catena-Poly[[[(3,5-dimethyl-1H-pyrazole)­copper(II)]-μ-{N-[1-(2-oxidophen­yl)ethyl­idene]-l-valinato}] methanol monosolvate]

Gan-Qing Zhao; Xu-Dong Li; Yong-Jun Han; Ling-Wei Xue; Qin-Long Peng

doi:10.1107/S1600536811000304

. 2011 Jan 15;67(Pt 2):m173–m174. doi: 10.1107/S1600536811000304

catena-Poly[[[(3,5-dimethyl-1H-pyrazole)copper(II)]-μ-{N-[1-(2-oxidophenyl)ethylidene]-l-valinato}] methanol monosolvate]

Gan-Qing Zhao ^a,^*, Xu-Dong Li ^a, Yong-Jun Han ^a, Ling-Wei Xue ^a, Qin-Long Peng ^a

PMCID: PMC3051769 PMID: 21522850

Abstract

The asymmetric unit of the title compound, {[Cu(C₁₃H₁₅NO₃)(C₅H₈N₂)]·CH₃OH}_n, contains two complex molecules and two solvent molecules. Each Cu^II ion is in a distorted square-pyramidal coordination with one N and two O atoms from the Schiff base ligand and one N atom from the heterocycle in the basal positions and one carboxylate O atom from a neighbouring ligand in the apical position. The apical Cu—O bonds are much longer than the basal Cu—O and Cu—N bonds. The carboxylate groups of the Schiff base ligands bridge the Cu^II ions, forming helical chains along [100]. The crystal packing is stabilized by intermolecular O—H⋯O and N—H⋯O hydrogen bonds.

Related literature

For background to metal complexes with Schiff bases derived from amino acids, see: Basu Baul et al. (2007 ▶); Casella & Guillotti (1983 ▶); Ganguly et al. (2008 ▶); Parekh et al. (2006 ▶); Vigato & Tamburini (2004 ▶); Zhao et al. (2008 ▶, 2009 ▶). For synthetic details, see: Plesch et al. (1997 ▶).

Experimental

Crystal data

[Cu(C₁₃H₁₅NO₃)(C₅H₈N₂)]·CH₄O
M _r = 424.98
Orthorhombic,
a = 14.12 (2) Å
b = 15.44 (2) Å
c = 21.25 (3) Å
V = 4634 (11) Å³
Z = 8
Mo Kα radiation
μ = 0.97 mm⁻¹
T = 296 K
0.25 × 0.21 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.794, T _max = 0.853
23421 measured reflections
8496 independent reflections
4724 reflections with I > 2σ(I)
R _int = 0.071

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.130
S = 1.01
8496 reflections
496 parameters
2 restraints
H-atom parameters constrained
Δρ_max = 0.49 e Å⁻³
Δρ_min = −0.31 e Å⁻³
Absolute structure: Flack (1983 ▶), 4318 Friedel pairs
Flack parameter: −0.012 (18)

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); 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: publCIF (Westrip, 2010 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536811000304/wm2441sup1.cif

e-67-0m173-sup1.cif^{(29.5KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811000304/wm2441Isup2.hkl

e-67-0m173-Isup2.hkl^{(415.6KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cu1—O1	1.899 (5)
Cu1—N1	1.978 (5)
Cu1—O2	1.989 (4)
Cu1—N5	2.027 (6)
Cu1—O6ⁱ	2.437 (6)
Cu2—O4	1.917 (5)
Cu2—N2	1.979 (5)
Cu2—O5	1.984 (4)
Cu2—N3	2.014 (5)
Cu2—O3	2.369 (5)

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Symmetry code: (i) Inline graphic .

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N6—H6E⋯O5ⁱ	0.86	2.01	2.843 (8)	164
N4—H4E⋯O2	0.86	2.06	2.873 (8)	157
O7—H7⋯O4	0.85	2.22	3.066 (14)	179
O8—H8D⋯O1ⁱⁱ	0.82	2.24	3.009 (12)	157

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

This research was supported by the National Sciences Foundation of China (Nos. 20676057 and 20877036) and the Top-class Foundation of Pingdingshan University (No. 2008010).

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 (Basu Baul et al., 2007; Parekh et al., 2006; Zhao et al., 2008, 2009). We report here the crystal structure of the title Cu^II complex, [Cu(C₁₃H₁₅NO₃)(C₅H₈N₂)].CH₃OH.

The asymmetric unit of the polymeric title compound consists of two Cu^II complex molecules and two solvate methanol molecules (Fig. 1). Each of the two Cu^II ions has a square-pyramidal coordination where the four basal positions are occupied by an O,N,O, donor set from the tridentate Schiff base ligand and the fourth position occupied by one N atom from the 3,5-dimethylpyrazole ligand. The apical position is occupied by a carboxylate O atom from the adjacent tridentate Schiff base ligand. The apical Cu···O bonds are much longer than the basal Cu···O and Cu···N bonds (Table 1). The closest distance between neighbouring Cu^II ions are 5.803 (6) Å and 5.890 (6) Å, respectively.

The crystal structure is stabilized by intermolecular N—H···O hydrogen bonds between the pyrazole N—H groups as donors and the carboxylate O atoms as acceptors. Additional O—H···O hydrogen bonding involving the methanol solvent molecules is also observed (Table 2 and Fig. 2).

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 3,5-dimethylpyrazole (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. Blue crystals had formed that were filtered off, washed with water, and dried under vacuum.