Synthesis And Photoelectrical Properties Of Oligo(Phenylenethynylene)s

Molecular wires, highly conjugated linear molecules, are one of the basic elements for constructing molecular devices. Among these conjugated compounds, oligo (phenyleneethynylene) as well as its derivatives have been attracting great interest because of their ideal conductivity and fascinating rigidity. With proper modification, OPEs can behave as molecular wires, molecular switch and molecular memory devices. This thesis foucus on the synthesis, characterization and photoelectrical properties of oligo(phenyleneethynylene)s. The main contents are summarized as follows.1. Sealed tube reaction, diazotization, electronic substitute, introduction/removal of protecting group and Sonogashira reaction were utilized to synthesize the following oligo(phenyleneethynylenes)s with stepwise approach.(1) Synthesis of ethynyl-based conjugated oligo(phenyleneethynylene) derivatives with terminal diamine;(2) Synthesis of oligo(phenyleneethynylene)s ofπ-conjugation, structural rigidity based on the facts that thio-compounds can easily form monolayers on the surface of nobel metals;(3) Synthesis of bifunctional oligo(phenyleneethynylene)s terminated with a thioacetate or thioether on one end and a functional group on the other end.The structures of the new intermediates and target compounds were identified by IR,1H NMR,13C NMR and MS.2. Studies on Photoelectrical Properties of oligo (phenylene-ethynylene)s.The UV and fluorescence spectra showed that the target compounds exhibited favorable optical property. The self-assembled monolayer (SAM) of these functional molecular wires was fabricated on a gold substrate. The electrical conductivity and electrochemical activity of the prepared SAMs were investigated from the measurements of cyclic voltammertry.