Syntheses, crystal structures and properties of copper(II) complexes of 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propan-2-ol and 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino] propane

The syntheses of two polydentate ligands comprising imidazole donors, 1,3-b is[(4-methyl-5-imidazol-1-yl) ethylideneamino]propan-2-ol (BIPO), 1,3-bis[( 4-methyl-5-imidazol-1-yl)ethylideneamino]propane (BIP), and their copper(II ) complexes [Cu(BIPO)(ClO4)(H2O)] (NO3) . H2O (1) and [Cu(BIP)(ClO4)](ClO4) . 2H(2)O (2) are reported. Single-crystal structural analyses show that (1 ) adopts an elongated octahedral geometry with the axial positions occupied by a perchlorate oxygen atom and an aqua ligand, while (2) adopts a distor ted square-pyramidal geometry with the axial positions occupied by a perchl orate oxygen atom. Electronic spectra in aqueous solution indicate that bot h (1) and (2) adopt square-pyramidal geometry. Cyclic voltammetry in aqueou s solution gives reduction waves at -0.07 and -0.08 V versus s.c.e. for (1) and (2), respectively. The low reduction potential and general reversibili ty of the redox reaction of (1) and (2) indicate that BIPO and BIP are flex ible enough to stabilize both Cu-II and Cu-I forms of the complexes.