D-π-A′-π-A chromophores with quinoxaline core in the π-electron bridge and charged heterocyclic acceptor moiety: Synthesis, DFT calculations, photophysical and electro-chemical properties

Chmmophores with charged heterocyclic acceptor moiety in combination with divinylquinoxaline conjugated pi-bridge show a significant solvatochromic shift, small energy gap value (determined by various methods), and large values of the first hyperpolarizability estimated by DFT. A quinoxaline-based chromophore with an indolium acceptor exhibits an outstanding solvatochmmic shift (0.38 eV), probably a record one for D-pi-A chromophores with a dialkyl aniline donor moiety. A good correlation between the above characteristics and the calculated NBO pi-charge on the aniline nitrogen atom has been found. A change in the trend by opposite one in the characteristics in the series of quinolinium/benzothiazolium/indolium chromophores is exhibited when passing from gas to solvent.

Automated summary

Chromophores with charged heterocyclic acceptor moiety in combination with divinylquinoxaline conjugated pi-bridge exhibit a significant solvatochromic shift, small energy gap value, and large first hyperpolarizability. A change in trend by opposite one in the characteristics in the series of chromophores is exhibited when passing from gas to solvent.