Reaction of Selenoamide Dianions with Thio- and Selenoformamides Leading to the Formation of 5‑Aminoselenazoles: Photophysical and Electrochemical Properties

5-Amino-2-selenazolines were synthesized by reacting selenoamide dianions generated from secondary selenoamides and BuLi with tertiary thio- and selenoformamides followed by treatment with iodine. The resulting 5-amino-2-selenazolines were further oxidized with iodine to give 5-aminoselenazoles in moderate to good yields. The general tendencies in the 77Se NMR spectra of the starting selenoamides, 5-amino-2-selenazolines, and 5-aminoselenazoles were determined. The chemical shifts of these compounds were highly influenced by the skeletons involving the selenium atom as well as the substituents on the carbon atoms of each skeleton. The molecular structures of 5-aminoselenazoles were clarified by X-ray analyses, and their electronic structures were elucidated by DFT calculations. Finally, UV–vis and fluorescence spectroscopy and cyclic voltammetry (CV) of 5-aminoselenazoles were performed, and their properties are discussed in relation to the substituents on the selenazole rings.