Synthesis, Structure, and Optical Properties of 1,4-Dithiafulvene-Based Nonlinear Optic-phores

Polyenic nonlinear optic (NLO)-phores with a proaromatic 1,4-dithiafulvene electron donor and the little
explored 1,1,3-tricyano-2-phenylpropene acceptor have been synthesized. Their configurational and
conformational features, ground state polarization, and linear and nonlinear optical properties have been
determined experimentally and theoretically, and the results are compared to those of tetrathiafulvalene-related derivatives. The newly prepared compounds show close to optimal bond length alternation values
for maximizing the first molecular hyperpolarizability, and one of them displays the highest μβ0 value
ever reported for a dithiafulvene-based NLO-phore. The first example of a dithiafulvenylmethylene transfer
reaction is also reported.