Electronic Spectra of Phenanthrolinediones, Phenanthrolinones, Bipyridinediones, and Amino-Substituted Phenanthrolines

The electronic spectra of three types of 1,10-phenanthroline derivatives having different π-conjugated systems, phenanthrolinedione, phenanthrolinone, and the parent phenanthroline, showed characteristic patterns easily distinguished from each other. Analogous spectral patterns were noted in amino-substituted 1,10-phenanthrolines, and the protonated structures of these compounds were characterized on the basis of such spectral features.