Cationic complexes of magnesium with phenanthroline. Synthesis, structural features and antibacterial activity

The interaction of magnesium oxide/magnesium pivalate with aromatic heterocyclic acids (3-indolecarboxylic (Hind); 2-thiophenecarboxylic (Htph)) and 1,10-phenanthroline (phen) led to the formation of cationic complexes [Mg(phen)(ind)(H2O)3]+ind−·2phen·1.5H2O (I) and [Mg(phen)(H2O)4]32+·6thp−·2phen (II), the structure of which was established by direct X-ray diffraction analysis (CCDC Nos. 2422043 (I) and 2422042 (II)). According to X-ray data, the complexing agent in compounds I and II is in a distorted octahedral environment {MgN2O4} with the coordination number of the magnesium atom equal to 6. In the crystal packing of I, stacking interactions are observed between the aromatic phen cycles, forming parallel stacks held together by hydrogen bonds. Outer-sphere tph− in II form strong hydrogen bonds with the coordinated water molecules, forming an 1D hydrogen-bonded framework. Antibacterial activity against a non-pathogenic strain of M. smegmatis and two strains — Lactobacterium brevis and Lactobacillus fermentum was determined for I and II. Antiproliferative activity of I was determined against cancer lines of human ovarian adenocarcinoma (SKOV3), breast adenocarcinoma (MCF7) and glioblastoma (A172).