Indolizine-based chromophores with octatetraene pi-bridge and tricyanofurane acceptor: Synthesis, photophysical, electrochemical and electro-optic properties

摘要

Two isomeric indolizine-based chromophores (MPI-1)-OT-TCF and (MPI-3)-OT-TCF with octatetraene pi-bridge and tricyanofuran acceptor moieties have been synthesized and systematically investigated. Chromophores exist as a mixture of E- and Z-isomers in low-polar dioxane and chloroform solutions, while in polar solvents only one isomer is observed. The chromophores show excellent thermal stability with T-d > 260 degrees C (DSC) and small energy gap between the frontier orbitals (about 0.8-0.9 eV) established by DPV method. The chromophores exhibit absorption in the visible and near IR region. Solvatochromic shifts amounting to ca. 100 nm when passing from dioxane to DMSO solutions are accompanied by appearance of an additional narrow intensive absorption band at ca. 915-950 nm resulting from the cross of cyanine limit. For the first time electro-optic activity of composite materials doped by indolizine based chromophores have been investigated; EO coefficient of poled (MPI-3)-OTTCF/PMMA film afforded value of 29 pm/V at 10 wt% load.