Solid-State Conformation, Molecular Packing, and Electrical and Optical Properties of Processable β-Methylated Sexithiophenes
摘要:
Newly synthesized sexithiophenes, di- and tetramethylated at the P-positions, are shown to be soluble and processable compounds, giving single crystals suitable fur X-ray structure determination. The molecular packing was characterized in terms of crystal cohesion and short C-H ... S and C-H ...pi intermolecular distances. In particular, the dimethylated sexithiophene displayed very compressed molecular packing and a thin film field effect transistor, fabricated with this material, was characterized by high charge mobility [2 x 10(-2) cm(2)/(V s)]. The tetramethylated compound crystallizes at room temperature in two different systems and with different conformations. The conformational polymorphs, which are easily interconverted at room temperature, are characterized by different wavelengths of light emission and excitation decay rates.
Synthesis and optical properties of soluble sexithiophenes with one central head-to-head junction
作者:G Sotgiu、M Zambianchi、G Barbarella、C Botta
DOI:10.1016/s0040-4020(02)00098-4
日期:2002.3
The regioselective synthesis of three sexithiophenes characterized by the presence of one central 3,3'-dimethyl-2,2'-bithiophene subsystem is described. One of these compounds was obtained under mild conditions by microwave-mediated synthesis. All sexithiophenes were soluble in organic solvents and displayed 30-40% fluorescence quantum yields in solution. In thin films the fluorescence quantum yields dropped to 1-2%, indicating conformational changes and strong intermolecular interactions in the solid state. (C) 2002 Elsevier Science Ltd. All rights reserved.