7-Chloro-3-(4-methyl­benzene­sulfon­yl)pyrrolo[1,2-c]pyrimidine

Narayan, E.; Fu, L.; Gribble, G.W.; Kaur, M.; Jasinski, J.P.

doi:10.1107/S241431462000382X

organic compounds

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ISSN: 2414-3146

Volume 5| Part 3| March 2020| x200382

https://doi.org/10.1107/S241431462000382X

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7-Chloro-3-(4-methylbenzenesulfonyl)pyrrolo[1,2-c]pyrimidine

Easha Narayan,^a Liangfeng Fu,^a Gordon W. Gribble,^a ^* Manpreet Kaur ^b and Jerry P. Jasinski ^b ^*

^aDepartment of Chemistry, Dartmouth College, Hanover, NH 03755 , USA, and ^bDepartment of Chemistry, Keene State College, 229 Main Street, Keene, NH 03435 , USA
^*Correspondence e-mail: Gordon.W.Gribble@dartmouth.edu, jjasinski@keene.edu

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 4 March 2020; accepted 15 March 2020; online 27 March 2020)

In the title compound, C₁₄H₁₁ClN₂O₂S, the dihedral angle between the pyrrolo[1,2-c]pyrimidine ring system (r.m.s. deviation = 0.008 Å) and the benzene ring is 80.2 (9)°. In the crystal, inversion dimers linked by pairs of C—H⋯O interactions generate R²₂(16) loops. Several aromatic π–π stacking interactions between the pyrrolo[1,2-c]pyrimidine rings, as well as separately between the pyrrolo and pyrimidine groups [shortest centroid–centroid separation = 3.5758 (14) Å], help to consolidate the packing.

Keywords: crystal structure; weak intermolecular interactions; pyrrolo[1,2-c]pyrimidine and pyrimidine rings; π–π stacking.

CCDC reference: 1990547

Structure description

Pyrrolo[1,2-c]pyrimidines are a class of fused heterocycles of interest for their biological activity, electrochemical properties, and as components of natural products (Tatu et al., 2018 ). As part of our studies in this area, we now report the crystal structure of the title compound, C₁₄H₁₁N₂O₂SCl (Fig. 1). We believe that this is the first crystal structure to be reported of a pyrrolo[1,2-c]pyrimidine and one of the few unsymmetrical `diaryl sulfones' to be described.

Figure 1
The molecular structure of the title compound, showing 50% probability ellipsoids.

The dihedral angle between the C1–C7/N1/N2 pyrrolo[1,2-c]pyrimidine ring system (r.m.s. deviation = 0.008 Å) and the C8–C13 benzene ring is 80.2 (9)°. The rings adopt a typical diaryl sulfone `open-book' conformation with respect to the sulfonyl group (Koch & Moffitt, 1951 ; Sime & Woodhouse, 1974 ; Bocelli & Rizzoli, 1990 ; Colquhoun, 1997 ; Colquhoun et al., 2002 ; Rudolph et al., 2010 ; Benhalima et al., 2012 ). Notably, the torsion angles differ from the ideal 90°. Thus, the torsion angles in the title compound reveal that the p–d π overlap in the benzene ring between C8 and S1 [torsion angle C1—S1—C8—C9 = 105.19 (19)°], is favored over the p–d π overlap in the pyrrolo[1,2-c]pyrimidine ring between C1 and S1 [C8—S1—C1—C2 = 110.70 (18)°], probably because the benzene ring is electron-rich relative to the pyrrolo[1,2-c]pyrimidine ring. Consistent with this notion is the observation that the S1—C8 bond length [1.767 (2) Å] is slightly shorter than S1—C1 [1.773 (2) Å]. The O1—S1—O2 bond angle of 119.68 (11)° agrees with the literature values for diaryl sulfones (Sime & Woodhouse, 1974; Colquhoun, 1997; Colquhoun et al., 2002; Rudolph et al., 2010; Benhalima et al., 2012). Likewise, the C1—S1—C8 bond angle of 105.03 (10)° is consistent with the literature data (Sime & Woodhouse, 1974; Bocelli & Rizzoli, 1990; Colquhoun et al., 2002).

In the crystal, a weak C14—H14B⋯O2 hydrogen bond (Table 1) links two molecules together in a ring face–ring face arrangement (Fig. 2). This packing motif was also observed by Sime & Woodhouse (1974) in the crystal structure of diphenyl sulfone and by Colquhoun et al. (2002) in the crystal structure of poly(1,4-phenylenesulfone). Several aromatic π–π stacking interactions between the pyrrolo[1,2-c]pyrimidine rings as well as separately between the pyrrolo and pyrimidine groups (Table 2) are observed and help to consolidate the packing.

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C14—H14B⋯O2ⁱ	0.96	2.49	3.329 (3)	146
Symmetry code: (i) -x+1, -y+1, -z+2.

Table 2
π–π distances (Å) and angles (°) for the title compound

Cg(I)—Cg(J) is the distance between ring centroids, α is dihedral angle between planes Cg(I) and Cg(J) and slippage is the distance between Cg(I) and perpendicular the projection of Cg(J) on ring I. Cg(1), Cg(2) and Cg(4) are the centroids N2/C3–C6, N1/C1/C2/C3/N2/C7 and C1–C7/N1/N2 rings, respectively.

Cg(I)^a	Cg(J)^b	d[Cg(I)⋯Cg(J)]	α	slippage
Cg(1)	Cg(1)ⁱ	3.5758 (14)	0.00 (13)	1.169
Cg(1)	Cg(2)ⁱ	3.6261 (14)	0.73 (12)	1.348
Cg(1)	Cg(2)ⁱⁱ	3.6495 (14)	0.73 (12)	1.092
Cg(1)	Cg(4)ⁱ	3.4423 (13)	0.42 (11)	0.699
Cg(1)	Cg(4)ⁱⁱ	3.8876 (13)	0.42 (11)	1.738
Cg(2)	Cg(2)ⁱⁱ	3.9724 (13)	0.00 (10)	1.932
Cg(2)	Cg(4)ⁱⁱ	3.6901 (12)	0.32 (9)	1.233
Cg(4)	Cg(4)ⁱ	3.7241 (11)	0.00 (7)	1.586
Cg(4)	Cg(4)ⁱⁱ	3.6280 (11)	0.00 (7)	1.010
Symmetry codes: (i) 1 − x, −y, 1 − z; (ii) −x, 1 − y, 1 − z.

Figure 2
Packing diagram of the title compound viewed along the a axis direction showing inversion dimers linked by pairs of weak C—H⋯O interactions.

Synthesis and crystallization

A stirred solution of 5-chloropyrrole-2-carbaldehyde (Leen et al., 2011 ) (0.023 g, 0.18 mmol) in dioxane (10 ml) was cooled in an ice bath and toluenesulfonylmethyl isocyanide (TosMIC) (0.046 g, 0.26 mmol) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (0.04 ml) were added. The solution was then stirred for 20 h at 52°C. The reaction was quenched with 1M hydrochloric acid (25 ml) and extracted with ethyl acetate (50 ml). The organic layer was washed once each with 1 M hydrochloric acid (20 ml), saturated aqueous sodium bicarbonate solution (20 ml), and brine (20 ml). The organic layer was dried over anhydrous sodium sulfate, filtered over glass wool and concentrated in vacuo. The resulting crude product was purified by flash chromatography using 6:1 hexane:ethyl acetate. Evaporation of the solvent afforded 0.036 g (66%) of 7-chloro-3-tosylpyrrolo[1,2-c]pyrimidine as a light-yellow solid: mp 181–184°C; ¹H NMR (500 MHz, CDCl₃) δ 8.77 (s, 1H), 8.24 (d, J = 1 Hz, 1H), 7.95 (d, J = 8 Hz, 2H), 7.33 (d, J = 8 Hz, 2H), 6.92 (d, J = 4 Hz, 1H), 6.84 (d, J = 4 Hz, 1H), 2.42 (s, 3H); ¹³C NMR (500 MHz, CDCl₃) δ 144.8, 141.2, 136.4, 135.9, 130.0, 129.60, 128.9, 116.9, 115.0, 110.7, 106.2, 21.8; HRMS m/z calculated for C₁₄H₁₂N₂O₂SCl: 307.0308, found: 307.0303. Colorless prisms suitable for X-ray crystal structure determination were recrystallized from ethanol solution. The reaction scheme is shown in Fig. 3.

Figure 3
Reaction scheme.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3.

Table 3
Experimental details

Crystal data
Chemical formula	C₁₄H₁₁ClN₂O₂S
M_r	306.76
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	173
a, b, c (Å)	7.2285 (5), 7.2385 (5), 13.7586 (11)
α, β, γ (°)	102.192 (7), 99.616 (6), 104.149 (6)
V (Å³)	663.91 (9)
Z	2
Radiation type	Cu Kα
μ (mm⁻¹)	4.05
Crystal size (mm)	0.16 × 0.13 × 0.08

Data collection
Diffractometer	Rigaku Oxford Diffraction Eos, Gemini
Absorption correction	Multi-scan
T_min, T_max	0.748, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	3839, 2498, 2177
R_int	0.036
(sin θ/λ)_max (Å⁻¹)	0.614

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.043, 0.114, 1.04
No. of reflections	2498
No. of parameters	183
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.53, −0.31
Computer programs: CrysAlis PRO (Rigaku OD, 2019 ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 1990547

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S241431462000382X/hb4342sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S241431462000382X/hb4342Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S241431462000382X/hb4342Isup3.cml

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Rigaku OD, 2019); cell refinement: CrysAlis PRO (Rigaku OD, 2019); data reduction: CrysAlis PRO (Rigaku OD, 2019); 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).

7-Chloro-3-(4-methylbenzenesulfonyl)pyrrolo[1,2-c]pyrimidine top

Crystal data top

C₁₄H₁₁ClN₂O₂S	Z = 2
M_r = 306.76	F(000) = 316
Triclinic, P1	D_x = 1.535 Mg m⁻³
a = 7.2285 (5) Å	Cu Kα radiation, λ = 1.54184 Å
b = 7.2385 (5) Å	Cell parameters from 1885 reflections
c = 13.7586 (11) Å	θ = 6.5–71.4°
α = 102.192 (7)°	µ = 4.05 mm⁻¹
β = 99.616 (6)°	T = 173 K
γ = 104.149 (6)°	Prism, colourless
V = 663.91 (9) Å³	0.16 × 0.13 × 0.08 mm

Data collection top

Rigaku-Oxford Diffraction Eos, Gemini diffractometer	2498 independent reflections
Radiation source: fine-focus sealed X-ray tube	2177 reflections with I > 2σ(I)
Detector resolution: 16.0416 pixels mm^-1	R_int = 0.036
ω scans	θ_max = 71.2°, θ_min = 3.4°
Absorption correction: multi-scan	h = −5→8
T_min = 0.748, T_max = 1.000	k = −8→8
3839 measured reflections	l = −16→16

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.043	w = 1/[σ²(F_o²) + (0.0554P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.114	(Δ/σ)_max < 0.001
S = 1.04	Δρ_max = 0.53 e Å⁻³
2498 reflections	Δρ_min = −0.31 e Å⁻³
183 parameters	Extinction correction: SHELXL-2018/1 (Sheldrick 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0018 (6)
Primary atom site location: dual

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. All of the H atoms were placed in their calculated positions and then refined with atom-H lengths of 0.93 Å (CH); 0.96 Å (CH₃) using the riding model with U_iso (H) = 1.2 (CH) or 1.5 times U_eq (CH₃) of the parent atom. The idealized methyl group was refined as a rotating group.

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

	x	y	z	U_iso*/U_eq
Cl1	0.01870 (9)	0.02376 (9)	0.27155 (4)	0.03578 (19)
S1	0.40553 (8)	0.62315 (7)	0.76558 (4)	0.02404 (18)
O1	0.5458 (3)	0.7802 (2)	0.74516 (13)	0.0334 (4)
O2	0.2700 (3)	0.6692 (3)	0.82618 (13)	0.0340 (4)
N1	0.3648 (3)	0.4137 (3)	0.57537 (14)	0.0250 (4)
N2	0.0639 (3)	0.2272 (3)	0.46404 (13)	0.0216 (4)
C1	0.2605 (3)	0.4612 (3)	0.64732 (16)	0.0221 (4)
C2	0.0627 (3)	0.3971 (3)	0.63311 (16)	0.0231 (4)
H2	0.001144	0.434521	0.685034	0.028*
C3	−0.0462 (3)	0.2721 (3)	0.53723 (17)	0.0228 (4)
C4	−0.2410 (3)	0.1749 (3)	0.49171 (18)	0.0282 (5)
H4	−0.346453	0.178047	0.521972	0.034*
C5	−0.2517 (3)	0.0705 (3)	0.39148 (18)	0.0289 (5)
H5	−0.365477	−0.008063	0.343710	0.035*
C6	−0.0663 (3)	0.1047 (3)	0.37665 (16)	0.0257 (5)
C7	0.2645 (3)	0.3009 (3)	0.48672 (16)	0.0235 (4)
H7	0.331004	0.268421	0.436325	0.028*
C8	0.5354 (3)	0.4809 (3)	0.82241 (16)	0.0253 (4)
C9	0.7327 (4)	0.5134 (3)	0.82356 (17)	0.0293 (5)
H9	0.796540	0.608266	0.794615	0.035*
C10	0.8339 (4)	0.4003 (4)	0.86927 (19)	0.0316 (5)
H10	0.966752	0.421378	0.871207	0.038*
C11	0.7390 (4)	0.2571 (3)	0.91184 (16)	0.0269 (5)
C12	0.5414 (4)	0.2299 (4)	0.90997 (19)	0.0331 (5)
H12	0.476588	0.134692	0.938446	0.040*
C13	0.4392 (4)	0.3421 (4)	0.86641 (19)	0.0326 (5)
H13	0.307487	0.324508	0.866706	0.039*
C14	0.8477 (4)	0.1336 (4)	0.95979 (18)	0.0335 (5)
H14A	0.794694	−0.002190	0.921296	0.050*
H14B	0.833361	0.145628	1.028789	0.050*
H14C	0.984104	0.178670	0.959859	0.050*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.0431 (4)	0.0340 (3)	0.0238 (3)	0.0029 (2)	0.0081 (2)	0.0033 (2)
S1	0.0260 (3)	0.0219 (3)	0.0216 (3)	0.0068 (2)	0.0011 (2)	0.00387 (19)
O1	0.0329 (9)	0.0238 (8)	0.0372 (9)	0.0025 (7)	−0.0034 (7)	0.0107 (7)
O2	0.0357 (9)	0.0376 (9)	0.0269 (8)	0.0160 (7)	0.0033 (7)	0.0016 (7)
N1	0.0239 (9)	0.0272 (9)	0.0235 (9)	0.0050 (7)	0.0050 (7)	0.0091 (7)
N2	0.0240 (9)	0.0212 (8)	0.0200 (8)	0.0054 (7)	0.0031 (7)	0.0089 (7)
C1	0.0240 (10)	0.0209 (10)	0.0214 (10)	0.0054 (8)	0.0040 (8)	0.0080 (8)
C2	0.0271 (11)	0.0234 (10)	0.0228 (10)	0.0108 (8)	0.0080 (8)	0.0090 (8)
C3	0.0220 (10)	0.0247 (10)	0.0263 (10)	0.0093 (8)	0.0067 (8)	0.0124 (8)
C4	0.0207 (10)	0.0310 (12)	0.0338 (12)	0.0076 (9)	0.0030 (9)	0.0128 (9)
C5	0.0276 (11)	0.0257 (11)	0.0302 (11)	0.0044 (9)	−0.0018 (9)	0.0109 (9)
C6	0.0309 (11)	0.0210 (10)	0.0230 (10)	0.0050 (8)	0.0021 (9)	0.0070 (8)
C7	0.0230 (10)	0.0236 (10)	0.0244 (10)	0.0056 (8)	0.0069 (8)	0.0077 (8)
C8	0.0275 (11)	0.0241 (10)	0.0216 (10)	0.0063 (8)	−0.0004 (8)	0.0065 (8)
C9	0.0342 (12)	0.0299 (11)	0.0278 (11)	0.0096 (9)	0.0111 (9)	0.0124 (9)
C10	0.0262 (11)	0.0391 (13)	0.0331 (11)	0.0120 (10)	0.0091 (9)	0.0124 (10)
C11	0.0331 (12)	0.0260 (11)	0.0193 (9)	0.0095 (9)	0.0011 (8)	0.0038 (8)
C12	0.0322 (12)	0.0326 (12)	0.0360 (12)	0.0064 (10)	0.0074 (10)	0.0161 (10)
C13	0.0248 (11)	0.0350 (12)	0.0375 (12)	0.0047 (9)	0.0054 (9)	0.0145 (10)
C14	0.0435 (14)	0.0328 (12)	0.0275 (11)	0.0179 (11)	0.0058 (10)	0.0088 (9)

Geometric parameters (Å, º) top

Cl1—C6	1.711 (2)	C2—C3	1.407 (3)
S1—O1	1.4370 (18)	C3—C4	1.380 (3)
S1—O2	1.4429 (18)	C4—C5	1.405 (3)
S1—C1	1.773 (2)	C5—C6	1.360 (3)
S1—C8	1.767 (2)	C8—C9	1.384 (3)
N1—C1	1.378 (3)	C8—C13	1.384 (3)
N1—C7	1.294 (3)	C9—C10	1.399 (3)
N2—C3	1.417 (3)	C10—C11	1.390 (3)
N2—C6	1.371 (3)	C11—C12	1.389 (4)
N2—C7	1.373 (3)	C11—C14	1.507 (3)
C1—C2	1.358 (3)	C12—C13	1.384 (4)

O1—S1—O2	119.68 (11)	C3—C4—C5	107.8 (2)
O1—S1—C1	108.51 (10)	C6—C5—C4	108.0 (2)
O1—S1—C8	107.90 (11)	N2—C6—Cl1	119.51 (18)
O2—S1—C1	106.24 (11)	C5—C6—Cl1	130.89 (18)
O2—S1—C8	108.56 (11)	C5—C6—N2	109.6 (2)
C8—S1—C1	105.03 (10)	N1—C7—N2	122.67 (19)
C7—N1—C1	116.87 (19)	C9—C8—S1	119.13 (17)
C6—N2—C3	107.32 (18)	C13—C8—S1	119.48 (18)
C6—N2—C7	131.24 (19)	C13—C8—C9	121.4 (2)
C7—N2—C3	121.44 (18)	C8—C9—C10	118.5 (2)
N1—C1—S1	114.68 (16)	C11—C10—C9	121.1 (2)
C2—C1—S1	119.95 (16)	C10—C11—C14	121.0 (2)
C2—C1—N1	125.37 (19)	C12—C11—C10	118.8 (2)
C1—C2—C3	117.78 (19)	C12—C11—C14	120.2 (2)
C2—C3—N2	115.87 (19)	C13—C12—C11	121.1 (2)
C4—C3—N2	107.3 (2)	C8—C13—C12	119.2 (2)
C4—C3—C2	136.8 (2)

S1—C1—C2—C3	178.70 (15)	C3—C4—C5—C6	−0.2 (3)
S1—C8—C9—C10	179.69 (17)	C4—C5—C6—Cl1	−179.09 (17)
S1—C8—C13—C12	179.40 (19)	C4—C5—C6—N2	0.2 (2)
O1—S1—C1—N1	44.81 (18)	C6—N2—C3—C2	179.87 (17)
O1—S1—C1—C2	−134.12 (16)	C6—N2—C3—C4	0.0 (2)
O1—S1—C8—C9	−10.4 (2)	C6—N2—C7—N1	−178.8 (2)
O1—S1—C8—C13	168.42 (19)	C7—N1—C1—S1	−177.86 (15)
O2—S1—C1—N1	174.70 (15)	C7—N1—C1—C2	1.0 (3)
O2—S1—C1—C2	−4.23 (19)	C7—N2—C3—C2	0.5 (3)
O2—S1—C8—C9	−141.51 (19)	C7—N2—C3—C4	−179.37 (18)
O2—S1—C8—C13	37.3 (2)	C7—N2—C6—Cl1	−1.5 (3)
N1—C1—C2—C3	−0.1 (3)	C7—N2—C6—C5	179.1 (2)
N2—C3—C4—C5	0.2 (2)	C8—S1—C1—N1	−70.37 (17)
C1—S1—C8—C9	105.19 (19)	C8—S1—C1—C2	110.70 (18)
C1—S1—C8—C13	−76.0 (2)	C8—C9—C10—C11	0.6 (4)
C1—N1—C7—N2	−1.1 (3)	C9—C8—C13—C12	−1.8 (4)
C1—C2—C3—N2	−0.6 (3)	C9—C10—C11—C12	−1.1 (4)
C1—C2—C3—C4	179.2 (2)	C9—C10—C11—C14	179.2 (2)
C2—C3—C4—C5	−179.7 (2)	C10—C11—C12—C13	0.2 (4)
C3—N2—C6—Cl1	179.28 (14)	C11—C12—C13—C8	1.2 (4)
C3—N2—C6—C5	−0.1 (2)	C13—C8—C9—C10	0.9 (3)
C3—N2—C7—N1	0.4 (3)	C14—C11—C12—C13	179.9 (2)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C14—H14B···O2ⁱ	0.96	2.49	3.329 (3)	146

Symmetry code: (i) −x+1, −y+1, −z+2.

π–π distances (Å) and angles (°) for the title compound top

Cg(I)—Cg(J) is the distance between ring centroids, α is dihedral angle between planes Cg(I) and Cg(J) and slippage is the distance between Cg(I) and perpendicular the projection of Cg(J) on ring I. Cg(1), Cg(2) and Cg(4) are the centroids N2/C3–C6, N1/C1/C2/C3/N2/C7 and C1–C7/N1/N2 rings, respectively.

Cg(I)^a	Cg(J)^b	d[Cg(I)···Cg(J)]	α	slippage
Cg(1)	Cg(1)ⁱ	3.5758 (14)	0.00 (13)	1.169
Cg(1)	Cg(2)ⁱ	3.6261 (14)	0.73 (12)	1.348
Cg(1)	Cg(2)ⁱⁱ	3.6495 (14)	0.73 (12)	1.092
Cg(1)	Cg(4)ⁱ	3.4423 (13)	0.42 (11)	0.699
Cg(1)	Cg(4)ⁱⁱ	3.8876 (13)	0.42 (11)	1.738
Cg(2)	Cg(2)ⁱⁱ	3.9724 (13)	0.00 (10)	1.932
Cg(2)	Cg(4)ⁱⁱ	3.6901 (12)	0.32 (9)	1.233
Cg(4)	Cg(4)ⁱ	3.7241 (11)	0.00 (7)	1.586
Cg(4)	Cg(4)ⁱⁱ	3.6280 (11)	0.00 (7)	1.010

Symmetry codes: (i) 1 - x, -y, 1 - z; (ii) -x, 1 - y, 1 - z.

Funding information

This work was supported by Dartmouth College. JPJ acknowledges the NSF–MRI program (grant No. CHE-1039027) for funds to purchase the X-ray diffractometer.

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