Electron and H-atom phototransfer: ESR investigation in doped crystals and glassy matrices

The present report discusses the investigation of intermediate products in photoactive molecules which can be included in organic crystals as impurity. This method in doped crystals allows to obtain new results in the field of photoreactions of quinones, quinone diazides, iminoquinones and another acceptors of electron or H-atom. Asymmetric relaxation effects were observed in X-band spectra of some radical pairs. Anisotropy of electron transfer in photoreactions of porphyrins was investigated in glassy matrices at 77 K. The data obtained are explained by anisotropy of dark tunnel recombination of ion- radical pairs. Polarized light was used to produce oriented spin probes: radical complexes of phenol and quinones in frozen organic solutions. Kinetics of reorientation of these probes in time range from 10 min. to several months were measured at different temperatures (77 K - 140 K). Correlation between the molecular mobility of oriented radical complexes and the rate of radical reactions in the same frozen matrices were found. Photochemical transfer of electron and proton across the interface in microemulsion were investigated. The preliminary results obtained using pulsed and 2-Dimensional ESR BRUKER 380E spectrometer in cooperation with Professor John Pilbrow and Dr. Y.C. Zhong will be discussed