Hydrogen peroxide and dioxygen activation by dinuclear copper complexes in aqueous solution: hydroxyl radical production initiated by internal electron transfer |
| |
Authors: | Zhu Qing Lian Yuxiang Thyagarajan Sunita Rokita Steven E Karlin Kenneth D Blough Neil V |
| |
Institution: | Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA. |
| |
Abstract: | Dinuclear Cu(II) complexes, CuII2Nn (n = 4 or 5), were recently found to specifically cleave DNA in the presence of a reducing thiol and O2 or in the presence of H2O2 alone. However, CuII2N3 and a closely related mononuclear Cu(II) complex exhibited no selective reaction under either condition. Spectroscopic studies indicate an intermediate is generated from CuII2Nn (n = 4 or 5) and mononuclear Cu(II) solutions in the presence of H2O2 or from CuI2Nn (n = 4 or 5) in the presence of O2. This intermediate decays to generate OH radicals and ligand degradation products at room temperature. The lack of reactivity of the intermediate with a series of added electron donors suggests the intermediate discharges through a rate-limiting intramolecular electron transfer from the ligand to the metal peroxo center to produce an OH radical and a ligand-based radical. These results imply that DNA cleavage does not result from direct reaction with a metal-peroxo intermediate but instead arises from reaction with either OH radicals or ligand-based radicals. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|