Biomedical subjects

Mitsuo Sawamoto

Publications and source records attributed to Mitsuo Sawamoto.

6 recordsLinked to original sources

PubMed2006

In situ hydrogenation of terminal halogen in poly(methyl methacrylate) by ruthenium-catalyzed living radical polymerization: direct transformation of "polymerization catalyst" into "hydrogenation catalyst".

An in situ, selective, and quantitative hydrogenation of the terminal chlorine (alpha-haloester) in living PMMA-Cl into PMMA-H was achieved via direct transformation of a "polymerization catalyst" into a "hydrogenation catalyst" in the Ru(II)-catalyzed living radical polymerization, where the polymerization mixture of MMA was directly treated in situ with K2CO3 as a base and 2-propanol as a hydrogen donor. The reaction terminated the polymerization and, more importantly, the terminal chlorine was quantitatively hydrogenated, as confirmed by SEC, 1H NMR, and MALDI-TOF MS.

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PubMed2004

Cation pool-initiated controlled/living polymerization using microsystems.

The "cation pool" of an N-acyliminium ion was found to serve as an effective initiator of cationic polymerization of vinyl ethers in a microsystem consisting of two micromixers and a microtube reactor. The polymerization led to very narrow molecular weight distribution (Mw/Mn = 1.14). The molecular weight (Mn) increased linearly with an increase in the amount of the monomer. The carbocationic polymer end was effectively trapped by allyltrimethylsilane. The present observations illustrate the potential of microsystems, in conjunction with the cation pool, to effect polymerization in a highly controlled manner without the deceleration inherent in the dynamic equilibrium between active and dormant species.

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PubMed2004

Metal-catalyzed living radical polymerization: discovery and developments.

Control of radical polymerization has been one of the most challenging frontiers in polymerization chemistry. This review presents the discovery of metal-catalyzed living radical polymerization and recent developments in the evolution of catalysts in terms of versatility and activity, scope of monomers, controlled polymerization in water, catalyst removal, and precision synthesis of well-controlled polymers such as random, block, end-functionalized, and star polymers.

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PubMed2003

Polymer catalysts from polymerization catalysts: direct encapsulation of metal catalyst into star polymer core during metal-catalyzed living radical polymerization.

Star polymers containing ruthenium complex in the core were prepared by ruthenium-catalyzed living radical polymerization, where the metal catalysts were directly encapsulated on linking reactions of living poly(MMA) in the presence of ethylene glycol dimethacrylate as a linker and diphenyl-4-styrylphosphine as a ligand incorporated in the core. The products were characterized by SEC/MALLS, UV-vis, NMR, AFM, TEM, and ICP-AES and were employed as polymer catalysts for the oxidation reaction of alcohol.

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PubMed2002

A highly active Fe(I) catalyst for radical polymerisation and taming the polymerisation with iodine.

A fast and controlled radical polymerisation of acrylates and acrylamides can be achieved with a combination of a highly active metal catalyst, Fe2Cp2(CO)4, and a mild radical scavenger, iodine, in the presence of an iodide initiator.

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PubMed2002

A new ruthenium complex with an electron-donating aminoindenyl ligand for fast metal-mediated living radical polymerizations.

A new ruthenium complex with an electron-donating aminoindenyl ligand induces a fast living radical polymerization of methyl methacrylate (MMA) in the presence of a chloride initiator to give polymers with controlled and variable molecular weights (Mn = 103-105) and very narrow molecular weight distributions (Mw/Mn < 1.1). The structure and high activity of the catalyst were analyzed by X-ray crystallography and cyclic voltammetry in comparison to those of a similar complex with an indenyl ligand.

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