[Bis(3,5-dimethylpyrazol-1-yl)methane]{N-[1-(2-oxidophenyl)ethylidene]-dl-alaninato}copper(II) monohydrate

In the title compound, [Cu(C11H11NO3)(C11H16N4)]·H2O, the CuII atom is five-coordinate in a distorted square-pyramidal geometry. The basal positions are occupied by three donor atoms from the tridentate Schiff base ligand and by one N atom from a bis(3,5-dimethylprazol-l-yl)methane ligand. The apical position is occupied by the N atom of the other ligand of this type. There are only van der Waals contacts in the crystal structure.

In the title compound, [Cu(C 11 H 11 NO 3 )(C 11 H 16 N 4 )]ÁH 2 O, the Cu II atom is five-coordinate in a distorted square-pyramidal geometry. The basal positions are occupied by three donor atoms from the tridentate Schiff base ligand and by one N atom from a bis(3,5-dimethylprazol-l-yl)methane ligand. The apical position is occupied by the N atom of the other ligand of this type. There are only van der Waals contacts in the crystal structure.

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;Baul et al., 2007;Parekh et al., 2006). We report here the crystal structure of the title Cu II complex, (I).
The structure consists of discrete monomeric square-pyramidal Cu II complex ( Fig. 1 and Table 1). The 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 1,1-bis(3,5-dimethylprazol-l-yl)methane ligand. The apical position is occupied by the other N atom of this ligand.
The two nitrogen heterocycles are planar and lie at angles of 95.5° and 30.9° to the plane of the C1-C6 ring. The two nitrogen heterocycles form a dihedral angle of 66.2° with each other.
The van der Waals contacts are major factors in the crystal packing. The H atoms of water could not be fixed because of the high disorder of O4. So, no comment can be given about the probable O-H···O type hydrogen bonds which should be formed through the solvent water molecule with neighboring carboxylate oxygen O3.

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 1,1-bis(3,5-dimethylprazol-l-yl)methane (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.

Refinement
In (I), All H atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 (CH) or 0.97 Å (CH 2 ) and U iso (H) = 1.2U eq (C), with C-H = 0.96 Å (CH 3 ) and U iso (H) = 1.5U eq (C). The oxygen (O4) of the water molecule is extremely disorder. So, no H-atom could be attached.