1,3‐Thiazolium‐4‐aminides: Syntheses and Characterizations of Fluorescent Mesoionic Compounds

A series of mesoionic 1,3-thiazolium-4-aminides was synthesized starting from thioamides and chloroacetonitrile via cyanomethylbenzimidothioates which were cyclized by benzoylchloride. Depending on the reaction conditions 4-amino-1,3-thiazolium salts 4-N-benzamido-1,3-thiazolium obtained (X-ray structure analysis). Substitution amino groups with benzoyl chloride gave a title compounds analysis) examined spectroscopically. Negative solvatochromism found temperature-dependent as well time-resolved fluorescence measurements made. Long lifetimes excited states (30–50 ns) detected. Calculated frontier orbital profiles gain insight into characteristics conjugated mesomeric betaines.