Stereochemistry of some high coordination compounds of dioxouranium(VI) With thiosemicarbazones

Abstract

The UO2 ion is peculiar in its coordination behaviour, because of its inherent capacity of forming compounds with higher coordination number. In the present work we describe the synthesis of a series of eight, nine and ten coordinated compounds of dioxouranium(VI) with 4[N-(2'-nitrobenzalidene)- amino] antipyrinethiosemicarbazone (2'-NO2BAAPT) and 4[N-(3'-nitrobenzalidene) amino] antipyrinethiosemicarbazone (3'-NO2BAAPT) with the general composition UO2X2.nL (X = Br, I, NCS or CIO4, n=2; X = NO3 or CH3COO, n = 1; L = 2'-NO2BAAPT or 3'-NO2BAAPT). These compounds were synthesized in non-aqueous solvents, and were characterized by various physico-chemical techniques. The ligands behave as tridentate ^S-donors. Wilson's G-F matrix mehtod was used to determine the stretching and interaction force constants from which the U-O bond distances were calculated. Thermal stabilities of these complexes were also investigated.