Soluble Polymer-Supported Catalysts Research Articles

Synthesis of aryloxide-containing half-titanocene catalysts grafted to soluble polynorbornene chains and their application in ethylene polymerization: Integration of multiple active centres in a random coil

A series of monodisperse polynorbornene (PNB) chains bearing different contents of aryloxide ligands at their side chain were synthesized by Grubbs ring-opening metathesis copolymerization between norbornene and 2-aryloxonorbornene. These PNB chains were employed as a soluble support for grafting half-titanocene complexes to afford structurally well-defined supported catalysts, where a pre-defined number of Ti centres was confined in a nano-sized random coil of PNB chains. Extensive investigation in ethylene polymerization revealed unique catalytic features of these soluble polymer-supported catalysts, represented by a synergistic activity enhancement among multiple active centres confined in a random coil. The well-defined nature of these novel polymer-supported catalysts is powerful in studying interactions between active centres and supports as well as among active centres themselves in catalysis.

Liquid/Liquid Biphasic Recovery/Reuse of Soluble Polymer‐Supported Catalysts

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Soluble polymer-supported catalysts containing azo dyes.

[structure: see text] Azo benzene derivatives were incorporated into soluble polymer-bound catalysts by two different approaches. The first was to attach the dye to the polymer-bound catalysts, using the dye as an innocent spectator to study the phase preference, concentration, and recoverability of a catalyst. The second approach used an azo dye as a ligand to form an effective soluble polymer-bound Pd(II) catalyst for Heck reactions.

Preparation and use of MeO-PEG-supported chiral diphosphine ligands: soluble polymer-supported catalysts for asymmetric hydrogenation

Two new chiral MeO-PEG-supported ( R)-BINAP and (3 R,4 R)-Pyrphos ligands were synthesized and employed in the Ru(II)- and Rh(I)-catalyzed asymmetric hydrogenation of 2-(6′-methoxy-2′-naphthyl)propenoic acid 5 and prochiral enamides 10. The results showed that these new soluble polymeric catalysts exhibited high catalytic activity and enantioselectivity. Enantiomeric excesses (e.e.s) in the ranges 90–96% and 86–96% were achieved in the hydrogenation of 5 and 10, respectively. Furthermore, these catalysts could be recovered easily and the recycled catalysts were shown to maintain their efficiency in subsequent reactions.

Highly Effective Soluble Polymer-Supported Catalysts for Asymmetric Hydrogenation

Highly Effective Soluble Polymer-Supported Catalysts for Asymmetric Hydrogenation

Liquid-phase chemistry: recent advances in soluble polymer-supported catalysts, reagents and synthesis

Chemistry on soluble polymer-matrices, termed liquid-phase organic synthesis, is emerging as a viable alternative or adjunct to the classical solid-phase approach across the broad spectrum of polymer-supported organic chemistry. This review details the significant advances in liquid-phase synthetic methodologies, reagents, catalysts and supports that have appeared from 1997 to the present.

Soluble Polymer-Supported Catalysts Containing Pendant Quaternary Onium Salt Residues for Regioselective Addition Reaction of Epoxy Compound with Active Ester

Various soluble polymer-supported catalysts containing pendant quaternary onium salts were synthesised by the radical copolymerisation of p-chloromethylated styrene with styrene followed by the addition reaction of the resulting copolymers with tributylamine or trialkylphosphines. The catalytic activity of the soluble polymer-supported quaternary onium salts on the regioselective addition reaction of phenyl glycidyl ether (PIE) with S-phenyl thioacetate (PTA) was evaluated from the rates of the reaction and yields of the product, 1-phenoxy-3-(phenylthio)-2-propyl acetate (PPA). The catalytic activity was strongly affected by the content ofpendant quaternary onium salt in the polymer chains, by the structure of onium salt residues, and by the reaction solvents used