Electro-optic and spectroscopic properties of push–pull-chromophores with non-aromatic π-bridges

We present electronic structure calculations of the ultraviolet/visible (UV–Vis) spectra as well as hyperpolarizabilities (HP) of push–pull chromophores based on a donor-cyclic bridge-acceptor framework. The bridges are comprised of anti-aromatic polycycles or fulvalene analogues. Both UV/Vis and HP are sensitive functions of the conjugated framework and do not follow conventional wisdom, in particular for fulvalene analogues. Effects can be rationalized by determining mesomers of the bridge that can be stabilized or destabilized by the donor or acceptor. In particular, fulvalene analogues display high susceptibility to this effect and the strongest HP-chromophores exhibit a computed static hyperpolarizability of 372 × 10−30 cm5 esu−1 and 311 × 10−30 cm5 esu−1.