Synthesis, optical, electrochemical, and computational study of benzene/thiophene based D-π-A chromophores

We report the design, synthesis, electrochemical, UV-vis, fluorescence, and computational study of nine pi-linked donor-acceptor (D-pi-A) chromophores. The series of novel compounds comprises a terphenyl, terthiophene, or 2,5-diphenyl thiophene linker, with one electron-donating group (methyl or p-N,N-diethyl) and one electron-withdrawing group (nitrone, formyl, or dicyanovinyl) at opposite ends of the molecule. The HOMO-LUMO gaps were determined via cyclic voltammetry and found to correspond well to DFT-calculated values. Furthermore, the influence of the pi-linker character and substituent on the HOMO-LUMO gap was analysed and interpreted in terms of MO composition via DFT.