Magnetic field effect on the photoinduced electron transfer reaction between benzophenone and starburst dendrimers in water

Magnetic field effect (MFE) on the photoinduced electron transfer reaction between benzophenone and starburst dendrimers are studied in water by laser flash photolysis. In the presence of a magnetic field of 0.6 T, the relative yields of benzophenone anion radical at a 4-7 mu s delay increase by about 158 in the case of 3-, 4-, and 5-generation dendrimers, whereas there is no appreciable MFE in the case of 1- and 2-generation dendrimers, 1,3-diaminopropane, and N,N,N',N'-tetraethyl-1,3-diaminopropane. The MFE is interpreted in terms of a radical pair mechanism. Present results indicate clearly that the dendrimers of higher generation act not only as an electron donor but also as a supercage in the photoreaction. (C) 2000 Elsevier Science B.V. All rights reserved.