Kanibolotsky, A.L. and Berridge, R. and Skabara, P.J. and Perepichka, I.F. and Bradley, D.D.C. and Koeberg, M. (2004) Synthesis and properties of monodisperse oligofluorene-functionalized truxenes : highly fluorescent star-shaped architectures. Journal of the American Chemical Society, 126 (42). pp. 13695-13702. ISSN 0002-7863Full text not available in this repository. (Request a copy from the Strathclyde author)
This paper describes the strategy toward novel monodisperse, well-defined, star-shaped oligofluorenes with a central truxene core and from monofluorene to quaterfluorene arms. Introduction of solubilizing n-hexyl groups at both fluorene and truxene moieties results in highly soluble, intrinsically two-dimensional nanosized macromolecules T1-T4. The radius for the largest oligomer of ca. 3.9 nm represents one of the largest known star-shaped conjugated systems. Cyclic voltammetry experiments reveal reversible or quasi-reversible oxidation and reduction processes (E-ox = +0.74 to 0.80 V, E-red = -2.66 to 2.80 eV vs Fc/Fc(+)), demonstrating excellent electrochemical stability toward both p- and n-doping, while the band gaps of the oligomers are quite high (E-g(CV) = 3.20-3.40 eV). Close band gaps of 3.05-3.29 eV have been estimated from the electron absorption spectra. These star-shaped macromolecules demonstrate good thermal stability (up to 400-420 degreesC) and improved glass transition temperatures with an increase in length of the oligofluorene arms (from T-g = 63 degreesC for T1 to 116 degreesC for T4) and show very efficient blue photoluminescence (lambda(PL) = 398-422 nm) in both solution (Phi(PL) = 70-86%) and solid state (PhiPL = 43-60%). Spectroelectrochernical experiments reveal that compounds T1-T4 are stable electrochromic systems which change their color reversibly from colorless in the neutral state (similar to340-400 nm) to colored (from red to purple color; similar to500-600 nm) in the oxidized state.
|Keywords:||light-emitting-diodes, discotic liquid-crystals, field-effect transistors, phenylboronic acid, deuterium nmr, blue emission, derivatives, phase, copolymers, alignment, Chemistry, Biochemistry, Colloid and Surface Chemistry, Chemistry(all), Catalysis|
|Subjects:||Science > Chemistry|
|Department:||Faculty of Science > Pure and Applied Chemistry|
|Depositing user:||Mr Derek Boyle|
|Date Deposited:||24 Apr 2006|
|Last modified:||09 Sep 2016 02:03|