39732-73-5Relevant articles and documents
Light-induced electron transfer from a lipid-soluble zinc(II) porphyrin to various electron acceptors in frozen vesicle solutions: effects of cholesterol on the solubilization sites and radical yields
Lanot,Kevan
, p. 5280 - 5284 (1989)
The photoionization of zinc tetraphenylporphyrin (ZnTPP) has been studied by electron spin resonance (ESR) at 77 K in rapidly frozen dipalmitoylphosphatidylcholine (DPPC) vesicle solutions, and in the presence of various electron acceptors like tetrachloro- and tetrabromobenzoquinone (TCBQ and TBBQ) and potassium ferricyanide (K3Fe(CN)6). The photoproduced ZnTPP+ yield was found to increase, and photoinduced anion formation was also detected for added tetrahalobenzoquinones. Incorporation of cholesterol in these systems altered the ZnTPP+ radical yields via two main structural changes: (1) ZnTPP-water contact increased due to intercalation of cholesterol between the surfactant headgroups, and (2) TCBQ moved deeper into the vesicle bilayer because of increased bilayer fluidity.
Electron transfer reaction of porphyrin and porphycene complexes of Cu(II) and Zn(II) in acetonitrile
Aoki, Kaori,Goshima, Toshimitsu,Kozuka, Yohei,Kawamori, Yukiko,Ono, Noboru,Hisaeda, Yoshio,Takagi, Hideo D.,Inamo, Masahiko
, p. 119 - 125 (2009)
The outer-sphere one-electron oxidation reaction of the Cu(ii) and Zn(ii) complexes of nonplanar 2,3,7,8,12,13,17,18-octaethyl-5,10,15,20- tetraphenylporphyrin and planar porphycenes as well as those of 2,3,7,8,12,13,17,18-octaethylporphyrin and 5,10,15,2
Time-Resolved Electron Spin Resonance Study of Photooxidation of Zinc Tetraphenylporphyrin by benzoquinone
Willigen, Hans van,Vuolle, Mikko,Dinse, K. P.
, p. 2441 - 2444 (1989)
The pulsed-dye laser-induced photooxidation of ZnTPP by benzoquinone has been studied with time-resolved direct-detected electron spin resonance (ESR).Spectra of free radicals can be obtained within 1 μs after the laser pulse.For the first time the ESR sp
Photophysics of a Cofacial Porphyrin-Quinone Cage Molecule and Related Compounds: Fluorescence Properties, Flash Transients, and Electron-Transfer Reactions
Lindsey, Jonathan S.,Delaney, John K.,Mauzerall, David C.,Linschitz, Henry
, p. 3610 - 3621 (1988)
Fluorescence yields, fluorescence lifetimes, and flash photolysis transients have been measured for a tetrabridged cofacial porphyrin-quinone cage molecule and related derivatives.When the quinone is present and in the oxidized form, two fluorescence lifetimes are observed for the zinc complex, both shorter than the single lifetimes of control compounds.These are assigned to two conformers, with porphyrin to quinone interplanar separation of about 8.5 and 6.5 Angtroem, respectively.The fluorescence lifetime data lead to electron-transfer times for the two conformers of between 0.5 and 15 ns.The fast electron-transfer time is only weakly dependent on solvent and is independent of temperature between 290 and 124 K.Following flash photolysis of the zinc-porphyrin-quinone in polar solvents, a transient band at 415 nm grown in more slowly (150 ns) and decays much more rapidly (1.4 mms) than the triplet seen in control compounds and is assigned to a charge-separated ZnP+Q- state.The reation leading to this state exhibits an activation energy of only 6 kJ/mol.In contrast to the zinc chelate, the free base porphyrin-quinone shows no electron-transfer interactions.These support a distance-sensitive nonadiabatic electron-tunneling mechanism for the transfer.Effects of solvent and protonation are interpreted in terms of conformational changes that modify the porphyrin-quinone distance.Attempts to study effects of orbital symmetry in a pair of chlorin-quinones were inconclusive.A larger fraction of energy is stored in forming the charge-separated state (1.4 eV, ΔG) from the triplet state (1.6 eV,ΔE) of the zinc-porphyrin-quinone than is stored in the bacterial reaction center (0.5 eV) from the singlet state (1.2 eV).
Quadratic nonlinearity of one- and two-electron oxidized metalloporphyrins and their switching in solution
Wahab, Abdul,Bhattacharya, Mily,Ghosh, Sampa,Samuelson,Das, Puspendu K.
, p. 2842 - 2847 (2009/02/03)
We report the quadratic nonlinearity of one- and two-electron oxidation products of the first series of transition metal complexes of meso-tetraphenylporphyrin (TPP). Among many MTPP complexes, only CuTPP and ZnTPP show reversible oxidation/reduction cycles as seen from cyclic voltammetry experiments. While centtosymmetric neutral metalloporphyrins have zero first hyperpolarizability, ??, as expected, the cation radicals and dications of CuTPP and ZnTPP have very high ??values. The one- and two-electron oxidation of the MTPPs leads to symmetry-breaking of the metal-porphyrin core, resulting in a large ??value that is perhaps aided in part by contributions from the two-photon resonance enhancement. The calculated static first hyperpolarizabilities, ??0, which are evaluated in the framework of density functional theory by a coupled perturbed Hartree-Fock method, support the experimental trend. The switching of optical nonlinearity has been achieved between the neutral and the one-electron oxidation products but not between the one- and the two-electron oxidation products since dications that are electrochemically reversible are unstable due to the formation of stable isoporphyrins in the presence of nucleophiles such as halides. ? 2008 American Chemical Society.
