Study on Synthesis and Biological Activities of Novel Water-Soluble Metalloporphyrins

The synthesis and characterization of a series of metal porphyrins, MII(Por), {Por=dianionic of 5, 10, 15, 20-tetrakis [4-(4′-bromobutyloxy) phenyl]porphyrinato and 5, 10, 15, 20-tetrakis [4-(4′-butyloxypyridine bromide)phenyl]porphyrinato, M=Zn, Cu, Mn, Co, Ni, Ru-CO} were described. The complexes 3a-3e were prepared from the reactions of compound 2 with metal acetates in chloroform, and the treatment of 3a-3f with excess of pyridine gave corresponding complexes 4a-4f. These new compounds were identified by absorption spectroscopies,1H-NMR and elemental analyses. The results of biological activity testing for 4a-4f revealed that 4a and 4c had stronger inhibiting action on the growth metabolism ofEsche richia coli.

Dimerization of 1-Phenyl-1<i>H</i>-Tetrazole-5-Thiol over Metalloporphyrin Catalysts

In an alkaline methanol solution, dimerization of 1-phenyl-1H-tetrazole-5-thiol (HL) was carried out over metalloporphyrin catalysts under mild conditions. The dimer product, 1,2-bis (1-phenyl-1H-tetrazol-5-yl) disulfane (L-L), was characterized by determinations of infrared (IR), HPLC, NMR and elementary analysis respectively. In situ UV-Vis spectroscopic analysis and cyclic voltammetric (CV) determinations suggested that the active intermediate for L-L formation is an axially ligated complex, RS-MnⅢTHPP, which decomposes into a MnⅡTHPP molecule and a stable radical (SR) for coupling to form the disulfane. Meanwhile MnIITHPP molecule can be oxidized easily to form MnⅢTHPP species again by oxygen from the air for using in next catalytic circle.

Selective aerobic oxidation of p-cresol with co-catalysts between metalloporphyrins and metal salts

A green and efficient method for the selective aerobic oxidation of p-cresol to p-hydroxybenzaldehyde catalyzed by co-catalysts between metalloporphyrins and metal salts was investigated and developed. The relationship between the synergistic catalytic effects and the composition as well as amount of co-catalysts was investigated. Moreover, the influence of different reaction conditions was studied in details. A high p-cresol conversion （〉99%） and p-hydroxybenzaldehyde selectivity （83%） were obtained using only 1.125 × 10- 5 mol T（p-CH3O）PPFe111Cl-Co（OAc）2 used under mild, optimized reaction conditions. A possible mechanism for the reaction was also proposed. This work would be meaningful and instructive for the further researches and applications of co-catalyst system on oxidation of cresols and could give some enlightenment on the selectively catalytic oxidation of the side-chain alkyls of aromatics.

Selective oxidation of ethylbenzene catalyzed by fluorinated metalloporphyrins with molecular oxygen

This paper reported the oxidation of ethylbenzene catalyzed by fluorinated metalloporphyrins under mild conditions without any additives. The results showed that the cobalt(II)(5,10,15,20-tetrakis(pentafluorophenyl))porphyrin was the best catalyst among the fluorinated metalloporphyrins. The conversion of ethylbenzene reached 38.6%, the selectivity to acetophenone reached 94.0%, and the turnover number is 2719 under the optimal conditions.

Toluene Oxyfunctionalization with Air over Metalloporphyrins and Reaction Condition Optimization

Catalytic activities of a series of metalloporphyrin complexes in selective aerobic oxidation of toluene were investigated.The effects of different central metal ions in metalloporphyrins[T(p-Cl)PPMCl(M=Fe,Co,Mn,Cu)] on the reaction course had been examined and it was found that T(p-Cl)PPCu presented the highest catalytic activ- ity in the reaction.The reaction conditions of toluene oxidation were optimized by using orthogonal experiment de- sign.Five relevant factors were investigated:temperature,air pressure,catalyst loading,air flow rate and reaction time.The effects of the five factors on both toluene conversion and total yield of benzaldehyde and benzyl alcohol were discussed.The research results showed that the reaction temperature was the most significant factor influenc- ing toluene oxidation.On the basis of the margin analysis,the optimum conditions for the toluene conversion and the total yield of benzaldehyde and benzyl alcohol respectively were achieved,under which the toluene conversion was up to 14.67%and the total yield of benzaldehyde and benzyl alcohol reached 5.89%.

Photoelectrocatalytic CO2 reduction based on metalloporphyrin-modified TiO2 photocathode

The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system composed of a metalloporphyrin-functionalized TiO2 photocathode and BiVO4 photoanode can efficiently transform CO2 and water to methanol, which is accompanied by oxygen release. This photoelectrocatalytic system smoothly produces methanol at a rate of 55.5 μM h^–1 cm^– 2, with 0.6 V being the membrane voltage in plants. The production of hydrogen can also be observed when the voltage is more than 0.75 V, due to photocatalysis. Our results evidently indicate that the molecules of metalloporphyrin attached onto the surface of anatase (TiO2) behave as chlorophyll, NADP, and Calvin cycle in plant cells.

Oxidation of p/o-Cresols to p/o-Hydroxybenzaldehydes Catalyzed by Metalloporphyrins with Molecular Oxygen

The two novel green oxidation processes of p/o-cresols to p/o-hydroxybenzaldehydes catalyzed by metalloporphyrins in the presence of molecular oxygen were developed in this work.Among the metalloporphyrins with different central ions and substituents studied,T(p-NO 2)PPCoCl and T(p-OCH 3)PPFeCl presented the highest activities for p-cresol and o-cresol oxidation reactions respectively.The molar ratio of sodium hydroxide to cresols and different reaction parameters including reaction temperature,reaction time and reaction pressure have been investigated,and 69.8%/50.4% conversions of p/o-cresol and 86.6%/26.6% selectivities for p/o-hydroxybenzaldehydes were reached under optimized conditions.

Water-Soluble Metalloporphyrins as Mimics of Heme-containing Enzymes

This letter compared catalase-, peroxidase- and cytochrome P450-like catalytic activities of 15 water-soluble metalloporphyrins produced from Fe, Mn and Co ions and 5 porphyrins. The metalloporphyrins with Fe and Mn as central ions show relatively high catalytic activities of catalase and peroxidase at pH 11.0. Only Mn-meso-tetrakis (4-N-methylpyridinium) porpho-phine of the 15 metalloporphyrins exhibits high cytochrome P450-like activity. Effects of imidazole on the catalytic reactions were also studied.

Synthesis, Characterization and Biological Activities of Novel Water-soluble Metalloporphyrins

The synthesis, characterization, and biological activities of a series of metal porphyrins were described. The complexes 3a similar to 3e were prepared from the reaction of compound 2 with M(OAc)(2) in CHCl3, and the treatment of 3a similar to 3f with pyridine gave corresponding complexes 4a similar to 4f. These new compounds were identified by absorption spectroscopies, H-1 NMR and elemental analysis. The results of biological activity,testing revealed that 4a and 4c had stronger inhibiting action for Escherichia coli (CCTCC AB91115).

Preparation of p-menthane hydroperoxide from p-menthane in presence of metalloporphyrins

The aerobic oxidation of p-menthane to p-menthane hydroperoxide （PMHP） in the presence of metalloporphyrins was investigated in an intermittent mode under an atmospheric pressure of air. Several important reaction parameters, such as the structure of metalloporphyrin, the air flow rate, and the temperature, were studied. The preliminary mechanism of the aerobic oxidation of p-menthane catalyzed by metalloporphyrins was also discussed. The results show that the reaction is greatly accelerated by the addition of metalloporphyrins at very low concentration, in terms of both the yield and formation rate of PMHP, and the high selectivity of PMHP is maintained during the reaction. Temperature of 120 ℃ and reaction time of around 5 h are the optimal conditions for the best result in the presence of 0.06 mmol/L monomanganeseporphyrins （（p-Cl）TPPMnC1）. Furthermore, the yield of PMHP is increased remarkably when the reaction is carried out under programmed temperature compared with the constant temperature. When the reaction is catalyzed by 0.06 mmol/L（（p-Cl）TPPMnCl） at the air flow rate of 600 mL/min and 120 ℃ for 4 h, and then the temperature is reduced to 110 ℃, for another 4 h, the yield of PMHP reaches 24.3 %, which is higher than that of the reaction at a constant temperature of 120 ℃ or 110 ℃ for 8 h.

A Study of Synthesis, Immobilization and Catalytic Capability of Metalloporphyrin

A stepwise synthesis method was used to immobilize tetrachloro tetramethyl porphyrins in the supercages of NaCoX molecular sieve. The immobilized porphyrin was characterized by means of UV Vis, IR, DTA, SEM and EPR. A comparision was made for the activities among tetrachloro tetramethyl porphyrins, its cobalt(Ⅱ) complex, NaCoX molecular sieve and the immobilized porphyrin as catalysts in the oxidation reaction of styrene and p cresol. The stability and catalytic capability of the metalloporphyrin is increased after the combination of porphyrin with molecular sieve. In addition, this new type of catalyst tetrachloro tetramethyl porphyrin immobilized in the supercages of NaCoX molecular sieve not only possesses the advantages of both porphyrin and molecular sieve, but also makes up for their respective deficiencies. The experimental results confirmed that both the stability and catalytic capability of metalloporphyrin immobilized in the supercages of molecular sieve are increased.

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYZED BY METALLOPORPHYRINS(Ⅱ)——ELECTROSYNTHESIS OF SOME ORGANIC COMPOUNDS WITH CO_2 CATALYZED BY CoTPP

The catalyzation of CoTPP for electrocarboxylation of alkyl halides, alkenes and ketones with CO_2 are studied. The electrocarboxylation of these organic compounds with CO_2 in the presenec of catalyst can occur at more positive potential than that of no catalyst. The products of electrocarboxylation were identified by UV, IR and GC-MS. The electrocarboxylation mechanisms of different organic compounds are discussed.

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYTZED BY METALLOPORPHYRINS(Ⅳ)——EFFECT OF VARIOUS FACTORS ON ELECTROCARBOXYLATION

The effects of various factors on the electrocarboxylation of organic compounds with carbon dioxide catalyzed by metalloporphyrin are studied.The optimal potential of electrocar- boxylation is -1.6 V(vs.SCE).A weak protic solvent methanol can enhance catalytic activity. Tetrabutylammonium iodide is the best one of five electrolytes.The yields and current efficiencies of electrocarboxylation are increased slowly as the concentration of catalyst increases.

ELECTROCARBOXYLATION OF ORGANIC COMPOUNDS WITH CARBON DIOXIDE CATALYZED BY METALLOPORPHYRINS(Ⅲ)——EFFECTS OF AXIAL LIGANDS ON CATALYTIC ACTIVITY OF CoTPP

The effects of peptides,amino acids and organic bases as an axial ligand on reaction ac- tivities in the electrocarboxylation of benzyl chloride with CO_2 catalyzed by CoTPP are reported. The imidazole organic base,peptide containing —SH and amino acid containing imidazolyl en- hance the catalytic activity.The effect of imidazole amounts on the catalytic activity of CoTPP is studied.

Cationic Metalloporphyrins Imobilized in Faujasite Zeolites as a Cytochrome P-450 Mimic

Metalloporphyrins immobilized into NaY zeolite are described as catalysts for hydrocarbon oxyfuntionalization. Manganese(III) and iron(III)tetrakis(4-N-methylpyridyl)-porphyrin (MnP1 and FeP1), and manganese(III) and iron(III) tetrakis(4-N-benzylpiridil)-porphyrin (MnP2 and FeP2) were impregnated (MnP1-NaYimp, FeP1-NaYimp, MnP2-NaYimp, FeP2-NaYimp, respectively) and encapsulated (MnP1-NaY, FeP1-NaY, MnP2-NaY and FeP2-NaY) into the NaY zeolite. These catalysts were used in the oxidation of (Z)-cyclooctene, cyclohexane, and adamantane by iodosylbezene (PhIO). These systems were able to epoxidize (Z)-cyclooctene with cis-epoxycyclooctane yields as high as 100%. By using cyclohexane and adamantane as substrate, the susceptibility of the benzyl groups on the porphyrin ring of the MnP materials, led to a different distribution of the oxidized products. With FePs, this susceptibility was not detected because the species responsible for the oxidations, FeIV(O)P·+, is more active than MnV(O)P. In conclusion, cationic metalloporphyrins immobilized into NaX zeolites, are good cytochrome P-450 models is less polar solvents since the selectivity of the system indicates the “in cage” solvent oxygen rebound oxidative process.

PREPARATION AND CATALYTIC BEHAVIOUR OF POLYMER-BOUND METALLOPORPHYRIN IN HYDROGENATION OF OLEFIN

The meso-tetraarylporphyrin has been anchored to styrene-divinylbenzene copolymers by reaction or meso-tetra(4-hydroxylphenyl) porphyrin with chloromethylated resin under mild condition. A number of polymer transition metal complexes have been prepared with the polymer ligand and metal salts. The polymeric ligand and its complexes have been characterized by electronic spectra, and vibrational spectra. Cyclohexene can be hydrogenated with the polymeric porphyrin palladium complex(P-THPPPd) as catalyst, and its catalytic activity was influenced by the polarity of solvents, the contents of water in ethanol or reaction temperature. However, its catalytic activity was lower for nitro groups, carbonyl groups and olefins with steric hindrance substituents, and showed no activity for aromatic rings under these conditions.

The Synthesis of Star Style Metalloporphyrin

The present paper covers a novel star style metalloporphyrin [tetra(4 (4 methoxycarbonylbenzoxyl)phenyl)porphyrin cobalt, TMBPPCo] with four paw groups [4(4 methoxycarbonylbenzoxyl)phenyl(—C 6H 4CO 2C 6H 4CO 2CH 3)]. Its structure was characterized by means of UV Vis, IR, 1H NMR and MS spectrometries.

Electrocatalysis of Metalloporphyrins(Ⅷ)——Electrocatalytic Reduction of Molecular Oxygen with Water-Soluble Cobalt (Ⅱ) Tetrakis(4-Trimethyl Ammonium Phenyl) Porphyrin Catalyst

Reported here is the electrocatalytic reduction of molecular oxygen in the presence of water-soluble cobalt(Ⅱ) tetrakis(4-trimethyl ammonium phenyl) porphyrin (Co(Ⅱ)TTAPP) as catalyst in solutions of various pH values. The overpotential of molecular oxygen reduction is reduced by ca. 200-400 mV in acidic and neutral solutions compared with several decades of millivolts in alkaline solutions, indicating that Co(Ⅱ)TTAPP possesses much higher catalytic activity in acidic and neutral solutions than in alkaline. H2TTAPP in solutions of various pH exhibits no significant catalytic activity for oxygen reduction. The significant difference in the electrocatalytic activity of Co(Ⅱ)TTAPP from that of H2TTAPP for oxygen reduction indicates that the electrocatalytic activity of Co(Ⅱ)TTAPP should be attributed to the central cobalt atom (Co(Ⅱ)) coordinated by N4 internal ring in Co(Ⅱ)TTAPP. The total number of electrons involved in oxygen reduction electrocatalyzed by Co (Ⅱ)TTAPP is 2, and the product of such reaction is H2O2 or HO2-in solutions of various pH. The reaction mechanism of oxygen reduction in acidic and alkaline solutions is also discussed.

One- and two-photon absorption properties of two metalloporphyrin complexes

The linear and nonlinear optical properties of two metalloporphyrin complexes formed by the complementary coordination of central zinc or magnesium ions to the ligand 5, 10, 15-tri-（p-tolyl）-20-phenylethynylporphyrin are theo- retically investigated by using the analytic response theory at the density functional theory level. The results indicate that the studied complexes present more symmetric geometry structures than the ligand. The charge-transfer states of the two complexes in the lower energy region are all almost degenerate but those of the ligand are well separated. The ratio of the two-photon absorption cross sections of the ligand, zinc-porphyrin and magnesium-porphyrin com- plexes is 1.0：1.5：1.8, demonstrating that the two-photon absorption capability can be greatly increased when the ligand is coordinated with a metal ion. Moreover, several physical micro-mechanisms including electron transitions and in- tramolecular charge-transfer processes are discussed to explore the differences in optical property between the ligand and two complexes.