Synthesis, Characterization and Biological Profile of Cationic Cobalt Complexes with First-Generation Quinolones.

The interaction of cobalt(II) with first-generation quinolones oxolinic acid (Hoxo), flumequine (Hflmq), pipemidic acid (Hppa) and cinoxacin (Hcx) in the presence of the ,-donor heterocyclic ligands 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen) afforded a series of novel cobalt complexes, namely Co(bipy)(oxo)·HO (), Co(phen)(oxo)·0.5CHOH·0.5HO (), Co(bipy)(flmq)·0.5CHOH·0.5HO (), Co(bipy)(ppa)·CHOH·0.5HO (), Co(phen)(cx)·CHOH·0.5HO (), and Co(phen)(flmq)·0.5CHOH·HO (). The characterization of the complexes involved physicochemical techniques, various spectroscopies and single-crystal X-ray crystallography. The affinity of complexes to calf-thymus (CT) DNA was monitored with various techniques, suggesting intercalation in-between the DNA-nucleobases as the most probable interaction mode, which may be combined with electrostatic interactions as a result of the cationic nature of the complexes. The affinity of the complexes for bovine and human serum albumin proteins was monitored, and the determined corresponding albumin-binding constants revealed a tight and reversible interaction.