A cyano and end-to-end azido bridged 3D copper(ii)–copper(i) mixed-valence coordination polymer and its transformation to copper nitride nanoparticles

Abstract

A new cyano and end-to-end azido bridged 3D copper(II)–copper(I) mixed valence polymer, {[Cu₅(CN)₆(NH₃)₆(N₃)₂]}_n (1), copper-azide systems without cyanide {[Cu(NH₃)₂(N₃)₂]₄}_n (2), and a cyano-bridged copper analogue without azide {[Cu₃(NH₃)₃(CN)₄]}_n (3) have been prepared and their structures have been revealed by X-ray crystallography. The cyano groups acting as μ₂,η² and azido anions have a rare asymmetric μ-1,1,3 bridging mode connecting the copper centers in 1 to form an infinite 3-D layered motif, whereas 2 consists of one dimensional polymer chains bridged by two azide moieties in μ-1 and μ-1,1,3 modes and 3 is a two dimensional Cu^IICu^I infinite polymeric network formed by cyanide bridges. The solid-state transformation of all the three compounds has also been investigated. The present investigation suggests application of {[Cu₅(CN)₆(NH₃)₆(N₃)₂]}_n (1) as a precursor for copper nitride nanoparticles.