Benzoic acid-2,2'-biimidazole (2/1).

In the title compound, C(6)H(6)N(4)·2C(7)H(6)O(2), the asymmetric unit contains a half-mol-ecule of biimidazole and one benzoic acid mol-ecule. The unit cell contains two biimidazole mol-ecules and four benzoic acid mol-ecules, giving the reported 2:1 ratio of benzoic acid to biimidazole. The biimidazole mol-ecule is located on an inversion center (passing through the central C-C bond). Strong N-H⋯O and O-H⋯N hydrogen bonds link the benzoic acid mol-ecules with the neutral biimidazole mol-ecules, which lie in planar sheets. In the crystal packing, the parallel sheets are related by a twofold rotation axis and an inversion centre, respectively, forming an inter-woven three-dimensional network via weak C=O⋯π inter-molecular inter-actions between neighboring mol-ecules.

Related literature

For background to the use of 2,2′-biimidazoles in crystal engineering, see: Matthews et al. (1990 ▶); Tadokoro & Nakasuji (2000 ▶). For similar structures, see: Gao et al. (2009 ▶); Li & Yang (2006 ▶); Mori & Miyoshi (2004 ▶).

Experimental

Crystal data

C6H6N4·2C7H6O2

M = 378.38

Monoclinic,

a = 11.232 (5) Å

b = 5.082 (2) Å

c = 16.342 (7) Å

β = 99.832 (6)°

V = 919.2 (7) Å3

Z = 2

Mo Kα radiation

μ = 0.10 mm−1

T = 298 K

0.40 × 0.20 × 0.10 mm

Data collection

Bruker SMART 1K CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2000 ▶) T min = 0.962, T max = 0.990

3367 measured reflections

1550 independent reflections

1243 reflections with I > 2σ(I)

R int = 0.047

Refinement

R[F 2 > 2σ(F 2)] = 0.098

wR(F 2) = 0.188

S = 1.25

1550 reflections

131 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.20 e Å−3

Δρmin = −0.19 e Å−3

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and SHELXTL/PC (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL/PC.

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810045368/fl2323sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810045368/fl2323Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C6H6N4·2C7H6O2	F(000) = 396
Mr = 378.38	Dx = 1.367 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 698 reflections
a = 11.232 (5) Å	θ = 2.5–20.8°
b = 5.082 (2) Å	µ = 0.10 mm−1
c = 16.342 (7) Å	T = 298 K
β = 99.832 (6)°	Block, colorless
V = 919.2 (7) Å3	0.40 × 0.20 × 0.10 mm
Z = 2

Bruker SMART 1K CCD area-detector diffractometer	1550 independent reflections
Radiation source: fine-focus sealed tube	1243 reflections with I > 2σ(I)
graphite	Rint = 0.047
ω scans	θmax = 25.0°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 2000)	h = −13→12
Tmin = 0.962, Tmax = 0.990	k = −6→2
3367 measured reflections	l = −19→19

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)] = 0.098	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.188	H atoms treated by a mixture of independent and constrained refinement
S = 1.25	w = 1/[σ2(Fo2) + (0.0425P)2 + 1.0781P] where P = (Fo2 + 2Fc2)/3
1550 reflections	(Δ/σ)max < 0.001
131 parameters	Δρmax = 0.20 e Å−3
0 restraints	Δρmin = −0.19 e Å−3

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.

	x	y	z	Uiso*/Ueq
N1	0.3655 (3)	0.6966 (8)	0.4607 (2)	0.0406 (10)
H1	0.383 (4)	0.809 (10)	0.423 (3)	0.064 (17)*
N2	0.3784 (3)	0.3740 (7)	0.5510 (2)	0.0389 (9)
C1	0.4360 (4)	0.5176 (8)	0.5031 (2)	0.0307 (10)
C2	0.2533 (4)	0.6694 (10)	0.4821 (3)	0.0436 (12)
H2	0.1846	0.7679	0.4624	0.052*
C3	0.2630 (4)	0.4717 (10)	0.5372 (3)	0.0453 (12)
H3	0.2003	0.4097	0.5625	0.054*
C4	0.4969 (4)	0.1219 (9)	0.3172 (3)	0.0376 (11)
C5	0.4964 (4)	0.3271 (9)	0.2521 (2)	0.0347 (10)
C6	0.5982 (4)	0.3745 (10)	0.2158 (3)	0.0451 (12)
H6	0.6687	0.2790	0.2329	0.054*
C7	0.5946 (4)	0.5616 (10)	0.1549 (3)	0.0516 (13)
H7	0.6625	0.5916	0.1308	0.062*
C8	0.4913 (4)	0.7050 (10)	0.1294 (3)	0.0491 (13)
H8	0.4897	0.8321	0.0883	0.059*
C9	0.3913 (4)	0.6618 (10)	0.1641 (3)	0.0458 (12)
H9	0.3216	0.7595	0.1468	0.055*
C10	0.3934 (4)	0.4739 (10)	0.2247 (3)	0.0441 (12)
H10	0.3244	0.4447	0.2478	0.053*
O1	0.5977 (3)	−0.0029 (7)	0.3367 (2)	0.0532 (10)
H1A	0.5971	−0.1186	0.3747	0.080*
O2	0.4086 (3)	0.0801 (7)	0.3491 (2)	0.0517 (9)

	U11	U22	U33	U12	U13	U23
N1	0.043 (2)	0.037 (2)	0.042 (2)	−0.0004 (19)	0.0097 (18)	0.009 (2)
N2	0.041 (2)	0.035 (2)	0.043 (2)	−0.0011 (18)	0.0116 (17)	0.0088 (19)
C1	0.044 (2)	0.022 (2)	0.027 (2)	0.003 (2)	0.0077 (19)	0.0055 (19)
C2	0.037 (3)	0.048 (3)	0.046 (3)	0.004 (2)	0.007 (2)	0.000 (3)
C3	0.032 (2)	0.057 (3)	0.048 (3)	0.000 (2)	0.009 (2)	0.011 (3)
C4	0.041 (3)	0.029 (2)	0.043 (3)	−0.004 (2)	0.009 (2)	−0.002 (2)
C5	0.038 (2)	0.032 (3)	0.034 (2)	−0.004 (2)	0.0064 (19)	−0.005 (2)
C6	0.037 (3)	0.046 (3)	0.053 (3)	0.002 (2)	0.012 (2)	0.008 (3)
C7	0.048 (3)	0.052 (3)	0.060 (3)	−0.001 (3)	0.024 (2)	0.013 (3)
C8	0.051 (3)	0.048 (3)	0.049 (3)	−0.003 (3)	0.008 (2)	0.013 (3)
C9	0.036 (3)	0.046 (3)	0.054 (3)	0.006 (2)	0.004 (2)	0.009 (3)
C10	0.033 (2)	0.055 (3)	0.046 (3)	−0.005 (2)	0.013 (2)	0.002 (3)
O1	0.0371 (17)	0.058 (2)	0.065 (2)	0.0067 (18)	0.0089 (15)	0.0244 (19)
O2	0.0465 (19)	0.051 (2)	0.063 (2)	0.0094 (17)	0.0220 (16)	0.0155 (18)

N1—C1	1.322 (5)	C5—C10	1.385 (6)
N1—C2	1.371 (5)	C5—C6	1.397 (6)
N1—H1	0.88 (5)	C6—C7	1.371 (6)
N2—C1	1.319 (5)	C6—H6	0.9300
N2—C3	1.370 (5)	C7—C8	1.374 (6)
C1—C1i	1.469 (8)	C7—H7	0.9300
C2—C3	1.342 (6)	C8—C9	1.359 (6)
C2—H2	0.9300	C8—H8	0.9300
C3—H3	0.9300	C9—C10	1.373 (6)
C4—O2	1.216 (5)	C9—H9	0.9300
C4—O1	1.289 (5)	C10—H10	0.9300
C4—C5	1.489 (6)	O1—H1A	0.8564
C1—N1—C2	106.9 (4)	C6—C5—C4	121.4 (4)
C1—N1—H1	129 (3)	C7—C6—C5	120.1 (4)
C2—N1—H1	124 (3)	C7—C6—H6	119.9
C1—N2—C3	104.4 (4)	C5—C6—H6	119.9
N2—C1—N1	112.4 (4)	C6—C7—C8	120.5 (4)
N2—C1—C1i	124.0 (5)	C6—C7—H7	119.8
N1—C1—C1i	123.6 (5)	C8—C7—H7	119.8
C3—C2—N1	105.9 (4)	C9—C8—C7	120.2 (5)
C3—C2—H2	127.0	C9—C8—H8	119.9
N1—C2—H2	127.0	C7—C8—H8	119.9
C2—C3—N2	110.4 (4)	C8—C9—C10	120.0 (4)
C2—C3—H3	124.8	C8—C9—H9	120.0
N2—C3—H3	124.8	C10—C9—H9	120.0
O2—C4—O1	123.6 (4)	C9—C10—C5	121.2 (4)
O2—C4—C5	121.7 (4)	C9—C10—H10	119.4
O1—C4—C5	114.7 (4)	C5—C10—H10	119.4
C10—C5—C6	118.0 (4)	C4—O1—H1A	113.7
C10—C5—C4	120.6 (4)
C3—N2—C1—N1	0.0 (5)	O1—C4—C5—C6	0.5 (6)
C3—N2—C1—C1i	−179.6 (5)	C10—C5—C6—C7	0.0 (7)
C2—N1—C1—N2	0.0 (5)	C4—C5—C6—C7	178.9 (4)
C2—N1—C1—C1i	179.6 (5)	C5—C6—C7—C8	0.4 (7)
C1—N1—C2—C3	0.0 (5)	C6—C7—C8—C9	−0.3 (8)
N1—C2—C3—N2	0.0 (5)	C7—C8—C9—C10	−0.1 (7)
C1—N2—C3—C2	0.0 (5)	C8—C9—C10—C5	0.5 (7)
O2—C4—C5—C10	−1.3 (6)	C6—C5—C10—C9	−0.4 (7)
O1—C4—C5—C10	179.3 (4)	C4—C5—C10—C9	−179.3 (4)
O2—C4—C5—C6	179.8 (4)

Cg1 is the centroid of the [please define] ring.

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···N2ii	0.86	1.77	2.613 (5)	170
N1—H1···O2iii	0.88 (5)	1.89 (5)	2.767 (5)	173 (5)
C4—O2···Cg1	1.216 (5)	3.674 (2)	4.388 (2)	118.37 (6)

Table 1

Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the N1/C1/N2/C3/C2 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1A⋯N2i	0.86	1.77	2.613 (5)	170
N1—H1⋯O2ii	0.88 (5)	1.89 (5)	2.767 (5)	173 (5)
C4—O2⋯Cg1	1.22 (1)	3.67 (1)	4.388 (2)	118 (1)

Symmetry codes: (i) ; (ii) .