An investigation of electronic structure and properties of new chromophore: 3,3′-bithiazolo[3,4-a]pyridinium perchlorate

The chromophore 3,3′-bithiazolo[3,4-a]pyridinium 1, obtained by oxidative cyclization reactions using a tetrathiafulvalene as a leaving group, strongly absorbs at the violet end of the visible region as evidenced by its yellow color. The solution (MeCN) spectrum displays an intensive, broad absorption band around 377 nm with a ε value of 8×103 l mol−1 cm−1. The chromophore also shows a strongly Stokes-shifted fluorescence emission with a lifetime τ of 2.8±0.1 ns in acetonitrile solution. Herein, we describe the photophysical properties and a theoretical investigation of the electronic structure of the chiral dicationic, bis(bicyclic) ring assembly 1.