Synthesis,crystal structures,and catalytic hydrolysis activities of four dinuclear complexes with 1,4,7,10-tetraazacyclododecane and succinate ligands

Four new dinuclear complexes of the type [M₂(cyclen)₂(suc)]Cl₂ · nH₂O (M = Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, cyclen = 1,4,7,10-tetraazacyclododecane, suc = succinate) have been obtained by the reaction of cyclen and succinate with the corresponding metal dichlorides in aqueous solution. All the complexes were characterized by physico-chemical and spectroscopic methods. The crystal structure of [Ni₂(cyclen)₂(suc)]Cl₂ · 2H₂O was determined. The four complexes have similar compositions and structures and are all bridged by succinate. Furthermore, the hydrolysis of bis(2,4-dinitrophenyl)phosphate (BDNPP) promoted by the four complexes was studied. The experimental results indicate that these complexes can efficiently catalyze hydrolysis of BDNPP, and their catalytic activities are in the order Ni > Zn > Cu > Co.