Biomimetic Decarboxylation of Carboxylic Acids with PhI(OAc)_2 Catalyzed by Manganese Porphyrin [Mn(TPP)OAc]

Manganese（Ⅲ） meso-tetraphenylporphyrin acetate [Mn（TPP）OAc] served as an effective catalyst for the oxidative decarboxylation of carboxylic acids with （diacetoxyiodo）benzene [PhI（OAc）2] in CH2CI2-H2O（95：5, volume ratio）. The aryl substituted acetic acids are more reactive than the less electron rich linear carboxylic acids in the presence of catalyst Mn（TPP）OAc. In the former case, the formation of carbonyl products was complete within just a few minutes with 〉97% selectivities, and no further oxidation of the produced aldehydes was achieved under these catalytic conditions. This method provides a benign procedure owing to the utilization of low toxic（diacetoxyiodo） benzene, biologically relevant manganese porphyrins, and carboxylic acids.

Liquid-phase epoxidation of propylene with molecular oxygen by chloride manganese meso-tetraphenylporphyrins

Propylene molecule owns two active sites,the direct epoxidation of propylene by dioxygen is still a challenge due to the limitation of selectivity.In this work,the direct liquid-phase propylene aerobic epoxidation protocol by chloride manganese meso-tetraphenylporphyrin(MnTPPCl)was developed.The conversion of propylene was 12.7%,and the selectivity towards PO(propylene oxide)reached up to 80.5%.The formation of PO was attributed to the mechanism via high-valent Mn species,which was confirmed by means of in situ UV–vis spectrum.

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Chloride is the most abundant anion in living systems.Most natural or synthetic chloride anionophores function via hydrogen-bonding interactions.However,dynamic metal-anion coordination can also be an efficient way of transporting chloride across membranes.Here,we investigate anion transport by manganese(Ⅲ)meso-tetraphenylporphyrin chloride{[Mn(TPP)Cl],TPP=meso-tetraphenylporphyrin}complex that exhibits labile axial coordination.[Mn(TPP)Cl]showed high chloride transport activity in a bilayer vesicle model with an EC_(50) value of 4.42×10^(−3) mol%.In living cells,[Mn(TPP)Cl]induced rapid chloride influx and autophagy.The release of Ca^(2+)and adenosine 5′-triphosphate(ATP),as well as the relocation of calreticulin,revealed that[Mn(TPP)Cl]caused immunogenic cell death.Proteomic analysis indicated that[Mn(TPP)Cl]impaired several physiological processes,including DNA synthesis,transcription,mitochondrial respiration,RNA translation,and immune response.Our study suggests that dynamic metal-anion interactions across membranes might provide a practical strategy for the interference of chloride homeostasis.

Combination and cleavage of HBV DNA fragments by triple helix-forming oligonucleotides modified with manganese porphyrin in vitro

Objective To observe the ability of triple helix-forming oligonucleotides (TFOs) modified with manganese porphyrin to combine with and cleave HBV DNA fractions. Methods TFO were modified with manganese porphyrin and acridines,and then reacted with the 32 P labeled HBV DNA fragments at 37℃ in vitro (pH 7.4). Electrophoretic mobility shift assays and DNase Ⅰ footprinting tests were used to show the affinity and specificity of TFO to bind to target sequences. The ability of TFO to cleave HBV DNA fragments was tested by cleavage experiments. Results TFO modified with manganese porphyrin and acridine could bind to the target sequence in a sequence-dependent manner,with a Kd value of 3.5×10 -7 mol/L and a relative affinity of 0.008. In the presence of potassium monopersulfate (KHSO 5),TFO modified with manganese porphyrin and acridine could cleave the target sequence where the triplex DNA was formed. Conclusion In the presence of KHSO 5,TFO modified with manganese porphyrin and acridine could bind and cleave the target HBV-DNA in a sequence-dependent manner.

Effects of some Nitrogen Bases on the Oxygenation of Tetralin with Sodium Periodate Catalyzed by Manganese（Ⅲ）meso- Tetraphenylporphyrin as a Model Compound of Cytochrome P-450

The effect of some nitrogen bases on the oxygenation of tetralin by sodium periodate, catalyzed by Mn（TPP）OAc, was evaluated. A series of eight bases, including imidazole, pyridine, and quinuclidine, was used. Binding of axial ligand to the four-coordinate Mn（Ⅲ）-center influenced the efficiency and selectivity of the catalytic oxygenation system.

Epoxidation of styrene catalyzed by manganese (Ⅲ) porphyrins supported on chloromethylated polystyrene resin bearing crown ether groups

Metalloporphyrins and crown ether groups were simultaneously supported on chloromethylated polystyrene resin to produce a series of polymer-supported catalysts. The synthesis of these catalysts has been studied. The influence of pH, concentrations of NaOCl and phase transfer catalysts on the epoxidation of styrene catalyzed by these catalysts has also been investigated. The experimental results show that manganese(Ⅲ) porphyrin bound to chloromethylated polystyrene which bears crown ether groups is effective catalysts for the epoxidation of styrene by sodium hypochlorite. The introduction of crown ether groups increases the catalytic efficiency of supported metalloporphyrins. The kinetics of epoxidation catalyzed by supported manganese(Ⅲ) porphyrins obeys Michaelis-Menten equation-the characteristic of enzyme-driven reaction.

The preparation of terephthalic acid by solvent-free oxidation of p-xylene with air over T(p-C1)PPMnC1 and Co(OAc)_2

An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）_2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）_2 were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）_2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.