Copper(II) complexes with tetradentate imine-phenols: synthesis, characterization and molecular structures

Four copper(II) complexes of N,N'-bis(methoxysalicylidene)-1,2-diimino ethanemonohydrate (1), N,N'-bis(5-methoxysalicylidene)-1,2-diiminoethane (2), N,N-bis(3-methoxysalicylidene)2,2-dimethyl-1,3-diiminopropine (3) and N,N'-bis(4-methoxysalicylidene)-2,2-dimethyl-1,3-diiminopropane (4) have been prepared and characterized spectroscopically. The solid-state structures of the complexes were established by X-ray crystallography. Complexes 2, 3 and 4 contain Cu(II) in a tetrahedrally distorted square planar environment with two phenolate O atoms being deprotonated. Complex 1 is five-coordinate and displays color isomerism.