Adaptable 2,5-bis((1,2,3-triazol-4-yl)methoxy)pyrazine ligands for the simple self-assembly of homoleptic 1D coordination polymers

Abstract

The self-assembly of a new class of bis-tridentate ligands has led to the spontaneous formation of polymeric complexes with transition metal ions (M = Fe²⁺, Zn²⁺, Co²⁺, Cu²⁺, Ni²⁺, Mn²⁺). A straightforward synthetic route to prepare a series of 2,5-bis(1,2,3-triazol-4-yl) pyrazine (tzopz) ligands containing two N,O,N-tridentate chelation pockets, through a double Cu(I) catalysed azide–alkyne cycloaddition reaction of 2,5-bis((prop-2-yn-1-yloxy)methyl)pyrazine with a functionalised azido group is described. Complexes of the tzopz ligand have been investigated by UV-vis spectroscopy and single crystal X-ray crystallography. Complexes using this ligand motif consistently self-assemble into 1D zig-zag polymers, from which secondary interactions allow for the solid-state assembly of 2D sheets, providing an avenue for future functionalised materials.