Synthesis of an optically active polymer containing a planar phthalimide backbone by asymmetric polymerization

Herein we present the precise design and synthesis of a novel polymer backbone that induces a helical structure through asymmetric polymerization reactions of a phthalimide-based monomer catalyzed by a planar-chiral cyclopentadienyl–ruthenium complex.

The Chirality Induction and Modulation of Polymers by Circularly Polarized Light

Chirality is a natural attribute nature of living matter and plays an important role in maintaining the metabolism, evolution and functional activities of living organisms. Asymmetric conformation represents the chiral structure of biomacromolecules in living organisms on earth, such as the L-amino acids of proteins and enzymes, and the D-sugars of DNA or RNA, which exist preferentially as one enantiomer. Circularly polarized light (CPL), observed in the formation regions of the Orion constellation, has long been proposed as one of the origins of single chirality. Herein, the CPL triggered asymmetric polymerization, photo-modulation of chirality based on polymers are described. The mechanisms between CPL and polymers (including polydiacetylene, azobenzene polymers, chiral coordination polymers, and polyfluorene) are described in detail. This minireview provides a promising flexible asymmetric synthesis method for the fabrication of chiral polymer via CPL irradiation, with the hope of obtaining a better understanding of the origin of homochirality on earth.

Preparation of Chiral Polydiacetylene Films by Using Three-Photon Polymerization

Asymmetric polymerization of polydiacetylene (PDA) from commercially available achiral derivative of diacetylene monomer using circularly polarized pulse laser is demonstrated. Chiral source was only circularly polarized laser, and irradiation of left- and right-circularly polarized light effectively promoted the polymerization of chiral PDAs with opposite handedness. Difference between the laser wavelength and the absorption peak of monomer suggested the contribution of the multiphoton excitation to the photo-polymerization. Laser power dependence of the polymerization rate indicated the possibility of three-photon polymerization.

Micelle-provided microenvironment facilitating the formation of single-handed helical polymer-based nanoparticles

Micelles provide microenvironment effects for asymmetric polymerization: an unprecedented methodology for controlling the preferential helicity of synthetic helical polymers.