MECHANISM OF CHARGE-TRANSFER IN THE MOLECULAR DPQ COMPLEX STUDIED BY TIME-RESOLVED FLUORESCENCE SPECTROSCOPY

The pathways of charge separation in the dimethylaniline-mesoporphyrin II-naphthoquinone triad DPQ and its Zn complex were established. The rate constants of electron transfer from P and ZnP to Q were measured to be k = 1.5 x 10(9) s-1 and k > 5 x 10(10) s-1, respectively, from the results of picosecond fluorescence spectroscopy. The transformation of the DPQ and DZnPQ triads to the reduced form by NaBH4 treatment results in blocking of the electron-transfer channel from both P and ZnP to Q. The transformation of the DPQ and DZnPQ triads to the reduced forms by NaBH4 results in blocking of the electron-transfer channel from both P and ZnP to Q. The role of structural and conformational changes of triads in the electron-transfer process is discussed.