Dimethyl 2,2′-di­nitro­biphenyl-4,4′-di­carboxyl­ate

Lehane, R.L.; Golen, J.A.; Rheingold, A.L.; Manke, D.R.

doi:10.1107/S1600536814003067

organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 70| Part 3| March 2014| Page o305

doi:10.1107/S1600536814003067

Open

access

Dimethyl 2,2′-dinitrobiphenyl-4,4′-dicarboxylate

Ryan L. Lehane,^a James A. Golen,^b Arnold L. Rheingold ^b and David R. Manke ^a ^*

^aDepartment of Chemistry and Biochemistry, University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747, USA, and ^bDepartment of Chemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
^*Correspondence e-mail: dmanke@umassd.edu

(Received 3 February 2014; accepted 10 February 2014; online 15 February 2014)

The title compound, C₁₆H₁₂N₂O₈, exhibits two near-planar aromatic ester groups with aryl–ester dihedral angles of 2.1 (2) and 4.2 (3)°. The dihedral angle between the aromatic rings is 58.0 (1)°. The two nitro groups are tilted slightly from the plane of the aromatic rings, making dihedral angles of 14.1 (1) and 8.2 (2)°. In the crystal, molecules are connected by weak C—H⋯O interactions, forming a three-dimensional network.

CCDC reference: 986204

Related literature

For the synthesis of the title compound, see: Ol'khovik et al. (2008 ). For the structure of 2,2′-dinitrobiphenyl-4,4′-dicarboxylic acid, see: Wu et al. (2010 ). For metal-organic frameworks and coordination polymers featuring this linker, see: Qu (2007 ); Li, Zhou et al. (2011 ); Li, Li et al. (2011 ); Li, Zhang et al. (2011 ); Zhang, Ma et al. (2011 ); Zhang, Jing et al. (2011 ); Li, Yang et al. (2012 ); Zhang, Li et al. (2012 ).

Experimental

Crystal data

C₁₆H₁₂N₂O₈
M_r = 360.28
Triclinic, $[P \overline 1]$
a = 8.0520 (5) Å
b = 10.4193 (7) Å
c = 10.5310 (11) Å
α = 108.423 (4)°
β = 95.142 (4)°
γ = 111.617 (3)°
V = 757.71 (11) Å³
Z = 2
Mo Kα radiation
μ = 0.13 mm⁻¹
T = 90 K
0.28 × 0.20 × 0.15 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ) T_min = 0.965, T_max = 0.981
9906 measured reflections
2787 independent reflections
2297 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.034
wR(F²) = 0.096
S = 1.02
2787 reflections
237 parameters
H-atom parameters constrained
Δρ_max = 0.21 e Å⁻³
Δρ_min = −0.20 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C16—H16A⋯O3ⁱ	0.98	2.50	3.253 (2)	134
C1—H1C⋯O2ⁱⁱ	0.98	2.57	3.5214 (19)	164
C14—H14A⋯O2ⁱⁱⁱ	0.95	2.47	3.2399 (19)	138
C8—H8A⋯O3^iv	0.95	2.41	3.3239 (19)	162
Symmetry codes: (i) -x+2, -y+1, -z+1; (ii) -x, -y, -z+2; (iii) -x, -y, -z+1; (iv) x-1, y, z.

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL.

Supporting information

CCDC reference: 986204

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: 10.1107/S1600536814003067/ff2126sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536814003067/ff2126Isup2.hkl

Supporting information file. DOI: 10.1107/S1600536814003067/ff2126Isup3.cml

checkCIF report

Comment top

Biphenyl-4,4'-dicarboxylate and its derivatives are widely used in metal-organic frameworks (MOFs) as linkers. One of the many advantages of MOFs is the ability to incorporate different functional groups within their pores. As a part of our efforts in this field, we prepared the previously reported dimethyl 2,2'-dinitrobiphenyl-4,4'-dicarboxylate (Ol'khovik et al. 2008) and report its structure herein.

The molecular structure of the title compound is shown in Figure 1. The structure demonstrates two near planar aromatic ester groups with aryl-ester dihedral angles of 2.1 (2)° and 4.2 (3)°. The two aromatic rings demonstrate a dihedral angle of 58.0 (1)°. The nitro groups are skewed slightly with aryl-nitro dihedral angles of 8.2 (2)° and 14.1 (1)°. No π-π interactions were noted between the aromatic rings. The packing for the title compound is shown in Figure 2.

Related literature top

For the synthesis of the title compound, see: Ol'khovik et al. (2008). For the structure of 2,2'-dinitrobiphenyl-4,4'-dicarboxylic acid, see: Wu et al. (2010). For metal-organic frameworks and coordination polymers featuring this linker, see: Qu (2007); Li, Zhou et al. (2011); Li, Li et al. (2011); Li, Zhang et al. (2011); Zhang, Ma et al. (2011); Zhang, Jing et al. (2011); Li, Yang et al. (2012); Zhang, Li et al. (2012).

Experimental top

The compound was prepared by literature procedure (Ol'khovik et al. 2008). Crystals suitable for single-crystal X-ray analysis were grown by slow evaporation of an ethanol solution.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. Molecular structure of the title compound, showing the atom labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as spheres of arbitrary radius.
	Fig. 2. Molecular packing of the title compound.

Dimethyl 2,2'-dinitrobiphenyl-4,4'-dicarboxylate top

Crystal data top

C₁₆H₁₂N₂O₈	Z = 2
M_r = 360.28	F(000) = 372
Triclinic, P1	D_x = 1.579 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 8.0520 (5) Å	Cell parameters from 5153 reflections
b = 10.4193 (7) Å	θ = 2.8–25.4°
c = 10.5310 (11) Å	µ = 0.13 mm⁻¹
α = 108.423 (4)°	T = 90 K
β = 95.142 (4)°	BLOCK, yellow
γ = 111.617 (3)°	0.28 × 0.20 × 0.15 mm
V = 757.71 (11) Å³

Data collection top

Bruker APEXII CCD diffractometer	2787 independent reflections
Radiation source: fine-focus sealed tube	2297 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
φ and ω scans	θ_max = 25.4°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2005)	h = −9→9
T_min = 0.965, T_max = 0.981	k = −12→12
9906 measured reflections	l = −12→12

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)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.096	H-atom parameters constrained
S = 1.02	w = 1/[σ²(F_o²) + (0.0515P)² + 0.234P] where P = (F_o² + 2F_c²)/3
2787 reflections	(Δ/σ)_max = 0.001
237 parameters	Δρ_max = 0.21 e Å⁻³
0 restraints	Δρ_min = −0.20 e Å⁻³

Crystal data top

C₁₆H₁₂N₂O₈	γ = 111.617 (3)°
M_r = 360.28	V = 757.71 (11) Å³
Triclinic, P1	Z = 2
a = 8.0520 (5) Å	Mo Kα radiation
b = 10.4193 (7) Å	µ = 0.13 mm⁻¹
c = 10.5310 (11) Å	T = 90 K
α = 108.423 (4)°	0.28 × 0.20 × 0.15 mm
β = 95.142 (4)°

Data collection top

Bruker APEXII CCD diffractometer	2787 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2005)	2297 reflections with I > 2σ(I)
T_min = 0.965, T_max = 0.981	R_int = 0.026
9906 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.034	0 restraints
wR(F²) = 0.096	H-atom parameters constrained
S = 1.02	Δρ_max = 0.21 e Å⁻³
2787 reflections	Δρ_min = −0.20 e Å⁻³
237 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	0.28379 (14)	−0.04398 (11)	0.86338 (10)	0.0223 (3)
O2	0.02811 (15)	−0.01405 (13)	0.81152 (11)	0.0283 (3)
O3	0.80395 (15)	0.15657 (14)	0.70622 (13)	0.0350 (3)
O4	0.80373 (15)	0.23016 (13)	0.53753 (11)	0.0283 (3)
O5	0.72326 (16)	0.49239 (12)	0.69694 (11)	0.0327 (3)
O6	0.93059 (15)	0.61445 (13)	0.61157 (11)	0.0323 (3)
O7	0.80462 (15)	0.55730 (12)	0.14341 (11)	0.0292 (3)
O8	0.56913 (17)	0.35679 (13)	−0.01199 (11)	0.0355 (3)
N1	0.72907 (16)	0.18850 (13)	0.62186 (13)	0.0196 (3)
N2	0.78359 (17)	0.51402 (14)	0.59936 (12)	0.0206 (3)
C1	0.1936 (2)	−0.12748 (18)	0.94307 (16)	0.0253 (4)
H1A	0.2829	−0.1467	0.9949	0.038*
H1B	0.0943	−0.2224	0.8810	0.038*
H1C	0.1427	−0.0698	1.0072	0.038*
C2	0.1814 (2)	0.00368 (16)	0.79992 (15)	0.0199 (3)
C3	0.2780 (2)	0.07985 (15)	0.71294 (14)	0.0181 (3)
C4	0.4574 (2)	0.10299 (15)	0.70668 (14)	0.0182 (3)
H4A	0.5234	0.0717	0.7606	0.022*
C5	0.53980 (19)	0.17125 (15)	0.62247 (15)	0.0179 (3)
C6	0.4489 (2)	0.21904 (15)	0.53960 (15)	0.0181 (3)
C7	0.2683 (2)	0.19281 (16)	0.54750 (15)	0.0199 (3)
H7A	0.2004	0.2214	0.4919	0.024*
C8	0.1845 (2)	0.12668 (16)	0.63336 (15)	0.0201 (3)
H8A	0.0622	0.1132	0.6379	0.024*
C9	0.5175 (2)	0.28358 (16)	0.43647 (15)	0.0186 (3)
C10	0.6699 (2)	0.41620 (16)	0.45972 (15)	0.0187 (3)
C11	0.7209 (2)	0.46404 (16)	0.35496 (15)	0.0196 (3)
H11A	0.8284	0.5524	0.3740	0.024*
C12	0.6138 (2)	0.38191 (16)	0.22211 (15)	0.0208 (3)
C13	0.4585 (2)	0.25263 (17)	0.19660 (16)	0.0232 (3)
H13A	0.3833	0.1967	0.1060	0.028*
C14	0.4123 (2)	0.20443 (16)	0.30184 (15)	0.0217 (3)
H14A	0.3060	0.1149	0.2819	0.026*
C15	0.6575 (2)	0.42811 (17)	0.10439 (16)	0.0239 (4)
C16	0.8490 (3)	0.6119 (2)	0.03466 (17)	0.0354 (4)
H16A	0.9564	0.7083	0.0729	0.053*
H16B	0.7443	0.6240	−0.0062	0.053*
H16C	0.8765	0.5404	−0.0362	0.053*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
O1	0.0235 (6)	0.0248 (6)	0.0241 (6)	0.0100 (5)	0.0094 (4)	0.0154 (5)
O2	0.0227 (6)	0.0362 (7)	0.0344 (7)	0.0134 (5)	0.0140 (5)	0.0205 (5)
O3	0.0253 (6)	0.0526 (8)	0.0442 (7)	0.0200 (6)	0.0117 (5)	0.0348 (6)
O4	0.0251 (6)	0.0383 (7)	0.0328 (6)	0.0153 (5)	0.0158 (5)	0.0230 (6)
O5	0.0419 (7)	0.0275 (6)	0.0197 (6)	0.0035 (5)	0.0098 (5)	0.0099 (5)
O6	0.0255 (6)	0.0306 (6)	0.0274 (6)	−0.0018 (5)	0.0033 (5)	0.0109 (5)
O7	0.0336 (7)	0.0274 (6)	0.0213 (6)	0.0032 (5)	0.0068 (5)	0.0140 (5)
O8	0.0512 (8)	0.0268 (6)	0.0189 (6)	0.0071 (6)	0.0035 (5)	0.0088 (5)
N1	0.0185 (7)	0.0177 (6)	0.0228 (7)	0.0066 (5)	0.0056 (5)	0.0087 (5)
N2	0.0227 (7)	0.0186 (6)	0.0208 (7)	0.0072 (6)	0.0059 (5)	0.0095 (5)
C1	0.0312 (9)	0.0242 (8)	0.0245 (8)	0.0097 (7)	0.0113 (7)	0.0149 (7)
C2	0.0200 (8)	0.0174 (7)	0.0190 (8)	0.0060 (6)	0.0042 (6)	0.0050 (6)
C3	0.0196 (8)	0.0153 (7)	0.0173 (7)	0.0064 (6)	0.0051 (6)	0.0042 (6)
C4	0.0207 (8)	0.0158 (7)	0.0170 (7)	0.0074 (6)	0.0029 (6)	0.0057 (6)
C5	0.0168 (7)	0.0160 (7)	0.0194 (7)	0.0065 (6)	0.0050 (6)	0.0049 (6)
C6	0.0213 (8)	0.0130 (7)	0.0173 (7)	0.0054 (6)	0.0044 (6)	0.0045 (6)
C7	0.0195 (8)	0.0194 (8)	0.0228 (8)	0.0094 (6)	0.0041 (6)	0.0090 (6)
C8	0.0184 (8)	0.0191 (8)	0.0223 (8)	0.0080 (6)	0.0066 (6)	0.0065 (6)
C9	0.0198 (8)	0.0174 (7)	0.0223 (8)	0.0106 (6)	0.0069 (6)	0.0083 (6)
C10	0.0200 (8)	0.0180 (7)	0.0183 (8)	0.0086 (6)	0.0042 (6)	0.0062 (6)
C11	0.0210 (8)	0.0160 (7)	0.0233 (8)	0.0078 (6)	0.0069 (6)	0.0087 (6)
C12	0.0263 (8)	0.0187 (8)	0.0203 (8)	0.0113 (7)	0.0069 (6)	0.0083 (6)
C13	0.0272 (8)	0.0191 (8)	0.0203 (8)	0.0074 (7)	0.0021 (6)	0.0073 (6)
C14	0.0218 (8)	0.0173 (7)	0.0248 (8)	0.0068 (6)	0.0040 (6)	0.0087 (6)
C15	0.0309 (9)	0.0197 (8)	0.0223 (9)	0.0111 (7)	0.0069 (7)	0.0089 (7)
C16	0.0409 (10)	0.0378 (10)	0.0272 (9)	0.0071 (8)	0.0099 (8)	0.0225 (8)

Geometric parameters (Å, º) top

O1—C2	1.3363 (18)	C5—C6	1.405 (2)
O1—C1	1.4469 (17)	C6—C7	1.393 (2)
O2—C2	1.2024 (18)	C6—C9	1.494 (2)
O3—N1	1.2256 (16)	C7—C8	1.381 (2)
O4—N1	1.2188 (16)	C7—H7A	0.9500
O5—N2	1.2239 (16)	C8—H8A	0.9500
O6—N2	1.2197 (16)	C9—C14	1.392 (2)
O7—C15	1.3315 (19)	C9—C10	1.399 (2)
O7—C16	1.4486 (18)	C10—C11	1.383 (2)
O8—C15	1.1995 (19)	C11—C12	1.384 (2)
N1—C5	1.4682 (18)	C11—H11A	0.9500
N2—C10	1.4708 (19)	C12—C13	1.385 (2)
C1—H1A	0.9800	C12—C15	1.491 (2)
C1—H1B	0.9800	C13—C14	1.381 (2)
C1—H1C	0.9800	C13—H13A	0.9500
C2—C3	1.485 (2)	C14—H14A	0.9500
C3—C8	1.387 (2)	C16—H16A	0.9800
C3—C4	1.385 (2)	C16—H16B	0.9800
C4—C5	1.374 (2)	C16—H16C	0.9800
C4—H4A	0.9500

C2—O1—C1	115.18 (11)	C6—C7—H7A	118.9
C15—O7—C16	115.00 (12)	C3—C8—C7	120.31 (14)
O4—N1—O3	122.78 (12)	C3—C8—H8A	119.8
O4—N1—C5	119.80 (12)	C7—C8—H8A	119.8
O3—N1—C5	117.40 (12)	C14—C9—C10	116.34 (13)
O6—N2—O5	123.65 (13)	C14—C9—C6	115.67 (13)
O6—N2—C10	118.19 (12)	C10—C9—C6	127.94 (13)
O5—N2—C10	118.13 (12)	C11—C10—C9	122.64 (13)
O1—C1—H1A	109.5	C11—C10—N2	116.29 (13)
O1—C1—H1B	109.5	C9—C10—N2	121.07 (13)
H1A—C1—H1B	109.5	C12—C11—C10	119.37 (14)
O1—C1—H1C	109.5	C12—C11—H11A	120.3
H1A—C1—H1C	109.5	C10—C11—H11A	120.3
H1B—C1—H1C	109.5	C11—C12—C13	119.30 (14)
O2—C2—O1	123.67 (14)	C11—C12—C15	122.49 (14)
O2—C2—C3	124.01 (14)	C13—C12—C15	118.20 (14)
O1—C2—C3	112.32 (12)	C14—C13—C12	120.55 (14)
C8—C3—C4	118.93 (13)	C14—C13—H13A	119.7
C8—C3—C2	118.95 (13)	C12—C13—H13A	119.7
C4—C3—C2	122.11 (13)	C13—C14—C9	121.72 (14)
C5—C4—C3	120.01 (14)	C13—C14—H14A	119.1
C5—C4—H4A	120.0	C9—C14—H14A	119.1
C3—C4—H4A	120.0	O8—C15—O7	124.10 (14)
C4—C5—C6	122.65 (13)	O8—C15—C12	123.56 (14)
C4—C5—N1	115.70 (13)	O7—C15—C12	112.33 (13)
C6—C5—N1	121.64 (13)	O7—C16—H16A	109.5
C7—C6—C5	115.81 (13)	O7—C16—H16B	109.5
C7—C6—C9	116.20 (13)	H16A—C16—H16B	109.5
C5—C6—C9	127.81 (13)	O7—C16—H16C	109.5
C8—C7—C6	122.27 (14)	H16A—C16—H16C	109.5
C8—C7—H7A	118.9	H16B—C16—H16C	109.5

C1—O1—C2—O2	3.3 (2)	C7—C6—C9—C10	122.53 (16)
C1—O1—C2—C3	−176.29 (11)	C5—C6—C9—C10	−62.6 (2)
O2—C2—C3—C8	−3.9 (2)	C14—C9—C10—C11	−3.2 (2)
O1—C2—C3—C8	175.74 (12)	C6—C9—C10—C11	179.48 (14)
O2—C2—C3—C4	177.44 (14)	C14—C9—C10—N2	175.83 (13)
O1—C2—C3—C4	−2.96 (19)	C6—C9—C10—N2	−1.5 (2)
C8—C3—C4—C5	−0.1 (2)	O6—N2—C10—C11	−12.78 (19)
C2—C3—C4—C5	178.64 (13)	O5—N2—C10—C11	165.42 (13)
C3—C4—C5—C6	−0.5 (2)	O6—N2—C10—C9	168.14 (13)
C3—C4—C5—N1	−179.15 (12)	O5—N2—C10—C9	−13.7 (2)
O4—N1—C5—C4	170.63 (13)	C9—C10—C11—C12	2.8 (2)
O3—N1—C5—C4	−7.86 (19)	N2—C10—C11—C12	−176.24 (13)
O4—N1—C5—C6	−8.1 (2)	C10—C11—C12—C13	−0.6 (2)
O3—N1—C5—C6	173.45 (13)	C10—C11—C12—C15	178.61 (13)
C4—C5—C6—C7	−0.1 (2)	C11—C12—C13—C14	−1.1 (2)
N1—C5—C6—C7	178.50 (12)	C15—C12—C13—C14	179.67 (13)
C4—C5—C6—C9	−174.94 (13)	C12—C13—C14—C9	0.6 (2)
N1—C5—C6—C9	3.7 (2)	C10—C9—C14—C13	1.4 (2)
C5—C6—C7—C8	1.2 (2)	C6—C9—C14—C13	179.09 (13)
C9—C6—C7—C8	176.70 (13)	C16—O7—C15—O8	2.6 (2)
C4—C3—C8—C7	1.2 (2)	C16—O7—C15—C12	−177.15 (13)
C2—C3—C8—C7	−177.57 (13)	C11—C12—C15—O8	178.12 (15)
C6—C7—C8—C3	−1.8 (2)	C13—C12—C15—O8	−2.7 (2)
C7—C6—C9—C14	−54.82 (18)	C11—C12—C15—O7	−2.1 (2)
C5—C6—C9—C14	120.00 (16)	C13—C12—C15—O7	177.07 (13)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C16—H16A···O3ⁱ	0.98	2.50	3.253 (2)	134
C1—H1C···O2ⁱⁱ	0.98	2.57	3.5214 (19)	164
C14—H14A···O2ⁱⁱⁱ	0.95	2.47	3.2399 (19)	138
C8—H8A···O3^iv	0.95	2.41	3.3239 (19)	162

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C16—H16A···O3ⁱ	0.98	2.50	3.253 (2)	133.6
C1—H1C···O2ⁱⁱ	0.98	2.57	3.5214 (19)	164.0
C14—H14A···O2ⁱⁱⁱ	0.95	2.47	3.2399 (19)	138.2
C8—H8A···O3^iv	0.95	2.41	3.3239 (19)	161.7

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

Acknowledgements

RLL thanks the Jean Dreyfus Boissevain Lectureship for Undergraduate Institutions, the UMass Dartmouth Office of Undergraduate Research Award and the UMass Dartmouth Honors Summer Research Grant for funding. DRM gratefully acknowledges the National Science Foundation (CHE-1229339).

References

Bruker (2005). APEX2, SAINT and SADABS. Bruker AXS, Inc., Madison, Wisconsin, USA. Google Scholar
Li, B., Li, G., Liu, D., Peng, Y., Zhou, X., Hua, J., Shi, Z. & Feng, S. (2011). CrystEngComm, 13, 1291–1298. Web of Science CSD CrossRef CAS Google Scholar
Li, B., Yang, F., Zhang, Y., Li, G., Zhou, Q., Hua, J., Shi, Z. & Feng, S. (2012). Dalton Trans. 41, 2677–2684. Web of Science CSD CrossRef CAS PubMed Google Scholar
Li, B., Zhang, Y., Li, G., Liu, D., Chen, Y., Hu, W., Shi, Z. & Feng, S. (2011). CrystEngComm, 13, 2457–2463. Web of Science CSD CrossRef CAS Google Scholar
Li, B., Zhou, X., Zhou, Q., Li, G., Hua, J., Bi, Y., Li, Y., Shi, Z. & Feng, S. (2011). CrystEngComm, 13, 4592–4598. Web of Science CSD CrossRef CAS Google Scholar
Ol'khovik, V. K., Pap, A. A., Vasilevskii, V. A., Galinovskii, N. A. & Tereshki, S. N. (2008). Russ. J. Org. Chem. 44, 1172–1179. CAS Google Scholar
Qu, Z. (2007). Chin. J. Inorg. Chem. 23, 1837–1839. CAS Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Wu, R. F., Zhang, T. L. & Qiao, X. J. (2010). Chin. Chem. Lett. 21, 1007–1010. Web of Science CrossRef CAS Google Scholar
Zhang, J.-Y., Jing, X.-H., Ma, Y., Cheng, A.-L. & Gao, E.-Q. (2011). Cryst. Growth Des. 11, 3681–3685. Web of Science CSD CrossRef CAS Google Scholar
Zhang, J.-Y., Li, X.-B., Wang, K., Ma, Y., Cheng, A.-L. & Gao, E.-Q. (2012). Dalton Trans. 41, 12192–12199. Web of Science CSD CrossRef CAS PubMed Google Scholar
Zhang, J.-Y., Ma, Y., Cheng, A.-L., Sun, Q. & Gao, E.-Q. (2011). Dalton Trans. 40, 7219–7227. Web of Science CSD CrossRef CAS PubMed Google Scholar