CONNECTIVE CC DOUBLE-BOND FORMATION FOR THE SYNTHESIS OF DONOR-SUBSTITUTED AND ACCEPTOR-SUBSTITUTED POLY(P-PHENYLENEVINYLENE)S

A carbon-carbon bond formation through cation-anion coupling allows th e synthesis of poly(p-phenylenevinylene)s (PPV) 1 and 2a-f, which cont ain donor and acceptor groups in each vinylene unit. The crucial step in the double bond formation is the quantitative elimination of methan ethiol at room temperature. In this work we describe the optimization of the molecular weight of polymers of structure types 1 and 2a-f with regard to (i) solubility of the monomers and polymers and (ii) the re activity and side reactions of the monomers. The simultaneous donor an d acceptor substitution on the central double bond in PPV-analogous st ructures raises the question of the additivity of dipoles in each repe at unit of a conjugated polymer chain from the viewpoint of potential use in electrooptical applications. The sequence of donor and acceptor groups along the pi-conjugated chain can be controlled by the choice of suitable monomers and is crucial for the alignment of the dipole co mponents. The aggregation of polymers 1 and 2a-f, observed in the GPC, makes it necessary to introduce MALDI-TOF mass spectrometry for the d etermination of the molecular weight of the donor-and acceptor-substit uted polymers. The thermal properties are determined with regard to th e high-temperature stability demanded for use in nonlinear optics (NLO ).