Electro- and Magneto-Responsible Chiral Polymers

Abstract

Helical polymers and macromolecules have precisely ordered stereostructures, and their potential applications include chiral separation and sensing based on molecular recognition and liquid crystalline formation by molecular ordering. Among them, π-conjugated polymers with a helical structure have often exhibited unique electro-and magnetoresponsibilies. In this review, we describe the helical π-conjugated macromolecules as electro-and magneto-responsible materials including our recent studies. In Chapter 2, the recent studies of helical polymeric molecules with π-conjugated structures are reviewed. We focus on "helicene" derivatives, which consist of fused-benzene and/or thiophene rings, in Chapter 3 and summarize their syntheses, characteristics, and optical properties based on the stiff structures and molecular ordering. Helical ladder polymers, "poly(thiaheterohelicene)s" comprised of fused-benzothiophene rings, are discussed in Chapter 4 among their stiff helical structure and π-conjugation. The combined functions of electro-and magnetoproperties of the chiral polymer are described using the example of poly(thiaheterohelicene)s, such as electron transmission along the helical main-chain and a molecule model of a molecular solenoid, in the final section.

Synthesis and chiral recognition of helical poly(phenylacetylene)s bearing l‐phenylglycinol and its phenylcarbamates as pendants

“…As examples, PPA‐1 and PPA‐1b showed [ α ] D 20 values of +443° and +360°, respectively, in DMF, while the optical rotations of the corresponding monomers PA‐1 and PPA‐1b were −87.0° and −15.3°, respectively, in the same solvent. The opposite and high optical rotations of the polymers suggest that a new structure, most likely a secondary helical structure, must be formed in the polymer chains . The optical activities of the polymers were influenced by the helicity of the polymer backbones.…”

Synthesis and Self-Assembly of Chiral Cylindrical Molecular Complexes: Functional Heterogeneous Liquid-Solid Materials Formed by Helicene Oligomers

“…Helicenes are an interesting group of synthetic aromatic molecules with a helical structure and have been known since the 1950s. Their properties have not been well examined, although many syntheses are reported [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. On the basis of a large-scale synthesis of 1,12-dimethylbenzo[ c ]phenanthrene developed in this laboratory, we have studied the synthesis and function of helical substances using helicenes as building blocks [ 34 , 35 , 36 , 37 , 38 ] Helical substances treated here range from molecules to oligomers, molecular complexes and self-assembly materials, each of which exhibited notable properties and functions.…”

Formation Mechanism of Helical Polyacetylene with Spiral Morphology in Asymmetric Reaction Field Consisting of Chiral Nematic Liquid Crystal

“…Helical conjugated polymers 1 are useful for various applications, such as nanowires, 2 electrical and magnetic devices, 3 chiral resolution reagents, 4 and biotechnologies. 5 Polyacetylene (PA) is the simplest conjugated polymer and a prototype of an electrical conductive polymer.…”

“…Helical conjugated polymers are useful for various applications, such as nanowires, electrical and magnetic devices, chiral resolution reagents, and biotechnologies . Polyacetylene (PA) is the simplest conjugated polymer and a prototype of an electrical conductive polymer. − Because helical polyacetylene (H-PA) was synthesized in chiral nematic liquid crystal (N*-LC) used as an asymmetric reaction field, , substituted PA derivatives of helical conformations have been extensively studied. , The N*-LC can be prepared by adding a small amount of chiral compound as a chiral dopant into a nematic LC (N-LC) .…”