Bis[(E)-4-bromo-2-(methoxy­imino­meth­yl)phenolato-κ2N,O1]copper(II)

Chai, L.-Q.; Yao, J.; Gong, S.-S.

doi:10.1107/S1600536809047989

metal-organic compounds

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Volume 65| Part 12| December 2009| Page m1599

doi:10.1107/S1600536809047989

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Bis[(E)-4-bromo-2-(methoxyiminomethyl)phenolato-κ²N,O¹]copper(II)

Lan-Qin Chai,^a ^* Jian Yao ^a and Shang-Sheng Gong ^a

^aSchool of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, People's Republic of China
^*Correspondence e-mail: chailanqin@163.com

(Received 5 November 2009; accepted 12 November 2009; online 18 November 2009)

In the title centrosymmetric mononuclear copper(II) complex, [Cu(C₈H₇BrNO₂)₂], the Cu^II atom, lying on an inversion centre, is four-coordinated in a trans-CuN₂O₂ square-planar geometry by two phenolate O atoms and two oxime N atoms from two symmetry-related N,O-bidentate oxime-type ligands. Intermolecular C—H⋯O hydrogen bonds link neighbouring molecules into a one-dimensional supramolecular structure with an R₂²(14) ring motif. This structure is further stabilized by π–π stacking interactions between adjacent benzene rings [centroid–centroid distance = 3.862 (1) Å].

Related literature

For general background to oxime compounds, see: Chaudhuri (2003 ); Dong et al. (2007a , 2008 ). For related structures, see: Dong et al. (2007b , 2009 ). For the ligand synthesis, see: Wang et al. (2008 ); Zhao et al. (2009 ).

Experimental

Crystal data

[Cu(C₈H₇BrNO₂)₂]
M_r = 521.65
Monoclinic, C 2/c
a = 24.691 (3) Å
b = 3.8623 (5) Å
c = 20.260 (2) Å
β = 117.453 (2)°
V = 1714.4 (3) Å³
Z = 4
Mo Kα radiation
μ = 5.96 mm⁻¹
T = 298 K
0.40 × 0.12 × 0.11 mm

Data collection

Siemens SMART 1000 CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.199, T_max = 0.560
3981 measured reflections
1521 independent reflections
1128 reflections with I > 2σ(I)
R_int = 0.040

Refinement

R[F² > 2σ(F²)] = 0.032
wR(F²) = 0.053
S = 1.04
1521 reflections
116 parameters
H-atom parameters constrained
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.40 e Å⁻³

Table 1
Selected bond lengths (Å)

Cu1—O2	1.910 (2)
Cu1—N1	2.000 (3)

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1C⋯O1ⁱ	0.96	2.52	3.328 (5)	142
Symmetry code: (i) x, y+1, z.

Data collection: SMART (Siemens, 1996 ); cell refinement: SAINT (Siemens, 1996); 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) and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809047989/hy2253sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536809047989/hy2253Isup2.hkl

checkCIF report

Comment top

Oximes are a traditional class of chelating ligands widely used in coordination and analytical chemistry and extraction metallurgy (Chaudhuri, 2003; Dong et al., 2007a,b, 2008, 2009). We report here the title mononuclear copper(II) complex with an oxime-type ligand.

The molecular structure of the title compound is shown in Fig. 1. The Cu^II ion, lying on an inversion centre is four-coordinated in a trans-CuN₂O₂ square-planar geometry, with two phenolate O atoms and two oxime N atoms from two N,O-bidentate oxime-type ligands. Bond lengths and angles are within normal ranges (Table 1). The Cu—O and Cu—N bond lengths are 1.910 (2) Å and 2.000 (3) Å, respectively, which are slightly longer than those observed in a similar Schiff base copper(II) complex [the mean bond lengths of Cu—O and Cu—N are 1.894 (2) and 1.990 (3) Å] (Dong et al., 2009).

In the crystal structure, intermolecular C1—H1C···O1 hydrogen bonds link neighbouring molecules into a one-dimensional supramolecular structure, with an R₂²(14) ring motif (Table 2 and Fig. 2). The one-dimensional structure is further stabilized by weak π–π stacking interactions between the adjacent benzene rings [centroid–centroid distance = 3.862 (1) Å] (Fig. 2).

Related literature top

For general background to oxime compounds, see: Chaudhuri (2003); Dong et al. (2007a, 2008). For related structures, see: Dong et al. (2007b, 2009). For the ligand synthesis, see: Wang et al. (2008); Zhao et al. (2009).

Experimental top

(E)-5-Bromo-2-hydroxybenzaldehyde O-methyl oxime (HL) was synthesized according to an analogous method in literature (Wang et al., 2008; Zhao et al., 2009). A blue solution of copper(II) acetate monohydrate (1.7 mg, 0.008 mmol) in methanol (4 ml) was added dropwise to a solution of HL (4.1 mg, 0.016 mmol) in methanol (5 ml) at room temperature. The colour of the mixing solution turned to yellow immediately then turned to brown slowly. The mixture was allowed to stand at room temperature for several days. With evaporating of the solvent, dark-brown needle-like single crystals suitable for X-ray crystallographic analysis were obtained (yield 49.3%). IR: ν(C═N) 1607, ν(Ar—O) 1243, ν(Cu—N) 447, ν(Cu—O) 422 cm^-1. Analysis, calculated for C₁₆H₁₄Br₂CuN₂O₄: C 39.30, H 3.32, Cu 11.51, N 5.13%; found: C 39.21, H 3.39, Cu 11.64, N 4.85%.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top

	Fig. 1. The molecular structure of the title compound. Displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted. [Symmetry code: (i) 1-x, 1-y, 1-z.]
	Fig. 2. Packing diagram for the title compound, showing the one-dimensional supramolecular structure formed by intermolecular C—H···O hydrogen bonds (dashed lines) and π–π stacking interactions (dashed lines). H atoms not involved in hydrogen bonding have been omitted for clarity. [Symmetry code: (ii) x, 1+y, z.]

Bis[(E)-4-bromo-2-(methoxyiminomethyl)phenolato- κ²N,O¹]copper(II) top

Crystal data top

[Cu(C₈H₇BrNO₂)₂]	F(000) = 1020
M_r = 521.65	D_x = 2.021 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1233 reflections
a = 24.691 (3) Å	θ = 2.2–23.4°
b = 3.8623 (5) Å	µ = 5.96 mm⁻¹
c = 20.260 (2) Å	T = 298 K
β = 117.453 (2)°	Needle-like, dark-brown
V = 1714.4 (3) Å³	0.40 × 0.12 × 0.11 mm
Z = 4

Data collection top

Siemens SMART 1000 CCD diffractometer	1521 independent reflections
Radiation source: fine-focus sealed tube	1128 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.040
ϕ and ω scans	θ_max = 25.0°, θ_min = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −21→28
T_min = 0.199, T_max = 0.560	k = −4→4
3981 measured reflections	l = −24→23

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)] = 0.032	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.053	H-atom parameters constrained
S = 1.04	w = 1/[σ²(F_o²) + (0.0126P)²] where P = (F_o² + 2F_c²)/3
1521 reflections	(Δ/σ)_max < 0.001
116 parameters	Δρ_max = 0.54 e Å⁻³
0 restraints	Δρ_min = −0.40 e Å⁻³

Crystal data top

[Cu(C₈H₇BrNO₂)₂]	V = 1714.4 (3) Å³
M_r = 521.65	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 24.691 (3) Å	µ = 5.96 mm⁻¹
b = 3.8623 (5) Å	T = 298 K
c = 20.260 (2) Å	0.40 × 0.12 × 0.11 mm
β = 117.453 (2)°

Data collection top

Siemens SMART 1000 CCD diffractometer	1521 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	1128 reflections with I > 2σ(I)
T_min = 0.199, T_max = 0.560	R_int = 0.040
3981 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.032	0 restraints
wR(F²) = 0.053	H-atom parameters constrained
S = 1.04	Δρ_max = 0.54 e Å⁻³
1521 reflections	Δρ_min = −0.40 e Å⁻³
116 parameters

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

	x	y	z	U_iso*/U_eq
Cu1	0.5000	0.5000	0.5000	0.0478 (2)
Br1	0.169435 (18)	0.60817 (11)	0.35138 (2)	0.04703 (16)
N1	0.46014 (14)	0.4521 (8)	0.56593 (15)	0.0359 (8)
O1	0.48859 (12)	0.2994 (7)	0.63799 (13)	0.0454 (7)
O2	0.43631 (11)	0.8108 (7)	0.43906 (13)	0.0459 (8)
C1	0.54119 (19)	0.4966 (11)	0.6868 (2)	0.0563 (13)
H1A	0.5672	0.5306	0.6638	0.084*
H1B	0.5632	0.3737	0.7328	0.084*
H1C	0.5284	0.7173	0.6964	0.084*
C2	0.40218 (17)	0.4722 (9)	0.54291 (19)	0.0353 (10)
H2	0.3870	0.3956	0.5747	0.042*
C3	0.35910 (16)	0.6052 (9)	0.47123 (18)	0.0303 (9)
C4	0.37870 (17)	0.7699 (10)	0.42340 (19)	0.0337 (10)
C5	0.33223 (17)	0.9004 (10)	0.35507 (19)	0.0357 (10)
H5	0.3434	1.0184	0.3232	0.043*
C6	0.27127 (17)	0.8574 (9)	0.33473 (19)	0.0358 (10)
H6	0.2418	0.9423	0.2894	0.043*
C7	0.25404 (16)	0.6861 (9)	0.3825 (2)	0.0308 (9)
C8	0.29692 (16)	0.5679 (9)	0.45035 (19)	0.0323 (9)
H8	0.2847	0.4628	0.4826	0.039*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.0365 (4)	0.0708 (6)	0.0413 (4)	0.0207 (4)	0.0224 (4)	0.0218 (4)
Br1	0.0330 (3)	0.0476 (3)	0.0530 (3)	−0.0031 (2)	0.0134 (2)	−0.0005 (2)
N1	0.035 (2)	0.044 (2)	0.0273 (18)	0.0067 (17)	0.0131 (15)	0.0089 (15)
O1	0.0378 (17)	0.057 (2)	0.0334 (15)	0.0074 (14)	0.0095 (13)	0.0140 (14)
O2	0.0311 (17)	0.064 (2)	0.0454 (16)	0.0148 (15)	0.0198 (13)	0.0245 (14)
C1	0.057 (3)	0.060 (3)	0.037 (2)	0.003 (2)	0.009 (2)	−0.001 (2)
C2	0.038 (3)	0.036 (3)	0.036 (2)	0.001 (2)	0.020 (2)	0.0039 (18)
C3	0.034 (2)	0.032 (2)	0.026 (2)	0.0051 (19)	0.0140 (18)	0.0016 (19)
C4	0.034 (2)	0.037 (2)	0.030 (2)	0.007 (2)	0.015 (2)	0.0004 (19)
C5	0.043 (3)	0.036 (2)	0.033 (2)	0.008 (2)	0.0216 (19)	0.004 (2)
C6	0.036 (3)	0.038 (3)	0.027 (2)	0.009 (2)	0.0097 (19)	0.003 (2)
C7	0.031 (2)	0.024 (2)	0.036 (2)	0.0008 (18)	0.0148 (19)	−0.0039 (18)
C8	0.039 (2)	0.032 (2)	0.034 (2)	0.000 (2)	0.0224 (19)	0.0001 (19)

Geometric parameters (Å, º) top

Cu1—O2	1.910 (2)	C2—H2	0.9300
Cu1—N1	2.000 (3)	C3—C8	1.399 (5)
Br1—C7	1.907 (4)	C3—C4	1.418 (5)
N1—C2	1.287 (4)	C4—C5	1.422 (5)
N1—O1	1.424 (3)	C5—C6	1.375 (5)
O1—C1	1.435 (4)	C5—H5	0.9300
O2—C4	1.316 (4)	C6—C7	1.391 (5)
C1—H1A	0.9600	C6—H6	0.9300
C1—H1B	0.9600	C7—C8	1.370 (5)
C1—H1C	0.9600	C8—H8	0.9300
C2—C3	1.442 (5)

O2ⁱ—Cu1—O2	180.000 (2)	C3—C2—H2	117.7
O2ⁱ—Cu1—N1	91.27 (11)	C8—C3—C4	120.8 (3)
O2—Cu1—N1	88.73 (11)	C8—C3—C2	117.7 (3)
O2ⁱ—Cu1—N1ⁱ	88.73 (11)	C4—C3—C2	121.5 (3)
O2—Cu1—N1ⁱ	91.27 (11)	O2—C4—C3	124.1 (3)
N1—Cu1—N1ⁱ	180.000 (1)	O2—C4—C5	119.3 (3)
C2—N1—O1	109.7 (3)	C3—C4—C5	116.6 (3)
C2—N1—Cu1	124.0 (2)	C6—C5—C4	122.0 (4)
O1—N1—Cu1	124.1 (2)	C6—C5—H5	119.0
N1—O1—C1	110.4 (3)	C4—C5—H5	119.0
C4—O2—Cu1	123.8 (2)	C5—C6—C7	119.5 (3)
O1—C1—H1A	109.5	C5—C6—H6	120.2
O1—C1—H1B	109.5	C7—C6—H6	120.2
H1A—C1—H1B	109.5	C8—C7—C6	120.9 (4)
O1—C1—H1C	109.5	C8—C7—Br1	120.0 (3)
H1A—C1—H1C	109.5	C6—C7—Br1	119.0 (3)
H1B—C1—H1C	109.5	C7—C8—C3	120.1 (3)
N1—C2—C3	124.5 (3)	C7—C8—H8	120.0
N1—C2—H2	117.7	C3—C8—H8	120.0

O2ⁱ—Cu1—N1—C2	−148.5 (3)	C8—C3—C4—O2	−179.3 (3)
O2—Cu1—N1—C2	31.5 (3)	C2—C3—C4—O2	1.1 (6)
O2ⁱ—Cu1—N1—O1	13.2 (3)	C8—C3—C4—C5	1.5 (5)
O2—Cu1—N1—O1	−166.8 (3)	C2—C3—C4—C5	−178.1 (3)
C2—N1—O1—C1	−133.0 (3)	O2—C4—C5—C6	178.2 (3)
Cu1—N1—O1—C1	63.0 (3)	C3—C4—C5—C6	−2.6 (5)
N1—Cu1—O2—C4	−38.8 (3)	C4—C5—C6—C7	1.0 (6)
N1ⁱ—Cu1—O2—C4	141.2 (3)	C5—C6—C7—C8	1.8 (5)
O1—N1—C2—C3	−178.3 (3)	C5—C6—C7—Br1	−176.9 (3)
Cu1—N1—C2—C3	−14.3 (5)	C6—C7—C8—C3	−2.8 (5)
N1—C2—C3—C8	171.7 (3)	Br1—C7—C8—C3	175.9 (3)
N1—C2—C3—C4	−8.6 (6)	C4—C3—C8—C7	1.1 (5)
Cu1—O2—C4—C3	29.8 (5)	C2—C3—C8—C7	−179.2 (3)
Cu1—O2—C4—C5	−151.0 (3)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1C···O1ⁱⁱ	0.96	2.52	3.328 (5)	142

Symmetry code: (ii) x, y+1, z.

Experimental details

Crystal data
Chemical formula	[Cu(C₈H₇BrNO₂)₂]
M_r	521.65
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	298
a, b, c (Å)	24.691 (3), 3.8623 (5), 20.260 (2)
β (°)	117.453 (2)
V (Å³)	1714.4 (3)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	5.96
Crystal size (mm)	0.40 × 0.12 × 0.11

Data collection
Diffractometer	Siemens SMART 1000 CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.199, 0.560
No. of measured, independent and observed [I > 2σ(I)] reflections	3981, 1521, 1128
R_int	0.040
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.032, 0.053, 1.04
No. of reflections	1521
No. of parameters	116
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.54, −0.40

Computer programs: SMART (Siemens, 1996), SAINT (Siemens, 1996), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008) and Mercury (Macrae et al., 2006), SHELXTL (Sheldrick, 2008).

Selected bond lengths (Å) top

Cu1—O2

1.910 (2)

Cu1—N1

2.000 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1C···O1ⁱ	0.96	2.52	3.328 (5)	142

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

Acknowledgements

This work was supported by the Foundation of the Education Department of Gansu Province (0904–11) and the `Jing Lan' Talent Engineering Funds of Lanzhou Jiaotong University, which are gratefully acknowledged.

References

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