Electron paramagnetic resonance fullerenes

In a supramolecular approach to fullerene-porphyrin hybrids, the assembly of a rigidly connected dyad, in which a zinc tetraphenylporphyrin, Zn(TPP), is noncovalently linked to a C60 derivative via axial pyridine coordination to the metal, was reported [219-222]. Photo excitation of the dyad Zn-complex led to electron transfer with very long lifetimes of the charge-separated pairs, as revealed by optical spectroscopy and confirmed by time-resolved electron paramagnetic resonance spectroscopy. Accordingly, two different solvent-dependent pathways can be considered for the electron-transfer processes. Either the excitation of the porphyrin chromophore is followed by fast intramolecular electron transfer inside the complex, or alternatively the free porphyrin is excited undergoing intermolecular electron transfer when the acceptor molecules ap-... 

Keywords fullerene, electron paramagnetic resonance, photoconductivity... 

Wasielewski MR, O Neil MP, Lykke KR, Pellin MJ, Gruen DM. Triplet states of fullerenes C60 and C70. Electron paramagnetic resonance spectra, photophysics, and electronic structures. J Am Chem Soc 1991 113 2774-6. 

The amino-modified MCM-41 (Lee, 2002) doped with Ceo have been employed to study by electronic paramagnetic resonance (EPR) the free radical reactions of fullerenes in... 

To understand better the complicated electrochemical behavior of solid fullerenes, numerous complementary techniques have been used. These include SECM, EQCM, laser desorption mass spectrometry, surface enhanced Raman spectroscopy, electron paramagnetic resonance, spectroelectrochemical techniques, optical microscopy, conductivity measurements, SEM, and X-ray diffraction. The results of these studies are summarized below. 

When the higher fullerenes are treated with TDAE, the radical anions of the higher fullerenes are generated The generation of the radical anions of higher fullerenes was confirmed by the electron paramagnetic resonance (EPR) measurements. It should be noted that the radical anion... 

A powerful technique to detect paramagnetic radical species, such as the one-electron reduced 7t-radical anions (Ceo ) and oxidized 7t-radical cation (Ceo ) is electron spin resonance (ESR) (9,10). Studies, regarding the characterization of fullerene intermediates via employing the ESR technique are, however, still somewhat controversial. Absorption spectrophotometry, on the other hand, is been successfully employed in matrix irradiation, silver mirror reduction in tetrahydrofuran (THF), and detection of transients in time-resolved laser photolysis and pulse radiolysis (10,11). 

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