Synthesis, crystal structure and redox properties of bis-imidazolyl-containing copper(II) complexes

Two copper(II) complexes, [Cu(L1)Cl]Cl and [Cu(L2)Cl]Cl, with tetradentate ligands L1 = N,N'-bis[(1-methylimidazol-2yl)methyl]-1,3-diaminopropan-2-ol and L2 = N,N-bis[(1-methylimidazol-2-yl)methyl]-1,3-diaminopropane were prepared and characterized. Ligands L1 and L2 were synthesized by NaBH4 hydrogenation of the corresponding Schiff bases obtained from condensation of 1-methyl-2-imidazolecarboxaldehyde with 1,3-diaminopropan-2-ol and 1,3-diaminopropane, respectively. The crystal structures of the complexes are determined by X-ray diffraction. The complexes display a square-pyramidal geometry about the copper centers coordinating with Cl- and N-4 donor set of the ligands. Electrochemical studies indicate that the complexes undergo quasi-reversible one-electron reduction in both acetonitrile and aqueous solutions. (C) 2002 Elsevier Science B.V. All rights reserved.