New property of the fullerenes: the anomalously effective quenching of electronically excited states owing to energy transfer to the C70 and C60 molecules

The quenching of the electronically excited states of various energy donors—Tb³⁺; 9,10-anthracene dibromide; and adamantanone—by C70 fullerene has been detected and analyzed. The quenching is characterized by anomalously high biomolecular quenching rate constants, which are obtained from the Stern-Volmer dependences of the energy-donor photoluminescence intensity on the concentration of the C70 molecules. It has been shown that the high efficiency of quenching by the C70 fullerene as compared to the C60 fullerene is due to the higher polarizability of the C70 molecule and large overlap integrals of the energy-donor photoluminescence spectra with the absorption spectrum of the C70 fullerene.