Preparation, spectroscopic, structural, and thermal characterization of vanadium complexes with 2-quinaldic acid

The reactions of vanadyl sulfate pentahydrate or vanadyl acetylacetonate with 2-quinaldic acid (2-quinH) were investigated. Six new vanadium complexes [VO(2-quin)(2)], [VO(2-quin)(2)]center dot CHCl3, [VO(2-quin)(2)(py)], [VO(2-quin)(2)(4-pic)], [VO2(2-quin)(4-pic)], and [VO(2-quin)(2)(H2O)]center dot 2DMSO were prepared and characterized by infrared spectroscopy and thermal analysis (TGA/DTA). The vanadium(V) complex [VO2(2-quin)(4-pic)] was obtained accidently by the oxidation of [VO(2-quin)(2)], dissolved in 4-picoline, upon prolonged standing in air. The crystal structure of [VO2(2-quin)(4-pic)] was determined by single-crystal X-ray structural analysis. The coordination environment of the vanadium(V) ion in [VO2(2-quin)(4-pic)] is intermediate between a trigonal bipyramid and a square pyramid, with two oxo O atoms in the cis position, one 2-quinaldate ligand bound in an N,O-chelated mode, and one 4-picoline molecule. The compound crystallizes in the P2(1) /a space group of the monoclinic crystal system, with the parameters of the unit cell a = 7.2691(7) , b = 13.0769(12) , c = 15.7840(15) , beta = 91.252(8)A degrees, Z = 4.