Structure property relationship of linear and angular pyrazine-based structural isomers with terminal D-A groups and evaluation of their photophysical properties

A series of pyrazine-based linear and angular shaped push-pull chromophores were synthesized by Sonogashira reaction and were further investigated by X-ray analysis. The photophysical properties were comprehensively studied both experimentally and through quantum chemical methods. The drastic influence of the electrondonor and acceptor on the absorption and emission spectra of the linear and angular scaffolds was established. Quantum chemical computations provided a reliable theoretical rationalization of the observed spectral features. These results suggest that extending the conjugation of a pyrazine acceptor in a linear direction can dramatically improve the intramolecular charge transfer interactions.