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

Abstract

The syntheses of two polydentate ligands comprising imidazole donors, 1,3-bis[(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) · 2H2O (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 distorted square-pyramidal geometry with the axial positions occupied by a perchlorate oxygen atom. Electronic spectra in aqueous solution indicate that both (1) and (2) adopt square-pyramidal geometry. Cyclic voltammetry in aqueous 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 reversibility of the redox reaction of (1) and (2) indicate that BIPO and BIP are flexible enough to stabilize both CuII and CuI forms of the complexes.