Crystal Structure, Hirshfeld Surface Analysis and Biological Activities of trans-Dipyridinebis (3-Acetyl-2-Oxo-2H-Chromen-4-Olato) Cobalt(II)

The novel cobalt(II) complex, trans-dipyridinebis(3-acetyl-2-oxo-2H-chromen-4-olato) cobalt(II), was synthesized in ethanol. The coordination sphere of the cobalt cation was elucidated using single-crystal X-ray diffraction analysis and spectroscopic techniques (FT-IR, UV-Visible and fluorescence). Hirshfeld surface analysis indicates that hydrogen bond interactions, such as C-H center dot center dot center dot O hydrogen bonding between the oxygen of lactone group and the pyridine appear as a primary interaction between the complex's molecules. The presence of pi-pi stacking was evident by the shape index and curvature. Analysis of 2D fingerprint plots confirm that intermolecular H center dot center dot center dot H, C center dot center dot center dot H and H center dot center dot center dot O interactions are well dominated and are in complement to the Hirshfeld surface. The metal-ligand coordination strongly influences the fluorescence intensity (the fluorescence quenching) and the offset of the emission wavelength. The metal complex was monitored for antimicrobial activity using the disk diffusion method and showed significant activity compared to the coumarin ligand.