Binding studies of (N-(methylpyridin-2-yl)-amidino-O-methylurea) copper(II) complexes to four nitrogenous bases and 5 '-GMP

摘要

Two copper(II) complexes of N-(methylpyridin-2-yl)-amidino-O-methylurea (L) containing different anions, Cl (1) and ClO4 (2), were prepared and investigated the nucleobase-binding ability toward adenine (A), cytosine (C), guanine (G) and thymine (T). Eight bound adducts were characterized by elemental analysis, spectroscopic methods (infrared, electrospray ionization mass, diffuse reflectance, UV-Vis and electron spin resonance) and thermal analysis. Results have shown the coordination of one or two nucleobase molecules to the copper(II) center of 1 and 2 through the N(7) adenine, N(3) cytosine, N(7) guanine and O(4) thymine by the replacement of anion ligands. Further investigation on the binding potential of 1 and 2 was carried out towards 5'-guanosine monophosphate (5'-GMP), a DNA model, and have found that the N(7) atom of 5'-GMP can bind to their copper(II) center. These two coordination compounds, which display the similar base-binding capability, exhibit the antibacterial activity against the three bacteria involved in human-food poisoning (Salmonella, Escherichia coli and Campylobacter) with the most potent toward Campylobacter for 1 and Salmonella and E. coli for 2. Such a behavior suggests that differences in the anionic ligands on 1 and 2 slightly influence on their antibacterial properties. (C) 2014 Elsevier B.V. All rights reserved.