(Methanol-κO)(methanolato-κO)oxido[N-(2-oxidobenzylidene)phenylalaninato-κ3 O,N,O′]vanadium(V)

In the title complex, [V(C16H13NO3)(CH3O)O(CH3OH)], the VV atom is six-coordinated by a tridentate ligand derived from the condensation of salicylaldehyde and l-phenylalanine, a vanadyl O atom, a methanolate O atom and a methanol O atom, forming a distorted octahedral coordination geometry. In the crystal, intermolecular O—H⋯O and C—H⋯O hydrogen bonds result in a two-dimensional structure parallel to (001).

In the title complex, [V(C 16 H 13 NO 3 )(CH 3 O)O(CH 3 OH)], the V V atom is six-coordinated by a tridentate ligand derived from the condensation of salicylaldehyde and l-phenylalanine, a vanadyl O atom, a methanolate O atom and a methanol O atom, forming a distorted octahedral coordination geometry. In the crystal, intermolecular O-HÁ Á ÁO and C-HÁ Á ÁO hydrogen bonds result in a two-dimensional structure parallel to (001).

Comment
The coordination chemistry of vanadium has been receiving increasing interest since it was found that vanadium compounds in various oxidation states have insulin-mimetic properties (Diego et al., 2003;Kenji et al., 2000;Thompson & Orvig, 2006). Compared with other transition metal complexes, less vanadium complexes have been synthesized and characterized (Thompson et al., 1999;Wikksky et al., 2001). We report here the synthesis and crystal structure of an oxovanadium(V) complex with a tetradentate Schiff-base ligand derived from the condensation of salicylaldehyde and L-phenylalanine.
As shown in Fig. 1, the V V ion is six-coordinated by the tridentate (O,N,O) donor ligand and three O atoms from an oxido group, a methanolate group and a methanol molecule (Table 1), forming a distorted octahedral geometry. In the complex, O2, N1 and O4 of the tridentate Schiff base ligand and O6 of the methanolate ligand define the equatorial plane and the oxido O1 and the methanol O5 occupy the axial positions. The Schiff base ligand coordinating to the V V atom forms two chelating rings, the five-membered V1-O2-C1-C2-N1 ring and the six-membered V1-N1-C10-C11-C16-O4 ring. The dihedral angle of the two rings is 15.69 (15)°, which increases the stability of the complex.
In the crystal, the intermolecular O-H···O and C-H···O hydrogen bonds (Table 2) result in a two-dimensional structure ( Fig. 2).
Experimental L-Phenylalanine (1 mmol, 0.165 g) and potassium hydroxide (1 mmol, 0.056 g) were dissolved in hot methanol (10 ml) with stirring. The mixture was added successively to a methanol solution (5 ml) of salicylaldehyde (1 mmol, 0.11 ml) with stirring at 323 K for 2 h. Subsequently, an aqueous solution (2 ml) of vanadyl sulfate hydrate (1 mmol, 0.225 g) was added dropwise and stirred for 3 h continuously. The resultant solution was filtered and the filtrate was held at room temperature for several days, whereupon red blocky crystals suitable for X-ray diffraction were obtained.

Refinement
H atoms on C atoms were placed in calculated positions and refined as riding atoms, with C-H = 0.93-0.98 Å and with U iso (H) = 1.2(1.5 for methyl)U eq (C). The hydroxy H atom (H19) of the methanol molecule was located from a difference Fourier map and refined isotropically. Fig. 1. The molecular structure of the title compound, showing 50% probability displacement ellipsoids.