Linear copper ‘chain’ complexes with bulky tritopic hydrazoneligands—structural and magnetic studies

Abstract

Tritopic 2,6-picolyl-bis-hydrazone ligands with bulky terminal groups derived from phenyl-pyridyl ketone do not form the expected [3 × 3] grids on reaction with copper(II), but instead form Cu₈ ‘pinwheels’, and in the present case linear trinuclear, pentanuclear and chain structures also. Direct bridging between copper ions occurs through µ₂-N–N diazine groups, and longer O–C–N hydrazone connections, leading to moderately strong antiferromagnetic exchange between adjacent metal centres. Structural and magnetic properties are discussed in the context of specific orthogonal and non-orthogonal bridges, which can be distinguished and quantified.