Poly(ionic liquid)s: An update

A Renaissance in Living Cationic Polymerization

Nanocatalysts are characterised by the unique nanoscale properties that originate from their highly reduced dimensions. Extensive studies over the past few decades have demonstrated that the size and shape of a catalyst particle on the nanometre scale profoundly affect its reaction performance. In particular, controlling the catalyst particle morphology allows a selective exposure of a larger fraction of the reactive facets on which the active sites can be enriched and tuned. This desirable surface coordination of catalytically active atoms or domains substantially improves catalytic activity, selectivity, and stability. This phenomenon is called morphology-dependent nanocatalysts: catalyst particles with anisotropic morphologies on the nanometre scale greatly affect the reaction performance by selectively exposing the desired facets. In this review, we highlight important progress in morphology-dependent nanocatalysts based on the use of rod-shaped metal oxides with characteristic redox and acid-base features. The correlation between the catalytic properties and the exposed facets verifies the chemical nature of the morphology effect. Moreover, we provide an overview of the interactions between the rod-shaped oxides and the metal nanoparticles in metal-oxide catalyst systems, involving crystal-facet-selective deposition of metal particles onto different crystal facets in the oxide supports. A fundamental understanding of active sites in morphologically tuneable oxides enclosed by the desired reactive facets is expected to direct the development of highly efficient nanocatalysts.

Morphology-dependent nanocatalysts: Rod-shaped oxides

Star polymers: Advances in biomedical applications

Iron oxide nanoparticles (NPs) hold great promise for future biomedical applications because of their magnetic properties as well as other intrinsic properties such as low toxicity, colloidal stability, and surface engineering capability. Numerous related studies on iron oxide NPs have been conducted. Recent progress in nanochemistry has enabled fine control over the size, crystallinity, uniformity, and surface properties of iron oxide NPs. This review examines various synthetic approaches and surface engineering strategies for preparing naked and functional iron oxide NPs with different physicochemical properties. Growing interest in designed and surface-engineered iron oxide NPs with multifunctionalities was explored in in vitro/in vivo biomedical applications, focusing on their combined roles in bioseparation, as a biosensor, targeted-drug delivery, MR contrast agents, and magnetic fluid hyperthermia. This review outlines the limitations of extant surface engineering strategies and several developing strategies that may overcome these limitations. This study also details the promising future directions of this active research field.

Designed synthesis and surface engineering strategies of magnetic iron oxide nanoparticles for biomedical applications

An upper critical solution temperature (UCST)-type phase separation in water was achieved using well-defined polymeric ionic liquids (ILs) with imidazolyl groups in their side chains, prepared base...

Well-Defined Polymeric Ionic Liquids with an Upper Critical Solution Temperature in Water

Alkyl vinyl ethers and isobutylene oxide were concurrently copolymerized through cationic vinyl addition and ring opening using B(C6F5)3 as a catalyst. NMR analyses and acid hydrolysis of the products demonstrated that the copolymerization successfully proceeded through crossover reactions between vinyl and cyclic monomers to yield multiblock-like copolymers. Appropriate catalyst and monomer combinations with suitable reactivities were key for copolymerization.

Concurrent Cationic Vinyl-Addition and Ring-Opening Copolymerization Using B(C6F5)3 as a Catalyst: Copolymerization of Vinyl Ethers and Isobutylene Oxide via Crossover Propagation Reactions

Fast living cationic polymerization of vinyl ethers with iron(III) chloride in the presence of a cyclic ether: Most active and environmentally benign catalyst for the living cationic polymerization of vinyl ethers

Heterogeneously catalyzed living cationic polymerization of isobutyl vinyl ether (IBVE) with Fe2O3 in the presence of an added base is described. Cationic polymerization of IBVE using Fe2O3 in conjunction with ethyl acetate or 1,4-dioxane and IBVE−HCl, a suitable cationogen, proceeded smoothly in a heterogeneous system to produce polymers with very narrow molecular weight distributions (Mw/Mn ≤ 1.1). The living polymerization was also achieved under unfavorable conditions:  at higher temperature (30 °C) or in the presence of a small amount of water. Furthermore, Fe2O3 was readily separable from product polymers according to simple procedures. The reused Fe2O3 was very similar in catalytic activity to the virgin counterpart even after multiple use, producing nearly monodisperse polymers.

Heterogeneously catalyzed living cationic polymerization of isobutyl vinyl ether using iron (III) oxide.

A metal-free initiating system for the living cationic polymerization of alkyl vinyl ethers (VEs) and styrene derivatives was developed using diaryliodonium salts as an organic Lewis acid catalyst....

Arihiro Kanazawa

Papers

Well-Defined Polymeric Ionic Liquids with an Upper Critical Solution Temperature in Water

Concurrent Cationic Vinyl-Addition and Ring-Opening Copolymerization Using B(C6F5)3 as a Catalyst: Copolymerization of Vinyl Ethers and Isobutylene Oxide via Crossover Propagation Reactions

Fast living cationic polymerization of vinyl ethers with iron(III) chloride in the presence of a cyclic ether: Most active and environmentally benign catalyst for the living cationic polymerization of vinyl ethers

Heterogeneously catalyzed living cationic polymerization of isobutyl vinyl ether using iron (III) oxide.

Metal-Free Living Cationic Polymerization Using Diaryliodonium Salts as Organic Lewis Acid Catalysts