2-(1,1-dicyanomethylene)rhodanine: A novel, efficient electron acceptor

The push–pull behaviour of novel 2-(1,1-dicyanomethylene)rhodanines bearing an electron donor N,N-dimethylaniline or tetrathiafulvalene group on the C-5 of the heterocyclic ring was studied using experimental (electrochemical and spectroscopical analysis) and theoretical (DFT/B3LYP/631G∗∗) methods. Calculations showed a remarkable push–pull trend with the HOMO mainly located on the donor moiety and the LUMO on the acceptor dicyanomethylene moiety. In agreement with the theoretical predictions, a solvatochromic, behavior intramolecular charge transfer band was observed in the visible region.