The ligational behaviour of thiosemicarbazones and semicarbazones with tellurium(IV)—reactions with TeCl 4

Abstract

The reactions of thiosemicarbazones and semicarbazones of benzaldehyde, salicylaldehyde, acetophenone and 2-hydroxyacetophenone with TeCl 4 give the complexes LTeCl 4, (LH)TeCl 3 or (LH)Te 2Cl 7 (L = semicarbazone or thiosemicarbazone). The structural features of these tellurium derivatives are explored by IR, 1H and 13C NMR, and conductance (in acetonitrile) measurements, and structures based on an octahedral arrangement of ligands around tellurium are proposed. The presence of facial and meridian isomers in equilibrium is indicated in some cases. The complexation occurs through S/O, the nitrogen of the > CN group and O − (if present on benzene ring). The (LH)Te 2Cl 7 species seem to have chlorine bridged and octahedrally coordinated tellurium.