Nonlinear optical properties of chromophores with indolizine donors: Theoretical study

New class of nonlinear optical chromophores with donors containing indolizine moiety is proposed. Dipole moment and first hyperpolarizability values of the chromophores, which are analogs of FTC, CLD and OLD chromophores, containing 1-methyl-2-phenylindolizin-3-yl (MPI-3) or 3-methyl-2-phenylindolizin-1-yl (MPI-1) donors (instead of diethylaminophenyl), 3-cyano-2-dicyanomethylene-5,5-dimethyl-1,5-dihydrofuran-4-yl (TCF) acceptor, and 2,5-divinylthiophene, octatetraene and 2,2'-divinylbithiophene pi-electron bridge, are calculated by DFT technique. Chromophores with named donors and acceptors and 3,7-divinylquinoxalin-2-one pi-electron bridge are also studied. In most cases higher values of first hyperpolarizability were obtained for chromophores with MPI-3 donor, this being in accordance with the electron density distribution in these fragments. The change of dimethylaniline donor fragment for indolizine one results in the growth of the first hyperpolarizability values. This observation holds also for chromophores with divinylquinoxalinone pi-electron bridge, in which higher values of first hyperpolarizability are obtained when the donor moiety is connected through vinylene group at position 3 rather than at position 7 of the quinoxalinone system. (C) 2016 Elsevier B.V. All rights reserved.