1,3-BIS(2-THIENYLMETHYLENE)-1H,3H-THIENO[3,4-C]THIOPHENE - A PRECURSOR FOR A NEW LOW-BAND-GAP POLYMER

A new precursor, 1,3-bis(2-thienylmethylene)-1H,3H-thieno[3,4-c]thiophene (9), for polyarenemethylenes (PAM), which are predicted to be low band gap polymers, is obtained by a Knoevenagel-type condensation of 1H,3H-thieno[3,4-c]thiophene 2-oxide (7) with 2-thiophenecarbaldehyde followed by reduction of the intermediate sulfoxide 8 with 2-chloro-1,3,2-benzodioxaphosphole. Several investigations with cyclic voltammetry and UV-Vis-NIR spectroelectrochemistry (SEC) are carried out on 9. The experimental data are compared with the results of electronic band structure calculated on the basis of an MNDO-optimized geometric structure by VEH pseudopotential method.