Dm. Guldi et al., ONE-ELECTRON OXIDATION OF METALLOPORPHYCENES AS STUDIED BY RADIOLYTICMETHODS, Journal of physical chemistry, 100(32), 1996, pp. 13609-13614
One-electron and two-electron oxidations of 2,7,12,17-tetrapropylporph
ycene (H(2)TPrPc) and its Fe, Co, Ni, Cu, and Sn complexes in CH2Cl2,
CCl4, and 2-PrOH solutions have been studied by radiolytic techniques.
Formation and decay of intermediates formed upon one-electron oxidati
on have been followed by kinetic spectrophotometric pulse radiolysis,
and the absorption spectra of stable oxidation products have been reco
rded following gamma-radiolysis. H(2)TPrPc is oxidized to the pi-radic
al cation and then to the dication, which is stable in aprotic solvent
s but is transformed to a different product in 2-PrOH. Similar oxidati
on to the pi-radical cation and then to the dication was observed for
the Cu-II, Sn-IV, Co-III, and Fe-III porphycenes. Co-II and Ni-II porp
hycenes underwent radiolytic oxidation to form stable C-III and Ni-III
products. The stability of the latter is in contrast with previous el
ectrochemical observations, and the difference is ascribed to the effe
ct of the axial ligand.