Abstract: | The synthesis and structure of two Cu(II) complexes, {Cu2(L1)2]?·?DMF} n (1) and CuL2(phen)] (2), are described. The dinegative hydrazones are obtained by deprotonation of both phenolic and amide moieties of N′-(5-bromo-2-hydroxybenzylidene)-3,5-dimethoxybenzohydrazide (H2L1) and N′-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide (H2L2). In each complex the planar ligand binds the metal ion via phenolate-O, imine-N, and amide-O. Complex 1 is a polymer in which phenoxo-bridged binuclear Cu(II) units are further joined by equatorial–apical amide-O bridges. The Cu···Cu separations are 3.0306 and 3.8217?Å for the phenolate-O bridged pair and the amide-O bridged pair, respectively. Complex 2 is a monomer where chelating phen displays axial–equatorial bonding, with square-pyramidal Cu(II). |