Thermal routes to metal complexed polyimines; facile conversion of CoX2(NH2CH2CH{OEt}2)2 to CoX2{=NCH2CH=}2

Cobalt(II) complexes of the form CoX2(NH2CH2CH{OEt}2)2 [X=Cl, Br, I] react hydrolytically in solution to convert hemiacetal moieties to aldehydes, the latter undergoing Schiff base condensation. Complex decomposition and the separation of metal salt and organic material occur concomitantly. In contrast, thermal reactions afford metal complexed polyimines of the form CoX2{=NCH2CH=}2. Analyses are consistent with the liberation of four equivalents of ethanol per mole of CoX2(NH2CH2CH{OEt}2)2 via an autocatalytic cycle of hemiacetal hydrolysis and Schiff base condensation. Such thermal routes offer facile access to metal complexed polyimines.