Infrared, thermal and structural properties of first transition series metal chloride and perchlorate complexes of quinoxaline

Abstract

The chloride complexes of divalent Mn, Fe, Co, Ni, Cu and Zn containing one or two quinoxaline molecules and different numbers of H 2O molecules, when subjected to thermal analysis under dynamic N 2 atmosphere, decomposed to the metal chloride which then gave the metal oxide. The chlorides of Cu and Zn partly sublimed. The perchlorate complexes contained two or three quinoxaline molecules and in the case of Mn, Fe and Zn did not decompose to pure metal perchlorate during the heating before an explosion occurred; this depended on the heating rate. The IR spectra of the complexes show M-N bands under 500 cm −1, confirming the quinoxaline coordination. Copper in particular shows a tendency to form polymeric structures. The correlation between the results and the complex structure is discussed.