Manganese(II) Complexes with 3,5–Dibromosalicylaldehyde: Characterization and Interaction Studies with DNA and Albumins

The interaction of manganese(II) with deprotonated 3,5–dibromo–salicylaldehyde (3,5–diBr–saloH) in the absence or the presence of the N,N′-donors 2,2′–bipyridylamine (bipyam), 2,2′–bipyridine (bipy), 1,10–phenanthroline (phen), and 2,9–dimethyl–1,10–phenanthroline (neoc) as co-ligands yielded five neutral mononuclear complexes, namely Mn(3,5-diBr-salo)2(CH3OH)2] (complex 1), [Mn(3,5-diBr-salo)2(bipyam)] (complex 2), [Mn(3,5-diBr-salo)2(bipy)] (complex 3), [Mn(3,5-diBr-salo)2(phen)] (complex 4), and [Mn(3,5-diBr-salo)2(neoc)] (complex 5), respectively. The resultant complexes were characterized with physicochemical and spectroscopic techniques, and single-crystal X-ray crystallography was applied to determine the crystal structure of complex 2. The evaluation of the potential biological profile of the complexes focused on the interaction with linear calf-thymus (CT) DNA, and bovine (BSA) and human (HSA) serum albumin. According to the data derived, the complexes interact intercalatively and strongly with CT DNA and associate tightly and reversibly with both albumins studied.