2,2',5,5'-Tetra-chloro-benzidine.

In the crystal structure of the title compound, C(12)H(8)Cl(4)N(2), mol-ecules lie on crystallographic twofold axes at the centre of the C-C bonds linking the benzene rings, such that the asymmetric unit consists of a half-mol-ecule. The individual mol-ecules participate in inter-molecular N-H⋯N, N-H⋯Cl, C-H⋯Cl and Cl⋯Cl [3.4503 (3) Å] inter-actions.

Related literature

For studies involving the use of benzidines in organic syntheses, see: Schwenecke & Mayer (2005 ▶). For studies on 2,2′,5,5′-tetra­chloro­benzidine in crystal engineering, see: Dobrzycki & Wozniak (2007 ▶, 2008 ▶). For our studies on related structures, see: Beatty et al. (2002a ▶, 2002b ▶); Ugono et al. (2009 ▶).

Experimental

Crystal data

C12H8Cl4N2

M = 322.00

Monoclinic,

a = 17.2346 (11) Å

b = 3.8767 (2) Å

c = 18.1573 (19) Å

β = 94.872 (3)°

V = 1208.77 (16) Å3

Z = 4

Mo Kα radiation

μ = 0.96 mm−1

T = 100 K

0.23 × 0.22 × 0.14 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.806, T max = 0.879

11878 measured reflections

2961 independent reflections

2595 reflections with I > 2σ(I)

R int = 0.025

Refinement

R[F 2 > 2σ(F 2)] = 0.025

wR(F 2) = 0.075

S = 1.07

2961 reflections

82 parameters

H-atom parameters constrained

Δρmax = 0.62 e Å−3

Δρmin = −0.67 e Å−3

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); 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 and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810030886/fj2305sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810030886/fj2305Isup2.hkl

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

C12H8Cl4N2	F(000) = 648
Mr = 322.00	Dx = 1.769 Mg m−3
Monoclinic, I2/a	Melting point = 309–311 K
Hall symbol: -I 2ya	Mo Kα radiation, λ = 0.71073 Å
a = 17.2346 (11) Å	Cell parameters from 5249 reflections
b = 3.8767 (2) Å	θ = 4.5–36.4°
c = 18.1573 (19) Å	µ = 0.96 mm−1
β = 94.872 (3)°	T = 100 K
V = 1208.77 (16) Å3	Blocks, colorless
Z = 4	0.23 × 0.22 × 0.14 mm

Bruker APEXII CCD diffractometer	2961 independent reflections
Radiation source: fine-focus sealed tube	2595 reflections with I > 2σ(I)
graphite	Rint = 0.025
φ and ω scans	θmax = 36.4°, θmin = 3.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −28→28
Tmin = 0.806, Tmax = 0.879	k = −3→6
11878 measured reflections	l = −30→26

Refinement on F2	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F2 > 2σ(F2)] = 0.025	w = 1/[σ2(Fo2) + (0.0404P)2 + 0.5838P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.075	(Δ/σ)max < 0.001
S = 1.07	Δρmax = 0.62 e Å−3
2961 reflections	Δρmin = −0.67 e Å−3
82 parameters

Experimental. All H atoms were added in their calculated positions and were treated using appropriate riding models.

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
Cl1	0.160889 (12)	0.57866 (5)	0.112011 (11)	0.01179 (5)
Cl2	0.490222 (11)	−0.04833 (5)	0.098542 (11)	0.01279 (6)
N1	0.42631 (4)	0.2547 (2)	0.23242 (4)	0.01399 (13)
H1A	0.4109	0.3405	0.2736	0.017*
H1B	0.4733	0.1666	0.2320	0.017*
C1	0.25315 (5)	0.4094 (2)	0.10312 (5)	0.00977 (13)
C2	0.27558 (5)	0.2934 (2)	0.03511 (4)	0.00940 (12)
C3	0.35064 (5)	0.1556 (2)	0.03688 (4)	0.01012 (13)
H3	0.3688	0.0715	−0.0077	0.012*
C4	0.39925 (5)	0.1373 (2)	0.10113 (5)	0.00990 (13)
C5	0.37670 (5)	0.2584 (2)	0.16844 (4)	0.01036 (13)
C6	0.30195 (5)	0.3964 (2)	0.16774 (5)	0.01065 (13)
H6	0.2842	0.4830	0.2123	0.013*

	U11	U22	U33	U12	U13	U23
Cl1	0.00978 (9)	0.01507 (9)	0.01067 (9)	0.00235 (6)	0.00183 (6)	0.00083 (6)
Cl2	0.00832 (9)	0.01894 (10)	0.01088 (10)	0.00207 (6)	−0.00065 (6)	0.00105 (6)
N1	0.0119 (3)	0.0218 (3)	0.0076 (3)	0.0000 (3)	−0.0027 (2)	−0.0006 (2)
C1	0.0089 (3)	0.0118 (3)	0.0086 (3)	0.0002 (2)	0.0006 (2)	0.0005 (2)
C2	0.0084 (3)	0.0118 (3)	0.0079 (3)	−0.0002 (2)	0.0000 (2)	0.0000 (2)
C3	0.0093 (3)	0.0127 (3)	0.0081 (3)	0.0001 (2)	−0.0002 (2)	−0.0006 (2)
C4	0.0076 (3)	0.0130 (3)	0.0088 (3)	0.0001 (2)	−0.0004 (2)	0.0003 (2)
C5	0.0098 (3)	0.0128 (3)	0.0082 (3)	−0.0021 (2)	−0.0009 (2)	0.0005 (2)
C6	0.0110 (3)	0.0135 (3)	0.0074 (3)	−0.0007 (2)	0.0005 (2)	−0.0005 (2)

Cl1—C1	1.7402 (8)	C2—C3	1.3974 (11)
Cl2—C4	1.7295 (8)	C2—C2i	1.4872 (16)
N1—C5	1.3827 (11)	C3—C4	1.3791 (11)
N1—H1A	0.8800	C3—H3	0.9500
N1—H1B	0.8800	C4—C5	1.3948 (12)
C1—C6	1.3854 (12)	C5—C6	1.3940 (12)
C1—C2	1.3993 (12)	C6—H6	0.9500
C5—N1—H1A	120.0	C2—C3—H3	118.9
C5—N1—H1B	120.0	C3—C4—C5	121.97 (7)
H1A—N1—H1B	120.0	C3—C4—Cl2	119.03 (6)
C6—C1—C2	122.84 (8)	C5—C4—Cl2	118.98 (6)
C6—C1—Cl1	115.40 (6)	N1—C5—C6	121.10 (8)
C2—C1—Cl1	121.75 (6)	N1—C5—C4	122.30 (8)
C3—C2—C1	115.29 (7)	C6—C5—C4	116.56 (7)
C3—C2—C2i	120.00 (8)	C1—C6—C5	121.05 (8)
C1—C2—C2i	124.63 (8)	C1—C6—H6	119.5
C4—C3—C2	122.26 (8)	C5—C6—H6	119.5
C4—C3—H3	118.9
C6—C1—C2—C3	1.26 (12)	C3—C4—C5—N1	−177.11 (8)
Cl1—C1—C2—C3	−178.33 (6)	Cl2—C4—C5—N1	4.10 (11)
C6—C1—C2—C2i	178.20 (6)	C3—C4—C5—C6	0.59 (12)
Cl1—C1—C2—C2i	−1.39 (9)	Cl2—C4—C5—C6	−178.20 (6)
C1—C2—C3—C4	−0.36 (12)	C2—C1—C6—C5	−1.26 (12)
C2i—C2—C3—C4	−177.46 (6)	Cl1—C1—C6—C5	178.35 (6)
C2—C3—C4—C5	−0.56 (13)	N1—C5—C6—C1	178.02 (8)
C2—C3—C4—Cl2	178.23 (6)	C4—C5—C6—C1	0.29 (12)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl2ii	0.88	2.79	3.3650 (8)	124
C3—H3···Cl1iii	0.95	2.71	3.5013 (9)	141
N1—H1B···N1ii	0.88	2.90	3.2159 (12)	103

Cl1···Cl2i

3.4503 (3)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Cl2i	0.88	2.79	3.3650 (8)	124
C3—H3⋯Cl1ii	0.95	2.71	3.5013 (9)	141
N1—H1B⋯N1i	0.88	2.90	3.2159 (12)	103

Symmetry codes: (i) ; (ii) .