Study on Synthesis and Deplete Harmful Radical of Cobalt Porphyrins as the Mimic of Enzyme

The four cobalt porphyrins [Co (3, 4, 5 MeO TPP) (1) ; Co (TTP) (2) ; Co (4 CI TPP) (3);Co (4 HSO 3 TPP) (4)] were synthesized and considered as two mimic of superoxide dismutaes (SOD) and catalase (CAT). The catalytic efficiency of them on deplete the harmful radical have been proved using riboflavin methionine photoreduction method in the concentration range of 10 6 ～10 5 mol/L. The catalytic efficiency of them at decomposing H 2O 2 has been performed by spectrophotometer. The percentage of decomposing H 2O 2 while the increasing the concentration of the imitating compounds. The lipid peroxidationproduced in liver homogenatcd of mice was determined by spectrophotometer detecting the content of MDA.

A cobalt(Ⅱ)porphyrin with a tethered imidazole for efficient oxygen reduction and evolution electrocatalysis

Electrocatalytic oxygen reduction and evolution reactions are involved in new energy conversion and storage technologies,such as various fuel cells and metal-air batteries and also water splitting devices[1,2].However,both reactions are very slow in kinetics,and thus catalysts are required[3,4].

Molecular Insights into the Structure-Activity Relationship in Cobalt Porphyrin Catalyzed Oxygen Reduction Reaction

We present a microscopic investigation on the structure-activity relationship of the Co-N4 site in the oxygen reduction reaction(ORR)by electrochemical scanning tunneling microscopy(ECSTM)at the molecular scale.The cobalt porphyrins with various substituents(CoTPPX_(4),X=Cl,H,OCH_(3))that delicately regulate the electronic structure of the active site were investigatedasmodel catalysts.Electrochemical measurements evidenced that the CoTPPCl_(4)exhibits better activity,higher product selectivity for H_(2)O,and lower stability.The CoTPPX_(4)-O_(2)complex with higher contrast can be observed in the STM images and the proportion of the CoTPPCl_(4)-O_(2)is appreciably larger than that of CoTPP-O_(2)and CoTPP(OCH_(3))4-O_(2).Theoretical simulations of the model catalysts and the reaction processes of the ORR reveal the relationship between the electronic structure and the catalytic behavior of the model catalysts.The transformation of the CoTPPX_(4)-O_(2)and CoTPPX_(4)in the electrocatalytic reaction was monitored by in situ ECSTM characterization.The structure-activity relationship clarified by experimental and theoretical investigations in this work should help to guide the rational design and optimization of high-performance catalysts.

ALTERNATING COPOLYMERIZATION OF CYCLOHEXENE OXIDE AND CARBON DIOXIDE UNDER COBALT PORPHYRIN CATALYST

Cobalt porphyrin complexes （TPPConIX） （TPP = 5,10,15,20-tetraphenyl-porphyrin; X = halide） in combination with bis（triphenylphosphine） iminium chloride （PPNC1） were used for the eopolymerization of cyelohexene oxide and CO2. The highest turnover frequency of 67.2 h^-1 was achieved after 13 h at 20℃, and the obtained poly（1,2-cyclohexylene carbonate） （PCHC） showed number average molecular weight （Mn） of 10 × 10^3. Though the obtained PCHC showed atactie structure, the m-centered tetrads content reached 58.1% at CO2 pressure of 1.0 MPa, and decreased to 51.9% at CO2 pressure of 6.0 MPa, indicating that it was inclined to form atactic polymer at high CO2 pressure.

Electropolymerization of cobalt porphyrins and corroles for the oxygen evolution reaction

Developing large-scale electrocatalysts using molecular complexes for the oxygen evolution reaction(OER)is of great importance. Herein, four cobalt porphyrins and corroles are deposited on electrode substrates using a simple and fast electropolymerization method. Our results showed that Co-1-P@CC, formed by electropolymerizing Co tetrakis(p-N-pyrrolylphenyl)porphyrin(Co-1-P) on carbon cloth(CC), is the most active OER catalyst in the examined Co porphyrins and corroles in alkaline aqueous solutions by displaying an onset overpotential of 380 m V. Long-term electrolysis tests confirmed the stability of these electropolymerized films by functioning as OER electrocatalysts.

Synthesis of Axially Coordinated Cobalt Porphyrin/graphene Oxide Nanocomposite for Enhanced Electrocatalytic CO_(2) Reduction to CO

The electrocatalysts containing cobalt-pyrrolic nitrogen-carbon(Co-N_(4)-C)moiety for CO_(2)reduction reaction(CO_(2)RR)have caught much attention.However;the effects of Co valence state and its synergy with gra-phene substrate are not clear yet.In this work;cobalt porphyrin(CoTPP)molecule with the intrinsic Co-N_(4)-C moiety is successfully combined with graphene oxide(GO)via three kinds of liquid-phase methods.The ratio of CoTPP to GO and the valence state of Co atom are studied to explore their catalysis for CO_(2)RR to CO.It is found that axial-ly-coordinated Co(III)TPPCl/GO nanocomposites synthesized via a chemical method exhibit better ability for CO_(2)RR;as compared with Co(II)TPP+GO and/or Co(III)TPPCl+GO nanocomposites obtained via a physically mixing way.After optimizing the ratio of CoTPP to GO;the Faradaic efficiency(FE)is more than 90%for CO_(2)RR to CO between−0.7 and−0.8 V vs.reversible hydrogen electrode(RHE)in Co(III)TPPCl/GO75.The synergy be-tween CoTPP and GO and the effect of Co valence state are systematically investigated;indicating that their strong interaction plays the key role in electrocatalytic CO_(2)RR.

Effect of TiO_(2) support on immobilization of cobalt porphyrin for electrochemical CO_(2) reduction

Electrochemical reduction of CO_(2) is a promising strategy to manage the global carbon balance by transforming CO_(2) into chemicals. The efficiency of CO_(2) electroreduction is largely dependent on the design of hybrid electrode where both support and catalyst govern the performance of the electrolyzer. In this work,TiO_(2) calcined at different temperatures, was used as a support for immobilization of cobalt tetraphenyl porphyrin(CoTPP) and its effect on CO_(2) reduction was studied. It is demonstrated that the crystalline phase of TiO_(2) and doping of TiO_(2) apparently affecting CO_(2) electroreduction. It is found that anatase phase exhibits higher activity and selectivity compared to rutile due to the enhanced conductivity which in turn enables faster electron transfer between the support and CoTPP. As for dopants, the carbon doping in anatase TiO_(2) is proven to further enhance its conductivity, consequently resulting in the enhanced performance. This study implies that the rational design of supports is important for the performance of the hybrid electrode towards electrochemical CO_(2) reduction.

Encapsulation and Regeneration of Perovskite Film by in Situ Forming Cobalt Porphyrin Polymer for Efficient Photovoltaics

Inhibiting the ions migration and even irreversible reactions have been regarded as one of the most important factors for fabricating efficient and stable perovskite solar cells(PSCs).Here,we employed the diamine cobalt(II)porphyrin[Co(II)P]to treat a perovskite film to construct in situ Co(II)P-based coordination polymer on the perovskite film.The crystal structure of the polymer indicated a central cobalt(Co)ion in one Co(II)P coordinated with two amine units from a different neighboring Co(II)P to form an overall three-dimensional(3D)structure.Such a 3D network covered on the perovskite surface could prevent the migration of ions from the perovskite.Furthermore,the limited amount of diatomic iodine(I2)released in the perovskite due to iodide oxidation defects could be reduced to I–by the Co(II)ion in the polymer,and thus,achieve regeneration.Finally,the Co(Ⅱ/Ⅲ)ion pair formed in the polymer facilitated the charge transfer and boosted to the best efficiency up to 21.3%.Remarkably improved cell stability under moisture,heating,or light was also achieved.The control PSCs with Zn-based 3D polymer and Co-based 1D polymer exhibited the poor cell efficiencies and stabilities than those of the 3D Co porphyrin-based PSC to verify the effect of 3D Co porphyrin-based polymer in stabilizing the perovskite film.This work provides a new encapsulation and regeneration strategy via in situ construction of a Co(Ⅱ)porphyrin-based coordination polymer on perovskite film for efficient and stable PSCs.

Axial ligands tailoring the ORR activity of cobalt porphyrin

In an effort to provide visualization and understanding to the electronic ‘‘push effect' of axial ligands on the catalytic activity of cobalt macrocyclic molecules, we design a simple model system involving an[5,10,15,20-tetrakis(4-methoxyphenyl)porphyrin]cobalt(II)(TMMPCo) monolayer axially-coordinated on thiol ligand modified Au electrode and explore the activity of the axial-ligand coordinated TMPPCo toward oxygen reduction reaction(ORR) in acidic medium. Three different ligands, with a decreasing order of coordinating ability as: 4-mercaptopyridine(MPy) > 4-aminothiolphenol(APT) > 4-mercaptobenzonitrile(MBN) are used and a maximum difference in ORR onset potential of 80 mV is observed between the MPy(highest onset potential) and MBN systems(lowest onset potential). The ORR activity of TMPPCo increases with the increase in binding strength of the axial ligand. A detailed mechanism study reveals that ORR on the three ligand coordinated TMPPCo systems shares the same2-electron mechanism with H2 O2 as the terminal product. Theoretical calculation into the structure of the ligand coordinated cobalt porphyrins uncovers the variation in atomic charge of the Co(II) center and altered frontier molecular orbital distribution among the three ligand systems. Both properties have great influence on the back-bonding formation between the Co(II) center and O2 molecules, which has been suggested to be critical toward the O2 adsorption and subsequent activation process.

Synthesis and spectroscopic characterization of cobalt porphyrins and their catalytic activity towards dioxygen reduction

The synthesis and spectroscopic characterization of cobalt(Ⅱ) 5-(4-pyridyl)-10,15,20-triphe- nylporphyrin,cobalt(Ⅱ) 5-(4-N-hexadecylpyridiniumyl)-10,15,20-triphenylporphyrin bromide and cobalt(Ⅱ) 5-(2-aminophenyl)-10,15,20-triphenyl-porphyrin are reported.The corresponding copper and vanadyl derivatives ((TriP)Cu,[(hTriP)Cu]^+Br^- and [(hTriP)VO]^+Br^-) were also studied.Each metalloporphyrin was characterized by UV-visible,ESR and ~1H NMR spectroscopy.These me- talloporphyrins can be firmly adsorbed on the glassy carbon (GC) surface.The catalytic reduction of dioxygen at GC electrodes modified by these catalysts was studied by cyclic voltammetry (CV).The kinetic process of dioxygen reduction at the cobalt porphyrin-modified electrodes was studied with a rotating ring disk electrode.

A comparison of iron phthalocyanine and cobalt porphyrin on the electrochemical catalysis in Ni-MH battery

The effects of iron phthalocyanine (FePc) and cobalt porphyrin (CoPp) on inner pressure and cycle behavior of sealed Ni-MH batteries were investigated in this study. The morphology of battery elec- trode was observed by SEM. The electrochemical impedance spectroscopy of floating-charge/dis- charge battery was also measured. Experimental results show that the addition of FePc or CoPp to the alloy electrode is an effective approach to decrease the internal pressure of battery during the process of charge and overcharge. In contrast to CoPp, the battery with FePc exhibits a slower capacity decay and a smaller overpotential at the same charge-discharge rate. As an electrocatalyst, FePc may more effectively speed up the reduction of oxygen, and decrease its reduction potential. As a result, the charge process is accelerated, the gas evolution is reduced and the pulverization of electrode materials is slowed down.

Synthesis, structural and spectroscopic characterization of the bis(nitrito-<i>N</i>) octaethylporphyrin cobalt(III) complex

The bis(nitrito-N) cobalt(III) octaethylporphyrin derivative with the formula [K(18-C-6)(NO2)0.5(H2O)0.5]2 [CoIII(OEP)(NO2)2] (1) (OEP = octaethylporphyrin and 18-C-6 is the crown ether18-crown-6) has been synthesized and characterized by UV-vis, IR and proton NMR spectroscopy which indicate, inter alia, that the cobalt ion presents the oxidation state III. The synthesis utilizes 18-crown-6 to solubilize potassium nitrite in the synthetic procedure. This compound crystallizes in the triclinic system, with the centric space group P-1 and the following unit cell parameters: 11.6724(2) ?, b = 12.5715(2) ?, c = 13.4722(3) ?, α = 101.1290(6)°, β = 106.6498(6)°, γ= 109.1507(6)°, Z = 1 and V = 1696.74(5) ?3. The crystal structure has been solved and refined to R = 0.0499 and R(w) = 0.1319. The X-rays molecular structure of 1 shows that there is a relatively close interaction of both two NO2- axial ligands of the ion complex [CoIII(OEP)(NO2)2]- with the potassium atoms of the two counterions [K(18-C-6) (NO2)0.5(H2O)0.5]0.5+. The title compound exhibits one-dimension polymer-like structure where “monomers” are linked together through strong O(H2O)—H…O(nitrito-O) hydrogen bonds.

Cobalt‐N_(4) macrocyclic complexes for heterogeneous electrocatalysis of the CO_(2) reduction reaction

Metal-N_(4)(M-N_(4))macrocyclic complexes are interesting electrocatalysts due to their well-defined structures and rich molecular tuning.Among them,metal phthalocyanines have been widely studied for the carbon dioxide reduction reaction(CO_(2)RR)in heterogeneous systems and demonstrated good electrocatalytic performance.However,other complexes like metal corroles and metal porphyrins are much less explored,and often show inferior performances.In this study,three cobalt macrocyclic complexes,cobalt phthalocyanine,cobalt meso-tetraphenylporphyrin,and cobalt meso-triphenylcorrole(CoPc,CoTPP and CoTPC)are investigated in heterogeneous electrocatalysis of CO_(2)RR.Although CoPc/carbon nanotube(CNT)hybrid exhibits high electrocatalytic activity,CNT hybridization does not work for CoTPC and CoTPP that hold weak interactions with CNTs.By the drop-dry method with a high molecular loading of 5.4×10^(–7) mol cm^(–2),CoTPC and CoTPP could deliver appreciable electrode activities.Poly(4-vinylpyridine)(PVP)introduction is further demonstrated as a facile method to afford enhanced activities for CoTPP at low molecular loadings through enhancing molecule-substrate interactions.The partial current density of carbon monoxide for CoTPP+CNT/PVP is around 8 times higher than the sample without PVP at–0.67 V versus reversible hydrogen electrode.This work provides solutions to enhance the electrode activities of molecular electrocatalysts with weak substrate interactions in heterogeneous systems.

Enhanced Electrocatalytic Reduction of Oxygen at Electrodes Coated with a Multi-Metallic Co(II)/Pt(II) Porphyrin

Edge plane pyrolytic graphite (EPG) electrodes coated with the Co(II)/Pt(II)2 analog of 5,15-bis-(4-pyridyl)-10,20-bis-(3-methoxy-4-hydroxyphenyl)porphyrin undergo an electrochemical-chemical-electrochemical (ECE) reaction when anodically scanned in 1.0 M sulfuric acid. The new redox couple formed from this anodic conditioning of the coated electrode is dependent on the pH of the solution. Roughened EPG electrodes coated with the Co(II)/Pt(II)2 trimetallic porphyrin show a catalytic shift of 400 mV for the reduction of O2 when compared to the reduction of O2 at a bare EPG electrode. An additional catalytic shift of ca. 150 mV is observed for O2 reduction at an EPG electrode coated with the Co(II)/Pt(II)2 porphyrin which has been oxidized in 1.0 M sulfuric acid. In addition to the added electrocatalysis, a significant percentage of O2 reduced at the oxidized Co(II)/Pt(II)2 EPG electrode is converted to H2O as determined by rotating disk electrode measurements.

钴卟啉催化剂的前线轨道能级与其催化活性的相关性研究

设计并合成了 12种钴卟啉催化剂 ,在温和反应条件 ( 5 5℃ ,2 .0MPa氧压 )下考察其催化氧气液相氧化对硝基甲苯制取对硝基苯甲酸的催化活性 ,发现其对上述反应均有显著的催化活性 .采用PM3半经验分子轨道法对所设计的钴卟啉化合物模型体系进行了计算 ,将计算结果与实验结果相结合 ,探讨了钴卟啉分子前线轨道能级与其催化活性之间的关系 .经研究发现 ,四配位或五配位钴卟啉催化剂的催化活性与EHOMO和ΔEL H均有一定的相关性 ,且ΔEL H对催化活性的影响大于EHOMO对催化活性的影响 ;EHOMO值越低、ΔEL H越小 。

在交联聚苯乙烯微球表面实现苯基卟啉的同步合成与固载

以键合有对羟基苯甲醛（HBA）的交联聚苯乙烯（CPS）微球HBA-CPS、苯甲醛和吡咯为反应物，采用Adler方法，实现了苯基卟啉（PP）在CPS表面的同步合成与固载，制得了固载有苯基卟啉的微球PP-CPS．研究了卟啉同步合成与固载过程的影响因素，同时进行了微球PP-CPS与钴盐的配合反应，制备了固载有钴卟啉（CoP）的功能微球CoP-CPS，初步考察了其对分子氧氧化乙苯的催化活性．实验结果表明，在苯基卟啉同步合成与固载的反应过程中，催化剂的酸性与溶剂的极性是两个主要的影响因素，使用强极性溶剂与pK．在2．8-3．4范围的酸，微球PP-CPS表面的苯基卟啉固载量高．微球CoP-CPS对分子氧氧化乙苯的反应具有明显的催化活性。

在交联聚苯乙烯微球表面同步合成与固载吡啶基卟啉及固载化钴卟啉的催化氧化性能

先通过季铵化反应将吡啶甲醛(PyAL)基团键合于交联聚苯乙烯微球(CPS)表面,制得改性微球PyAL-CPS,再通过Adler反应,成功地实现了吡啶基卟啉(PyP)在CPS微球表面的同步合成与固载,制得功能微球PyP-CPS,它再与碘甲烷发生季铵化反应制成N-甲基吡啶基卟啉(MPyP)季铵盐,从而制得固载有阳离子卟啉的微球MPyP-CPS;最后通过与钴盐的配合反应,制备了固载有阳离子钴卟啉的固体催化剂CoMPyP-CPS.考察了影响吡啶基卟啉在CPS微球表面同步合成与固载的因素,固载化阳离子钴卟啉催化剂CoMPyP-CPS催化分子氧氧化乙苯的反应性能,也考察了CoMPyP-CPS(C)与磷钨杂多阴离子(PW)的复合催化剂CPW的催化性能.结果表明,以改性微球PyAL-CPS与溶液中的吡咯及4-吡啶甲醛为共反应物,通过固-液Adler反应,可以顺利地实现吡啶基卟啉在微球CPS表面的同步合成与固载,所制备的固体催化剂CoMPyP-CPS具有较好的催化分子氧氧化乙苯反应活性,而CPW催化剂的催化活性更高.

在聚合物微球GMA/MMA表面同步合成与固载卟啉及固载化金属卟啉的催化氧化性能

制备了甲基丙烯酸缩水甘油酯(GMA)与甲基丙烯酸甲酯(MMA)共聚微球GMA/MMA,并通过键合有对羟基苯甲醛(HBA)的改性微球HBA-GMA/MMA与苯甲醛(或取代苯甲醛)以及吡咯间的Adler反应,实现了卟啉在共聚微球GMA/MMA表面的同步合成与固载,制得了固载有苯基卟啉(PP)、对氯苯基卟啉(CPP)、对硝基苯基卟啉(NPP)的功能化微球PP-GMA/MMA,CPP-GMA/MMA和NPP-GMA/MMA.重点考察了影响卟啉同步合成与固载过程的因素.制备了固载有钴卟啉的催化剂,并以分子氧氧化乙苯为模型反应,考察了催化剂的活性.结果表明,苯甲醛取代基的结构、催化剂的酸性和溶剂的极性对卟啉的同步合成与固载都有较大的影响;钴卟啉催化剂对分子氧氧化乙苯反应具有较高的催化活性,且当钴卟啉外环上含有强吸电子基团硝基时,催化剂活性最高.

层状嵌接式卟啉钴的合成、表征及其对H_2O_2催化降解研究

采用有机溶剂在层状锑磷酸中在位分步合成了层状嵌接式卟啉钴材料；用红外光谱、紫外可见光谱、X射线衍射和顺磁共振技术对其进行了表征．该合成材料对H2O2降解反应体系的进一步研究表明，卟啉钴嵌接于锑磷酸层状环境中对H2O2具有良好的催化降解活性和抗失活稳定性．

钴卟啉溶液的光限幅特性研究

对大分子有机化合物钴卟啉的非线性光学特性在 4 5 7 9,4 88和 5 14 5nm三个连续激光波长下进行了研究。用单光束z scan技术测到三个曲线均是先出现峰值后出现谷值 ,按照Sheik bahae等人的理论该样品的非线性折射率为负值 ,即样品具有热自散焦效应。反饱和吸收特性的研究结果得到三个透射率T随入射激光功率的增大而减小的曲线 ,表明该样品在这三个波长下均呈现出反饱和吸收效应。众所周知 ,热自散焦效应和反饱和吸收效应都能导致光限幅。文章的实验结果也表明 :钴卟啉在三个波长下均具有光限幅特性 ,限幅阈值随着波长的减小而减小 ;其光学限幅效果好且限幅阈值低 ,是一种有较大潜在应用价值的新型光限幅材料。因此 ,可以利用这两种效应对钴卟啉的共同作用 。