4,5-Diamino-benzene-1,2-dicarbonitrile.

The mol-ecular skeleton of the title mol-ecule, C(8)H(6)N(4), is essentially planar [maximum deviation from the mean plane of 0.037 (2) Å]. All N atoms are involved in the formation of inter-molecular N-H⋯N hydrogen bonds. The crystal packing exhibits also dipole-dipole inter-actions between the cyano groups of neighbouring mol-ecules [C⋯C 3.473 (2) Å].

Related literature

For details of the synthesis, see: Cheeseman (1962 ▶); Mitzel et al. (2003 ▶). For applications of diamido compounds, see: Rusanova et al. (2002 ▶); Youngblood (2006 ▶). For a related crystal structure, see: Zhang & Lu (2007 ▶).

Experimental

Crystal data

C8H6N4

M = 158.17

Monoclinic,

a = 8.2966 (11) Å

b = 17.100 (2) Å

c = 5.5295 (7) Å

β = 102.256 (2)°

V = 766.60 (17) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 273 K

0.20 × 0.18 × 0.14 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T min = 0.980, T max = 0.988

4031 measured reflections

1502 independent reflections

1201 reflections with I > 2σ(I)

R int = 0.018

Refinement

R[F 2 > 2σ(F 2)] = 0.041

wR(F 2) = 0.146

S = 0.95

1502 reflections

109 parameters

H-atom parameters constrained

Δρmax = 0.25 e Å−3

Δρmin = −0.21 e Å−3

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT-Plus (Bruker, 2001 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: XP in SHELXTL.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809008733/cv2527sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809008733/cv2527Isup2.hkl

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

C8H6N4	F(000) = 328
Mr = 158.17	Dx = 1.370 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1651 reflections
a = 8.2966 (11) Å	θ = 2.5–26.5°
b = 17.100 (2) Å	µ = 0.09 mm−1
c = 5.5295 (7) Å	T = 273 K
β = 102.256 (2)°	Block, white
V = 766.60 (17) Å3	0.20 × 0.18 × 0.14 mm
Z = 4

Bruker APEXII CCD area-detector diffractometer	1502 independent reflections
Radiation source: fine-focus sealed tube	1201 reflections with I > 2σ(I)
graphite	Rint = 0.018
Detector resolution: 0 pixels mm-1	θmax = 26.0°, θmin = 2.5°
φ and ω scans	h = −10→9
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −18→21
Tmin = 0.980, Tmax = 0.988	l = −5→6
4031 measured reflections

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.146	H-atom parameters constrained
S = 0.95	w = 1/[σ2(Fo2) + (0.1P)2 + 0.1224P] where P = (Fo2 + 2Fc2)/3
1502 reflections	(Δ/σ)max < 0.001
109 parameters	Δρmax = 0.25 e Å−3
0 restraints	Δρmin = −0.21 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	0.03342 (15)	0.30649 (8)	0.3604 (3)	0.0488 (4)
H1A	0.0217	0.2745	0.4754	0.059*
H1B	−0.0488	0.3167	0.2412	0.059*
N2	0.07879 (17)	0.40517 (9)	−0.0247 (3)	0.0548 (4)
H2A	0.0940	0.4338	−0.1457	0.066*
H2B	−0.0173	0.3862	−0.0256	0.066*
N3	0.78147 (18)	0.46391 (10)	0.3631 (3)	0.0667 (5)
N4	0.7218 (2)	0.32364 (11)	0.9135 (3)	0.0736 (5)
C1	0.36358 (19)	0.42015 (9)	0.1736 (3)	0.0449 (4)
H1C	0.3794	0.4522	0.0448	0.054*
C2	0.20725 (18)	0.38986 (9)	0.1690 (3)	0.0396 (4)
C3	0.18407 (17)	0.34143 (8)	0.3672 (3)	0.0378 (4)
C4	0.31750 (18)	0.32537 (8)	0.5584 (3)	0.0409 (4)
H4A	0.3022	0.2937	0.6886	0.049*
C5	0.47413 (18)	0.35546 (9)	0.5606 (3)	0.0411 (4)
C6	0.49666 (18)	0.40366 (9)	0.3661 (3)	0.0417 (4)
C7	0.6563 (2)	0.43676 (10)	0.3652 (3)	0.0492 (4)
C8	0.6111 (2)	0.33725 (10)	0.7576 (3)	0.0506 (4)

	U11	U22	U33	U12	U13	U23
N1	0.0348 (7)	0.0570 (8)	0.0518 (8)	−0.0050 (6)	0.0027 (6)	0.0110 (6)
N2	0.0419 (8)	0.0688 (9)	0.0497 (8)	−0.0017 (6)	0.0008 (6)	0.0155 (7)
N3	0.0443 (9)	0.0755 (11)	0.0815 (12)	−0.0086 (7)	0.0157 (8)	0.0026 (8)
N4	0.0496 (9)	0.1007 (14)	0.0603 (10)	0.0000 (9)	−0.0112 (8)	0.0071 (9)
C1	0.0428 (9)	0.0485 (9)	0.0440 (9)	−0.0010 (7)	0.0103 (7)	0.0055 (7)
C2	0.0370 (8)	0.0410 (8)	0.0394 (8)	0.0035 (6)	0.0048 (6)	−0.0004 (6)
C3	0.0342 (7)	0.0375 (7)	0.0415 (8)	0.0009 (5)	0.0072 (6)	−0.0031 (6)
C4	0.0394 (9)	0.0446 (8)	0.0376 (8)	−0.0009 (6)	0.0054 (6)	0.0035 (6)
C5	0.0366 (8)	0.0448 (8)	0.0394 (8)	0.0008 (6)	0.0028 (6)	−0.0033 (6)
C6	0.0349 (8)	0.0463 (8)	0.0437 (8)	−0.0010 (6)	0.0080 (6)	−0.0030 (6)
C7	0.0425 (9)	0.0529 (9)	0.0527 (10)	−0.0008 (7)	0.0113 (7)	0.0011 (7)
C8	0.0399 (9)	0.0610 (10)	0.0480 (9)	−0.0040 (7)	0.0028 (7)	−0.0008 (7)

N1—C3	1.3787 (19)	C1—C2	1.392 (2)
N1—H1A	0.8600	C1—H1C	0.9300
N1—H1B	0.8600	C2—C3	1.419 (2)
N2—C2	1.366 (2)	C3—C4	1.387 (2)
N2—H2A	0.8600	C4—C5	1.395 (2)
N2—H2B	0.8600	C4—H4A	0.9300
N3—C7	1.140 (2)	C5—C6	1.399 (2)
N4—C8	1.142 (2)	C5—C8	1.432 (2)
C1—C6	1.390 (2)	C6—C7	1.441 (2)
C6···C7i	3.473 (2)
C3—N1—H1A	120.0	N1—C3—C2	120.18 (13)
C3—N1—H1B	120.0	C4—C3—C2	119.18 (13)
H1A—N1—H1B	120.0	C3—C4—C5	121.64 (14)
C2—N2—H2A	120.0	C3—C4—H4A	119.2
C2—N2—H2B	120.0	C5—C4—H4A	119.2
H2A—N2—H2B	120.0	C4—C5—C6	119.15 (13)
C6—C1—C2	121.61 (14)	C4—C5—C8	120.90 (14)
C6—C1—H1C	119.2	C6—C5—C8	119.95 (13)
C2—C1—H1C	119.2	C1—C6—C5	119.61 (13)
N2—C2—C1	120.78 (14)	C1—C6—C7	119.94 (14)
N2—C2—C3	120.42 (14)	C5—C6—C7	120.45 (14)
C1—C2—C3	118.80 (14)	N3—C7—C6	179.01 (18)
N1—C3—C4	120.48 (14)	N4—C8—C5	178.92 (19)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···N3ii	0.86	2.47	3.283 (2)	158
N2—H2B···N4iii	0.86	2.37	3.225 (2)	171
N1—H1A···N1iv	0.86	2.52	3.3729 (16)	169
N1—H1B···N4iii	0.86	2.34	3.188 (2)	171

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯N3i	0.86	2.47	3.283 (2)	158
N2—H2B⋯N4ii	0.86	2.37	3.225 (2)	171
N1—H1A⋯N1iii	0.86	2.52	3.3729 (16)	169
N1—H1B⋯N4ii	0.86	2.34	3.188 (2)	171

Symmetry codes: (i) ; (ii) ; (iii) .