Thermally induced isomerizatton and decomposition of diethylenetriamine complexes of zinc (II) and cadmium (II) in the solid state

Abstract

Complexes of the form [ML₂]X₂•nH₂O (where M  Zn^II or Cd^II, L = diethylenetriamine, and n = 1 when XCP⁻ or Br⁻, n = 3 when X = 0.5SO²⁻₄ or 0.5SeO²⁻₄, n = 0 when X = NO⁻₃ or SCN⁻) have been synthesized, characterized and investigated thermally in the solid state. The complexes [ZnL₂][SCN) ₂, [CdL₂](SCN) ₂ and [CdL₂](NO₃)₂ undergo irreversible endothermic phase transitions. The complex [ZnL₂]SeO₄•3H₂O undergoes reversible endothermic phase transition after dehydration. The species [ZnLCl]Cl, [CdLCl₂], [ZnLSO₄], [CdLSO₄] and [ZnLSeO₄] have been synthesized pyrolytically in the solid state from their corresponding parent bis complexes and also from solution. The bis complexes have octahedral geometry, with the ligands arranged meridionally. The mono complexes of Zn^II were found to have tetrahedral geometry, whereas those of Cd^II seem to be octahedral.