Photoinduced electron transfer between C70 fullerene and 3,3',5,5'-tetramethylbenzidine studied by electron paramagnetic resonance.
Electron paramagnetic resonance (EPR) in situ spectroscopy was applied in the study of photoinduced electron transfer between 3,3',5,5'-tetramethylbenzidine (TMB) and C70 in different solvent systems. The changes found in UV-vis spectra pointed at ground state charge transfer complex formation [C70-TMB] in benzonitrile. Upon selective excitation of C70 using steady-state monochromatic irradiation with a wavelength of 546 nm, two EPR singlets were observed, which were assigned to C70 mono- and di-anion. In the photochemical and cathodic in situ reductions, identical EPR spectra of anion radicals were obtained. C70 mono-anion was investigated also in frozen 1,2-dichlorobenzene solutions within the temperature range from 110 to 210 K, and at 110 K the anisotropic EPR spectrum of C70 mono-anion was simulated assuming an axially symmetric g-matrix with gparallel - gperpendicular = 0.00165.
Brezová
V
V
Department of Physical Chemistry, Faculty of Chemical Technology, Slovak Technical University, Bratislava, Slovak Republic. brezova@cvtstu.cvt.stuba.sk
Dvoranová
D
D
Rapta
P
P
Stasko
A
A
D001560:Benzidines / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004579:Electron Transport; D037741:Fullerenes; D010777:Photochemistry
D001560:Benzidines; D037741:Fullerenes; C069836:fullerene C70; C021758:3,3',5,5'-tetramethylbenzidine; D002244:Carbon