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.

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.

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.

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.

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.

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).

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.

Substrate specificity in the biomimetic catalytic aerobic oxidation of styrene and cyclohexanone by metalloporphyrins: kinetics and mechanistic study

Substrate specificity is a hallmark of enzymatic catalysis.In this work,the biomimetic catalytic oxidation of styrene and cyclohexanone by iron(III)porphyrins and molecular oxygen was carried out,and remarkable differences in efficiency were observed.The specificity of the substrates for biomimetic catalytic oxidation was investigated by kinetics and mechanistic studies.Kinetics studies revealed that the oxidation of styrene followed Michaelis-Menten kinetics with KM=8.99 mol L^(-1),but the oxidation of cyclohexanone followed first-order kinetics with kobs=1.46×10^(-4) s^(-1),indicating that the styrene epoxidation by metalloporphyrins exhibited characteristics of enzyme-like catalysis,while the oxidation of cyclohexanone was in agreement with the general rules of chemical catalysis.Different catalytic mechanisms for the two substrates were discussed by operando electron paramagnetic resonance spectroscopy,operando UV-vis spectroscopy,and KI/starch experiments.Substrate specificity was concluded to be attributed to the stability of high-valence species and oxygen transfer rate.

Selective epoxidation of linear terminal olefins with metalloporphyrins under mild conditions

The epoxidation of linear terminal olefins with metalloporphyrins in the presence of dioxygen and isobutyraldehyde under ambient temperature and atmo-spheric pressure was investigated.The results show that all olefins could be smoothly converted to epoxides with high selectivities(70%–90%).For the metalloporphyrins with different catalytic activities within 1-hexene epoxidation in the order of Fe>Mn>Co,T(o-Cl)PPFe(III)Cl was most effective,with a 41.7%yield and 80.2%selectivity of 1,2-epoxyhexane.Various amounts of catalyst were investi-gated,and it was found that with only 10ppm catalyst the yield of 1,2-epoxyhexane and turnover number(TON)could reach up to 41.9%and 41859,respectively.

Selective oxidation of o-nitrotoluene to o-nitrobenzaldehyde with metalloporphyrins as biomimetic catalysts

Selective oxidation of o-nitrotoluene to onitrobenzaldehyde with metalloporphyrins as biomimetic catalysts was studied.The peripheral substituent around porphyrin rings and various process parameters of NaOH concentration,reaction temperature,reaction time and oxygen pressure all affect the selectivity of onitrobenzaldehyde.Further,82.0%selectivity of onitrobenzaldehyde was achieved under the optimum conditions:1.0×10^(-5)mol·L^(-1)of T(p-NO_(2))PPFeCl catalyst,2.5 mol·L^(-1)of NaOH,0.2 mol·L^(-1)of o-nitrotoluene,45℃and 2.0 MPa for 6 h.

Efficient and Bio-inspired Conversion of Cellulose to Formic Acid Catalyzed by Metalloporphyrins in Alkaline Solution

A bio-inspired approach for efficient conversion of cellulose to formic acid （FA） was developed in an aqueous alkaline medium. Metalloporphyrins mimicking cytochrome P450 exhibit efficiently and selectively catalytic per- formance in catalytic conversion of cellulose. High yield of FA about 63.7% was obtained by using sulfonated iron（IlI） porphyrin as the catalyst and O2 as the oxidant. Iron（III）-peroxo species, TSPPFemOO , was involved to cleave the C--C bonds of gluconic acid to FA in this catalytic system. This approach used relatively high concen- tration of cellulose and ppm concentration of catalyst. This work may provide a bio-inspired route to efficient con- version of cellulose to FA.

Solvent and additive-free selective aerobic allylic hydroxylation of β-pinene catalyzed by metalloporphyrins

Metallodeuteroporphyrins（MDPs） were employed as the catalysts for aerobic oxidation of β-pinene in absence of solvents and additives. Allylic hydroxylation products were found to be the main products from this protocol. The catalytic activity of MDPs with different metal nuclei and the influences of technological conditions on this reaction were investigated. This catalytic system has bright application prospect since only eco-friendly and readily available dioxygen were needed.

Facile Synthesis of Metalloporphyrins-Ba^2+Composites as Recyclable and Efficient Catalysts for Olefins Epoxidation Reactions

A facile co-precipitation method was developed to prepare the novel metalloporphyrins-Ba^2+composites with ca.3μm diameter and olive-like morphology.Olefins epoxidation reactions were employed to investigate their catalytic performance.Compared with the free metalloporphyrins,the composites exhibited not only the improved stability and recyclability,but also the enhanced catalytic activity.Such catalytic behaviors could be related to the unique stnictiire of the composites,e.g.,the strong interaction between R-SO3^-and Ba^2+ions and the uniform distribution of metalloporphyrins on the catalyst surface,respectively.Furthermore,the composites showed good compatibility with a wide range of substrates.The well-designed composites are expected to be efficient catalysts,alternative to many sophisticated-synthesized metalloporplirins-based materials,in the industrially important reactions.

Meso-substituted cationic 3-and 4-N-Pyridylporphyrins and their Zn(II)derivatives for antibacterial photodynamic therapy

Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy(APDT)is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms.Among the photosensitizers(PSs),compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms.Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia.The aim of this work was to determine and test the most e®ective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms.It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria,including the methicillinresistant S.aureus strain.Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs.The e®ectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation.It was found that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors:the presence in the porphyrin macrocycle of a positive charge(+4),a central metal atom(Zn2þÞand hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen.The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins cannd wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT.

Synthesis of Metal Porphyrins Tailed with Salicylic Acid and their Interaction with Bovine Serum Albumin

A synthetic method of porphyrins tailed with salicylic substituents is described. Reaction of bromoalkoxyphenyl porphyrin 1 with salicylic acid gave porphyrins 2~5. These new compounds were confirmed by 1H NMR, IR, UV-vis, MS and elemental analysis, and observed their interaction with bovine serum albumin (BSA) in fluorescence spectrum.

Aerobic oxidation of benzylic aldehydes to acids catalyzed by iron (Ⅲ) meso-tetraphenylporphyrin chloride under ambient conditions

Highly efficient aerobic oxidation of benzylic aldehydes to the corresponding acids catalyzed by iron （Ⅲ） meso-tetrapbenylporphyrin chloride （Fe（TPP）Cl） under ambient conditions was developed. The catalyst has been proved to be an excellent catalyst for the system in the presence of molecular oxygen and isobutryaldehyde at room temperature.

Improvements in SOD mimic AEOL-10150, a potent broad-spectrum antioxidant

AEOL-10150 is a broad-spectrum metalloporphyrin superoxidase dismutase(SOD) mimic specifically designed to neutralize reactive oxygen and nitrogen species. Research has shown that AEOL-10150 is a potent medical countermeasure against national security threats including sulfur mustard(SM), nerve agent exposure and radiation pneumonitis following a radiological/nuclear incident sufficient to cause acute radiation syndrome(ARS). AEOL-10150 performed well in animal safety studies, and two completed phase 1 safety studies in patients demonstrated that the drug was safe and well tolerated, indicating that AEOL-10150 has potential as a new catalytic antioxidant drug. In this article, we review improvements in AEOL-10150 in preclinical pharmacodynamic studies, especially regarding anti-SM,chlorine gas and radiation exposure studies.

Analysis of vibrational spectra of nano-bio molecules: Application to metalloporphrins

In this paper, we have applied the Lie algebraic model to nano-bio molecules to determine the vibrational spectra of different stretching and bending vibrational modes. The determined vibrational energy levels by the Lie algebraic model are compared with the experimental data. The results from the theoretical mode[ are consistent with the experimental data. The vibrational energy levels are clustering in the excited states.