Catalysis direction selective asymmetric polymerization in chiral liquid crystal medium

Abstract

Highlights-Synthesis and characterization of a series of polyisocyanides.-Polymerization in asymmetric liquid crystal.-Preparation of chiroptically active polyisocyanides.-Helical sense controllable polymerization.-In situ ESR spectra of polyisocyanides.

Enantiocomplementary Chiral Polyhydroxyenoate: Chemoenzymatic Synthesis and Helical Structure Control

“…For the helical fibers formed in the mixed solvent of DCM/hexane (1:1), the helix feature of poly-3a was more remarkable than that of poly-3b (Figure 2a vs c, Figure 2b vs d), probably due to the more pyknotic structure of poly-3a induced by the "π−π" stacking interaction as abovementioned. 28 Interestingly, only left-handed folding sense was observed in helical structures for all the enantiomeric (R)-and (S)-polyesters, although one should expect opposite handedness for R and S helices. It is well-known that the stacking manner of the polymer chain could be changed by altering the steric hindrance and interaction of the polymer chains.…”

“…Furthermore, during the folding process, long aliphatic side chain of poly- 3b had stronger steric hindrance, which was conducive to the formation of incompact microsphere. For the helical fibers formed in the mixed solvent of DCM/hexane (1:1), the helix feature of poly- 3a was more remarkable than that of poly- 3b (Figure a vs c, Figure b vs d), probably due to the more pyknotic structure of poly- 3a induced by the “π–π” stacking interaction as above-mentioned . Interestingly, only left-handed folding sense was observed in helical structures for all the enantiomeric ( R )- and ( S )-polyesters, although one should expect opposite handedness for R and S helices.…”

“…For microspheres formed in the mixed solvent of DCM/hexane (1:10), comparatively, the microspheres of poly- 3a (Figure , left) had a smoother surface than those of poly- 3b (Figure , right). It might be attributed to the “ π–π ” stacking interaction of phenyl in poly- 3a . This interaction of aromatic side chain made sphere more pyknotic to form the smoother surface.…”

Synthesis of a Terpene-Based New Chiral Inducer and Preparation of an Asymmetric Polymer

“…Also, chiral 2,2'-bis(3,4-ethylenedioxythiophene) (BEDOT)-based copolymer was prepared by chemical and electrochemical polymerization [17]. Electrochemical polymerization [18], polycondensation [19], and polymerization by a Ni-based catalyst [20] have been carried out in cholesteric LC solution. Furthermore, binaphthyl molecules were synthesized in a chiral LC medium [21].…”

Vapor treatment, liquid crystal formation, magnetic orientation, and crystallization (VLMC) to form helical polyisocyanides with oriented crystal‐like structure

“…Previous studies reported synthesis of poly(phenyl isocyanide) derivatives with optical activity and a helical structure. [ 5–10 ] This required controlling the winding direction of the helix, as the orientation of the chiral side chain in the polymer dictates main‐chain helicity and macroscopic morphology of the polymer. Preparation of chiral polyisocyanides using a chiral oligomer as an initiator was previously employed to obtain chiral polymers, with the use of liquid crystal solvent isocyanide polymerization allowing the formation of one‐handed, optically active, helical polyisocyanides capable of analysis by atomic force microscopy and molecular calculations.…”