We have investigated the structural dependence of static second hyperpolarizabilities (γ) of polycyclic diphenalenyl radicals, i.e., IDPL, as-IDPL and TDPL, using the hybrid density functional theory method. It turns out that the diradical character of as-IDPL (0.923) is larger than that of IDPL (0.770) and is close to 1 (pure diradical state), which supports the fact that the γ of as-IDPL (472 × 103 a.u.) is smaller than that of IDPL (2284 × 103 a.u.). The replacement of a central benzene ring (as-IDPL) by a thiophene ring (TDPL) increases the γ (1375 × 103 a.u.). This is predicted to be caused by the reduction of aromaticity of the central ring and by the hypervalency of the sulfur atom of the thiophene.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry