Redetermination of (E)-N,N'-bis-(4-bromo-phen-yl)formamidine.

In comprison with the previous structural study [Anulewicz et al. (1991 ▶). Pol. J. Chem.65, 465-471], for which only the coordinates of all non-H atoms and of some H atoms were reported, the current redetermination of the title compound, C(13)H(10)Br(2)N(2), additionally reports anisotropic displacement parameters for all non-H atoms and the coordinates of all H atoms, accompanied by higher accuracy of the geometric parameters. Two independent half-mol-ecules are present in the asymmetric unit, which are completed by a twofold rotation axis as symmetry element. In the crystal, inter-molecular N-H⋯N hydrogen bonds link the mol-ecules into dimers. Linear chains parallel to [102] are formed by inter-molecular Br⋯Br inter-actions of 3.4328 (7) Å between two Br atoms of adjacent mol-ecules. The dihedral angles between the benzene rings are 50.05 (15) and 75.61 (11)° in the two independent molecules. Owing to the twofold symmetry of the mol-ecules, H atoms attached to the N atoms are only half-occupied, leading to them being disordered over two positions of equal occupancy.

Related literature

For the previous structure determination, see: Anulewicz et al. (1991 ▶). For Br⋯Br inter­actions, see: Fujiwara et al. (2006 ▶); Reddy et al. (1996 ▶). For N—H⋯N hydrogen bonds, see: Del Bene & Elguero (2006 ▶); Grotjahn et al. (2000 ▶); Thar & Kirchner (2006 ▶).

Experimental

Crystal data

C13H10Br2N2

M = 354.05

Monoclinic,

a = 11.563 (2) Å

b = 23.447 (5) Å

c = 9.881 (2) Å

β = 95.43 (3)°

V = 2666.9 (9) Å3

Z = 8

Mo Kα radiation

μ = 6.06 mm−1

T = 293 K

0.15 × 0.07 × 0.06 mm

Data collection

Bruker SMART CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T min = 0.403, T max = 0.695

5954 measured reflections

2611 independent reflections

1715 reflections with I > 2σ(I)

R int = 0.061

Refinement

R[F 2 > 2σ(F 2)] = 0.048

wR(F 2) = 0.114

S = 1.00

2611 reflections

155 parameters

H-atom parameters constrained

Δρmax = 0.48 e Å−3

Δρmin = −0.91 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 (Sheldrick, 2008 ▶) and DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXL97.

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811013419/wm2476sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811013419/wm2476Isup2.hkl

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

C13H10Br2N2	F(000) = 1376
Mr = 354.05	Dx = 1.764 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 4303 reflections
a = 11.563 (2) Å	θ = 2.5–26.7°
b = 23.447 (5) Å	µ = 6.06 mm−1
c = 9.881 (2) Å	T = 293 K
β = 95.43 (3)°	Needle, colourless
V = 2666.9 (9) Å3	0.15 × 0.07 × 0.06 mm
Z = 8

Bruker SMART CCD diffractometer	2611 independent reflections
Radiation source: fine-focus sealed tube	1715 reflections with I > 2σ(I)
graphite	Rint = 0.061
ω scans	θmax = 26.0°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −12→14
Tmin = 0.403, Tmax = 0.695	k = −26→28
5954 measured reflections	l = −12→11

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)] = 0.048	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.114	H-atom parameters constrained
S = 1.00	w = 1/[σ2(Fo2) + (0.0533P)2] where P = (Fo2 + 2Fc2)/3
2611 reflections	(Δ/σ)max = 0.001
155 parameters	Δρmax = 0.48 e Å−3
0 restraints	Δρmin = −0.91 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	Occ. (<1)
Br1	0.24399 (5)	0.73912 (2)	0.82770 (5)	0.0708 (2)
N1	0.4449 (3)	0.63281 (13)	0.3396 (3)	0.0429 (8)
H2A	0.4352	0.5975	0.3271	0.052*	0.50
C1	0.5000	0.6600 (2)	0.2500	0.0428 (13)
H1	0.5000	0.6997	0.2500	0.051*
C11	0.3994 (4)	0.65996 (16)	0.4505 (4)	0.0404 (9)
C12	0.4347 (4)	0.71277 (17)	0.4995 (4)	0.0525 (11)
H12A	0.4903	0.7329	0.4570	0.063*
C13	0.3885 (4)	0.73617 (18)	0.6108 (5)	0.0569 (11)
H13A	0.4131	0.7719	0.6428	0.068*
C14	0.3065 (4)	0.70681 (17)	0.6738 (4)	0.0459 (10)
C15	0.2716 (4)	0.65412 (19)	0.6293 (4)	0.0560 (11)
H15A	0.2171	0.6340	0.6737	0.067*
C16	0.3177 (4)	0.63066 (17)	0.5178 (4)	0.0546 (11)
H16A	0.2935	0.5947	0.4873	0.066*
Br2	0.02928 (6)	0.61567 (3)	1.05388 (8)	0.1036 (3)
N2	0.4121 (3)	0.49146 (13)	0.7963 (3)	0.0507 (8)
H3A	0.4085	0.4541	0.7936	0.061*	0.50
C2	0.5000	0.5180 (2)	0.7500	0.0520 (15)
H2B	0.5000	0.5577	0.7500	0.062*
C21	0.3242 (4)	0.52137 (16)	0.8556 (4)	0.0455 (10)
C22	0.2110 (4)	0.50352 (19)	0.8320 (5)	0.0588 (12)
H32A	0.1933	0.4723	0.7758	0.071*
C23	0.1229 (4)	0.53143 (19)	0.8908 (5)	0.0635 (12)
H33A	0.0466	0.5189	0.8746	0.076*
C24	0.1488 (4)	0.57764 (18)	0.9729 (5)	0.0561 (11)
C25	0.2603 (4)	0.59524 (19)	0.9991 (4)	0.0584 (12)
H35A	0.2774	0.6264	1.0557	0.070*
C26	0.3483 (4)	0.56719 (17)	0.9422 (4)	0.0561 (11)
H36A	0.4247	0.5791	0.9621	0.067*

	U11	U22	U33	U12	U13	U23
Br1	0.0872 (4)	0.0873 (4)	0.0409 (3)	0.0246 (3)	0.0215 (2)	−0.0074 (2)
N1	0.046 (2)	0.0446 (17)	0.0413 (18)	0.0019 (15)	0.0199 (15)	−0.0018 (14)
C1	0.040 (3)	0.042 (3)	0.047 (3)	0.000	0.006 (3)	0.000
C11	0.044 (2)	0.046 (2)	0.033 (2)	0.0046 (18)	0.0111 (17)	0.0051 (17)
C12	0.059 (3)	0.056 (2)	0.045 (2)	−0.014 (2)	0.017 (2)	−0.001 (2)
C13	0.070 (3)	0.056 (2)	0.046 (3)	−0.009 (2)	0.012 (2)	−0.007 (2)
C14	0.056 (3)	0.055 (2)	0.028 (2)	0.010 (2)	0.0129 (18)	−0.0038 (18)
C15	0.053 (3)	0.073 (3)	0.047 (2)	−0.005 (2)	0.029 (2)	0.000 (2)
C16	0.064 (3)	0.051 (2)	0.053 (3)	−0.009 (2)	0.025 (2)	−0.003 (2)
Br2	0.0764 (5)	0.0940 (5)	0.1485 (7)	0.0149 (3)	0.0538 (4)	−0.0264 (4)
N2	0.046 (2)	0.0459 (18)	0.063 (2)	0.0002 (16)	0.0217 (17)	−0.0012 (17)
C2	0.055 (4)	0.043 (3)	0.059 (4)	0.000	0.011 (3)	0.000
C21	0.047 (3)	0.044 (2)	0.047 (2)	0.0014 (18)	0.0127 (19)	0.0011 (18)
C22	0.049 (3)	0.061 (3)	0.067 (3)	−0.010 (2)	0.014 (2)	−0.019 (2)
C23	0.035 (3)	0.078 (3)	0.079 (3)	−0.006 (2)	0.014 (2)	−0.016 (3)
C24	0.052 (3)	0.057 (3)	0.062 (3)	0.011 (2)	0.019 (2)	0.000 (2)
C25	0.057 (3)	0.053 (3)	0.067 (3)	0.000 (2)	0.017 (2)	−0.014 (2)
C26	0.047 (3)	0.059 (3)	0.061 (3)	−0.007 (2)	0.005 (2)	−0.010 (2)

Br1—C14	1.901 (4)	Br2—C24	1.886 (4)
N1—C1	1.305 (4)	N2—C2	1.311 (4)
N1—C11	1.412 (5)	N2—C21	1.407 (5)
N1—H2A	0.8422	N2—H3A	0.8763
C1—N1i	1.305 (4)	C2—N2ii	1.311 (4)
C1—H1	0.9300	C2—H2B	0.9300
C11—C12	1.377 (5)	C21—C22	1.373 (6)
C11—C16	1.388 (6)	C21—C26	1.385 (5)
C12—C13	1.381 (6)	C22—C23	1.383 (6)
C12—H12A	0.9300	C22—H32A	0.9300
C13—C14	1.369 (6)	C23—C24	1.369 (6)
C13—H13A	0.9300	C23—H33A	0.9300
C14—C15	1.360 (6)	C24—C25	1.355 (6)
C15—C16	1.383 (6)	C25—C26	1.375 (6)
C15—H15A	0.9300	C25—H35A	0.9300
C16—H16A	0.9300	C26—H36A	0.9300
C1—N1—C11	123.2 (3)	C2—N2—C21	121.5 (3)
C1—N1—H2A	116.6	C2—N2—H3A	120.0
C11—N1—H2A	120.1	C21—N2—H3A	118.5
N1i—C1—N1	121.4 (5)	N2ii—C2—N2	123.3 (5)
N1i—C1—H1	119.3	N2ii—C2—H2B	118.4
N1—C1—H1	119.3	N2—C2—H2B	118.4
C12—C11—C16	118.0 (4)	C22—C21—C26	118.3 (4)
C12—C11—N1	123.9 (4)	C22—C21—N2	119.4 (3)
C16—C11—N1	118.0 (3)	C26—C21—N2	122.2 (4)
C11—C12—C13	120.9 (4)	C21—C22—C23	120.8 (4)
C11—C12—H12A	119.6	C21—C22—H32A	119.6
C13—C12—H12A	119.6	C23—C22—H32A	119.6
C14—C13—C12	120.0 (4)	C24—C23—C22	119.6 (4)
C14—C13—H13A	120.0	C24—C23—H33A	120.2
C12—C13—H13A	120.0	C22—C23—H33A	120.2
C15—C14—C13	120.5 (4)	C25—C24—C23	120.3 (4)
C15—C14—Br1	119.8 (3)	C25—C24—Br2	119.8 (3)
C13—C14—Br1	119.7 (3)	C23—C24—Br2	119.8 (3)
C14—C15—C16	119.6 (4)	C24—C25—C26	120.2 (4)
C14—C15—H15A	120.2	C24—C25—H35A	119.9
C16—C15—H15A	120.2	C26—C25—H35A	119.9
C15—C16—C11	121.1 (4)	C25—C26—C21	120.7 (4)
C15—C16—H16A	119.5	C25—C26—H36A	119.7
C11—C16—H16A	119.5	C21—C26—H36A	119.7

D—H···A	D—H	H···A	D···A	D—H···A
N1—H2A···N2iii	0.85	2.12	2.964 (4)	180
N2—H3A···N1iv	0.88	2.12	2.964 (4)	161

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H2A⋯N2i	0.85	2.12	2.964 (4)	180
N2—H3A⋯N1ii	0.88	2.12	2.964 (4)	161

Symmetry codes: (i) ; (ii) .