39732-73-5

Upstream product

• 14074-80-7 zinc tetraphenylporphyrin 
• 106-51-4 p-benzoquinone 

Downstream Products

• 14074-80-7 zinc tetraphenylporphyrin 
• 19229-76-6 iron(III) 

Relevant academic research and scientific papers

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

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.

Reversible light-driven redox switching of multifunctional dipolar ruthenium(III/II) pentaammine(4,4′-bipyridinium) complexes

We report the first example of a molecular switch of multifunctional dipolar ruthenium(III/II) pentaammine-N-methyl-(4,4-bipyridinium) complexes, exclusively driven by light. This is achieved by using a two-phase (water/benzene) system in which RuIII/II complexes are soluble only in the water phase. The reversible redox switching is triggered by the selective irradiation of the water and the benzene compartments with 254 and 528 nm light, respectively. Copyright

Electron transfer reaction of porphyrin and porphycene complexes of Cu(II) and Zn(II) in acetonitrile

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

Electron transfer quenching of S(2) state fluorescence of Zn-tetraphenylporphyrin

Fluorescence quenching of the second excited (S(2)) state of zinctetraphenylporphyrin (ZnTPP) with dichloromethane has been studied by steady state as well as time-resolved spectroscopy. Effective intermolecular electron transfer from the S(2) state of Zn

Time-Resolved Electron Spin Resonance Study of Photooxidation of Zinc Tetraphenylporphyrin by benzoquinone

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

ENDOR Studies of ?-Electron Delocalization in Covalently Linked Porphyrin Dimers

The spin density distributions in the cation radicals of various covalently linked tetraphenyl porphyrin dimers and of their monomeric constituents have been studied by liquid-phase EPR, ENDOR and TRIPLE resonance methods to find out wether the dimer syst

Photophysics of a Cofacial Porphyrin-Quinone Cage Molecule and Related Compounds: Fluorescence Properties, Flash Transients, and Electron-Transfer Reactions

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

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.

Electron transfer at liquid/liquid interfaces. The effects of ionic adsorption, electrolyte concentration, and spacer length on the reaction rate

Several factors affecting the rate of heterogeneous electron transfer (ET) reactions at the nonpolarized interface between two immiscible electrolyte solutions (ITIES) were investigated by scanning electrochemical microscopy (SECM). The reactions between zinc porphyrin in organic phase and aqueous Ru(CN)63/4-or Fe(CN)63/4- redox species, which have previously served as model systems for probing the potential dependence of the ET rate constant, were used to investigate the effects of adsorption of a reactant and a potential-determining ion on ET rate at the interfaces between water and different organic solvents. It was demonstrated that the rate constant of an interfacial ET can be either potential-independent or potential-dependent under different experimental conditions. The same model experimental systems were used to probe the kinetics of long-range ET across a monolayer of phospholipid adsorbed at the ITIES. The results obtained with a family of phosphatidylserine lipids are compared to those previously obtained with synthetic phosphatidylcholine lipids. The extent of blocking effect of adsorbed lipids on interfacial ET was investigated at different pHs and also in the presence of calcium ions in the aqueous phase. The micrometer-sized domain formation in the monolayer was observed in the presence of divalent cations.

Ligand-Assisted Electron Transfer from the Triplet State of Zinc Tetraphenylporphyrin to 1,4-Benzoquinone

Effects of axial ligands on the electron transfer from excited triplet state of zinc tetraphenylporphyrin (ZnTPP) to benzoquinone (BQ) have been studied by usung a laser flash technique.For the reaction of pyridinate complex of ZnTPP (Py-ZnTPP) as well as ZnTPP, quantum yield of the porphyrrin cation radicals resulting from the electron transfer, Φion, were determined in various solvents of different dielectric constant (ε).Remarkable enhancement in Φion due to axial ligation of pyridine has been found in the solvents having relatively moderate dielectric constant (9A comparison of the ε dependence of Φion for the reaction of the triplet ZnTPP to that for the triplet Py-ZnTPP has demonstrated that the axial pyridine causes partial neutralization of the effective charge of Py-ZnTPP cation radical.When the axial pyridine is replaced by several kinds of the substituted pyridines having different pKa, chloride ion, or ethanol, a significant change in Φion is revealed in dichloroethane.The change in Φion was found to depend on the ability of the ligand to transfer negative charge toward the porphyrin ring via the zinc ion.The ligand ability should cause reduction of effective charge on the porphyrin ring moiety of the ligand-bound ZnTPP cation radical which interacts with the BQ anion radical.Cosequently it has been concluded that the enhancement in Φion due to axial ligation is ascribed to the reduction of the effective charge of the cation radical which results in easier separation of the cation radical from its complex paired with BQ anion radical.