Electron phenylene-ethynylene

Carbon nanotubes have limited solubility in most organic solvents. Phenylene-ethynylene derivatives have been prepared and used to noncovalently functionalize and solubilize these materials by means of the electron donor/electron acceptor characteristics of the polymer backbone. 

Electron transfer across ferrocene-substituted oligo(phenylene-ethynylene)thiols (System 14) on gold has been studied using the ILIT technique [122] (see above) and electrochemistry [50]. Values of / = 0.57 + 0.02 and 0.36 A were obtained, respectively. Using the electrochemistry method, is 350 s for the 43 A, 36-bond, six-unit conjugated spacer, compared with 1.25 s for the 23 A, 18-bond alkanethiol... 

Among the polymers containing aromatic rings and unsaturated hydrocarbon groups in the backbone are poly(phenylene-ethynylenes) (PPE). This type of polymer has been synthesized by alkyne metathesis of 1,4-dipropynylated benzenes [11] and has applications in optical and electronic industry. A comprehensive study on thermal decomposition of several poly(substituted p-phenylene-ethynylenes) is available [12], The general formula for this group of polymers is the following ... 

Polymers in which the regular alternating arranganent of a disilanyl moiety, —SiR2—SiR2—, and a jr-electron systan such as phenylene, ethynylene and a... 

Fig. 7 (a) Structure of poly(phenylene ethynylene) oligomers, n = 1-3. (b) Small angle X-ray scattering data for vesicles only curve 7), and oligomers with n = 1-3 curves 2-4). (c) Electron density calculation for the lipid membrcine (A), and proposed structural model (B) [84]... 

M.S. Doescher. JM. Tour, A.M. Rawlett and M.L. Myrick, "Stripping voltammetry of Cu overlayers deposited on self-assembled-monolayers field emission of electrons through a phenylene ethynylene oligomer , J. Fkys. Chem. B, 2001,105,105-110. 

To date, most well-examined oligo(phenylene ethynylene)s bearing functional ends for adhesion to metal surfaces are trimers. Thus, in an attempt to broaden our library of candidate compounds, we have chosen to expand our synthetic efforts to tetrameric systems in which two central phenyl units can be functionalized. We report here the development of combinatorial strategies for the preparation of tetrameric phenylene ethynylenes in an effort to find better candidate molecules for applications in molecular electronics. 

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