A copper(II) complex of 1,4,7-triazacyclononane featuring acetate pendant: an efficient DNA cleavage agent

Abstract

A new water-soluble copper(II) complex, Cu(TACNA)Br · 0.375H₂O (1) [TACNA = 1,4,7-triazacyclononane-N-acetate], has been synthesized to serve as artificial nucleases. The X-ray crystal structure of 1 indicates that one bromide and an oxygen from acetate pendant coordinate to copper(II) in addition to the nitrogen atoms in the TACN macrocycle, resulting in a five-coordinate complex with square-pyramidal geometry. The interaction of 1 with calf thymus DNA (ct-DNA) has been investigated by UV absorption and fluorescence spectroscopies, and the mode of ct-DNA binding for 1 has been proposed. In the absence of external agents, supercoiled plasmid DNA cleavage by 1 was performed under aerobic condition; the influences on DNA cleavage of different complex concentrations and reaction times were also studied. The cleavage of plasmid DNA likely involves oxidative mechanism.

Keywords:

• Copper(II) complex
• 1,4,7-Triazacyclononane
• DNA-binding
• DNA cleavage

Acknowledgments

Financial support from the National Natural Science Foundation of China (Grant Nos 21171101 and 21001066) and the PhD Science Foundation of Tianjin Normal University (Grant No. 52LX28) are gratefully acknowledged.