129707-76-2Relevant articles and documents
Metalloporphyrins for quadratic nonlinear optics
Sen, Avijit,Ray, Paresh Chandra,Das, Puspendu Kumar,Krishnan, Varadachari
, p. 19611 - 19613 (1996)
CuII- and ZnII-based donor-acceptor porphyrins have been examined for second-order nonlinear optics using the hyper-Rayleigh scattering technique at 1064 nm. Introduction of the metal ions enhances the first hyperpolarizability (β) of the free-base donor-acceptor porphyrins significantly. The open shell CuII (d9) has a greater influence on β of these porphyrin systems than the closed shell ZnII (d10). The high β values in the ZnII porphyrins are understood in terms of the change in dipole moments upon excitation within the context of the two-state model as well as two-photon resonance enhancement. In CuII porphyrin complexes a large number of excited states seem to contribute to β with, perhaps, a little contribution from two-photon resonance at the excitation wavelength.
The oxidation of ethylbenzene and other alkylaromatics by dioxygen catalysed by iron(III) tetrakis(pentafluorophenyl)porphyrin and related iron porphyrins
Evans, Steven,Smith, John R. Lindsay
, p. 1541 - 1551 (2007/10/03)
The oxidation of ethylbenzene with dioxygen catalysed by iron(III) porphyrins in a solvent free system has been studied over the temperature range 30-110°C. The time dependence of the formation of the three main products, 1-phenylethanol, acetophenone and 1-phenylethyl hydroperoxide, and the fate of the iron porphyrin are interpreted in terms of a free radical autoxidation mechanism. The yields of the oxidation products are determined by the rate of reaction and by the lifetime of the catalyst. Catalyst degradation is shown to involve reaction of the porphyrin ligand with 1-phenylethoxyl and 1-phenylethylperoxyl radicals. The disadvantages of increased induction periods and longer reaction times of the oxidations observed at lower reaction temperatures are counter balanced by increased catalyst turnovers. Less extensive studies on the oxidations of toluene, cumene, (2-methylpropyl)-benzene and tert-butylbenzene support the overall mechanism proposed for ethylbenzene. A comparative study using the catalysts iron(III) 2,3,7,8,12,13,17,18-octachloro-5,10,15,20-tetrakis-(2,6-dichlorophenyl)porphyrin and iron(III) tetrakis(pentafluorophenyl)porphyrin and five of its derivatives reveals that halogenation of the β-pyrrole positions markedly increases the activity of the catalysts but not the stability of the porphyrin towards degradation. The highest yields were obtained with the μ-oxodimer of iron(III) tetrakis(pentafluorophenyl)porphyrin and iron(III) tetrakis(4-dimethylamino-2,3,5,6-tetrafluorophenyl)-porphyrin.
