trans-Dibromidobis(3-methyl-pyridine-κN)copper(II).

The asymmetric unit of the title compound, [CuBr(2)(C(6)H(7)N)(2)], contains one half-mol-ecule, the whole mol-ecule being generated by inversion through a center located at the Cu(II) atom. The geometry around the Cu(II) atom is square planar. Semicoordinate Cu⋯Br bonds [3.269 (1) Å] and nonclassical C-H⋯Br hydrogen bonds connect the mol-ecules, forming chains running parallel to the a axis. These chains are further linked via additional C-H⋯Br hydrogen bonds into a three-dimensional network.

Related literature

The title compound was prepared to investigate chloro-methyl and bromo-methyl exchange rules in the crystal structures of [Cu(3YP)2Br2] complexes (where 3YP = 3-substituted pyridine and Y = Cl, Br and meth­yl), see: Awwadi et al. (2006 ▶, 2011 ▶). Desiraju showed that the chloro-methyl exchange rule is obeyed if the final structure is stabilized by dispersive forces, see: Desiraju & Sarma (1986 ▶). For related structures, see: Marsh et al. (1981 ▶, 1982 ▶); Singh et al. (1972 ▶).

Experimental

Crystal data

[CuBr2(C6H7N)2]

M = 409.61

Monoclinic,

a = 4.0171 (8) Å

b = 14.105 (3) Å

c = 11.899 (2) Å

β = 92.54 (3)°

V = 673.5 (2) Å3

Z = 2

Mo Kα radiation

μ = 7.53 mm−1

T = 85 K

0.24 × 0.03 × 0.03 mm

Data collection

Bruker/Siemens SMART APEX diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T min = 0.265, T max = 0.806

5995 measured reflections

1536 independent reflections

1283 reflections with I > 2σ(I)

R int = 0.044

Refinement

R[F 2 > 2σ(F 2)] = 0.032

wR(F 2) = 0.075

S = 1.01

1536 reflections

80 parameters

H-atom parameters constrained

Δρmax = 0.97 e Å−3

Δρmin = −0.47 e Å−3

Data collection: SMART (Bruker, 2002 ▶); cell refinement: SAINT-Plus (Bruker, 2001 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Click here for additional data file.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813001414/lr2097sup1.cif

Click here for additional data file.

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813001414/lr2097Isup2.hkl

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

[CuBr2(C6H7N)2]	F(000) = 398
Mr = 409.61	Dx = 2.020 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2369 reflections
a = 4.0171 (8) Å	θ = 2.2–29.8°
b = 14.105 (3) Å	µ = 7.53 mm−1
c = 11.899 (2) Å	T = 85 K
β = 92.54 (3)°	Needle, green
V = 673.5 (2) Å3	0.24 × 0.03 × 0.03 mm
Z = 2

Bruker/Siemens SMART APEX diffractometer	1536 independent reflections
Radiation source: normal-focus sealed tube	1283 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
Detector resolution: 8.3 pixels mm-1	θmax = 27.5°, θmin = 2.9°
ω scans	h = −5→4
Absorption correction: multi-scan (SADABS; Bruker, 2001)	k = −16→18
Tmin = 0.265, Tmax = 0.806	l = −14→15
5995 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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.075	H-atom parameters constrained
S = 1.01	w = 1/[σ2(Fo2) + (0.0388P)2] where P = (Fo2 + 2Fc2)/3
1536 reflections	(Δ/σ)max < 0.001
80 parameters	Δρmax = 0.97 e Å−3
0 restraints	Δρmin = −0.47 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
Br1	0.12621 (8)	0.03733 (3)	0.83940 (3)	0.01337 (12)
Cu1	0.5000	0.0000	1.0000	0.01824 (18)
N1	0.5100 (7)	0.1368 (2)	1.0454 (2)	0.0154 (7)
C2	0.6317 (9)	0.2051 (3)	0.9789 (3)	0.0158 (8)
H2	0.7116	0.1869	0.9081	0.019*
C3	0.6464 (9)	0.2998 (3)	1.0082 (3)	0.0153 (8)
C4	0.5247 (9)	0.3257 (3)	1.1112 (3)	0.0165 (8)
H4	0.5317	0.3899	1.1350	0.020*
C5	0.3921 (9)	0.2560 (3)	1.1791 (3)	0.0163 (8)
H5	0.3024	0.2725	1.2490	0.020*
C6	0.3925 (8)	0.1636 (3)	1.1440 (3)	0.0160 (8)
H6	0.3057	0.1165	1.1916	0.019*
C7	0.7889 (9)	0.3717 (3)	0.9301 (3)	0.0211 (9)
H7A	0.8971	0.3389	0.8690	0.032*
H7B	0.9531	0.4110	0.9719	0.032*
H7C	0.6094	0.4120	0.8986	0.032*

	U11	U22	U33	U12	U13	U23
Br1	0.0162 (2)	0.0089 (2)	0.01488 (19)	−0.00020 (14)	−0.00062 (13)	0.00010 (13)
Cu1	0.0286 (4)	0.0059 (3)	0.0194 (3)	0.0034 (3)	−0.0089 (3)	−0.0029 (2)
N1	0.0213 (16)	0.0084 (17)	0.0160 (15)	0.0025 (12)	−0.0051 (12)	−0.0015 (11)
C2	0.0178 (19)	0.015 (2)	0.0144 (17)	0.0028 (15)	−0.0028 (14)	−0.0033 (14)
C3	0.0138 (19)	0.012 (2)	0.0199 (19)	−0.0013 (14)	−0.0027 (14)	0.0015 (14)
C4	0.019 (2)	0.0076 (19)	0.0221 (19)	−0.0002 (15)	−0.0038 (15)	−0.0030 (14)
C5	0.0191 (18)	0.017 (2)	0.0132 (18)	0.0000 (15)	0.0024 (14)	−0.0019 (14)
C6	0.0156 (19)	0.013 (2)	0.0193 (19)	−0.0044 (14)	−0.0007 (15)	0.0010 (14)
C7	0.024 (2)	0.016 (2)	0.023 (2)	−0.0033 (16)	0.0020 (16)	0.0028 (15)

Br1—Cu1	2.4351 (8)	C3—C7	1.506 (5)
Cu1—N1i	2.004 (3)	C4—C5	1.393 (5)
Cu1—N1	2.004 (3)	C4—H4	0.9500
Cu1—Br1i	2.4351 (8)	C5—C6	1.369 (5)
N1—C6	1.338 (4)	C5—H5	0.9500
N1—C2	1.351 (5)	C6—H6	0.9500
C2—C3	1.382 (5)	C7—H7A	0.9800
C2—H2	0.9500	C7—H7B	0.9800
C3—C4	1.388 (5)	C7—H7C	0.9800
N1i—Cu1—N1	180.000 (1)	C3—C4—C5	119.0 (4)
N1i—Cu1—Br1	89.57 (8)	C3—C4—H4	120.5
N1—Cu1—Br1	90.43 (8)	C5—C4—H4	120.5
N1i—Cu1—Br1i	90.43 (8)	C6—C5—C4	119.3 (3)
N1—Cu1—Br1i	89.57 (8)	C6—C5—H5	120.4
Br1—Cu1—Br1i	180.0	C4—C5—H5	120.4
C6—N1—C2	117.6 (3)	N1—C6—C5	122.8 (3)
C6—N1—Cu1	120.3 (3)	N1—C6—H6	118.6
C2—N1—Cu1	122.1 (2)	C5—C6—H6	118.6
N1—C2—C3	123.6 (3)	C3—C7—H7A	109.5
N1—C2—H2	118.2	C3—C7—H7B	109.5
C3—C2—H2	118.2	H7A—C7—H7B	109.5
C2—C3—C4	117.7 (3)	C3—C7—H7C	109.5
C2—C3—C7	120.6 (3)	H7A—C7—H7C	109.5
C4—C3—C7	121.8 (3)	H7B—C7—H7C	109.5
Br1—Cu1—N1—C6	117.1 (2)	N1—C2—C3—C7	179.4 (3)
Br1i—Cu1—N1—C6	−62.9 (2)	C2—C3—C4—C5	−0.6 (5)
Br1—Cu1—N1—C2	−62.5 (3)	C7—C3—C4—C5	179.2 (3)
Br1i—Cu1—N1—C2	117.5 (3)	C3—C4—C5—C6	1.6 (5)
C6—N1—C2—C3	1.2 (5)	C2—N1—C6—C5	−0.1 (5)
Cu1—N1—C2—C3	−179.1 (3)	Cu1—N1—C6—C5	−179.8 (3)
N1—C2—C3—C4	−0.9 (5)	C4—C5—C6—N1	−1.3 (5)

D—H···A	D—H	H···A	D···A	D—H···A
C2—H2···Br1ii	0.95	2.83	3.549 (4)	133
C6—H6···Br1iii	0.95	2.79	3.529 (4)	135
C5—H5···Br1iv	0.95	2.99	3.668 (4)	130

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2⋯Br1i	0.95	2.83	3.549 (4)	133
C6—H6⋯Br1ii	0.95	2.79	3.529 (4)	135
C5—H5⋯Br1iii	0.95	2.99	3.668 (4)	130

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