侧链键合锰卟啉的线型聚甲基丙烯酸缩水甘油酯的制备及其谱学性质

采用Adler法合成了Meso-四(对羟基苯基)卟啉(THPP), 在均相体系中使聚甲基丙烯酸缩水甘油酯(PGMA)与THPP发生开环反应, 得到侧链键合有羟基苯基卟啉的线型PGMA(HPP-PGMA); 进一步使HPP-PGMA与锰离子发生配合作用, 得到侧链键合有锰卟啉(MnP)的线型PGMA(MnP-PGMA), 测定了HPP-PGMA的1H NMR谱, 表征了其化学结构; 测定了HPP-PGMA与MnP-PGMA的UV-Vis光谱及荧光发射光谱, 考察了其光物理行为. 实验结果表明, 通过THPP外环上羟基与PGMA侧基环氧键的开环成醚反应, 可以顺利地将羟基苯基卟啉及其锰配合物键合在PGMA的侧链上. HPP-PGMA具有THPP的特征电子吸收光谱与荧光发射光谱, 且随着THPP键合度的增加, 光谱的强度增强. MnP-PGMA具有小分子锰卟啉的特征电子吸收光谱与荧光特征, 其Soret吸收带发生显著红移(红移58 nm), Q吸收带的数量减为3个吸收峰; 实验发现, MnP-PGMA与小分子锰卟啉类似, 在Q发射带没有荧光发射.     

Studies on preparation of metalloporphyrin‐functionalized PVI and PVI/SiO2 via axial coordination reaction

Cobalt tetraphenylporphyrin (CoTPP) was bond on the side chains of poly(N‐vinylimidazole) (PVI) and immobilized on PVI/SiO₂ via axial coordination reactions, respectively, leading to the soluble metalloporphyrin‐functionalized PVI (denoted as CoTPP–PVI) and the particles CoTPP–PVI/SiO₂. The above two target products were characterized using spectroscopy methods such as infrared spectrum, electronic absorption spectrum, and fluorescence emission spectrum. And the effects of various factors on the bonding reaction and immobilization reaction of CoTPP were studied in detail. The experimental results show that CoTPP–PVI and CoTPP–PVI/SiO₂ can be prepared favorably through axial coordination reaction of CoTPP with the side imidazole groups of PVI and PVI/SiO₂. In addition, the soluble CoTPP–PVI has all the spectral characteristics of CoTPP. As compared to CoTPP, the adsorption spectra of CoTPP–PVI exhibit red shift obviously. In the immobilization process of CoTPP on PVI/SiO₂, the higher the concentrations of CoTPP and the reaction temperature, the greater the immobilization amount of CoTPP is. Copyright © 2009 John Wiley & Sons, Ltd.     

Active and recyclable ordered mesoporous magnetic organometallic catalyst as high‐performance visible light photocatalyst for degradation of organic pollutants

A novel light‐active magnetic Pd complex as a photocatalyst was prepared through bonding organometallics to mesoporous silica channels formed on the surface of silica‐coated iron oxide nanoparticles. The nanocomposite (denoted as Fe₃O₄@SiO₂@m‐SiO₂@PDA‐Pd(0); PDA = 1,10‐phenanthroline‐2,9‐dicarbaldehyde) is more efficient and has higher photocatalytic capability in the degradation of 2,4‐dichlorophenol under visible light irradiation compared with virgin Pd complex (PDA‐Pd). This noteworthy photodegradation activity can be due to the high dispersion of Pd nanoparticles. High yield, low reaction time and non‐toxicity of the catalyst are the main merits of this protocol. Also magnetic separation is an environmentally friendly alternative method for the separation and recovery of the catalyst, since it minimizes the use of solvents and auxiliary materials, reduces operation time and minimizes catalyst loss by preventing mass loss and oxidation. The produced Pd catalyst was characterised using various techniques. Furthermore, transmission electron microscopy characterization was used for determining the structural properties of the Pd nanocatalyst.     

Catalytic activity of Mn(III) porphyrins supported onto graphene oxide nano-sheets for green oxidation of sulfides

Abstract

In this research, oxidation of various sulfides with urea hydrogen peroxide (UHP) in the presence of manganese porphyrin grafted onto graphene oxide ([Mn(THPP)OAc@GO]) in ethanol was studied. The heterogenized catalyst was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), and UV–Vis spectroscopy. The amount of Mn-porphyrin loaded on the GO nano-sheets was determined by atomic absorption spectroscopy (AAS) and the thermal stability of the heterogenized catalyst was investigated by thermo-gravimetric analysis (TGA). [Mn(THPP)OAc@GO] was applied for the green oxidation of different sulfides and the solid catalyst can be simply reused several times without losing its catalytic efficiency.     

Effective fixation of carbon dioxide into poly(glycidyl methacrylate) in the presence of pyrrolidone polymers

The homopolymer (PGMA) of glycidyl methacrylate (GMA) and the copolymer of GMA with N‐vinyl‐2‐pyrrolidone were prepared under radical conditions and employed for the fixation of CO₂ with LiBr as a catalyst, in which the oxirane groups were transformed into five‐membered cyclic carbonate groups. For the fixation of CO₂ into the oxirane groups on PGMA, poly(N‐vinyl‐2‐pyrrolidone), in which the catalyst was impregnated before the reaction, was found to be an effective additive. This was exploited for the reaction using the copolymer containing both the oxirane and pyrrolidone moieties. The oxirane groups on the copolymer were also converted readily to the cyclic carbonates through the fixation of CO₂. In such use of the pyrrolidone structures on the polymers, the fixation of CO₂ could be carried out effectively in a diluted chlorobenzene solution and also under solvent‐free conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4578–4585, 2005     

Protecting and Leaving Functions of Trimethylsilyl Groups in Trimethylsilylated Silicates for the Synthesis of Alkoxysiloxane Oligomers

The concept of protecting groups and leaving groups in organic synthesis was applied to the synthesis of siloxane‐based molecules. Alkoxy‐functionalized siloxane oligomers composed of SiO₄, RSiO₃, or R₂SiO₂ units were chosen as targets (R: functional groups, such as Me and Ph). Herein we describe a novel synthesis of alkoxysiloxane oligomers based on the substitution reaction of trimethylsilyl (TMS) groups with alkoxysilyl groups. Oligosiloxanes possessing TMS groups were reacted with alkoxychlorosilane in the presence of BiCl₃ as a catalyst. TMS groups were substituted with alkoxysilyl groups, leading to the synthesis of alkoxysiloxane oligomers. Siloxane oligomers composed of RSiO₃ and R₂SiO₂ units were synthesized more efficiently than those composed of SiO₄ units, suggesting that the steric hindrance around the TMS groups of the oligosiloxanes makes a difference in the degree of substitution. This reaction uses TMS groups as both protecting and leaving groups for SiOH/SiO⁻ groups.     

三维有序大孔杂化SiO2的制备、表征及应用

将有机-无机杂化功能材料与有序大孔材料独特的有序开孔结构相结合,在制备的三维有序大孔二氧化硅(3DOM Si O2)孔壁上可控接枝带有功能基团的聚合物链段,制备3DOM杂化材料。采用表面引发原子转移自由基(SI-ATRP)接枝技术在3DOM Si O2孔壁上可控接枝聚甲基丙烯酸缩水甘油酯(PGMA)链段,讨论了接枝条件对接枝量及接枝链段分子量的影响,并利用FTIR、SEM、TGA、GPC等对接枝过程进行了表征。PGMA接枝链段上环氧基团可进一步与亲核试剂(二乙醇胺,浓硫酸和二乙烯三胺)发生开环反应,得到一系列带有不同官能团的具有较高接枝密度的功能杂化多孔材料,同时,利用该种材料对水中的水杨酸进行了吸附实验,吸附结果表明经二乙烯三胺开环后得到的功能化多孔材料对水杨酸具有很高的吸附量。     

三维有序大孔杂化SiO2的制备、表征及应用

本研究将有机-无机杂化功能材料与有序大孔材料独特的有序开孔结构相结合,在制备的三维有序大孔二氧化硅（3DOM SiO₂）孔壁上可控接枝带有功能基团的聚合物链段,制备3DOM杂化材料。采用表面引发原子转移自由基（SI-ATRP）接枝技术在3DOM SiO₂孔壁上可控接枝聚甲基丙烯酸缩水甘油酯（PGMA）链段,讨论了接枝条件对接枝量及接枝链段分子量的影响,并利用FT-IR、SEM、TGA、GPC等对接枝过程进行了表征。PGMA接枝链段上环氧基团可进一步与亲核试剂（二乙醇胺,浓硫酸和二乙烯三胺）发生开环反应,得到一系列带有不同官能团的具有较高接枝密度的功能杂化多孔材料,同时,利用该种材料对水中的水杨酸进行了吸附实验,吸附结果表明经二乙烯三胺开环后得到的功能化多孔材料对水杨酸具有很高的吸附量。本研究对于发展新型杂化多孔材料提供了新的方法。     

Hetero Face‐to‐Face Porphyrin Array with Cooperative Effects of Coordination and Host–Guest Complexation

We successfully synthesized a hetero face‐to‐face porphyrin array composed of ZnTPP and RuTPP(DABCO)₂ (TPP: 5, 10, 15, 20‐tetraphenylporphyrin, DABCO: 1,4‐diazabi‐cyclo[2.2.2]octane) in 2:1 molar ratio. A cyclic Zn porphyrin dimer (ZnCP) was also used as the host molecule for the Ru porphyrin. In the latter, the Ru‐DABCO bonding in RuTPP(DABCO)₂ was stabilized by the host‐guest complexation. Reaction progress kinetic analysis of the ligand substitution reaction of RuTPP(DABCO)₂ and that in ZnCP revealed the stabilization mechanism of the Ru‐DABCO bonding. Photoinduced electron transfer (PET) from the Zn porphyrin to the Ru porphyrin was observed in the porphyrin array. The host‐guest stabilization of unstable complex for construction of a donor—acceptor–donor structure is expected to be a new method for an artificial photosynthesis.     

Covalent and Non‐covalent Chemical Modification of Multi‐walled Carbon Nanotubes with Tetra‐(4‐hydroxylphenyl)porphyrin and Its Complexes

Multi‐walled carbon nanotubes (MWNTs) were covalently and non‐covalently functionalized with tetra‐(4‐hydroxylphenyl) porphyrin (THPPH₂) and its complexes (ZnTHPP) forming dispersible nanohybrids in organic solution. The morphology of the nanohybrids was observed with transmission electron microscopy. The structure of the product was characterized by FT‐IR, UV‐Vis spectrophotometer, fluorescence spectroscopy and thermogravimetric analysis. The photo‐induced electron‐transfer process of the nanohybrids in organic solution was also revealed.     

手性Ru复合物催化剂的固载化及其不对称氢转移反应催化应用

Chiral Ru-BsDPEN, (1R,2R)-N-p-benzenesulfonyl-1,2-diphenylethylenediamine, catalyst has been immobilized on a mesoporous molecular sieve of MCM-41 type successfully. A hybrid mesoporous molecular sieve was synthesized using a precursor bearing benzene group, which in organosilica were sulfonylated and reacted with (1R,2R)-l,2-diphenylethylenediamine and [RuC1E(p-cymene)]2 successively to afford immobilized catalyst. The Brunauer-Emmett-Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size decreased after immobilization of catalyst onto the mesoporous material. Enantioselective transfer hydrogenation of ketones catalyzed by immobilized catalyst showed the highest yield of 22.36% and e.e. value of 31.47% by using acetophenone as substrate when reaction time was 48 and 16 h respectively.     

Cross-aldol Condensation of Cycloalkanones and Aromatic Aldehydes in the Presence of Nanoporous Silica-based Sulfonic Acid (SiO2-Pr-SO3H) under Solvent Free Conditions

The aromatic aldehydes underwent cross aldol condensation with cycloalkanones in the presence of a catalytic amount of nanoporous silica-based sulfonic acid (SiO2-Pr-SO3H) under solvent-free conditions to afford the corresponding α,α’-bis(substituted benzylidene)cycloalkanones in excellent yields with short reaction time without any side reactions. This method is very general, simple and environmentally friendly in contrast with other existing methods. SiO2-Pr-SO3H was proved to be an efficient heterogeneous solid acid catalyst, which could be easily handled and removed from the reaction mixture by simple filtration, and also recovered and reused without loss of reactivity.     

Addition reactions of pendant epoxide group in poly(glycidyl methacrylate) with various active esters

Addition reactions of pendant epoxide groups in poly(glycidyl methacrylate) (PGMA) with various active esters such as 1-benzotriazolyl benzoate, S-(2-benzoxazolyl) thiobenzoate, S-(2-benzothiazolyl) thiobenzoate, 4-nitrophenyl benzoate (4NPB), and S-phenyl thiobenzoate (PTB) were carried out using quaternary salts as catalysts. The reactions of PGMA with those active esters proceeded in diglyme at 100°C for 24 h quantitatively without the formation of 2-hydroxyl pendant groups in the polymer when 10 mol % of tetraethylammonium bromide was used as a catalyst. Furthermore, it was found that the respective quaternary salts have higher catalytic activity than tertiary amines in the reaction of PGMA with the active esters, and the reaction of PGMA with 4NPB gave the corresponding polymer with the highest conversion by addition of tetrabutylammonium bromide as a catalyst, while tetraethylammonium chloride showed the highest activity for the reaction of PGMA with PTB. In addition, the rate of reaction of PGMA with 4NPB was proportional to third order kinetics of the epoxide concentration, the ester concentration and the catalyst concentration as follows: ?d[Epoxide]/dt = ?[Ester]/dt = k₃[Epoxide] [Ester] [Catalyst].     

Regarding Initial Ring Opening of Propylene Oxide in its Copolymerization with CO2 Catalyzed by a Cobalt(III) Porphyrin Complex

Cobalt(III) tetraphenylporphyrin chloride (TPPCoCl) was experimentally proved to be an active catalyst for poly(propylene carbonate) production. It was chosen as a model catalyst in the present work to investigate the initiation step of propylene oxide (PO)/CO₂ copolymerization, which is supposed to be the ring opening of the epoxide. Ring‐opening intermediates ( 1 – 7 ) were detected by using ¹H NMR spectroscopy. A first‐order reaction in TPPCoCl was determined. A combination of monometallic and bimetallic ring‐opening pathways is proposed according to kinetics experiments. Addition of onium salts (e.g., bis(triphenylphosphine)iminium chloride, PPNCl) efficiently promoted the PO ring‐opening rate. The existence of axial ligand exchange in the cobalt porphyrin complex in the presence of onium salts was suggested by analyzing collected ¹H NMR spectra.     

Development of a Sensor Based on Modified Carbon Paste with Com Iron(III) Protoporphyrin Immobilized on SiNbZn Silica Matrix for L‐tryptophan Determination

In this work, SiO₂/Nb₂O₅/ZnO prepared by the sol‐gel processing method was used as substrate base for immobilization of the protoporphyrin‐IX ion. Iron(III) ion was inserted into the porphyrin ring (SiNbZn‐PPFe). A simple square wave voltammetry method based on a composite sensor carbon paste electrode of this material,designed as EPC‐SiNbZn‐PPFe, was developed and validated successfully for the determination of L‐tryptophan (Trp). The optimum conditions were obtained by using sensor modified with 18.00 mg SiNbZn‐PPFe material, 12.00 mg graphite powder and 6.0 μL mineral oil and phosphate buffer 0.3 mol L⁻¹ pH 7.0. The sensitivity of the sensor was found to be 0.523 AL mol ⁻¹, linear range from 10 to 70 μmol L⁻¹ and limit of detection of 3.28 μmol L⁻¹. Therefore, the developed method was successfully applied for the Trp determination in real samples of pharmaceutical formulation and can be used for routine quality control pharmaceutical formulations containing Trp.     

N‐heterocyclic carbene–palladium(II) complex supported on magnetic mesoporous silica for Heck cross‐coupling reaction

Magnetic mesoporous silica was prepared via embedding magnetite nanoparticles between channels of mesoporous silica (SBA‐15). The prepared composite (Fe₃O₄@SiO₂‐SBA) was then reacted with 3‐chloropropyltriethoxysilane, sodium imidazolide and 2‐bromopyridine to give 3‐(pyridin‐2‐yl)‐1H‐imidazol‐3‐iumpropyl‐functionalized Fe₃O₄@SiO₂‐SBA as a supported pincer ligand for Pd(II). The functionalized magnetic mesoporous silica was further reacted with [PdCl₂(SMe₂)₂] to produce a supported N‐heterocyclic carbene–Pd(II) complex. The obtained catalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray analysis, vibrating sample magnetometry, Brunauer–Emmett–Teller surface area measurement and X‐ray diffraction. The amount of the loaded complex was 80.3 mg g^?1, as calculated through thermogravimetric analysis. The formation of the ordered mesoporous structure of SBA‐15 was confirmed using low‐angle X‐ray diffraction and transmission electron microscopy. Also, X‐ray photoelectron spectroscopy confirmed the presence of the Pd(II) complex on the magnetic support. The prepared magnetic catalyst was then effectively used in the coupling reaction of olefins with aryl halides, i.e. the Heck reaction, in the presence of a base. The reaction parameters, such as solvent, base, temperature, amount of catalyst and reactant ratio, were optimized by choosing the coupling reaction of 1‐bromonaphthalene and styrene as a model Heck reaction. N‐Methylpyrrolidone as solvent, 0.25 mol% catalyst, K₂CO₃ as base, reaction temperature of 120°C and ultrasonication of the catalyst for 10 min before use provided the best conditions for the Heck cross‐coupling reaction. The best results were observed for aryl bromides and iodides while aryl chlorides were found to be less reactive. The catalyst exhibited noticeable stability and reusability.     

Highly Selective Aldol Condensation Using Amine-functionalized SiO2-Al2O3 Mixed-oxide under Solvent-free Condition

A series of amine catalysts supported on mesoporous molecular sieves SiO₂/Al₂O₃ with trimethoxysilylpropylamine [(CH₃O)₃Si(CH₂)₃NH₂] loading varying from 3 mmol to 6 mmol were synthesized by impregnation method. The aldol condensation of various aromatic aldehydes and 1‐heptanal was used to test the acid‐base cooperativity of amine‐functionalized SiO₂/Al₂O₃. The effects of solvent, reaction temperature, benzaldehyde to 1‐heptanal molar ratio, different supports (SiO₂, Al₂O₃ and SiO₂‐Al₂O₃), catalyst amount and recyclability of the catalyst were investigated. Sample containing 5 mmol amine loaded showed highest benzaldehyde conversion (100%) and selectivity (97%) for jasminaldehyde.     

Solvent‐free ring‐opening polymerization of cyclohexene oxide catalyzed by palladium chloride

In this study, we have for the first time demonstrated that palladium chloride (PdCl₂) is an efficient catalyst for ring‐opening polymerization of cyclohexene oxide in a solvent‐free condition. The polymerization product was in atactic structure, and reaction conditions, such as reaction temperature, time, and catalyst amount, showed effects on polymerization conversion yield, turnover number, and number‐average molecular weight of the resulting poly(cyclohexene oxide). PdCl₂ catalysis follows a cationic ring‐opening mechanism. The polymerization result is highly determined by the chemical structure of the monomers.     

Controlled ring‐opening polymerization of propylene oxide catalyzed by double metal‐cyanide complex

A double metal‐cyanide catalyst based on Zn₃[Co(CN)₆]₂ was prepared. This catalyst is very effective for the ring‐opening polymerization of propylene oxide. Polyether polyols of moderate molecular weight having low unsaturation (<0.015 meq/g) can be prepared under mild conditions. The molecular weight of polymer is entirely controlled by a reacted monomer‐to‐initiator ratio. The polymers prepared with stepwise addition of monomer exhibit a narrower molecular weight distribution as compared with those prepared with one‐step addition of monomer. Various compounds containing active hydrogen, except basic compounds and low‐carbon carboxylic acid, may be used as initiators. The reaction rate increases with increasing catalyst amount and decreases with rising initiator concentration. Polymerization involves a rapid exchange reaction between the active species and the dormant species. It was also proven that, to a certain extent, the chain termination of this catalytic system is reversible or temporary. ¹³C NMR analysis showed that the polymer has a random distribution of the configurational sequences and head‐to‐tail regiosequence. It is assumed that the polymerization proceeds via a cationic coordination mechanism. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1142–1150, 2002     

Electrochemical Studies of a New Iron Porphyrin Entrapped in a Propylpyridiniumsilsesquioxane Polymer Immobilized on a SiO2/Al2O3 Surface

In this work, a new porphyrin, the 5,10,15,20‐tetrakis‐(2,6‐difluoro‐3‐sulfonatophenyl) porphyrinato iron(III) chloride (denoted as FeTsP) was immobilized on SiO₂/Al₂O₃ (SiAl) coated with n‐propylpyridiniumsilsesquioxane polymer (SiPy⁺Cl^?). The FeTsP was adsorbed on SiAl/SiPyCl by an ion exchange reaction, obtaining a modified solid, SiAl/SiPy/FeTsP, where the porphyrin complex was strongly adhered. Cyclic voltammograms of the SiAl/SiPy/FeTsP carbon paste electrode showed an irreversible response, with an oxidation peak at E_pa=0.40 V and nondefined reduction peak at E_pc=0.15 V (vs. SCE). These peaks were not observed for the nonmetallated porphyrin, indicating that they probably correspond to the Fe(III)/Fe(II) process. Studies made in solutions having different pH, (between pH 2 and 9) using the modified electrode showed that the peak potentials and the current density were not affect by pH changes, indicating that the iron porphyrin is very stable and strongly entrapped in the matrix. The modified electrode presented the property to electrocatalyze the eletrooxidation of hydrazine at 0.41 V (vs. SCE), at pH 7. The potentiality of the SiAl/SiPy/FeTsP electrode as a sensor for hydrazine was evaluated by the using the chronoamperometric technique. A linear response was obtained in the concentration range between 5×10^?5 and 6×10^?4 mol L^?1 of hydrazine.