Dinuclear Cu(II) complexes based on p‐xylylene‐bridged bis(1,4,7‐triazacyclononane) ligands: Synthesis,characterization, DNA cleavage abilities and evaluation of superoxide dismutase‐ and catalase‐like activities |
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| Authors: | Qi Tang Ji‐Qing Wu Hong‐Yan Li Yan‐Fang Feng Zhong Zhang Yu‐Ning Liang |
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| Affiliation: | Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry and Pharmacy of Guangxi Normal University, Guilin, People's Republic of China |
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| Abstract: | Three new dinuclear Cu(II) complexes with the formulas Cu2(pxdmbtacn)Cl4] ( 1 ), Cu2(pxdmbtacn)Cl0.7(NO3)1.3(OH)2(H2O)1.3]?6H2O ( 2 ) and Cu2(pxdiprbtacn)Cl4] ( 3 ) together with one previously reported complex, Cu2(pxbtacn)Cl4] ( 4 ), were obtained from Cu(II) salts with three p‐xylylene‐bridged bis‐tacn ligands bearing pendant alkyl substituents or without pendant group. Complex 2 was structurally characterized as a centrosymmetric dinuclear molecule with each metal center being coordinated to some labile ligands in addition to one tacn ring. Based on the results of mass spectrometry and UV–visible spectroscopy, complexes 1 and 3 are capable of existing in aqueous solution as dinuclear species but 4 can partially form a dimer of the original dinuclear motif. Complexes 1 , 3 and 4 can all effectively cleave supercoiled DNA oxidatively in the presence of hydrogen peroxide. The superoxide dismutase (SOD) activities of 1 and 3 measured under physiological conditions are comparable to that of the native CuZnSOD enzyme but the enzymatic activity of 4 is about three‐ to fourfold lower. Furthermore, complexes 1 , 3 and 4 demonstrate moderate scavenging effect on hydrogen peroxide and their catalase activities are in the decreasing order of 3 > 1 > 4 . |
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| Keywords: | catalase mimic copper(II) complex nuclease activity SOD mimic triazacyclononane |
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