A Traceless Chiral Shift Reagent Based on Nonbonding Interactions with Single‐Handed Helical Poly(quinoxaline‐2,3‐diyl)

Abstract

A single-handed poly(quinoxaline-2,3-diyl) (PQX) has been found to serve as a new type of chiral shift reagent (CSR) for determining the enantiomeric ratio by NMR spectroscopy. Even though there is no specific binding site in the PQX, its nonbonding interaction with chiral analytes leads to a significant shift of the NMR chemical shift, allowing quantification of the enantiomeric ratio. The new type of CSR has the advantages of a wide scope of analytes including ethers, haloalkanes, and alkanes, easy tunability of the degree of chemical shifts by measurement temperature, and erasability of proton signals of CSR because of the short spin-spin (T 2 ) relaxation of the macromolecular scaffold.

Cobalt-Catalyzed Hydrosilylation Polymerization for the Synthesis of Linear Polycarbosilanes

“…Chiral polymers have gained great attention due to their wide applications in chiral recognition, asymmetric catalysis, and organic optoelectronic materials. − As a representative axial chiral moiety, 1,1′-binaphthyl-based enantiomers ( S )- M1h and ( R )- M1h were designed as monomers. The axial chirality embedded in these monomers did not hamper the polymerization, giving the corresponding polymers P1h2a in moderate molecular weight and narrow dispersity (Scheme ).…”

Redox‐Modulated Circularly Polarized Luminescence in Chiral Photonic Films Derived from Cellulose Nanocrystals and Polyoxometalate

“…Self-assembly has been proved to be a powerful strategy for precisely controlling the arrangement of building blocks and amplifying the g lum . [21][22][23][24][25][26] Chiral nematic liquid crystals (NLCs) as a typical 1D chiral photonic crystals (CPCs) of helical structures have been recognized as powerful platforms to generate CPL. [27] For instance, in our previous work, we achieved tunable CPL with a large |g lum | value up to 0.25 through the coassembly of inorganic nanowires and quantum dots into CPCs via Langmuir-Schaefer technique.…”