Photoinduced Charge Separation in Cyclohexylidene-Based Donor−(σ-Bridge)−Acceptor Compounds − Building Blocks for Materials

Autor: Paul C. M. van Gerven, Cornelis A. van Walree, Wibren D. Oosterbaan, Remco W. A. Havenith, Jacob J. Piet, Mattijs Koeberg, Rolf Gleiter, Leonardus W. Jenneskens, Jan W. Zwikker
Rok vydání: 2003
Předmět:
Zdroj: European Journal of Organic Chemistry. 2003:3117-3130
ISSN: 1099-0690
1434-193X
Popis: We describe the syntheses and properties of five semi-rigid donor−(σ-bridge)−acceptor (D−σ−A) compounds. These compounds, which are candidates for incorporation in materials, have aniline-type donors and (mixed) cyano- and alkoxycarbonyl-1,1-difunctionalized vinyl acceptors that are separated by a four-σ-bond bridge. Their electronic properties were studied by means of photoelectron spectroscopy in combination with ab initio MO calculations, cyclic voltammetry, UV-Vis absorption spectroscopy, (time-resolved) fluorescence spectroscopy, and time-resolved microwave conductivity (TRMC). We found that these D−σ−A compounds exhibit a weak intramolecular charge-transfer absorption band that borrows its intensity from local transitions. Upon photoexcitation, a charge-separated state is generated in virtually quantitative yield. Conformational contraction or “folding” of this state takes place for the two D−σ−A compounds with a dicyanovinyl acceptor in apolar solvents. The absence of folding in compounds with an alkoxycarbonyl-functionalized acceptor is attributed to a reduced lifetime of the charge-separated state. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Databáze: OpenAIRE
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