Synthesis and structures of bimetallic and polymeric zinc coordination compounds supported by salicylaldiminato and anilido-aldimine ligands.

A series of bimetallic zinc complexes bearing salicylaldiminato (1b-3b) or anilido-aldimine (4c-5c) ligand frameworks, in which the metal centres are separated by aliphatic spacer groups containing 3-6 methylene units, were targeted. X-Ray analysis of salicylaldiminato derivative 2b, with a 4 carbon spacer group, revealed a coordination polymer in the solid state where each zinc centre is ligated by two salicylaldiminato ligands. Contrastingly, the structure of the anilido-aldimine complex 4c, with a 3 carbon methylene spacer group, was found to be a discrete bimetallic complex. These differences are attributed to the differing steric protection at the anilido vs phenoxy donors, the latter more readily facilitating bridges between metal centres.