Group II complexes of N- and O-donors Mixed-ligands as anticancer agents.

We report synthesis, characterization and anti-cancer activities of four new magnesium, calcium and strontium complexes containing 1, 10 – phenanthroline, p-amino benzoic acid and cinnamic acid. [Display omitted] Reactions of 1,10-phenanthroline (phen), p-amino benzoic acid (paba) and cinnamic acid (cina) with MCO 3 (M = Mg, Ca, Sr) yielded two mononuclear magnesium complexes [{Mg(phen)(H 2 O) 4 }(phen)(paba) 2 ] (1) and [{Mg(phen)(H 2 O) 4 }(phen)(cina) 2 ] (2) and two one dimensional chains of both calcium and strontium [Ca(phen)(cina)] n (3), and [Sr(phen)(cina)] n (4) respectively. The structures were characterized by a variety of analytical techniques including IR, UV–Vis, 1H NMR, elemental analysis, and single crystal X–ray diffraction analysis. In these complexes, phen binds via an N,Ń –chelate pocket, while the monoanionic paba— / cina— ligands either remains uncoordinated (in case of 1 and 2) or coordinated in a tridentate fashion (in case of 3 and 4). Complexes 1 , 3 and 4 crystallize in the same orthorhombic space group Pbcn while complex 2 crystallizes in triclinic space group P 1. In complex 1 and 2 , Mg2+ cation adopts a distorted six-coordinate octahedral geometry comprising an [N 2 O4] donor set while in complexes 3 and 4 , Ca2+ and Sr2+ cations adopt a distorted eight-coordinate geometry comprising [N2O6] donor sets. Complexes 1, 2 and 4 were found to be potent anticancer against oral cancer cell line i.e. CAL-27 with IC 50 1.85 ± 0.11 , 2.98 ± 1.2 and 5.05 ± 0.35 respectively while complex 3 was inactive. [ABSTRACT FROM AUTHOR]