Synthesis, crystal structure and properties of complex VO(C10H9NO3) (C13H10NO2)

Complex VO(C10H9NO3)(C13H10NO2)(C10H9NO2=N-salicylidene-L-alaninate, C13H10NO (2) over bar =N-phenyl-benzohydroxamate) was synthesized and characterized by means of elemental analysis, IR, UV, H-1 NMR spectroscopies, cyclic voltammetry and single crystal X-ray diffraction. The complex crystallized in a monoclinic system with space group P2(1) and crystal cell parameters a=0.9720(1) nm, b=1.8274(2) nm, c= 1.2542(1) nm, beta=104.868(9)degrees, V=2.1532(4) nm(3), M-r=470.34, Z=2. The two oxygen atoms and the one nitrogen atom of the tridentate Schiff base ligand and the one oxime oxygen atom of the hydroxamate ligand coordinate to the vanadium atom, forming an equatorial plane, the two axial positions are respectively occupied by the oxygen atom of the oxovanadium and the carbonyl oxygen atom of the hydroxamate and the vanadium atom exhibits a distorted octahedral VO(ONO)(OO) coordination sphere. The H-1 NMR spectrum suggests that the two isomers, endo and exo in a molar ratio of 1/1.7, coexist in the solution of the title complex in CDCl3. There exists a quasi-reversible one-electron redox reaction corresponding to V-v/V-v couple in the three non-aqueous solvents, and the redox potential E-1/2 of the title complex substantially shifts in the direction of the positive voltage increase in the order; CH2Cl2<CH3CN<DMF.