1 ,10-phenanthroline Absorption spectroscopy Antitumor agent Bioinorganic chemistry Carbolines Crystal atomic structure Cytotoxicity Density functional theory Electronic transition Ground state Ground state geometry Ligands Mass spectrometry Molecular Structure Rhenium Rhenium compounds Rhenium tricarbonyl complexes Spectrometry Spectrometry technique Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization Spectrophotometry, Ultraviolet Spectroscopic characterization Spectroscopy, Fourier Transform Infrared Structure elucidation Synthesis (chemical) Trifluoromethanesulfonate UV-VIS absorption spectra Ultraviolet spectroscopy X ray diffraction X ray structural analysis