Cationic Complexes of Magnesium with Phenanthroline: Synthesis, Structural Features, and Antibacterial Activity

Abstract The reaction of magnesium oxide/magnesium pivalate with aromatic heterocyclic acids (3-indolecarboxylic (HInd); 2-thiophenecarboxylic (HTph)) and 1,10-phenanthroline (Phen) gave cationic complexes [Mg(Phen)(Ind)(H 2 O) 3 ] + ⋅Ind – ·2Phen·1.5H 2 O ( I ) and [Mg(Phen)(H 2 O) 4 $$]_{3}^{{2 + }}$$ ·6Tph – ·2Phen ( II ). The structures of I and II were established by direct X-ray diffraction analysis (CCDC nos. 2422043 ( I ) and 2422042 ( II )). According to X-ray diffraction data, the central atom in I and II has a distorted octahedral environment {MgN 2 O 4 }, with the magnesium coordination number being six. In the crystal packing of I , stacking interactions between the Phen aromatic rings give rise to parallel stacks held together by hydrogen bonds. The outer-sphere Tph – in II form strong hydrogen bonds with the coordinated water molecules, thus forming 1D hydrogen-bonded framework. The antibacterial activity of I and II against a non-pathogenic Mycolicibacterium smegmatis strain and two lactobacillus strains, Lactobacillus brevis and Lactobacillus fermentum , was evaluated. The antiproliferative activity of I was determined against the human ovarian adenocarcinoma (SKOV3), breast adenocarcinoma (MCF7), and glioblastoma (A172) cells.