Pina João, de Melo J Sérgio Seixas, Burrows Hugh D, Batista Rosa M F, Costa Susana P G, Raposo M Manuela M
Departament of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal.
J Phys Chem A. 2007 Sep 6;111(35):8574-8. doi: 10.1021/jp0730646. Epub 2007 Aug 14.
A comprehensive study has been made in solution at room temperature (293 K), low temperature (77 K), and in thin films (Zeonex matrixes) of the spectral and photophysical properties of six arylthienyl- and bithienyl-benzothiazole derivatives functionalized with different donor groups. Similar experiments have been carried out with two related precursors (containing the arylthienyl and aryl-bithienyl conjugated systems), and results are compared. Singlet-singlet and triplet-triplet absorption spectra, emission spectra together with lifetimes and quantum yields have been obtained, and from these data the rates for all the radiative and nonradiative processes determined, providing information on the dominant decay processes. The arylthienyl-benzothiazole derivatives show high fluorescence quantum yields (phi(F)) with negligible internal conversion (phi(IC)), whereas the bithienyl-benzothiazoles display lower but still significant phi(F) values, but now radiationless processes (phi(IC) and phi(ISC)) are competitive. A comparison with the analogous oligothiophenes is made. Singlet oxygen yields were also determined and the triplet energy transfer to (3)O2 to produce (1)O2 was found to be highly efficient with values of S(Delta)(= phi(Delta)/phi(T)) varying from 0.4 to 1.
对六种用不同供体基团官能化的芳基噻吩基和联噻吩基苯并噻唑衍生物在室温（293K）、低温（77K）的溶液以及薄膜（Zeonex基质）中的光谱和光物理性质进行了全面研究。对两种相关前体（含有芳基噻吩基和芳基联噻吩基共轭体系）进行了类似实验，并比较了结果。获得了单重态-单重态和三重态-三重态吸收光谱、发射光谱以及寿命和量子产率，并根据这些数据确定了所有辐射和非辐射过程的速率，提供了关于主要衰减过程的信息。芳基噻吩基苯并噻唑衍生物显示出高荧光量子产率（φ(F)），内转换（φ(IC)）可忽略不计，而联噻吩基苯并噻唑显示出较低但仍显著的φ(F)值，但此时无辐射过程（φ(IC)和φ(ISC)）具有竞争力。与类似的低聚噻吩进行了比较。还测定了单线态氧产率，发现三重态能量转移至(3)O2以产生(1)O2的效率很高，S(Δ)(= φ(Δ)/φ(T))值在0.4至1之间变化。
