2,2′,5,5′-Tetra­chloro­benzidine

Ugono, O.; Douglas Jr, M.; Rath, N.P.; Beatty, A.M.

doi:10.1107/S1600536810030886

organic compounds

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ISSN: 2056-9890

Volume 66| Part 9| September 2010| Page o2285

https://doi.org/10.1107/S1600536810030886

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2,2′,5,5′-Tetrachlorobenzidine

Onome Ugono,^a Marcel Douglas Jr,^a Nigam P. Rath ^a and Alicia M. Beatty ^a ^*

^aDepartment of Chemistry and Biochemistry, University of Missouri–St Louis, St Louis, Missouri, USA
^*Correspondence e-mail: beattya@umsl.edu

(Received 17 May 2010; accepted 2 August 2010; online 11 August 2010)

In the crystal structure of the title compound, C₁₂H₈Cl₄N₂, molecules 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-molecule. The individual molecules participate in intermolecular N—H⋯N, N—H⋯Cl, C—H⋯Cl and Cl⋯Cl [3.4503 (3) Å] interactions.

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_r = 322.00
Monoclinic, I 2/a
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[F² > 2σ(F²)] = 0.025
wR(F²) = 0.075
S = 1.07
2961 reflections
82 parameters
H-atom parameters constrained
Δρ_max = 0.62 e Å⁻³
Δρ_min = −0.67 e Å⁻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) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (ii) $[-x+{\script{1\over 2}}, y-1, -z]$ .

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 ).

Supporting information

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

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536810030886/fj2305Isup2.hkl

checkCIF report

Comment top

Benzidines are of great importance in the pigments industry, as their derivatives are employed in the syntheses of a variety of azo-dyes (Schwenecke and Mayer 2005). Furthermore, the presence of two amine functionalities renders this class of molecules attractive to crystal engineers, who may wish to incorporate this class of rigid linear molecule in larger extended networks via hydrogen bonds (Dobrzycki and Wozniak 2008 a, b). During the course of experiments aimed at reacting the title compound with pyrazole-3,5-dicarboxylic acid, a crystalline phase was obtained and shown to be composed solely of 2,2',5,5'-tetrachlorobenzidine. A search of the Cambridge crystallographic structural database showed that this phase has not previously been reported. This molecule packs in monoclinic I2/a, a non-standard setting of C2/c, with one half of the molecule in the asymmetric unit. Very weak hydrogen bonding interactions exist in the structure; the increased lengths are probably due to the bulky chlorine atoms ortho to the amine functionalities.

Related literature top

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).

For related literature, see: .

Experimental top

A 20 ml scintillation vial was charged with 52.0 mg (0.30 mmol) of 3,5-pyrazole dicarboxylic acid monohydrate, which was dissolved in 5.0 ml of a 3:2 MeOH:H₂O mixture affording a homogenous solution. To this solution was then added 48.3 mg (0.15 mmol) of 2,2',5,5'-tetrachlorobenzidine. The mixture obtained was filtered and the filtrate was allowed to slowly evaporate to yield colorless single crystals of 2,2',5,5'-tetrachlorobenzidine after a week.

Structure description top

For related literature, see: .

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXS97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Figures top

Fig. 1. Molecular structure showing 50% probability displacement ellipsoid.

2,2',5,5'-Tetrachlorobenzidine top

Crystal data top

C₁₂H₈Cl₄N₂	F(000) = 648
M_r = 322.00	D_x = 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

Data collection top

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

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.025	w = 1/[σ²(F_o²) + (0.0404P)² + 0.5838P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.075	(Δ/σ)_max < 0.001
S = 1.07	Δρ_max = 0.62 e Å⁻³
2961 reflections	Δρ_min = −0.67 e Å⁻³
82 parameters

Crystal data top

C₁₂H₈Cl₄N₂	V = 1208.77 (16) Å³
M_r = 322.00	Z = 4
Monoclinic, I2/a	Mo Kα radiation
a = 17.2346 (11) Å	µ = 0.96 mm⁻¹
b = 3.8767 (2) Å	T = 100 K
c = 18.1573 (19) Å	0.23 × 0.22 × 0.14 mm
β = 94.872 (3)°

Data collection top

Bruker APEXII CCD diffractometer	2961 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2595 reflections with I > 2σ(I)
T_min = 0.806, T_max = 0.879	R_int = 0.025
11878 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.025	0 restraints
wR(F²) = 0.075	H-atom parameters constrained
S = 1.07	Δρ_max = 0.62 e Å⁻³
2961 reflections	Δρ_min = −0.67 e Å⁻³
82 parameters

Special details top

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.

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

	x	y	z	U_iso*/U_eq
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*

Atomic displacement parameters (Å²) top

	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)

Geometric parameters (Å, º) top

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)

Symmetry code: (i) −x+1/2, y, −z.

Hydrogen-bond geometry (Å, º) top

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

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

Experimental details

Crystal data
Chemical formula	C₁₂H₈Cl₄N₂
M_r	322.00
Crystal system, space group	Monoclinic, I2/a
Temperature (K)	100
a, b, c (Å)	17.2346 (11), 3.8767 (2), 18.1573 (19)
β (°)	94.872 (3)
V (Å³)	1208.77 (16)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.96
Crystal size (mm)	0.23 × 0.22 × 0.14

Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.806, 0.879
No. of measured, independent and observed [I > 2σ(I)] reflections	11878, 2961, 2595
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.836

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.075, 1.07
No. of reflections	2961
No. of parameters	82
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.62, −0.67

Computer programs: APEX2 (Bruker, 2007), SAINT (Bruker, 2007), SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).

Hydrogen-bond geometry (Å, º) top

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) −x+1, y+1/2, −z+1/2; (ii) −x+1/2, y−1, −z.

Cl···Cl interactions (Å) top

Cl1···Cl2ⁱ

3.4503 (3)

Symmetry code: (i) -1/2+x, 1-y, z.

Acknowledgements

The authors are grateful to the University of Missouri–St. Louis for generous support and instrumentation. MD is grateful to the ACS Project SEED for a summer research fellowship. AMB acknowledges support from the NSF-CAREER # 0645758.

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