The typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly-heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3'-bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co-planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system.
Solute-solvent interactions on the keto-enol tautomerism of 2-nitrocyclohexanone in several organic solvents and room-temperature ionic liquids (RTILs) have been analyzed in terms of multiparameter equations. Permittivity and cohesive pressure values of the RTILs, unavailable by direct measurements, have been derived.
Dynamic HPLC on enantioselective stationary phases has become a well-established technique to investigate chiral molecules with internal motions that result in stereoinversion and occur on the time scale of the separation process. Kinetic parameters for the on-column interconversion phenomena can be extracted from experimental peak profiles by computer simulation or by direct calculation methods. The technique has been used in a wide range of temperatures and is complementary in scope to dynamic NMR spectroscopy.
Resorc[4]arene octamethyl ethers 1-3, when treated with NOBF4 salt in chloroform, form very stable 1:1 nitrosonium (NO+) complexes, which are deeply colored. The complexation process is reversible, and the complexes dissociate and bleach upon addition of methanol or water, to give the starting macrocycles. Resorc[4]arenes 1 and 2 are in the same cone conformation, but with different side-chains, whereas 3 possesses a different conformation (chair), while bearing the same side-chain as 2. Kinetic and spectral UV-visible analysis revealed that NO+ interacts with resorc[4]arenes 1 and 2 both outside and inside their basket, leading to complexes with two absorption patterns growing at different rates, one featuring high-energy bands (HEB) within the near-UV zone, and the other one low-energy bands (LEB), attributed to charge-transfer interactions, within the visible range. The presence of ester carbonyl groups in 2 strongly drives the NO+ cation outside the resorcarene. Resorc[4]arene 3 showed a spectral pattern pointing out a clear involvement of the ester moieties in the NO+ entrapping, beside the formation of significant charge-transfer interactions. 1H NMR spectroscopy and molecular modeling clearly supported these findings.
The typical design of chiral electroactive materials involves attaching chiral pendants to an electroactive polyconjugated backbone and generally results in modest chirality manifestations. Discussed herein are electroactive chiral poly‐heterocycles, where chirality is not external to the electroactive backbone but inherent to it, and results from a torsion generated by the periodic presence of atropisomeric, conjugatively active biheteroaromatic scaffolds, (3,3′‐bithianaphthene). As the stereogenic element coincides with the electroactive one, films of impressive chiroptical activity and outstanding enantiodiscrimination properties are obtained. Moreover, chirality manifestations can be finely and reversibly tuned by the electric potential, as progressive injection of holes forces the two thianaphthene rings to co‐planarize to favor delocalization. Such deformations, revealed by CD spectroelectrochemistry, are elastic and reversible, thus suggesting a breathing system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.