Thermal Studies of 1,2-Propanediamine Complexes of Zinc(II) and Cadmium(II) in the Solid Phase

Abstract

Abstract [ML3]X2·nH2O, where M=ZnII and CdII; L=1,2-propanediamine; X=Cl−, Br−, 0.5SO42−, and 0.5SeO42− and n=1, 1.5, and 2, have been synthesized and their thermal investigations carried out. ZnL1.5Cl2, CdL1.5X2 (X=Cl− and Br−), and CdLX2 (X=Cl−, 0.5SO42−, and 0.5SeO42−) have been synthesized pyrolytically in solid state from their parent diamine complexes. These ML1.5X2 complexes are expected to exist as [ML3][MX4]. Only [CdL3][CdBr4] species has been synthesized from solution. Syntheses of ZnLCl2, CdLCl2, and CdLBr2 from solution have also been reported. IR spectra suggest that symmetry of the chelate ring in mono (diamine) complexes is lowered in comparison to the other complexes. ML1.5Cl2 show isomorphism with each other. Thermal stability sequence of [ML3]X2 (X=Br−, 0.5SO42− and 0.5SeO42−) is SO42−<SeO42−≤Br−. [ZnL3]X2 and ZnLX2 appear thermally more stable than those of cadmium complexes. All these complexes are thermally less stable than those of 1,2-ethanediamine complexes reported by us earlier.