	0.0368 (4)
H4	0.6964	0.0755	0.4305	0.0490 (13)*
C5	0.7973 (2)	0.28116 (18)	0.44257 (11)	0.0378 (4)
H5	0.8407	0.3025	0.3869	0.0490 (13)*
C6	0.9350 (2)	0.2320 (2)	0.52188 (12)	0.0458 (5)
H6A	1.0433	0.2857	0.5259	0.0490 (13)*
H6B	0.9600	0.1310	0.5171	0.0490 (13)*
C7	0.8509 (2)	0.26146 (19)	0.60315 (11)	0.0439 (4)
H7A	0.8387	0.1743	0.6364	0.0490 (13)*
H7B	0.9196	0.3298	0.6443	0.0490 (13)*
C8	0.7165 (2)	0.40464 (17)	0.48246 (10)	0.0384 (4)
H8A	0.6123	0.4412	0.4420	0.0490 (13)*
H8B	0.7995	0.4814	0.5018	0.0490 (13)*
C9	0.12113 (18)	0.29423 (16)	0.29208 (9)	0.0307 (4)
C10	0.10837 (18)	0.15188 (16)	0.30274 (9)	0.0307 (4)
C11	−0.03269 (19)	0.07732 (17)	0.26098 (10)	0.0365 (4)
H11	−0.0406	−0.0211	0.2681	0.0490 (13)*
C12	−0.16353 (19)	0.15365 (18)	0.20764 (10)	0.0367 (4)
H12	−0.2643	0.1064	0.1778	0.0490 (13)*
C13	−0.1506 (2)	0.29664 (18)	0.19700 (10)	0.0375 (4)
H13	−0.2426	0.3454	0.1600	0.0490 (13)*
C14	−0.0054 (2)	0.37112 (17)	0.23937 (10)	0.0350 (4)
H14	0.0049	0.4693	0.2320	0.0490 (13)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0254 (6)	0.0743 (9)	0.0367 (7)	0.0025 (5)	0.0027 (5)	−0.0082 (6)
O2	0.0296 (6)	0.0719 (9)	0.0354 (6)	0.0024 (6)	0.0016 (5)	−0.0142 (6)
O3	0.0331 (6)	0.0367 (7)	0.0486 (7)	−0.0050 (5)	−0.0018 (5)	−0.0036 (5)
O4	0.0333 (6)	0.0351 (7)	0.0556 (7)	0.0031 (5)	−0.0107 (5)	0.0028 (5)
C1	0.0293 (9)	0.0449 (10)	0.0388 (9)	0.0000 (7)	0.0014 (7)	−0.0057 (7)
C2	0.0337 (8)	0.0357 (9)	0.0301 (8)	0.0013 (7)	0.0053 (6)	−0.0024 (6)
C3	0.0283 (8)	0.0362 (9)	0.0369 (8)	−0.0013 (6)	0.0034 (6)	0.0023 (7)
C4	0.0305 (8)	0.0389 (9)	0.0389 (9)	0.0032 (7)	0.0016 (6)	−0.0092 (7)
C5	0.0297 (8)	0.0489 (10)	0.0358 (9)	−0.0022 (7)	0.0089 (6)	−0.0042 (7)
C6	0.0283 (9)	0.0509 (11)	0.0552 (11)	0.0031 (7)	0.0015 (7)	−0.0084 (8)
C7	0.0365 (9)	0.0506 (11)	0.0401 (10)	−0.0041 (8)	−0.0031 (7)	0.0004 (8)
C8	0.0419 (9)	0.0320 (9)	0.0419 (9)	−0.0018 (7)	0.0096 (7)	0.0023 (7)
C9	0.0267 (8)	0.0362 (9)	0.0293 (8)	−0.0017 (6)	0.0059 (6)	−0.0036 (6)
C10	0.0261 (8)	0.0336 (9)	0.0315 (8)	0.0037 (6)	0.0033 (6)	0.0010 (6)
C11	0.0320 (8)	0.0335 (9)	0.0432 (9)	−0.0027 (7)	0.0057 (6)	−0.0007 (7)
C12	0.0261 (8)	0.0478 (11)	0.0351 (8)	−0.0012 (7)	0.0030 (6)	−0.0050 (7)
C13	0.0318 (8)	0.0468 (11)	0.0326 (8)	0.0083 (7)	0.0035 (6)	0.0031 (7)
C14	0.0388 (9)	0.0328 (9)	0.0346 (8)	0.0043 (7)	0.0102 (7)	0.0046 (7)

Geometric parameters (Å, º) top

O1—C1	1.367 (2)	C5—H5	1.0000
O1—C3	1.438 (2)	C6—C7	1.547 (3)
O2—C1	1.370 (2)	C6—H6A	0.9900
O2—C4	1.444 (2)	C6—H6B	0.9900
O3—C9	1.380 (2)	C7—H7A	0.9900
O3—C1	1.412 (2)	C7—H7B	0.9900
O4—C10	1.377 (2)	C8—H8A	0.9900
O4—C1	1.435 (2)	C8—H8B	0.9900
C2—C3	1.518 (2)	C9—C14	1.367 (2)
C2—C8	1.527 (2)	C9—C10	1.376 (2)
C2—C7	1.532 (2)	C10—C11	1.370 (2)
C2—H2	1.0000	C11—C12	1.390 (2)
C3—C4	1.542 (2)	C11—H11	0.9500
C3—H3	1.0000	C12—C13	1.382 (2)
C4—C5	1.522 (2)	C12—H12	0.9500
C4—H4	1.0000	C13—C14	1.396 (2)
C5—C8	1.526 (2)	C13—H13	0.9500
C5—C6	1.533 (2)	C14—H14	0.9500

C1—O1—C3	110.32 (12)	C5—C6—H6A	111.1
C1—O2—C4	109.66 (12)	C7—C6—H6A	111.1
C9—O3—C1	107.62 (12)	C5—C6—H6B	111.1
C10—O4—C1	107.09 (12)	C7—C6—H6B	111.1
O1—C1—O2	109.88 (12)	H6A—C6—H6B	109.1
O1—C1—O3	110.18 (13)	C2—C7—C6	103.41 (13)
O2—C1—O3	109.73 (14)	C2—C7—H7A	111.1
O1—C1—O4	110.22 (14)	C6—C7—H7A	111.1
O2—C1—O4	110.04 (13)	C2—C7—H7B	111.1
O3—C1—O4	106.75 (11)	C6—C7—H7B	111.1
C3—C2—C8	101.79 (12)	H7A—C7—H7B	109.0
C3—C2—C7	106.20 (13)	C5—C8—C2	95.02 (13)
C8—C2—C7	101.65 (13)	C5—C8—H8A	112.7
C3—C2—H2	115.2	C2—C8—H8A	112.7
C8—C2—H2	115.2	C5—C8—H8B	112.7
C7—C2—H2	115.2	C2—C8—H8B	112.7
O1—C3—C2	112.31 (13)	H8A—C8—H8B	110.2
O1—C3—C4	103.94 (12)	C14—C9—C10	122.58 (14)
C2—C3—C4	103.56 (12)	C14—C9—O3	128.15 (15)
O1—C3—H3	112.1	C10—C9—O3	109.27 (13)
C2—C3—H3	112.1	C11—C10—C9	122.08 (14)
C4—C3—H3	112.1	C11—C10—O4	128.66 (14)
O2—C4—C5	111.59 (13)	C9—C10—O4	109.27 (12)
O2—C4—C3	104.08 (12)	C10—C11—C12	116.29 (15)
C5—C4—C3	103.40 (12)	C10—C11—H11	121.9
O2—C4—H4	112.4	C12—C11—H11	121.9
C5—C4—H4	112.4	C13—C12—C11	121.58 (14)
C3—C4—H4	112.4	C13—C12—H12	119.2
C4—C5—C8	101.52 (13)	C11—C12—H12	119.2
C4—C5—C6	106.13 (14)	C12—C13—C14	121.51 (14)
C8—C5—C6	102.10 (13)	C12—C13—H13	119.2
C4—C5—H5	115.1	C14—C13—H13	119.2
C8—C5—H5	115.1	C9—C14—C13	115.96 (15)
C6—C5—H5	115.1	C9—C14—H14	122.0
C5—C6—C7	103.11 (13)	C13—C14—H14	122.0

C3—O1—C1—O2	−14.26 (19)	O2—C4—C5—C6	−177.46 (13)
C3—O1—C1—O3	−135.27 (13)	C3—C4—C5—C6	71.25 (15)
C3—O1—C1—O4	107.18 (14)	C4—C5—C6—C7	−72.05 (16)
C4—O2—C1—O1	15.22 (19)	C8—C5—C6—C7	33.89 (17)
C4—O2—C1—O3	136.51 (13)	C3—C2—C7—C6	70.90 (16)
C4—O2—C1—O4	−106.32 (14)	C8—C2—C7—C6	−35.19 (16)
C9—O3—C1—O1	−119.98 (13)	C5—C6—C7—C2	0.83 (17)
C9—O3—C1—O2	118.91 (13)	C4—C5—C8—C2	54.90 (14)
C9—O3—C1—O4	−0.31 (16)	C6—C5—C8—C2	−54.59 (14)
C10—O4—C1—O1	120.17 (13)	C3—C2—C8—C5	−54.54 (14)
C10—O4—C1—O2	−118.49 (14)	C7—C2—C8—C5	54.98 (14)
C10—O4—C1—O3	0.52 (17)	C1—O3—C9—C14	−179.57 (15)
C1—O1—C3—C2	118.72 (15)	C1—O3—C9—C10	−0.02 (16)
C1—O1—C3—C4	7.43 (17)	C14—C9—C10—C11	0.0 (2)
C8—C2—C3—O1	−77.54 (15)	O3—C9—C10—C11	−179.53 (14)
C7—C2—C3—O1	176.46 (13)	C14—C9—C10—O4	179.94 (14)
C8—C2—C3—C4	33.98 (15)	O3—C9—C10—O4	0.36 (17)
C7—C2—C3—C4	−72.02 (14)	C1—O4—C10—C11	179.34 (16)
C1—O2—C4—C5	−120.76 (14)	C1—O4—C10—C9	−0.54 (17)
C1—O2—C4—C3	−9.90 (17)	C9—C10—C11—C12	−0.6 (2)
O1—C3—C4—O2	1.48 (16)	O4—C10—C11—C12	179.57 (14)
C2—C3—C4—O2	−116.04 (13)	C10—C11—C12—C13	0.5 (2)
O1—C3—C4—C5	118.21 (13)	C11—C12—C13—C14	0.0 (2)
C2—C3—C4—C5	0.68 (15)	C10—C9—C14—C13	0.5 (2)
O2—C4—C5—C8	76.19 (15)	O3—C9—C14—C13	179.99 (14)
C3—C4—C5—C8	−35.11 (15)	C12—C13—C14—C9	−0.5 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O4ⁱ	1.00	2.71	3.623 (2)	151
C7—H7A···O4ⁱ	0.99	2.76	3.663 (2)	151
C14—H14···O2ⁱⁱ	0.95	2.61	3.501 (2)	156
C14—H14···O4ⁱⁱ	0.95	2.88	3.514 (2)	125
C2—H2···Cgⁱⁱⁱ	1.00	2.86	3.563 (2)	128
C5—H5···Cg^iv	1.00	2.66	3.568 (2)	152

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

Experimental details

Crystal data
Chemical formula	C₁₄H₁₄O₄
M_r	246.25
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	200
a, b, c (Å)	7.9125 (3), 9.5545 (5), 15.2813 (6)
β (°)	101.490 (3)
V (Å³)	1132.11 (9)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.11
Crystal size (mm)	0.30 × 0.25 × 0.16

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	–
No. of measured, independent and observed [I > 2σ(I)] reflections	8399, 2582, 1716
R_int	0.054
(sin θ/λ)_max (Å⁻¹)	0.649

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.044, 0.119, 1.05
No. of reflections	2582
No. of parameters	164
H-atom treatment	Only H-atom displacement parameters refined
Δρ_max, Δρ_min (e Å⁻³)	0.21, −0.19

Computer programs: COLLECT (Nonius, 2004), SCALEPACK (Otwinowski & Minor 1997), DENZO (Otwinowski & Minor 1997) and SCALEPACK (Otwinowski & Minor 1997), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 (Farrugia, 1997), PLATON (Spek, 2003; 2006 version).

Selected bond lengths (Å) top

O1—C1	1.367 (2)	O3—C1	1.412 (2)
O2—C1	1.370 (2)	O4—C1	1.435 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3···O4ⁱ	1.00	2.71	3.623 (2)	151
C7—H7A···O4ⁱ	0.99	2.76	3.663 (2)	151
C14—H14···O2ⁱⁱ	0.95	2.61	3.501 (2)	156
C14—H14···O4ⁱⁱ	0.95	2.88	3.514 (2)	125
C2—H2···Cgⁱⁱⁱ	1.00	2.86	3.563 (2)	128
C5—H5···Cg^iv	1.00	2.66	3.568 (2)	152

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

Acknowledgements

The authors thank Moritz Reichvilser for professional support.

References

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