Structural and electronic properties of substituted terthiophenes

Several 3′-(2-arene-l-yl-vinyl)-[2,2′;5′,2′′]terthiophenes and their thiophene analogues were synthesised by Wittig, Wadsworth-Emmons or Knovenagel condensations in good to moderate yields and their electronic absorption and emission spectra were investigated. The spectra are consistent with the presence of two independent chromophores in the ground state together with a single emission from the excited state. There would appear to be exceptions in the analogous cross-linked terthiophene derivatives. A charge transfer effect was also observed for the terthiophene with an indandione substituent.