SYNTHESIS AND STRUCTURAL STUDIES OF POLY(P-PHENYLENEVINYLENE) ANALOGOUS MODEL COMPOUNDS

Described is the synthesis and characterization of three poly(p-phenyl enevinylene) (PPV) three-ring model compounds, one unsubstituted at th e vinylene moiety (1) and two dicyano-substituted compounds (2, 3), di ffering in the positions of their cyano groups. Single-crystal analyse s of the two cyano-substituted compounds 2 and 3 show that introductio n of cyano groups into alkyl-substituted PPV analogous compounds leads to remarkable torsion of the conjugated backbones unlike hexyloxy-sub stituted compounds. In the case of introducing it into the alpha-posit ion as in 2, the torsion is distributed almost equally over the molecu le. Introducing the cyano group into the beta-position as in 3 leads t o a one-sided torsion between the inner phenylene ring and the vinylen e-CN planes.