Synthesis and crystal structure of a new dicopper(II) complex with N-benzoato-N′-(hydroxypropyl)oxamide as ligand: cytotoxic activities and reactivities towards DNA and BSA

Abstract

A new dicopper(II) complex bridged by N-benzoato-N′-(hydroxypropyl)oxamide (H₃oxbpa) and end-capped with 1,10-phenanthroline (phen), [Cu₂(oxbpa)(phen)(H₂O)](pic)·2H₂O (where pic denotes picrate anion) has been synthesized and characterized by elemental analyses, molar conductance, IR and electronic spectra studies, and single-crystal X-ray diffraction. In the crystal of the dicopper(II) complex, copper(II) ions are bridged by cis-oxamide with a CuCu separation of 5.258(5) Å. The ones at the inner and the exo-sites of the cis-oxbpa³⁻ are square-planar and square-pyramidal coordination, respectively. These complexes are assembled to a one-dimensional chain via classical O–HO hydrogen bonds. In vitro cytotoxicity shows that the dicopper(II) complex exhibits cytotoxic activity against SMMC7721 and A549 cell lines. The reactivity towards (Herring sperm DNA) and protein bovine serum albumin (BSA) revealed that the dicopper(II) complex can interact with DNA by intercalation, and the complex binds to protein BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism.

Keywords:

• Crystal structure
• Dicopper(II) complex
• Oxamidato-bridge
• In vitro anticancer activity
• DNA interaction
• Protein BSA binding

Acknowledgments

This project was supported by the National Natural Science Foundation of China (Nos. 21071133 51273184 and 81202399), the Program for Science and Technology of Shandong Province (2011GHY11521), the Natural Science Foundation of Qingdao City (Nos. 11-2-4-1-(9)gch, 12-1-3-52-(1)-nsh and 12-1-4-16-(7)-jch), and the Open Research Fund Program of Key Laboratory of Marine Drugs (Ocean University of China), Ministry of Education (No. KLMD(OUC)201204).