(Imidazole-κN 3){N-[1-(2-oxidophenyl)ethylidene]-l-valinato-κ3 O,N,O′}copper(II)

Gan-Qing Zhao; Qiao-Ru Liu; Wei-Chun Yang; Song-Tian Li; Xiang Wang

doi:10.1107/S1600536808028134

. 2008 Sep 6;64(Pt 10):m1250–m1251. doi: 10.1107/S1600536808028134

(Imidazole-κN ³){N-[1-(2-oxidophenyl)ethylidene]-l-valinato-κ³ O,N,O′}copper(II)

Gan-Qing Zhao ^a,^*, Qiao-Ru Liu ^a, Wei-Chun Yang ^a, Song-Tian Li ^a, Xiang Wang ^a

PMCID: PMC2959304 PMID: 21201007

Abstract

In each of the two independent molecules in the asymmetric unit of the title compound, [Cu(C₁₃H₁₅NO₃)(C₃H₄N₂)], the Cu^II atom is four-coordinated by two O atoms and the N atom of the tridentate Schiff base ligand and one N atom from the imidazole ligand in a distorted square-planar geometry. In the crystal structure, molecules are linked by intermolecular N—H⋯O hydrogen bonds.

Related literature

For related literature, see: Basu Baul et al. (2007 ▶); Casella & Guillotti (1983 ▶); Ganguly et al. (2008 ▶); Parekh et al. (2006 ▶); Plesch et al. (1997 ▶); Usman et al. (2003 ▶); Vigato & Tamburini (2004 ▶).

Experimental

Crystal data

[Cu(C₁₃H₁₅NO₃)(C₃H₄N₂)]
M _r = 364.88
Orthorhombic,
a = 12.2025 (13) Å
b = 13.5248 (14) Å
c = 19.791 (2) Å
V = 3266.2 (6) Å³
Z = 8
Mo Kα radiation
μ = 1.35 mm⁻¹
T = 296 (2) K
0.30 × 0.20 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.687, T _max = 0.773
17018 measured reflections
5764 independent reflections
4619 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.037
wR(F ²) = 0.086
S = 1.03
5764 reflections
421 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.50 e Å⁻³
Absolute structure: Flack (1983 ▶), 2509 Friedel pairs
Flack parameter: 0.004 (13)

Data collection: SMART (Bruker, 2000 ▶); cell refinement: SAINT (Bruker, 2000 ▶); 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 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808028134/at2627sup1.cif

e-64-m1250-sup1.cif^{(25.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808028134/at2627Isup2.hkl

e-64-m1250-Isup2.hkl^{(282.2KB, hkl)}

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

Table 1. Selected geometric parameters (Å, °).

Cu1—O1	1.867 (3)
Cu1—N1	1.941 (3)
Cu1—O2	1.945 (2)
Cu1—N2	1.972 (3)
Cu2—O4	1.868 (3)
Cu2—N4	1.937 (3)
Cu2—O5	1.949 (3)
Cu2—N5	1.969 (3)

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O1—Cu1—N1	92.94 (13)
O1—Cu1—O2	175.69 (13)
N1—Cu1—O2	85.25 (12)
O1—Cu1—N2	90.51 (12)
N1—Cu1—N2	169.97 (14)
O2—Cu1—N2	91.92 (11)
O4—Cu2—N4	92.79 (13)
O4—Cu2—O5	173.64 (14)
N4—Cu2—O5	84.85 (12)
O4—Cu2—N5	90.96 (12)
N4—Cu2—N5	170.17 (14)
O5—Cu2—N5	92.32 (12)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3A⋯O6ⁱ	0.86	1.91	2.764 (4)	172

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Symmetry code: (i) Inline graphic .

Acknowledgments

This research was supported by the National Science Foundation of China (No. 20676057).

supplementary crystallographic information

Comment

In the past decades, significant progress has been achieved in understanding the chemistry of transition metal complexes with Schiff base ligands composed of salicylaldehyde, 2-formylpyridine or their analogues, and α-amino acids (Vigato & Tamburini, 2004; Ganguly et al., 2008; Casella & Guillotti, 1983). A few stuctural studies have been performed on Schiff base complexes derived from 2-hydroxyacetophenone and animo acids (Usman et al., 2003; Basu Baul et al., 2007; Parekh et al., 2006). We report here the crystal structure of the title Cu^II complex, (I).

In the title compound (I), the asymmetric unit contains two independent molecules (Fig. 1). The structure consists of discrete monomeric square-planar Cu^II complex (Table 1). The four basal positions are occupied by three donor atoms from the tridentate Schiff base ligand, which furnishes an ONO donor set, with the fourth position occupied by one N atom from the imidazole ligand. In the molecules with Cu1 and Cu2, the nitrogen heterocycles are planar and they form the angles of 4.2 (2) and 6.0 (2)° with the C1—C6 and C17–C32 rings, respectively.

The crystal structure is stabilized by intermolecular N—H···O hydrogen bonds (Fig. 2 and Table 2), which the H atom attached to N3 is hydrogen-bonded to the neighboring carboxylate oxygen O6.

Experimental

The title compound was synthesized as described in the literature (Plesch et al., 1997). To L-valine (1.00 mmol) and potassium hydroxide (1.00 mmol) in 10 ml of methanol was added 2-hydroxyacetophenone (1.00 mmol in 10 ml of methanol) dropwise. The yellow solution was stirred for 2.0 h at 333 K. The resultant mixture was added dropwise to copper(II) acetate monohydrate (1.00 mmol) and imidazole (1.00 mmol) in an aqueous methanolic solution (20 ml, 1:1 v/v), and heated with stirring for 2.0 h at 333 K. The dark blue solution was filtered and left for several days, dark blue crystals had formed that were filtered off, washed with water, and dried under vacuum.