Oxido[N-(2-oxidobenzylidene-κO)leucinato-κ2 N,O](1,10-phenanthroline-κ2 N,N′)vanadium(IV)

In the title VIV complex, [VO(C13H15NO3)(C12H8N2)], the oxidovanadium cation is N,N′-chelated by a 1-10-phenanthroline ligand and N,O,O′-chelated by a Schiff base anion in a distorted octahedral geometry. Weak intermolecular C—H⋯O hydrogen bonds occur in the crystal structure which contains solvent-accessible voids of 81 Å3.

In the title V IV complex, [VO(C 13 H 15 NO 3 )(C 12 H 8 N 2 )], the oxidovanadium cation is N,N 0 -chelated by a 1-10-phenanthroline ligand and N,O,O 0 -chelated by a Schiff base anion in a distorted octahedral geometry. Weak intermolecular C-HÁ Á ÁO hydrogen bonds occur in the crystal structure which contains solvent-accessible voids of 81 Å 3 .
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: XU5555). Vanadium complexes have have been synthesized and characterized continuously due to its biological and pharmacological properties (Baran, 2003). Herein, we report the synthesis and crystal structure of a new oxovanadium(IV) complex with a tridentate Schiff base ligand derived from the condensation of salicylaldehyde and L-Leucine, with a 1,10-phenanthroline coligand.
As shown in Fig. 1, the central V(IV) ion is six-coordinated bound to two O atoms and one N atom of the Schiff base ligand, a vanadyl O atom and two N atoms of the 1,10-phenanthroline ligand, forming a distorted octahedral geometry.
Selected bond angles and bond distances of the title complex are given in Table 1.
In the crystal structure, weak intermolecular C-H···O hydrogen bonds (Table 2) occur.

Experimental
L-Leucine (1 mmol, 131.2 mg) and potassium hydroxide (1 mmol, 56.1 mg) were dissolved in hot methanol (10 ml) with stirring and added successively to a methanol solution (5 ml) of salicylaldehyde (1 mmol, 0.11 ml). The mixture was then stirred at 323 K for 2 h. Subsequently, an aqueous solution (2 ml) of vanadyl sulfate hydrate (1 mmol, 225.4 mg) was added dropwise and stirred for 2 h continuously. Finally, a methanol solution (5 ml) of 1,10-phenanthroline (1 mmol, 198 mg) was added dropwise and stirred for 2 h. Then the resultant solution was filtered and the filtrate was held at room temperature for several days, whereupon yellow blocky crystals suitable for X-ray diffraction were obtained.

Refinement
All the H atoms were placed in geometrically calculated positions, with C-H = 0.93-0.98 Å and allowed to ride on their respective parent atoms, with U iso (H) = 1.2U eq or 1.5U eq (C methyl ). program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 1999); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).  The molecular structure of the title compound, shown 30% probability displacement ellipsoids and the atom-numbering scheme.

Oxido[N-(2-oxidobenzylidene-κO)leucinato-κ 2 N,O](1,10-phenanthroline-κ 2 N,N′)vanadium(IV)
Crystal data Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.