Einfluß von Substituenten auf die Fluoreszenzquantenausbeute bei Donator-Akzeptor-substituierten trans-Stilbenen

Abstract

Abstract For 4'-acceptor substituted 4-dimethylaminostilbenes 1 the fluorescence quantum yield φf increases in n-heptane and toluene with decreasing acceptor interaction (i.e. with decreasing polarity in the S1-state). At the same time, the lifetimes τf w change with φf so that kf n remains approximately constant. Changes in φf for compounds 1 result from a strong change of the rate constant ktp of radiationless deactivation. This is interpreted in terms of the decreased stabilization of the Si-state occurring with the increase in the polarity of the investigated compounds in non-polar solvents, and remains in good agreement with the calculations carried out previously.