Viskositätsabhängigkeit der Fluoreszenzquantenausbeute von Donator-Akzeptor-substituierten trans-Stilbenen in unpolaren wenig viskosen Lösungsmitteln

Abstract

Abstract Fluorescence quantum yields, φf, of donor-acceptor substituted trans-stilbenes, 1, in n-heptane and toluene depend upon the solvent dynamic viscosity η according to the relation ln(φf -1 - 1) = a ln(η-1)+b. By changing the temperature (278 < T < 343 K) the viscosity was varied. The viscosity dependence of φf can be accounted for by a corresponding viscosity depending radiations less deactivation of the S1 state, which in low solutions is first of all determined by the intramolecular donor-acceptor and universal intermolecular solute-solvent interactions, and then by viscosity.