Syntheses, crystal structures, and properties of Cu(II) and Zn(II) complexes with an asymmetric tripodal ligand

Abstract

[Cu2L2](ClO4)2 (1) and [Zn2L2](ClO4)2 (2) (HL = 2-[bis(3-aminopropyl)amino]propanol) have been synthesized and characterized. X-ray crystallography analyses show that both are dinuclear with bis-μ-alkoxy-bridged structures. Their molecular structures are centro-symmetric. Each metal adopts a trigonal bipyramidal coordination. Cyclic voltammetry indicates that 1 undergoes two irreversible redox processes with big potential differences (E pa−E pc) and ratio of i pa/i pc, while only one reduction peak is observed in 2. Magnetic susceptibility shows that there is a strong antiferromagnetic interaction (J = −69.4(4) cm−1) between the two copper(II) centers in 1. Hydrolysis activities toward 4-nitrophenyl acetate of the two complexes have been investigated and second-order rate constants of 1 and 2 are (4.3 ± 0.3) × 10−2 and (3.1 ± 0.2) × 10−2 M−1s−1 in 10% (v/v) CH3CN aqueous solution at 25 °C.