Chiral BINAP-based hierarchical porous polymers as platforms for efficient heterogeneous asymmetric catalysis

Two vinyl‐functionalized chiral2,2'‐bis(diphenylphosphino)‐1,1'‐binaphthyl(BINAP)ligands,(S)‐4,4'‐divinyl‐BINAP and(S)‐5,5'‐divinyl‐BINAP,were successfully synthesized.Chiral BINAP‐based porous organic polymers(POPs),denoted as4‐BINAP@POPs and5‐BINAP@POPs,were efficiently prepared via the copolymerization of vinyl‐functionalized BINAP with divinyl benzene under solvothermal conditions.Thorough characterization using nuclear magnetic resonance spectroscopy,thermogravimetric analysis,extended X‐ray absorption fine structure analysis,and high‐angle annular dark‐field scanning transmission electron microscopy,we confirmed that chiral BINAP groups were successfully incorporated into the structure of the materials considered to contain hierarchical pores.Ru was introduced as a catalytic species into the POPs using different synthetic routes.Systematic investigation of the resultant chiral Ru/POP catalysts for heterogeneous asymmetric hydrogenation ofβ‐keto esters revealed their excellent chiral inducibility as well as high activity and stability.Our work thereby paves a path towards the use of advanced hierarchical porous polymers as solid chiral platforms for heterogeneous asymmetric catalysis.

PS-HQ:More convenient in situ polymeric cocatalyst for the PdC1_2-catalyzed acetalization in supercritical carbon dioxide

Polystyrene-supported hydroquinone （PS-HQ） is presented as an in situ polymeric cocatalyst to replace polystyrenesupported benzoquinone （PS-BQ） in the PdCl2-catalyzed acetalization of methyl acrylate with methanol in supercritical carbon dioxide （scCO2） under oxygen atmosphere. Due to deletion of H2O2 oxidation step, PS-HQ is more convenient and relatively inexpensive.

STUDY ON THE POLYMERIZATION OF ACRYLONITRILE INITIATED BY POLYPROPYLENE-BASED VANADYL POLYIMIDODIACETATE——THIOUREA REDOX SYSTEM

The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the temperature range from 25 to 40℃. The polymerization rate was measured by varying the concentrations of monomer, vanadyl polyimidodiacetate, thiourea and sulfuric acid. The overall rate of polymerization was summarized asRp=2.2×10~5e^(-6.560/RT) [AN]^(1.0)[PV]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)The molecular weight of polyacrylonitrile based on the experimental data was:(?)=k 1/T [pv]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)These results indicated that the chain radicals are terminated by combination and/or disproportionation rather than chain transfer. The cooperation effect of carboxylic groups and the macromolecular field effect of polymer supporter are the characters of vanadyl polyimidodiacetate such as the case reported in early paper.

Polymer Supported Synthesis of Multi-substituted Pyrimidine-4-one Derivatives via Pbf-activated Thiourea

Efficient polymer supported synthesis of multi-substituted pyrimidine-4-one derivatives was described. Target products were produced from fluorenylmethoxycarbonyl（Fmoc） protected β-amino acid loaded on hydro- xymethyl resin through deprotection, N-alkylation, guanidine formation, and cleavage of 2,2,4,6,7-pentamethyl dihy-drobenzofuran-sulfonyl（Pbf） by trifluoracetic acid（TFA） followed with cyclization. The procedure has the advantages of easy operation, mild reaction conditions, and forming multiple substituents.

POLYMER-SUPPORTED GRIGNARD REAGENT AND ITS USE IN THE FUNCTIONALIZATION OF POLYMER

Polymeric Grignard Reagent (PGR) based on the chloromethylated poly(ST-co-DVB) resinhas been prepared by means of anthracene-magnesium complex in THF (Anth-Mg-THF), andpolymer matrix with long polymethylene spacer was synthesized via the coupling reaction betweenPGR and α, ω-dibromoalkanes. Based on the studies of factors affecting the coupling, such ascatalyst,reaction time,the length of spacer etc.,this paper offers the optimal reaction conditionsand three typical experiment procedures. The mechanism for the formation and coupling reactionof PGR are also discussed.

SYNTHESIS, CHARACTERIZATION AND CATALYTIC ACTIVITY OF N,N'-BIS(3-ALLYL SALICYLIDENE)ETHYLENEDIAMINE COBALT(Ⅱ) SCHIFF BASE COMPLEX ANCHORED ON A NEW POLYMER SUPPORT

A new chelating polymer support has been prepared by suspension copolymerization of synthesized N,N'-bis(3- allyl salicylidene)ethylenediamine monomer Schiff base (N,N'-BSEDA) with styrene (St) and divinylbenzene (DVB) using azobisisobutyronitrile (AIBN) as initiator in the presence of poly(vinyl alcohol). The content and complexation ability of monomer Schiff base (N,N'-BSEDA) for cobalt ions in prepared crosslinked polymer beads have shown dependence on the amount of DVB used in reaction mixture. The amount of monomer Schiff base (N,N '-BSEDA) in crosslinked beads showed a substantial decreasing trend at high concentration of DVB in the reaction mixture (> 1.5 mol dm-3), hence the efficiency of complexation (EC%) and cobalt ion loading (EL%) of polymer beads showed a decreasing trend. The structure of monomer Schiff base (N,N'-BSEDA) and its cobalt complex on polymer support was elucidated by IR, UV and magnetic measurements. The catalytic activity of polymer bound cobalt Schiff base complex was evaluated by analyzing kinetic data of decomposition of hydrogen peroxide in the presence of either supported cobalt complex or free cobalt complex. The activation energy for the decomposition of hydrogen peroxide by polymer supported cobalt complex was found to be low (33.37 kJ mol-1) in comparison with unsupported cobalt complex (56.35 kJ mol-1). On the basis of experimental observations, reaction steps are proposed and a suitable rate expression derived.

POLYMER SUPPORT EFFECTS OF METAL COMPLEXES FOR CATALYSIS

In the course of investigating the catalytic behavior of metal complexes for ring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation and selective hydrogenation of olefins experimental results time and again indicate the presence of effects of macromolecular supports - the utilization of macromolecular supports increases obviously the activity, selectivity, and stability of the catalysts and so as to increase the conversion of substrates, yields of reactions, properties of formed polymers and so on. Discussed these effects on the basis of the authors' experiments. (Author abstract) 18 Refs.

Pretreatment of Polymer-Supported Pd-Co and Its Catalytic Activity

Various pretreatments of poly (N-vinyl-2-pyrrolidone) (PVP) protected palladium-cobalt system result in different catalytic activities in the hydrodechlorination of chlorobenzene.

PROPERTIES OF POLYMER SUPPORTED Ni-Cu BIMETALLIC CATALYSTS PREPARED BY SOLVATED METAL ATOM IMPREGNATION

D-72 resin supported nickel-copper catalysts prepared by solvated metal atom impregnation (SMAI) were studied by magnetic measurements and X-ray photoelectron spectroscopy (XPS). The Ni particles on the catalysts are very highly dispersed and display superparamagnetic behaviour. Ni-Cu alloy clusters were found to be formed. The surface compositions are different from the bulk concentrations. In contrast with the surface enrichment in copper generally observed on conventional Ni-Cu catalysts, the surfaces of these catalysts are enriched in nickel. The nickel is in both zero and valent states, while copper is mainly in metallic state. Catalytic data show that the formation of Ni-Cu alloy clusters has a profound effect on the catalytic activities of the catalysts in the hydrogenation of furfural. The activity of the Ni:Cu ratio of one bimetallic catalysts is much higher than that of the Ni or Cu monometallic catalyst.

THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

POLYMER-SUPPORTED CLUSTER II SYNTHESIS, CHARACTERIZATION AND CATALYTIC PROPERTIES OF POLYMERSUPPORTED HETEROPENTAMETALLIC CLUSTER FeCO_3 (CO)_(12) (μ_3-AuPph_2CH_2■-■)

The polymer-supported cluster FeCo3 (CO)_(12) (μ3-AuPph_2 CH_2) (4) has been synthesized through reaction of CH_2 ph_2 PAuCl with the cluster anion FeCo_3 (CO)_(12)^-. They are characterized through IR spectra, electronic spectra and XPS, with homogenous analog FeCo_3 (CO)_(12) (μ3-AuPph_3) (3) as reference compound. The cluster (3) and the polymer-supported cluster (4) are good catalysts for hydroformylation of olefins. They have better activity and selectivity than the cluster (1) and (2).The supported cluster (4) is more stable and has catalytic activity at higher temperature than its homogeneous analog (3). From the metal core level binding energies in XPS and λ_(max) in electronic spectra, it is found that the metal-metal bonds in (4) are reinforced bypolymer supporter. The cluster (3) and (4) can be reused , and possibly do not fragment to one metal species in the course of catalytic reaction.

Nano Fibrous Cerium（IV） Hydrogen Phosphate Membrane Self Supported Indole Polymerization Agent

Nanosized fibrous cerium（IV） hydrogen phosphate membrane, Ce（HPO4）2·2.9H20 （nCePf）, was prepared and characterized by chemical, XRD （X-ray diffraction）, TGA （thermogravimetric analysis）, SEM （scanning electron microscopy） and TEM （transmission electron microscopy）. Novel supported nanofibrous Ce（IV） phosphate/polyiondole nanocomposite membranes were prepared via in-situ chemical oxidation of the monomer that was promoted by the reduction of Ce（IV） ions present in the inorganic matrix. The presence of Ce（IV） ions allows redox reactions necessary to oxidative polymerization to occur. The resultant material was characterized by TGA, elemental （C, H, N） analysis and FT-IR （Fourier transform spectroscopy）. SEM images of the resulting nanocomposite reveals a uniform distribution of the polymer on the inorganic matrix. Amount of polyindole polymer present in the composite is found to be - 7.0%.

Immobilization of Glucoamylase onto Novel Porous Supports Containing Cyclic Carbonate

Glucoamylase was immobilized onto novel porous polymer supports containing cyclic carbonate. The relationship between activity of immobilized glucoamylase and the properties of porous polymer supports was investigated. The operation stability and storage stability of immobilized glucoamylase were studied.

STRUCTURAL CHARACTERIZATION OF Pd-SnO_2/D_(3520) CATALYSTS

Distribution of metals on Pd - SnO_2/D_(3520) catalysts and state of the catalysts were studied with SEM, XRD. The interaction between metals and support or between Pd and Sn or Ph were studied by IR, XPS. In addition, the relationship of the activity for catalytic hydrogenation of the olefins and outer layer valence electron density Of Pd was discussed. The results showed that these catalysts had suitable surface state, the metals were uniformly dispersed on the surface layer of the suPPort. There were not obvious lute7uction between the metals and the suPPort. There was strong interaction between Pd and Sn (or Pb) in the catalysts. The catalytic activity for hydrogenation was related to outer layer silence electron density of Pd.

STRUCTURAL CHARACTERIZATION OF Pd-SnO_2/D3520 CATALYSTS

Distribution of metals on Pd-SnO2/D3520 catalysts and state of the catalystswere studied with SEM, XRD. The interactlbn between metals and supped or between Pd and Sn or Ph were studied by IR, XPS. In addition, the relationship ofthe activity for catalytic hydrogenation of the olefins and outer layer valence electrondensity of Pd was discussed. The results showed that these catalysts had suitablesurface state, the metals were uniformly dispersed on the surface layer of the suppnd. There were not obvious interaction between the metals and the supal. Therewas strong interaction between Pd and Sn (or Ph) in the catalysts. The catalytic activity for hydrogenation was related to outer layer valence electron density of Pd.

STUDIES ON THE STATE OF PALLADIUM AND HYDROGENATION ACTIVITY OF RESIN SUPPORTED PALLADIUM──TIN OXIDE CATALYSTS

Several Pd--SnO2/ D3520 and Pd--PbO / D3520 catalysts with Pd/ D3J20, SnO2 / D3520 and PbO / D3520 catalysts as rference were studied by means of IR and XPS. Interaction between Pd and the second metal or between metal and support was observed. Results show that there is a strong interaction between Pd and the second metal, but there is not an obvious interaction between metal and support. The active constituent is Pd￣0. Hydrogenation activity of the catalysts is altered because of the interaction between Pd and the second,metal.The activity of the catalysts for hydrogenation has relation to outer layer valence electron density of Pd.

Synthesis of Thiourea Derivatives on Soluble Polymeric Support

A modified poly(ethylene glycol) (PEG) has been developed as the solublepolymeric supports for liquid phase synthesis of novel thiourea derivatives. In each step of thesequence, the PEG-bound products were precipitated in cold Et_2O and the unreacted materials andby-products were removed by simple filtration. The progress of reaction, purity of the isolation andthe structure of the PEG-bound products were easily monitored by TLC, IR and ~1H NMR spectra.Representative thiourea derivatives were obtained in moderate yields with excellent purity from thismodified PEG-bound product by the cleavage with 50% TFA/H_2O.

Stereoselective Synthesis of (E)-and (Z)-1,2-Disubstituted Ethene from Polymer-Supported Vinylic Selenide

This letter describes a method for the stereoselective synthesis of polymer supported vinylic selenides and their applications to synthesis of ( E ) and ( Z ) 1,2 disubstituted ethenes on solid phase by the coupling reaction with Grignard reagents under the catalysis of NiCl 2(PPh 3) 2.

Synthesis of a New Polymer-supported Reagent──Poly{[4- hydroxy(tosyloxy)iodo]styrene} and Its Application to the Synthesis of 2-Amino-4-arylthiazoles

A new polymer-supported reagent--poly{[4-hydroxy(tosyloxy)iodo]styrene} has good reactivity in the formation of 2-amino-4-arylthiazoles, and the procedure of regeneration and cycle are also described.