Advanced functional polymer membranes

2.2.1. Polyisocyanates 6117 2.2.2. Polysilanes 6118 2.2.3. Polyacetylenes 6120 2.3. Foldamer-Based Helical Polymers 6124 2.3.1. Click Polymerization 6126 2.3.2. Ring-Closing Reaction 6126 2.4. Other Types of Helical Polymers 6127 2.4.1. π-Conjugated Helical Polymers 6127 2.4.2. Metallosupramolecular Helical Polymers 6128 2.5. Induced Helical Polymers 6130 2.5.1. Induced Helical Polyacetylenes 6130 2.5.2. Other Induced Helical Polymers and Oligomers 6132

Helical polymers: synthesis, structures, and functions

In this review, we describe the recent advances in supramolecular helical assemblies formed from chiral and achiral small molecules, oligomers (foldamers), and helical and nonhelical polymers from the viewpoints of their formations with unique chiral phenomena, such as amplification of chirality during the dynamic helically assembled processes, properties, and specific functionalities, some of which have not been observed in or achieved by biological systems. In addition, a brief historical overview of the helical assemblies of small molecules and remarkable progress in the synthesis of single-stranded and multistranded helical foldamers and polymers, their properties, structures, and functions, mainly since 2009, will also be described.

Supramolecular Helical Systems: Helical Assemblies of Small Molecules, Foldamers, and Polymers with Chiral Amplification and Their Functions

Synthetic helical polymers: conformation and function.

Molecular imprinting science and technology: a survey of the literature for the years up to and including 2003

We have found a simple and novel synthetic method for obtaining a chiral polymer from an achiral monomer by using a chiral catalytic system. The chirality of the polymer was caused only by a one-handed helical backbone, and the polymer had no other chiral structures in the side groups. In addition, the helical conformation was stable in solution by itself. This is the first example of helix-sense-selective polymerization of a substituted acetylene. The stability of the helicity was found to be caused by intramolecular hydrogen bonds.

Helix-Sense-Selective Polymerization of Phenylacetylene Having Two Hydroxy Groups Using a Chiral Catalytic System

Synthesis of functional π-conjugated polymers from aromatic acetylenes

Poly[p-{L-(−)-menthoxycarbonyl}phenylacetylene]s prepared by [Rh(norbornadiene)Cl]2 as a polymerization catalyst exhibited a much higher [α]D20 (= −605) than that(= −68.8) of the monomer and a very high molar ellipticity(more than 104) at the π–π* region in the CD spectrum: A chiral helical conformation of the main chain in solution is suggested. The solid membrane of this polymer showed enantioselective permeability (54%ee) for DL-tryptophan.

Chiral Helical Conformation of the Polyphenylacetylene Having Optically-Active Bulky Substituent

Macromolecular design of permselective membranes

Optical resolution of various racemates such as (±)-tryptophan and (±)-1,3-butanediol was achieved by permeation through a self-supporting membrane of (+)-poly{1-[dimethyl(10-pinanyl)silyl]-1-propyne} [(+)-poly(DPSP)] prepared by homopolymerization of (−)-1-[dimethyl(10-pinanyl)silyl]-1-propyne [(−)-DPSP]. Almost complete optical resolution (% ee of the permeate = 81−100% ee) was achieved at an initial period of concentration-driven permeation, and stable permeation with moderate permselectivity (% ee of the permeate = 12−54% ee) continued for more than 600 h. In addition, by permeation of vapor permeant such as evapomeation and pervaporation, higher permeation rates were attained maintaining high enantioselectivity. The sign of the enantiomer that predominantly permeated through a (+)-poly(DPSP) membrane was opposite to that through a (−)-poly(DPSP) membrane. In the permeation through a (+)-poly(DPSP) membrane of a solute or a solvent having a high affinity for (+)-poly(DPSP) and in the permeation throug...

Toshiki Aoki

Papers

Helix-Sense-Selective Polymerization of Phenylacetylene Having Two Hydroxy Groups Using a Chiral Catalytic System

Synthesis of functional π-conjugated polymers from aromatic acetylenes

Chiral Helical Conformation of the Polyphenylacetylene Having Optically-Active Bulky Substituent

Macromolecular design of permselective membranes

Enantioselective Permeation of Various Racemates through an Optically Active Poly{1-[dimethyl(10-pinanyl)silyl]-1-propyne} Membrane