Bis[μ-2-(pyridin-2-yl)ethano­lato]bis­[bromidocopper(II)]

Shaikh, M.M.; Mathur, S.; Uddin, M.J.

doi:10.1107/S1600536811043637

metal-organic compounds

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Volume 67| Part 11| November 2011| Page m1612

doi:10.1107/S1600536811043637

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Bis[μ-2-(pyridin-2-yl)ethanolato]bis[bromidocopper(II)]

M. Mobin Shaikh,^a ^* Saloni Mathur ^a and Md. Jamal Uddin ^b

^aNational Single Crystal X-ray Diffraction Facility, IIT Bombay, Powai, Mumbai 400 076, India, and ^bDepartment of Natural Sciences, Coppin State University, 2500 West North Avenue, Baltimore, Maryland 21216, USA
^*Correspondence e-mail: xray@chem.iitb.ac.in

(Received 25 September 2011; accepted 20 October 2011; online 29 October 2011)

The title compound, [Cu₂Br₂(C₇H₈NO)₂], was synthesized by reaction of CuBr₂ with 2-(pyridin-2-yl)ethanol (hep-H) in methanol. The asymmetric unit consists of one hep ligand and a CuBr unit. The Cu²⁺ ion is thereby coordinated by the N atom and the deprotonated hydroxy O atom in a distorted square-planar geometry that is completed by another O atom. The latter acts as bridging ligand towards the second, symmetry-equivalent, Cu atom, thus generating a centrosymmetric dimeric unit, with the inversion centre halfway between the Cu atoms. These units are linked via C—H⋯Br and C—H⋯O hydrogen bonds, leading to the formation of a hydrogen-bonded one-dimensional-polymeric chain along a..

Related literature

For similar dinuclear copper complexes see Lah et al. (2006 ); Shaikh et al. (2010 ).

Experimental

Crystal data

[Cu₂Br₂(C₇H₈NO)₂]
M_r = 531.19
Triclinic, $[P \overline 1]$
a = 4.2066 (2) Å
b = 8.4338 (3) Å
c = 11.5113 (6) Å
α = 91.122 (4)°
β = 90.195 (3)°
γ = 97.033 (1)°
V = 405.24 (3) Å³
Z = 1
Mo Kα radiation
μ = 7.56 mm⁻¹
T = 150 K
0.28 × 0.21 × 0.17 mm

Data collection

Oxford Diffraction Xcalibur-S diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.]$ )T_min = 0.226, T_max = 0.360
3453 measured reflections
1388 independent reflections
1298 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.087
S = 1.05
1388 reflections
100 parameters
H-atom parameters constrained
Δρ_max = 0.84 e Å⁻³
Δρ_min = −0.74 e Å⁻³

Table 1
Selected geometric parameters (Å, °)

Cu1—O1ⁱ	1.910 (3)
Cu1—O1	1.943 (3)
Cu1—N1	1.977 (3)
Cu1—Br1	2.3670 (6)
Cu1—Cu1ⁱ	3.0294 (9)

O1ⁱ—Cu1—O1	76.32 (12)
Cu1ⁱ—O1—Cu1	103.68 (12)
Symmetry code: (i) -x+2, -y+2, -z+2.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯Br1ⁱⁱ	0.95	3.00	3.716 (4)	134
C6—H6A⋯O1ⁱⁱⁱ	0.99	2.64	3.545 (5)	153
Symmetry codes: (ii) x+1, y, z; (iii) x-1, y, z.

Data collection: CrysAlis CCD (Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.]$ ); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2009 $[Oxford Diffraction (2009). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Yarnton, Oxfordshire, England.]$ ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999 ); software used to prepare material for publication: publCIF (Westrip, 2010 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811043637/fi2115sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536811043637/fi2115Isup2.hkl

checkCIF report

Comment top

Dinuclear Cu(II) complexes have often been used as models to study the magnetic-exchange interactions and as building blocks for the construction of polynuclear compounds with interesting magnetic properties (Lah et al. 2006). The alkoxo bridged dinuclear Cu(II) complexes consists of two copper atoms bridged by two alkoxido oxygen atoms from alkoxypyridine-type ligands have drawn considerable interest in solid state transformations (Shaikh et al. 2010).

The dimeric title compound (Fig.1) features a dinuclear complex with site symmetry –1. The Cu (II) ions are linked via the two µ²-alcoholic oxygen atoms, yielding a four-membered planar ring Cu₂O₂. One pyridine nitrogen atom of hep and the bromide ligands complete the coordination environment, yielding a distorted square-planar geometry. The Cu ions are separated by 3.0294 (9) Å. The µ-O bridge is slightly asymmetric with Cu—O distances of 1.910 (3) and 1.943 (3) Å and Cu—O—Cu angle of 103.68°. (Table 1). These bond-distances and angles are in agreement with the reported dimeric molecules by Lah et al. (2006) and Shaikh et al. (2010).

Moreover, each dimeric unit is further extended through C—H···Br and C—H···O hydrogen bondings (Table 2) with the neighboring dimeric unit forming a one-dimensional-polymeric chains along a-axis (Fig. 2).

Related literature top

For similar dinuclear copper complexes see Lah et al. (2006); Shaikh et al. (2010).

Experimental top

A solution of hep-H (123 mg, 1.0 mmol) in 30 ml methanol was added to a 10 ml methanolic solution of CuBr₂ (223 mg, 1.0 mmol) and the resultant solution was stirred for 2 h at room temperature. The solution was then passed through filter paper (Whatman filter paper, 70 mm) in order to remove any unreacted materials. The filtrate was allowed to stand at room temperature for crystallization. On slow evaporation light blue single crystals of [Cu(µ-hep)Br]₂ were obtained after 10 days. M.P.:488–490 K. Yield: 82%. Anal. Calcd for C₁₄H₁₆Br₂Cu₂N₂O₂ (Mr = 531.19): C,31.66; H, 3.04; N, 5.27. Found: C,31.30; H,3.11; N, 5.67.

Computing details top

Data collection: CrysAlis PRO-CCD (Oxford Diffraction, 2009); cell refinement: CrysAlis PRO-CCD (Oxford Diffraction, 2009); data reduction: CrysAlis PRO-RED (Oxford Diffraction, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. View of the molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level. Symmetry-related moiety generated by i: –x, –y, –z.
	Fig. 2. A tilted perspective view of hydrogen bonded one-dimensional-polymeric chain along a-axis. Hydrogen bonds as dashed lines.

Bis[µ-2-(pyridin-2-yl)ethanolato]bis[bromidocopper(II)] top

Crystal data top

[Cu₂Br₂(C₇H₈NO)₂]	Z = 1
M_r = 531.19	F(000) = 258
Triclinic, P1	D_x = 2.177 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.2066 (2) Å	Cell parameters from 3586 reflections
b = 8.4338 (3) Å	θ = 3.5–30.0°
c = 11.5113 (6) Å	µ = 7.56 mm⁻¹
α = 91.122 (4)°	T = 150 K
β = 90.195 (3)°	Block, blue
γ = 97.033 (1)°	0.28 × 0.21 × 0.17 mm
V = 405.24 (3) Å³

Data collection top

Oxford Diffraction Xcalibur-S diffractometer	1388 independent reflections
Radiation source: Enhance (Mo) X-ray Source	1298 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
Detector resolution: 15.9948 pixels mm^-1	θ_max = 25.0°, θ_min = 3.5°
ω/q scans	h = −5→4
Absorption correction: multi-scan (CrysAlis PRO-RED; Oxford Diffraction, 2009)	k = −9→9
T_min = 0.226, T_max = 0.360	l = −13→13
3453 measured reflections

Refinement top

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.087	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.0549P)² + 0.5089P] where P = (F_o² + 2F_c²)/3
1388 reflections	(Δ/σ)_max = 0.001
100 parameters	Δρ_max = 0.84 e Å⁻³
0 restraints	Δρ_min = −0.74 e Å⁻³

Crystal data top

[Cu₂Br₂(C₇H₈NO)₂]	γ = 97.033 (1)°
M_r = 531.19	V = 405.24 (3) Å³
Triclinic, P1	Z = 1
a = 4.2066 (2) Å	Mo Kα radiation
b = 8.4338 (3) Å	µ = 7.56 mm⁻¹
c = 11.5113 (6) Å	T = 150 K
α = 91.122 (4)°	0.28 × 0.21 × 0.17 mm
β = 90.195 (3)°

Data collection top

Oxford Diffraction Xcalibur-S diffractometer	1388 independent reflections
Absorption correction: multi-scan (CrysAlis PRO-RED; Oxford Diffraction, 2009)	1298 reflections with I > 2σ(I)
T_min = 0.226, T_max = 0.360	R_int = 0.026
3453 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	0 restraints
wR(F²) = 0.087	H-atom parameters constrained
S = 1.05	Δρ_max = 0.84 e Å⁻³
1388 reflections	Δρ_min = −0.74 e Å⁻³
100 parameters

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
Cu1	0.91306 (11)	0.96968 (5)	0.87303 (4)	0.01736 (18)
Br1	0.60658 (9)	0.76112 (4)	0.76674 (3)	0.02191 (18)
O1	1.0535 (7)	1.1399 (3)	0.9846 (2)	0.0219 (6)
N1	1.0035 (8)	1.1189 (4)	0.7436 (3)	0.0174 (7)
C1	1.1498 (10)	1.0720 (5)	0.6475 (4)	0.0220 (9)
H1	1.1873	0.9635	0.6396	0.026*
C2	1.2475 (10)	1.1759 (5)	0.5598 (4)	0.0254 (9)
H2	1.3495	1.1398	0.4925	0.030*
C3	1.1933 (10)	1.3341 (5)	0.5722 (4)	0.0266 (10)
H3	1.2575	1.4082	0.5131	0.032*
C4	1.0444 (10)	1.3833 (5)	0.6716 (4)	0.0226 (9)
H4	1.0082	1.4917	0.6817	0.027*
C5	0.9486 (9)	1.2720 (5)	0.7564 (3)	0.0186 (8)
C6	0.7862 (9)	1.3159 (5)	0.8657 (4)	0.0197 (8)
H6A	0.5811	1.2456	0.8729	0.024*
H6B	0.7365	1.4273	0.8605	0.024*
C7	0.9894 (10)	1.3012 (4)	0.9745 (3)	0.0195 (8)
H7A	1.1934	1.3728	0.9691	0.023*
H7B	0.8737	1.3335	1.0441	0.023*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0243 (3)	0.0158 (3)	0.0116 (3)	0.0008 (2)	0.0009 (2)	0.0016 (2)
Br1	0.0253 (3)	0.0211 (3)	0.0183 (3)	−0.00140 (17)	−0.00193 (18)	0.00043 (17)
O1	0.0347 (17)	0.0151 (14)	0.0161 (15)	0.0033 (12)	−0.0002 (12)	0.0032 (11)
N1	0.0201 (17)	0.0206 (17)	0.0117 (17)	0.0031 (13)	−0.0019 (13)	0.0001 (13)
C1	0.025 (2)	0.024 (2)	0.018 (2)	0.0060 (16)	0.0004 (17)	0.0012 (17)
C2	0.025 (2)	0.035 (2)	0.016 (2)	0.0017 (18)	0.0049 (17)	−0.0003 (18)
C3	0.028 (2)	0.029 (2)	0.022 (2)	−0.0008 (18)	0.0017 (18)	0.0086 (18)
C4	0.027 (2)	0.019 (2)	0.021 (2)	−0.0008 (16)	−0.0011 (17)	0.0030 (16)
C5	0.0153 (19)	0.023 (2)	0.018 (2)	0.0019 (15)	−0.0031 (15)	0.0012 (16)
C6	0.020 (2)	0.0186 (19)	0.021 (2)	0.0043 (16)	0.0010 (16)	0.0007 (16)
C7	0.023 (2)	0.0172 (19)	0.018 (2)	0.0034 (15)	0.0048 (16)	0.0000 (16)

Geometric parameters (Å, º) top

Cu1—O1ⁱ	1.910 (3)	C2—H2	0.9500
Cu1—O1	1.943 (3)	C3—C4	1.387 (6)
Cu1—N1	1.977 (3)	C3—H3	0.9500
Cu1—Br1	2.3670 (6)	C4—C5	1.394 (6)
Cu1—Cu1ⁱ	3.0294 (9)	C4—H4	0.9500
O1—C7	1.426 (4)	C5—C6	1.496 (6)
O1—Cu1ⁱ	1.910 (3)	C6—C7	1.529 (6)
N1—C5	1.344 (5)	C6—H6A	0.9900
N1—C1	1.344 (5)	C6—H6B	0.9900
C1—C2	1.380 (6)	C7—H7A	0.9900
C1—H1	0.9500	C7—H7B	0.9900
C2—C3	1.385 (6)

O1ⁱ—Cu1—O1	76.32 (12)	C2—C3—C4	119.4 (4)
O1ⁱ—Cu1—N1	162.34 (14)	C2—C3—H3	120.3
O1—Cu1—N1	90.44 (12)	C4—C3—H3	120.3
O1ⁱ—Cu1—Br1	98.08 (8)	C3—C4—C5	119.3 (4)
O1—Cu1—Br1	163.87 (9)	C3—C4—H4	120.4
N1—Cu1—Br1	97.69 (10)	C5—C4—H4	120.4
O1ⁱ—Cu1—Cu1ⁱ	38.54 (8)	N1—C5—C4	120.8 (4)
O1—Cu1—Cu1ⁱ	37.78 (8)	N1—C5—C6	116.9 (3)
N1—Cu1—Cu1ⁱ	127.28 (10)	C4—C5—C6	122.4 (4)
Br1—Cu1—Cu1ⁱ	134.80 (3)	C5—C6—C7	112.9 (3)
C7—O1—Cu1ⁱ	125.6 (2)	C5—C6—H6A	109.0
C7—O1—Cu1	124.4 (2)	C7—C6—H6A	109.0
Cu1ⁱ—O1—Cu1	103.68 (12)	C5—C6—H6B	109.0
C5—N1—C1	119.7 (3)	C7—C6—H6B	109.0
C5—N1—Cu1	119.9 (3)	H6A—C6—H6B	107.8
C1—N1—Cu1	120.0 (3)	O1—C7—C6	109.4 (3)
N1—C1—C2	122.3 (4)	O1—C7—H7A	109.8
N1—C1—H1	118.9	C6—C7—H7A	109.8
C2—C1—H1	118.9	O1—C7—H7B	109.8
C1—C2—C3	118.5 (4)	C6—C7—H7B	109.8
C1—C2—H2	120.8	H7A—C7—H7B	108.2
C3—C2—H2	120.8

O1ⁱ—Cu1—O1—C7	−153.1 (4)	Cu1—N1—C1—C2	−173.3 (3)
N1—Cu1—O1—C7	38.7 (3)	N1—C1—C2—C3	0.3 (6)
Br1—Cu1—O1—C7	−81.8 (4)	C1—C2—C3—C4	0.2 (6)
Cu1ⁱ—Cu1—O1—C7	−153.1 (4)	C2—C3—C4—C5	−0.8 (6)
O1ⁱ—Cu1—O1—Cu1ⁱ	0.0	C1—N1—C5—C4	−0.6 (6)
N1—Cu1—O1—Cu1ⁱ	−168.20 (15)	Cu1—N1—C5—C4	172.6 (3)
Br1—Cu1—O1—Cu1ⁱ	71.3 (3)	C1—N1—C5—C6	−179.7 (4)
O1ⁱ—Cu1—N1—C5	−77.1 (5)	Cu1—N1—C5—C6	−6.5 (5)
O1—Cu1—N1—C5	−36.2 (3)	C3—C4—C5—N1	1.1 (6)
Br1—Cu1—N1—C5	129.8 (3)	C3—C4—C5—C6	−179.9 (4)
Cu1ⁱ—Cu1—N1—C5	−45.2 (3)	N1—C5—C6—C7	65.4 (5)
O1ⁱ—Cu1—N1—C1	96.1 (5)	C4—C5—C6—C7	−113.7 (4)
O1—Cu1—N1—C1	137.0 (3)	Cu1ⁱ—O1—C7—C6	−145.3 (3)
Br1—Cu1—N1—C1	−56.9 (3)	Cu1—O1—C7—C6	1.9 (4)
Cu1ⁱ—Cu1—N1—C1	128.0 (3)	C5—C6—C7—O1	−60.6 (4)
C5—N1—C1—C2	−0.1 (6)

Symmetry code: (i) −x+2, −y+2, −z+2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···Br1ⁱⁱ	0.95	3.00	3.716 (4)	134
C6—H6A···O1ⁱⁱⁱ	0.99	2.64	3.545 (5)	153

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

Experimental details

Crystal data
Chemical formula	[Cu₂Br₂(C₇H₈NO)₂]
M_r	531.19
Crystal system, space group	Triclinic, P1
Temperature (K)	150
a, b, c (Å)	4.2066 (2), 8.4338 (3), 11.5113 (6)
α, β, γ (°)	91.122 (4), 90.195 (3), 97.033 (1)
V (Å³)	405.24 (3)
Z	1
Radiation type	Mo Kα
µ (mm⁻¹)	7.56
Crystal size (mm)	0.28 × 0.21 × 0.17

Data collection
Diffractometer	Oxford Diffraction Xcalibur-S diffractometer
Absorption correction	Multi-scan (CrysAlis PRO-RED; Oxford Diffraction, 2009)
T_min, T_max	0.226, 0.360
No. of measured, independent and observed [I > 2σ(I)] reflections	3453, 1388, 1298
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.087, 1.05
No. of reflections	1388
No. of parameters	100
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.84, −0.74

Computer programs: CrysAlis PRO-CCD (Oxford Diffraction, 2009), CrysAlis PRO-RED (Oxford Diffraction, 2009), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999), publCIF (Westrip, 2010).

Selected geometric parameters (Å, º) top

Cu1—O1ⁱ	1.910 (3)	Cu1—N1	1.977 (3)
Cu1—O1	1.943 (3)	Cu1—Cu1ⁱ	3.0294 (9)

O1ⁱ—Cu1—O1	76.32 (12)	Cu1ⁱ—O1—Cu1	103.68 (12)

Symmetry code: (i) −x+2, −y+2, −z+2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···Br1ⁱⁱ	0.95	3.00	3.716 (4)	133.5
C6—H6A···O1ⁱⁱⁱ	0.99	2.64	3.545 (5)	152.5

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

Acknowledgements

Financial support received from the Department of Science and Technology (New Delhi, India) is gratefully acknowledged. We also gratefully acknowledge Professor Pradeep Mathur, National Single Crystal X-ray Diffraction Facility, IIT Bombay, and Professor Goutam K. Lahiri, Chemistry Department, IIT Bombay, for their kind support for this work.

References

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