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].CHCl , [VO(2-quin) (py)], [VO(2- quin)2(4-pic)], [VO (2-quin)(4-pic)], and [VO(2-quin)2 (H O)].2DMSO were prepared and characterized by infrared spectroscopy and thermal analysis (TGA/DTA). The vanadium(V) complex [VO (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 [VO (2-quin)(4-pic)] was determined by single-crystal X-ray structural analysis. The coordination environment of the vanadium(V) ion in [VO (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 P21/a space group of the monoclinic crystal system, with the parameters of the unit cell a = 7.2691(7) Å , b = 13.0769(12) Å , c = 15.7840(15) Å , b = 91.252(8)̊, Z = 4. © Springer-Verlag 2012.