One -alkoxo-μ-carboxylato bridged dinuclear copper(II) complex, [Cu2(L1)( μ-C6H5CO2)] (1) (H3L1 = 1,3-bis(salicylideneamino)-2-propanol)), and twoμ-alkoxo-μ-dicarboxylato doubly-bridged tetranuclear copper(II) complexes, [Cu4(L1)2(μ-C8H10O4)(DMF)2]‧H2O (2) and [Cu4(L2)2(μ-C5H6O4)]2H2O 2CH3CN (3) (H3L2 = 1,3-bis(5-bromo-salicylideneamino)-2-propanol)) have been prepared and characterized. The single crystal X-ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged byμ-alkoxo-μ-carboxylato ligands where the CuCu distances and Cu-O(alkoxo)-Cu angles are 3.511 A and 132.8, respectively. Complexes 2 and 3 consist of aμ-alkoxo-μ-dicarboxylato doubly-bridged tetranuclear Cu(II) complex with mean Cu-Cu distances and Cu-O-Cu angles of 3.092 A and 104.2 for 2 and 3.486 A and 129.9 for 3, respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J = -210 cm-1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm-1 and 82 cm-1 (averaged), respectively. The 2J values of 1-3 are correlated to dihedral angles and the Cu-O-Cu angles. Dependence of the pH at 25 C on the reaction rate of oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to the corresponding quinone (3,5-DTBQ) catalyzed by 1-3 was studied. Complexes 1-3 exhibit catecholase-like active at above pH 8 and 25 C for oxidation of 3,5-di-tert-butylcatechol.
Journal of the Chinese Chemical Society=中國化學會會誌 56(1), pp.89-97