Synthesis, structural and magnetic properties of diphenoxo-bridged binuclear mixed-ligand Cu(II) complexes

Abstract

The copper(II) complexes [Cu 2(phen) 2(HL 1) 2] (ClO 4) 2 ( 1) and [Cu 2(phen) 2(HL 2) 2] (ClO 4) 2 ( 2) synthesized from two potentially tridentate ligands N-(2-hydroxybenzyl) propanolamine (H 2L 1) and N-(5-methyl-2-hydroxybenzyl) propanolamine (H 2L 2) have centrosymmetric bis(μ 2-phenoxo)-bridged dicopper(II) structures. Variable temperature magnetic measurements have revealed the existence of relatively weak antiferromagnetic interactions ( 1: 2 J=−212.5, 2: 2 J=−337.0 cm −1) with respect to the bridging angles ( 1: θ=101.47(18)°, 2: θ=102.79(12)°). The results suggest that the distortion index of the Cu(II) atoms ( 1: τ=0.73, 2: τ=0.53) may be the major factor governing the spin coupling between the copper(II) centers of these diphenoxo-bridged binuclear complexes. The coordination moieties of complex 1 are connected into a 1D linear structure via intermolecular hydrogen bonds between alkoxyl, amine, and perchlorate groups.