Different reactivity patterns for [M(trien)]2+/3+ (M = NiII and CoIII) toward azido ions: Cationic charge dependence and different mode of ligand enfolding for 1D chain formation

Abstract

Linear and flexible N4 ligand trien (N′-{2-(2-aminoethylamino)-ethyl}-ethane-1,2-diamine) has been used to show octahderal coordination around NiII ions and cis coordination from two ancillary bridges from azide ions. Room temperature reaction of trien with Ni(NO3)·6H2O and NaN3 has led to an end-to-end (EE) azido bridged one-dimensional NiII based helical coordination chain of formula [NiII(μ-N3)2 (trien)]n (NO3)·H2O {1n·(NO3)·H2O}. Propagation of the chain in one dimension in a helical fashion is continued from the azido bridges in cis directions. Comparative reaction protocol using Co(NO3)2·6H2O on the other hand provided a discrete mononuclear octahedral cobalt (III) complex cis-[CoIII(N3)2 (trien)](NO3)·2H2O {2·(NO3)·2H2O} due to different type of ligand wrapping having only terminal coordination from azide ions.