Synthesis, characterization, and structure of a new cobalt(II) Schiff-base complex with quinoxaline-2-carboxalidine-2-amino-5-methylphenol

The mononuclear cobalt(II) complex [CoL2]center dot H2O (where HL is quinoxaline-2-carboxalidine-2-amino-5-methylphenol) has been prepared and characterized by elemental analysis, conductivity measurement, IR, UV-Vis spectroscopy, TG-DTA, and X-ray structure determination. The crystallographic study shows that cobalt(II) is distorted octahedral with each tridentate NNO Schiff base in a cis arrangement. The crystal exhibits a 2-D polymeric structure parallel to [010] plane, formed by O-H center dot center dot center dot N and O-H center dot center dot center dot O intermolecular hydrogen bonds and pi-pi stacking interactions, as a racemic mixture of optical enantiomers. The ligand is a Schiff base derived from quinoxaline-2-carboxaldehyde.