Thermal decomposition of oxovanadium(IV) complexes with N, N′-ethylenebis(amino acids)

Abstract

Six oxovanadium(IV) complexes with N, N′-ethylenebis(amino acid) of general formula, [VO(XeX)(H 2O)]· nH 2O, where e and X represent ethylene group and ( S)-α-amino acid, respectively; and X=G (Gly) 1, ( S)-A (Ala) 2, ( S)-V (Val) 3·2H 2O, ( S)-P (Pro) 4, mG or G m (Sar or N-methylglycine) 5·H 2O and ( S)-M (Met) 6) were prepared. These complexes were characterized by means of TG, DTA, and XRD, and the thermal decomposition processes of these complexes up to 650°C were investigated. The thermal studies showed that the dehydration processes for 3 and 5 having water of crystallization were endothermic, whereas decompositions of all the complexes were exothermic. Calcinations of these complexes at 650°C resulted in the formation of vanadium(V) oxide V 2O 5. Choosing 1 as a leading example of the oxovanadium(IV) complexes, an over all reaction scheme for the thermal decomposition was proposed on the basis of IR and MS analyses of both the solid and the volatile decomposition products at different temperatures.