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Acta Cryst. (2009). E65, m1599    [ doi:10.1107/S1600536809047989 ]

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

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

Abstract top

In the title centrosymmetric mononuclear copper(II) complex, [Cu(C8H7BrNO2)2], the CuII 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 [pi]-[pi] stacking interactions between adjacent benzene rings [centroid-centroid distance = 3.862 (1) Å].

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 CuII 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%.

Refinement top

H atoms were positioned geometrically and refined as riding atoms, with C—H = 0.96 (CH3) and 0.93 Å (CH) and with Uiso(H) = 1.2(1.5 for methyl)Ueq(C).

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
[Figure 1] 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.]
[Figure 2] 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
Mr = 521.65Dx = 2.021 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2ycCell parameters from 1233 reflections
a = 24.691 (3) Åθ = 2.2–23.4°
b = 3.8623 (5) ŵ = 5.96 mm−1
c = 20.260 (2) ÅT = 298 K
β = 117.453 (2)°Needle-like, dark-brown
V = 1714.4 (3) Å30.40 × 0.12 × 0.11 mm
Z = 4
Data collection top
Siemens SMART 1000 CCD
diffractometer		1521 independent reflections
Radiation source: fine-focus sealed tube1128 reflections with I > 2σ(I)
graphiteRint = 0.040
φ and ω scansθmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)		h = −21→28
Tmin = 0.199, Tmax = 0.560k = −4→4
3981 measured reflectionsl = −24→23
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.032Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.053H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0126P)2]
where P = (Fo2 + 2Fc2)/3
1521 reflections(Δ/σ)max < 0.001
116 parametersΔρmax = 0.54 e Å−3
0 restraintsΔρmin = −0.40 e Å−3
Crystal data top
[Cu(C8H7BrNO2)2]V = 1714.4 (3) Å3
Mr = 521.65Z = 4
Monoclinic, C2/cMo Kα radiation
a = 24.691 (3) ŵ = 5.96 mm−1
b = 3.8623 (5) ÅT = 298 K
c = 20.260 (2) Å0.40 × 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)
Tmin = 0.199, Tmax = 0.560Rint = 0.040
3981 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.032H-atom parameters constrained
wR(F2) = 0.053Δρmax = 0.54 e Å−3
S = 1.03Δρmin = −0.40 e Å−3
1521 reflectionsAbsolute structure: ?
116 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Cu10.50000.50000.50000.0478 (2)
Br10.169435 (18)0.60817 (11)0.35138 (2)0.04703 (16)
N10.46014 (14)0.4521 (8)0.56593 (15)0.0359 (8)
O10.48859 (12)0.2994 (7)0.63799 (13)0.0454 (7)
O20.43631 (11)0.8108 (7)0.43906 (13)0.0459 (8)
C10.54119 (19)0.4966 (11)0.6868 (2)0.0563 (13)
H1A0.56720.53060.66380.084*
H1B0.56320.37370.73280.084*
H1C0.52840.71730.69640.084*
C20.40218 (17)0.4722 (9)0.54291 (19)0.0353 (10)
H20.38700.39560.57470.042*
C30.35910 (16)0.6052 (9)0.47123 (18)0.0303 (9)
C40.37870 (17)0.7699 (10)0.42340 (19)0.0337 (10)
C50.33223 (17)0.9004 (10)0.35507 (19)0.0357 (10)
H50.34341.01840.32320.043*
C60.27127 (17)0.8574 (9)0.33473 (19)0.0358 (10)
H60.24180.94230.28940.043*
C70.25404 (16)0.6861 (9)0.3825 (2)0.0308 (9)
C80.29692 (16)0.5679 (9)0.45035 (19)0.0323 (9)
H80.28470.46280.48260.039*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0365 (4)0.0708 (6)0.0413 (4)0.0207 (4)0.0224 (4)0.0218 (4)
Br10.0330 (3)0.0476 (3)0.0530 (3)−0.0031 (2)0.0134 (2)−0.0005 (2)
N10.035 (2)0.044 (2)0.0273 (18)0.0067 (17)0.0131 (15)0.0089 (15)
O10.0378 (17)0.057 (2)0.0334 (15)0.0074 (14)0.0095 (13)0.0140 (14)
O20.0311 (17)0.064 (2)0.0454 (16)0.0148 (15)0.0198 (13)0.0245 (14)
C10.057 (3)0.060 (3)0.037 (2)0.003 (2)0.009 (2)−0.001 (2)
C20.038 (3)0.036 (3)0.036 (2)0.001 (2)0.020 (2)0.0039 (18)
C30.034 (2)0.032 (2)0.026 (2)0.0051 (19)0.0140 (18)0.0016 (19)
C40.034 (2)0.037 (2)0.030 (2)0.007 (2)0.015 (2)0.0004 (19)
C50.043 (3)0.036 (2)0.033 (2)0.008 (2)0.0216 (19)0.004 (2)
C60.036 (3)0.038 (3)0.027 (2)0.009 (2)0.0097 (19)0.003 (2)
C70.031 (2)0.024 (2)0.036 (2)0.0008 (18)0.0148 (19)−0.0039 (18)
C80.039 (2)0.032 (2)0.034 (2)0.000 (2)0.0224 (19)0.0001 (19)
Geometric parameters (Å, °) top
Cu1—O21.910 (2)C2—H20.9300
Cu1—N12.000 (3)C3—C81.399 (5)
Br1—C71.907 (4)C3—C41.418 (5)
N1—C21.287 (4)C4—C51.422 (5)
N1—O11.424 (3)C5—C61.375 (5)
O1—C11.435 (4)C5—H50.9300
O2—C41.316 (4)C6—C71.391 (5)
C1—H1A0.9600C6—H60.9300
C1—H1B0.9600C7—C81.370 (5)
C1—H1C0.9600C8—H80.9300
C2—C31.442 (5)
O2i—Cu1—O2180.000 (2)C3—C2—H2117.7
O2i—Cu1—N191.27 (11)C8—C3—C4120.8 (3)
O2—Cu1—N188.73 (11)C8—C3—C2117.7 (3)
O2i—Cu1—N1i88.73 (11)C4—C3—C2121.5 (3)
O2—Cu1—N1i91.27 (11)O2—C4—C3124.1 (3)
N1—Cu1—N1i180.000 (1)O2—C4—C5119.3 (3)
C2—N1—O1109.7 (3)C3—C4—C5116.6 (3)
C2—N1—Cu1124.0 (2)C6—C5—C4122.0 (4)
O1—N1—Cu1124.1 (2)C6—C5—H5119.0
N1—O1—C1110.4 (3)C4—C5—H5119.0
C4—O2—Cu1123.8 (2)C5—C6—C7119.5 (3)
O1—C1—H1A109.5C5—C6—H6120.2
O1—C1—H1B109.5C7—C6—H6120.2
H1A—C1—H1B109.5C8—C7—C6120.9 (4)
O1—C1—H1C109.5C8—C7—Br1120.0 (3)
H1A—C1—H1C109.5C6—C7—Br1119.0 (3)
H1B—C1—H1C109.5C7—C8—C3120.1 (3)
N1—C2—C3124.5 (3)C7—C8—H8120.0
N1—C2—H2117.7C3—C8—H8120.0
O2i—Cu1—N1—C2−148.5 (3)C8—C3—C4—O2−179.3 (3)
O2—Cu1—N1—C231.5 (3)C2—C3—C4—O21.1 (6)
O2i—Cu1—N1—O113.2 (3)C8—C3—C4—C51.5 (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—C6178.2 (3)
Cu1—N1—O1—C163.0 (3)C3—C4—C5—C6−2.6 (5)
N1—Cu1—O2—C4−38.8 (3)C4—C5—C6—C71.0 (6)
N1i—Cu1—O2—C4141.2 (3)C5—C6—C7—C81.8 (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—C8171.7 (3)Br1—C7—C8—C3175.9 (3)
N1—C2—C3—C4−8.6 (6)C4—C3—C8—C71.1 (5)
Cu1—O2—C4—C329.8 (5)C2—C3—C8—C7−179.2 (3)
Cu1—O2—C4—C5−151.0 (3)
Symmetry codes: (i) −x+1, −y+1, −z+1.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C1—H1C···O1ii0.962.523.328 (5)142
Symmetry codes: (ii) x, y+1, z.
Table 1
Selected geometric parameters (Å) top
Cu1—O21.910 (2)Cu1—N12.000 (3)
Table 2
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
C1—H1C···O1i0.962.523.328 (5)142
Symmetry codes: (i) x, y+1, z.
Acknowledgements top

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
References top

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