35218-75-8Relevant articles and documents
Selective oxidation of 2-naphthol to 2-hydroxy-1,4-naphthoquinone with hydrogen peroxide catalyzed by 5,10,15,20-tetrakis(p-sulfonatophenyl)porphinatomanganese(III) chloride in aqueous solution.
Hassanein,El-Khalafy,Shendy
, p. 134 - 137 (2017)
2-Naphthol has been selectively oxidized to 2-hydroxy-1,4-naphthoquinone (HNQ, Lawsone) with hydrogen peroxide in presence of 5,10,15,20-tetrakis-(p-sulfonatophenyl)porphinatomanganese (III) chloride as catalyst in alkaline aqueous solution. The catalytic oxidation afforded 2-hydroxy-1,4-naphthoquinone in high yield (95%). The effect of reaction parameters on the catalytic activity and the yield of HNQ have been investigated. UV–vis spectral analysis during oxidation reaction indicated that oxomanganese intermediate O = Mn(IV)TPPSCl was the active species in the oxidation reaction.
Highly efficient electrocatalytic hydrogen evolution from neutral aqueous solution by water soluble copper (II) porphyrin
Beyene, Belete B.,Yibeltal, Amogne W.,Hung
, (2020)
A water soluble Cu (II) porphyrin bearing para-sulfonic group at mesophenyl rings is reported as molecular electrocatalyst for H2 generation from neutral aqueous solution. Electrocatalysis study in buffer solution of pH 7.2 showed that the complex is highly active, efficient and stable toward H2 evolution. It features an observed rate constant (kobs) of 8.6 × 103 s?1 and Faradaic efficiency of 98.3% at an overpotential of 470 mV. The role of functional group on catalytic activity is also investigated by conducting heterogeneous catalysis involving Cu-porphyrin with (CuTPPS) and without (CuTPP) para-sulfonic groups. Hence differential pulse voltammetry, controlled-potential electrolysis and electrochemical impedance spectroscopic measurements show that, CuTPPS-modified electrode perform much better than that of CuTPP-modified. This may be attributed to an increase in the amount of catalyst at the vicinity of electrode surface because of the ability of para-sulfonic functional group to anchor to electrode surface. Moreover, its electron withdrawing behaviour and ability to donate proton to the solution in turn thermodynamically favour H2 evolution.
Metal chelates of porphyrin derivatives as sensitizers in photooxidation processes of sulfur compounds and in photodynamic therapy of cancer
Woerle, D.,Wendt, A.,Weitemeyer, A.,Stark, J.,Spiller, W.,et al.
, p. 1953 - 1964 (1994)
A number of porphyrin derivatives based on hematoporphyrin, 5,10,15,20-tetrasubstituted porphyrins, phthalocyanines, and naphthalocyanines were prepared either as low-molecular compounds or bonded with methoxypoly(ethylene glycol) or attached to silica of low surface area.The low-molecular weight and the polymer-bonded porphyrins exhibit comparable triplet lifetimes and activities in the photosensitized formation of singlet oxygen.For photon-induced processes, the monomeric state of sensitizers is fundamentally important.The porphyrins have been investigated as sensitizers for photooxidation of thiolates and sulfides, which occurs via singlet oxygen, and, therefore, is much more efficient that the corresponding catalytic dark oxidation.Polymer-bonded porphyrins and long-wavelength absorbing naphthalocyanines incorporated in liposomes exhibit in vivo high accumulation in tumor tissues.Under irradiation, singlet oxygen is produced, and efficient phototherapeutic effects are observed, which may be used for photodynamic cancer therapy. - Key words: metal chelates of porphyrin derivatives; photodynamic therapy of cancer.
Solvent effects on catalytic activity of manganese porphyrins with cationic, anionic and uncharged meso substituents: Indirect evidence on the nature of active oxidant species
Esfandiari bayat, Zahra,Rahiminezhad, Hajar,Zakavi, Saeed
, (2018/11/23)
Oxidation of cyclohexene and styrene with sodium periodate and tetra-n-butylammonium periodate (TBAP) catalyzed by MnT(3-MePy)P(OAc), MnT(4-SO3)PP(OAc) and MnTPP(OAc) has been studied in water, methanol, acetonitrile and dichloromethane as solvents. The results show significant dependence of the product distribution on the type of solvent and the electronic nature of the aryl substituents introduced at the porphyrin periphery. While the oxidation of cyclohexene and styrene in the presence of MnT(3-MePy)P(OAc) and MnTPP(OAc) in water (also in methanol) gave the corresponding epoxides as nearly the sole product, performing the reactions in the presence of MnT(4-SO3)PP(OAc) yielded the products of allylic oxidation, cyclohexene-2-ol and cyclohexene-2-one and acetophenone as the major products. In the case of styrene, performing the reaction in the presence of MnT(4-SO3)PP(OAc), MnT(3-MePy)P(OAc) and MnTPP(OAc) in acetonitrile gave a mixture of styrene oxide and acetophenone as the products. Under the same conditions, the oxidation of cyclohexene afforded cyclohexene oxide as approximately the exclusive product. Furthermore, the oxidation of olefins in dichloromethane gave the corresponding epoxide as the exclusive products. The product distributions observed in the protic and aprotic solvents were used to provide indirect evidence on the relative contribution and reactivity of high valent manganese oxo and periodato Mn(III) porphyrin species to the oxidation reactions.
Electrochemical hydrogen evolution by cobalt (II) porphyrins: Effects of ligand modification on catalytic activity, efficiency and overpotential
Beyene, Belete B.,Mane, Sandeep B.,Hung, Chen-Hsiung
, p. H481 - H487 (2018/07/06)
Electrochemical H2 evolution of a series of cobalt(II) porphyrins with electron-withdrawing (EW) and electron-donating (ED) substituents at the para positions of the meso-phenyl rings has been investigated in DMSO using acetic acid as a proton source. Our study showed that the nature of substituents significantly influences catalytic activity, efficiency, and the potential at which catalysis occurs. Faradaic efficiencies (FE) ranging from 44 to 99%, turnover numbers (TONs) from 1.5 to 104 (～11 h electrolysis), turnover frequencies (TOFs) from 0.23 to 9.1 h?1, and onset overpotentials from 25 to 445 mV were obtained by tuning the porphyrinic substituents. Cobalt porphyrins with -SO3H, -COOH, or -NH2 groups as the substituents showed high activity and efficiency with more positive onset potentials as compared to the parent [Co(TPP)]. Supports also from the low hydrogen generation activities for complexes with -COOMe, -OMe and -OH groups as the substituents suggest that the acidity of the meso-phenyl substituent plays a key role in enhancing the hydrogen evolution activities during the catalytic processes.
