Bungo Ochiai

Nucleophilic polyaddition in water based on chemo-selective reaction of cyclic carbonate with amine

The appropriate choice of the monomers and the polymerization temperatures enabled polyaddition of bifunctional cyclic carbonates and diamines in water completely free from surfactants and organic solvents, although the primary reaction is a nucleophilic addition.

Synthesis of Rare-metal Absorbing Polymer by Three-component Polyaddition through Combination of Chemo-selective Nucleophilic and Radical Additions

Sequential three-component polyaddition has been difficult, because the first addition typically consumes the two reactive monomers to produce a stable intermediate that cannot react smoothly with the remaining most stable monomer. The combination of nucleophilic and radical additions has overcome this thermodynamic problem. The first nucleophilic addition of diamines to cyclic dithiocarbonates produces bis(mercaptothiourethane)s that can attack diethynylbenzene radically, which consequently gives poly(thiourethane-phenylenevinylenesulfide)s in high atom efficiency up to 95%. The resulting polymer extracted palladium and gold cations from their aqueous solutions in excellent efficiencies.

Controlled cyclopolymerization through quantitative 19-membered ring formation.

Cyclopolymerization of a bis-methacrylate monomer derived from trans-cyclohexanediol and 2-methacryloyloxyethyl isocyanate proceeded through 19-membered ring formation. The unusual large ring formation originated from the designed steric regulation by the cyclohexane ring and the hydrogen bonds. The RAFT polymerization employing cumyl dithiobenzoate attained controlled polymerization, which supported the quantitative cyclization.

Selective gas–solid phase fixation of carbon dioxide into oxirane-containing polymers: synthesis of polymer bearing cyclic carbonate group

Gas–solid phase fixation of carbon dioxide into oxirane-containing polymers proceeds selectively without concomitant crosslinking reactions, which have previously been unavoidable due to the dense arrangement of oxirane groups. The fixation reaction obeys first-order kinetics, supporting the selectivity of the reaction.

Living Anionic Polymerization of 2‐Methyl‐4‐ phenyl‐1‐buten‐3‐yne

The anionic polymerization behavior of 2-methyl-4-phenyl-1-buten-3-yne (2) was investigated to get information on the effect of substitutent at the 2-position. The polymerization of 2 did not proceed in tetrahydorfuran at -78°C by lithium initiators, while sodium initiators can conduct the polymerization smoothly to give polymers consisting of a specific 1,2-polymerized unit. The living nature of the polymerization of 2 by diphenylmethylsodium was supported by the post-polymerization experiment.

Development of Hierarchical Polymer@Pd Nanowire-Network: Synthesis and Application as Highly Active Recyclable Catalyst and Printable Conductive Ink.

Abstract A facile one‐pot approach for preparing hierarchical nanowire‐networks of hollow polymer@Pd nanospheres is reported. First, polymer@Pd hollow nanospheres were produced through metal‐complexation‐induced phase separation with functionalized graft copolymers and subsequent self‐assembly of PdNPs. The nanospheres hierarchically assembled into the nanowire‐network upon drying. The Pd nanowire‐network served as an active catalyst for Mizoroki–Heck and Suzuki–Miyaura coupling reactions. As low as 500 μmol % Pd was sufficient for quantitative reactions, and the origin of the high activity is ascribed to the highly active sites originating from high‐index facets, kinks, and coalesced structures. The catalyst can be recycled via simple filtration and washing, maintaining its high activity owing to the micrometer‐sized hierarchical structure of the nanomaterial. The polymer@Pd nanosphere also served as a printable conductive ink for a translucent grid pattern with excellent horizontal conductivity (7.5×105 S m−1).

Organic-sulfur-zinc hybrid nanoparticle for optical applications synthesized via polycondensation of trithiol and Zn(OAc)2

Organic-sulfur-zinc hybrid materials were prepared via polycondensation of Zn(OAc)2 and trithiols bearing various alkyl groups. A soluble nanoparticle could be obtained by the polycondensation using a trithiol bearing octadecyl moieties. The good dispersing ability as nano-scaled particles was confirmed by dynamic light scattering and atomic force microscopy analyses. This hybrid nanoparticle was miscible with poly(methyl methacrylate) and served as a refractive additive to increase refractive indexes. The calculated refractive index value for the nanoparticle was 1.58.

One-Pot Synthesis of Organic-Sulfur-Zinc Hybrid Materials via Polycondensation of a Zinc Salt and Thiols Generated in Situ from Cyclic Dithiocarbonates.

Soluble organic-sulfur-zinc hybrid polymers were prepared via a one-pot reaction consisting of ring-opening addition and subsequent polycondensation. The first reaction is the nucleophilic ring-opening addition of 2-ethylhexylamine to multifunctional cyclic dithiocarbonates giving multiple thiols in situ. The sequential polycondensation of the in situ generated thiols with Zn(OAc)2 gave the target hybrid polymers. This one-pot method enabled the use of a shorter amine than the previous polycondensation of Zn(OAc)2 and purified thiols, which required octadecylamine to obtain a soluble product. The obtained hybrid polymers may be cast as composite films with polystyrene and poly(methyl methacrylate). Owing to the shorter alkyl chain, the calculated nD values of the products (1.60 or 1.61) are higher than that of the previous product bearing octadecyl chains (1.53).

Formation of Flat, Homogeneous Surfaces of Organized Molecular Films of Three-Armed Polymerizable Amphiphiles with Metal-Scavenging Properties

Surface complexing (i.e., metal-bridged polymerization in this study) of a three-armed amphiphilic compound with metal-scavenging properties has been investigated using the surface pressure-area (π-A) isotherms of a Langmuir monolayer from the subphase. Inductively coupled plasma mass spectrometry (ICP-MS) was also carried out on eluted solutions from corresponding multilayers of the solid. Furthermore, the molecular arrangement and surface morphology of organized molecular films of the resultant comb polymer were estimated by in-plane and out-of-plane X-ray diffraction (XRD) and by atomic force microscopy. From an analysis of the wide-angle X-ray diffraction of the corresponding monomer in the bulk, the long hydrocarbon chains are observed to pack hexagonally in the solid state. Compared to their monolayer on distilled water as the subphase, a polymerized monolayer on a buffer solution containing Cd(2+) ions is remarkably expanded at 15 °C. From ICP-MS and IR measurements, it is found that this monolayer stoichiometrically contains Cd(2+) ions on the -SH group. It is found by XRD that highly ordered layer structures and regular 2D lattices are constructed in the organized molecular films of the Cd-bridged comb polymer. Furthermore, the surface morphology of Langmuir-Blodgett films fabricated from the monolayers on a buffer solution containing Cd(2+) and Pd(2+) shows flat and smooth domains upon metal scavenging and polymerization.

Living cationic ring-opening polymerization by water-stable initiator: synthesis of a well-defined optically active polythiourethane

Living cationic ring-opening polymerization under air and water was achieved using a well-defined water-resistant cationic initiator in dichloromethane without purification at ambient temperature.