树状功能高分子负载锡配合物的合成及其催化酮的Baeyer-Villiger氧化反应性能研究

通过固相合成方法将聚酰胺-胺树状分子担载于氯球上,对其外围分别用2,4-二羟基苯甲醛和邻羟基苯甲醛进行修饰,再与SnCl2.2H2O反应,形成配体不同的两类树状高分子锡配合物.将此类配合物用作30%的双氧水氧化酮的Baeyer-Villiger反应的非均相催化剂,具有较好的催化活性.2-金刚烷酮、环己酮、3-甲基-2-戊酮等都转化为相应的酯和内酯,底物的转化率和产物选择性均较高.对2-羟基苯甲醛、2,4-二羟基苯甲醛和邻羟基苯甲醛修饰的不同类型催化剂催化下的反应进行比较,发现配体对锡的担载量和催化活性均有不同程度的影响.其中邻羟基苯甲醛修饰的配合物因具有较高的锡担载量而具有了最佳的催化活性.此催化体系使用环境友好的低浓度双氧水为氧化剂,催化剂制备方法简单、催化反应完成时间短、催化剂在多次重复利用后活性没有明显降低,可回收和重复利用.     

Immobilization of MoO2Cl2 on polystyrene via different linkers and oxidation of sulfides in the presence of hydrogen peroxide

Chloromethylated polystyrene was oxidized to aldehydic polystyrene and by reaction of this aldehydic polystyrene resin with furfuryl amine and 2-(amino methyl) pyridine, imine-bounded polystyrene resins 1a and 1b were obtained. Amine-bounded polystyrene resins 1c?C1f were also prepared by direct reaction of chloromethylated polystyrene and amines. These functionalized polystyrene resins were used to immobilize MoO₂Cl₂ on polystyrene. These functionalized polystyrene resins were characterized with elemental analysis (CHN) and FT-IR spectrum. Polymer-supported catalysts were characterized with FT-IR and neutron activation analysis (NAA). These catalysts were used in oxidation of methyl phenyl sulfide in the presence of H₂O₂ as oxidant and the results showed that these catalysts were highly active and selective. The reusability of these heterogeneous catalysts was also investigated and the results showed that the supported MoO₂Cl₂ catalyst on polystyrene via imidazole liker was highly reusable as it was used 15 times in oxidation of methyl phenyl sulfide in the presence of environmental benign oxidant (H₂O₂) and solvent (H₂O) without any decrease in its activity. Then the catalytic activity of these supported catalysts was investigated in oxidation of some aliphatic and aromatic sulfides. Almost all of these supported molybdenum-based catalysts were highly active and selective in the conversion of these sulfides to their corresponding sulfoxides.     

Design,synthesis and theoretical analysis of functionalized dicarboxylate moieties based on organotin(IV) dinuclear complexes: crystal structure elucidation and biological studies

Dinuclear tin(IV) dicarboxylate complexes of the types [(n-Bu)₂Sn(oda)(4-pic)]₂·2H₂O (1) and [(n-Bu)₂Sn(pda)(H₂O)]₂ (2) [H₂oda = oxydiacetic acid; H₂pda = pyridine 2,6-dicarboxylic acid) were synthesized and characterized via physicochemical and spectroscopic studies. The spectroscopic results indicated that Sn is seven-coordinate having pentagonal bipyramidal (pbp) geometry in both complexes. The X-ray study of complex 2 further specified pentagonal bipyramidal geometry with dinuclear structural arrangement due to the involvement of carboxylate bridges formed by pda^2? moiety. The crystal structure is further stabilized by different weak interactions viz., C–C?H, C–C?O, C–H?O, C–C?O, and C–H?H. These interactions are further supported by Hirshfeld surface analysis along with 2-D fingerprint plots of complex 2. In vitro DNA-binding studies of both complexes were evaluated using spectroscopic techniques (absorbance and fluorescence) which ascertained optimum binding affinity of both complexes. However, cleavage activity of the complexes was assessed using supercoiled DNA (pBR322) via gel electrophoresis technique which demonstrated significant cleavage pattern of both complexes at different concentrations. Furthermore, chemotherapeutic potential of complexes 1 and 2 against MCF-7 and Hep carcinoma cell lines also suggested significant antiproliferative effect of complexes. These results revealed momentous exploration of drug–DNA interactions which may engender new insinuation for the advancement of metallo-pharmaceuticals.     

EFFECT OF MORPHOLOGICAL STRUCTURE OF AMINOMETHYL POLYSTYRENE RESIN ON THE CATALYTIC PROPERTIES OF POLYMER-SUPPORTED RUTHENIUM COMPLEXES

 Polymer-supported ruthenium complexes Ⓟ-Phen-Ru-①, Ⓟ-Phen-Ru-②, Ⓟ-Phen-Ru-③, Ⓟ-Phen-Ru-④, Ⓟ-Phen-Ru-⑤, Ⓟ-Phen-Ru-⑥ and Ⓟ-Phen-Ru-⑦ were prepared using aminomethyl polystyrenes of different morphological structures as supports. A variety of alcohols were oxidized efficiently into the corresponding ketones, carboxylic acids or aldehydes with iodosylbenzene (PhIO) catalyzed by aminomethyl polystyrene-supported ruthenium complexes under mild reaction conditions in acetonitrile. The influences of morphological structure of the polymer supporters on the catalytic properties of these metal complexes were investigated in detail.     

固载聚乙二醇催化合成异黄樟油素

以聚乙二醇和固载聚乙二醇作为相转移催化剂, 在无溶剂条件下, 黄樟油素经催化异构合成异黄樟油素. 通过正交实验, 得到固载PEG-X (polyethylene glycol-X)催化最优工艺条件为: m(88.5%黄樟油)∶m(KOH)∶m(PEG-X)＝1∶0.2∶0.25, 反应温度90 ℃, 反应时间 5 h, 在此工艺条件下, 异黄樟油素得率为99.9%. 固载PEG-X催化剂循环使用10次后其催化活性未见下降. 结果显示, 固载聚乙二醇催化工艺具有操作简便、反应温度低、时间短、产率高以及对环境友好等优点. 用¹H NMR, GC-MS对异构黄樟油素结构进行了表征, 研究了固载聚乙二醇作为相转移催化剂合成异黄樟油素的反应机理.     

Ligand Exchange Chromatography of Cephalosporin C on Polystyrene Resins Containing Copper Complex of Lysine Derivatives

Abstract

A ligand-exchange chromatography procedure for the separation of cephalosporin C from an artificial mixture is described. Three new sorbents were synthesized by immobilizing the ligands ε-L-lysine, glycyl-ε-L-lysine and diglycyl-ε-L-lysine on a polystyrene matrix(SX 1 Bio-Rad). These resins were loaded with Cu(II) as a complexing agent. A good resolution of cephalosporin C was achieved only using the ε-L-lysine resin complexed with copper. Models of copper complexes involved are proposed, for the chromatographic separation of cephalosporin C.     

A convenient semicarbazide resin for the solid-phase synthesis of peptide ketones and aldehydes

Use of a semicarbazide resin for the solid-phase preparation of peptide ketones and aldehyde led to optimal results in terms of both purity of the final product and overall yield. This resin was prepared without complication by activation of the commercial available aminomethyl polystyrene with CDI at room temperature, followed by treatment with tert-butyl carbazate. Furthermore, the TNBSA colorimetric assay has been adapted for checking the incorporation of the carbonyl moiety onto hydrazine-based resins.     

Clean and efficient synthesis of air stable polymer-supported alkoxycarbonylcyclopentadienyl rhodium(I) complexes

Polymer-supported alkoxycarbonylcyclopentadienyl rhodium(I) complexes have been obtained through immobilization of [Rh{C₅H₄CO₂(CH₂)₂O₂C-Im}(NBD)] (2) (Im = imidazole) on an (aminomethyl)polystyrene resin. An alternative approach toward the grafting of [Rh{C₅H₄CO₂(CH₂)₂OH}(NBD)] (1) on a Wang resin has been also developed. Spectroscopic characterization of all the new functionalized resins with particular accent on ICP-OES measurements is presented and discussed.     

STUDIES ON MACROPOROUS POLYMER SUPPORTED ASYMMETRIC HYDROGENATION CATALYSTS

The supported Rh-DIOP complexes were prepared through functionalization of several macroporous polystyrene resins nd were evaluated by the hydrogenation of acetamidocinnamic acid in EtOH.The pore effect of the matrixes was discussed.     

Preparation and Catalytic Properties of Polymer Supported Dendritic Metal Complex

Polymer supported materials are extensively used as oxidizing agent, reducing agent catalysts, photosensitizers ion exchange resins and agriculturally and pharmacologically active agents1. The application of polymer metal complexes has been widely investigated2. The polymer supported complex undergoes swelling in a suitable solvent medium and provides enough surface area in carrying out electron transfer reactions, which clearly emphasizes the influence of a polymer network in heterogeneous catalysis.In the present, we have succeeded in the grafting of "dendrimer-like" hyperbranched polymer onto the surface of chloromethyl polystyrene reactions.All the catalysts show promising catalytic activities for the oxidation of iso-propylbenzene in the mild reaction condition, in each case, hypnone 1, 2-phenyl-2-propanol 2 were obtained as the major products     

Core-shell-type resins for solid-phase peptide synthesis: comparison with gel-type resins in solid-phase photolytic cleavage reaction

[reaction: see text] Novel core-shell-type resins with a rigid core and amino-functionalized flexible shell were prepared with 2,4,6-trichloro-1,3,5-triazine (CNC) and Jeffamine ED-600 starting from 1% cross-linked aminomethyl (AM) polystyrene resins. All of the amino groups were located outside the resin beads, and the loading capacity was 0.2-0.4 mmol/g. The amount of CNC treated was a determining factor in the properties of the final resins. The core-shell-type resins showed superior performances in terms of the initial loading of amino acid and the photocleavage reaction compared to the gel-type resins.     

New homobimetallic organotin(IV) dithiocarbamates as potent antileishmanial agents

In the present study, di- and triorganotin(IV) dithiocarbamates, (n-Bu₂SnCl)₂L (1), (Ph₂SnCl)₂L (2), (Ph₃Sn)₂L (3), and (Bz₃Sn)₂L (4), have been synthesized, where L is 4,4-trimethylenedipiperidine-1-carbodithioate. The coordination mode of the ligand to Sn, structural confirmation and geometry assignment around Sn(IV), in solid and solution forms, were made using FT-IR, multinuclear NMR (¹H and ¹³C), and X-ray single crystal analysis. The latter technique confirms anisobidentate mode of chelation of the ligand with Sn, in 1–4, with distorted trigonal bipyramidal or square pyramidal geometry. Complexes 1–4 present supramolecular structures mediated by different C?H and Cl?H intermolecular interactions. These complexes maintain five-coordination even in solution, except for 4. The antileishmanial activity of all complexes are well above the standard drug, especially (Bz₃Sn)₂L. The Docking studies suggest that high antileishmanial action of (Bz₃Sn)₂L is due to its lowest binding energy with enzyme trypanothione synthetase. The antileishmanial activity of the complexes is promising enough that they may be used for antileishmanial treatment after further investigations.     

Electrochemical synthesis and study of coordination compounds part 1: tin(II) catechol complexes

The electrochemical synthesis of tin(II) complexes of catechols, Sn(O₂Ar) (1a–9a), have carried out using tin metal as a sacrificial anode in acetonitrile, in the presence of catechol derivatives. The cyclic voltammetric characteristics of the synthesized complexes Sn(O₂Ar) (1a–9a) have been studied at glassy carbon electrode in dichloromethane. Anodic oxidation of Sn(O₂Ar) produces a single wave which shows irreversibility. Also, the electronic effects of ligands on the redox potential of complexes 1a–9a have been investigated. The synthesis of Sn(O₂Ar) species in high yields and purity has been successfully performed in an undivided cell using constant current conditions.     

Improving resins for solid phase synthesis: incorporation of 1-[2-(2-methoxyethoxy)ethoxy]-4-vinyl-benzene

The preparation, characterisation and application of a series of non-grafted polystyrene (PS) resins containing a styrenic methoxypoly(ethylene glycol) (MPEG) derivative is presented. These novel PS-MPEG resins were designed to balance swelling and solvation with improved handling. The monomer, 1-[2-(2-methoxyethoxy)ethoxy]-4-vinyl-benzene, contained an inert phenyl ether linkage designed to provide broad chemical compatibility and stability, yet imparting all the favourable properties of the PEG group into the new resin, whilst maintaining a high loading capacity. The synthetic performance of the new resins compared very favourably to those of TentaGel™, ArgoGel™ and aminomethyl PS.     

Synthesis and spectroscopic studies of new organotin(IV) complexes with tridentate N- and O-donor Schiff bases

The Schiff bases H₂L¹ and H₂L² have been prepared by the reaction of 2-amino-4-chlorophenol with pyrrole-2-carbaldehyde and 2-hydroxy-1-naphtaldehyde, respectively, and HL³ from reaction of 2-(aminomethyl)pyridine with 2-hydroxy-1-naphtaldehyde. Organotin complexes [SnPh₂(L¹)] (1), [SnPh₂(L²)] (2), [SnMe₂(L²)] (3) and [SnPhCl₂(L³)] (4) were synthesized from reaction of SnPh₂Cl₂ and SnMe₂Cl₂ with these Schiff bases. The synthesized complexes have been investigated by elemental analysis and FT-IR, ¹H NMR and ¹¹⁹Sn NMR spectroscopy. In complexes the Schiff bases are completely deprotonated and coordinated to tin as tridentate ligands via phenolic oxygen, pyrrolic, and imine nitrogens in 1, two phenolic oxygens and imine nitrogen in 2 and 3, and phenolic oxygen, imine and pyridine nitrogens in 4. The coordination number of tin in 1, 2, and 3 is five and in 4 is six.     

Pd catalysis on dendronized solid support: generation effects and the influence of the backbone structure

Recent studies revealed that catalysts, prepared on dendronized support, frequently exhibit enhanced activity and selectivity as compared to their non-dendronized analogues. Regretfully, in early studies of the supported dendritic catalysis, no particular attention was paid to the coordinative nature of the dendritic backbone. In this study, we functionalized Wang polystyrene support with three types of dendritic templates: poly(aril benzyl ether), poly(aryl benzyl thioether), and poly(aryl benzyl amine). These dendronized resins were further decorated with phosphine ligands on the periphery and complexed with a Pd(0) catalytic precursor. The catalysis of the Heck and Suzuki reactions of bromobenzene with the first to third generation supported dendritic catalysts was examined and compared to that of the non-dendritic analogues. All of the examined reactions revealed a positive dendritic effect, reflected in up to 5-fold increase in yield, in the most prominent case. The reasons for the observed effect are the proximity of the ligating sites translated into reduced cross-linking and, probably, the increased distance of the catalyst from the polymer matrix. We proved, however, that the latter could not be achieved with a linear spacer. Although the Suzuki reaction was rather insensitive to the backbone structure, the Heck reaction catalysis at 80 degrees C exhibited substantial sensitivity to the nature of the dendritic backbone, with the polyether structure demonstrating the best outcome. This is the first demonstration of the influence of the coordinative ability of the backbone on the activity of a supported dendritic catalyst.     

聚苯乙烯负载季鏻盐型树脂的制备及催化效应

用高分子材料负载季鏻盐相转移催化剂的开发和研究已有报导^[1,2]。Reeves^[3]和Idoux^[4]曾用氯甲基聚苯乙烯树脂经多步反应制得催化剂。Tomoi通过CF₃SO₃H催化ω-溴代烯烃与树脂付-克烷基化反应制得溴烃基树脂,再与三烃基膦反应制成高分子负载季磷盐催化剂, 具有良好的相转移催化效应。     

Amphiphilic polymer supported N-heterocyclic carbene palladium complex for Suzuki cross-coupling reaction in water

We synthesized amphiphilic polymer-supported N-heterocyclic carbene (NHC) precursor resins by loading polyethylene glycol (PEG) containing imidazolium groups on Merrifield resin. These PS-PEG-NHC precursor resins were compatible with water and readily formed a stable complex with palladium. These PS-PEG-NHC-Pd catalysts showed excellent catalytic activity for Suzuki cross-coupling reactions of various aryl iodides and bromides with phenylboronic acid in water than the previously described polystyrene based catalysts. In addition, the PS-PEG-NHC-Pd catalysts continued to provide excellent catalytic activity in Suzuki cross-coupling reactions after five consecutive recycles.     

聚苯乙烯支载聚氧乙烯季铵盐的合成及催化性能

本文合成了共聚苯乙烯-二乙烯基苯支载四聚乙二醇季铵盐以及共聚苯乙烯-二乙烯基苯支载聚乙二醇辛基苯基季铵盐, 并对它们在1-溴辛烷与碘化钾反应中的催化活性进行了研究。     

Polymer Supported Schiff Base Complexes of Iron(III), Cobalt(II) and Nickel(II) Ions and their Catalytic Activity in Oxidation of Phenol and Cyclohexene

The polymer supported transition metal complexes of N,N′‐bis (o‐hydroxy acetophenone) hydrazine (HPHZ) Schiff base were prepared by immobilization of N,N′‐bis(4‐amino‐o‐hydroxyacetophenone)hydrazine (AHPHZ) Schiff base on chloromethylated polystyrene beads of a constant degree of crosslinking and then loading iron(III), cobalt(II) and nickel(II) ions in methanol. The complexation of polymer anchored HPHZ Schiff base with iron(III), cobalt(II) and nickel(II) ions was 83.30%, 84.20% and 87.80%, respectively, whereas with unsupported HPHZ Schiff base, the complexation of these metal ions was 80.3%, 79.90% and 85.63%. The unsupported and polymer supported metal complexes were characterized for their structures using I.R, UV and elemental analysis. The iron(III) complexes of HPHZ Schiff base were octahedral in geometry, whereas cobalt(II) and nickel(II) complexes showed square planar structures as supported by UV and magnetic measurements. The thermogravimetric analysis (TGA) of HPHZ Schiff base and its metal complexes was used to analyze the variation in thermal stability of HPHZ Schiff base on complexation with metal ions. The HPHZ Schiff base showed a weight loss of 58% at 500°C, but its iron(III), cobalt(II) and nickel(II) ions complexes have shown a weight loss of 30%, 52% and 45% at same temperature. The catalytic activity of metal complexes was tested by studying the oxidation of phenol and epoxidation of cyclohexene in presence of hydrogen peroxide as an oxidant. The supported HPHZ Schiff base complexes of iron(III) ions showed 64.0% conversion for phenol and 81.3% conversion for cyclohexene at a molar ratio of 1∶1∶1 of substrate to catalyst and hydrogen peroxide, but unsupported complexes of iron(III) ions showed 55.5% conversion for phenol and 66.4% conversion for cyclohexene at 1∶1∶1 molar ratio of substrate to catalyst and hydrogen peroxide. The product selectivity for catechol (CTL) and epoxy cyclohexane (ECH) was 90.5% and 96.5% with supported HPHZ Schiff base complexes of iron(III) ions, but was found to be low with cobalt(II) and nickel(II) ions complexes of Schiff base. The selectivity for catechol (CTL) and epoxy cyclohexane (ECH) was different with studied metal ions and varied with molar ratio of metal ions in the reaction mixture. The selectivity was constant on varying the molar ratio of hydrogen peroxide and substrate. The energy of activation for epoxidation of cyclohexene and phenol conversion in presence of polymer supported HPHZ Schiff base complexes of iron(III) ions was 8.9 kJ mol^?1 and 22.8 kJ mol^?1, respectively, but was high with Schiff base complexes of cobalt(II) and nickel(II) ions and with unsupported Schiff base complexes.