Brightening up Circularly Polarized Luminescence of Monosubstituted Polyacetylene by Conformation Control: Mechanism, Switching, and Sensing

Abstract

The first example of luminescent monosubstituted polyacetylenes (mono‐PAs) is presented, based on a contracted cis‐cisoid polyene backbone. It has an excellent circularly polarized luminescence (CPL) performance with a high dissymmetric factor (up to the order of 10−1). The luminescence stems from the helical cis‐cisoid PA backbone, which is tightly fixed by the strong intramolecular hydrogen bonds, thereby reversing the energy order of excited states and enabling an emissive energy dissipation. CPL switches are facilely achieved by the solvent and temperature through reversible conformational transition. By taking advantages of fast response and high sensitivity, the thin film of mono‐PAs could be used as a CPL‐based probe for quantitative detection of trifluoroacetic acid with a wider linear dynamic range than those of photoluminescence and circular dichroism. This work opens a new avenue to develop novel smart CPL materials through modulating conformational transition.

Self‐Reporting Activated Ester‐Amine Reaction for Enantioselective Multi‐Channel Visual Detection of Chiral Amines

“…[12] 1 H NMR (Figures S11 and S12), 19 F NMR (Figure S13), FTIR (Figure S14), and Raman (Figure S15) spectroscopies further proved this speculation. [12,17] The strong fluorescence of sP-C8-C9* was rationalized by the reversed energy levels of 1B u and 2A g as well as the restricted intramolecular motions (Figure 1d). [12] Therefore, with activated ester-amine reaction, cc poly(3,5-diamide substituted phenylacetylene) was gradually formed, accompanied with the appearance of fluorescence.…”

“…[12,17] The strong fluorescence of sP-C8-C9* was rationalized by the reversed energy levels of 1B u and 2A g as well as the restricted intramolecular motions (Figure 1d). [12] Therefore, with activated ester-amine reaction, cc poly(3,5-diamide substituted phenylacetylene) was gradually formed, accompanied with the appearance of fluorescence. The consistent conclusion could also be obtained by comparing the spectroscopies of sP-C8-C9* and sP-C8-C9**, which was prepared as the standard sample of activated ester-amine reaction directly from the corresponding diamide monomer, (S)-3-octylcarbamoyl-5-(nonan-2ylcarbamoyl)phenylacetylene (sM-C8-C9*) (Supporting Information for detailed information).…”

“…[11] Recently, we reported the first example of luminescent mono-PAs bearing no pendant chromophore. [12] This was achieved by the formation of contracted cis-cisoid (cc) polyene backbone, which reversed the energy levels of 1B u and 2A g and restricted the intramolecular motions. Its excellent stimuli-responsive circularly polarized luminescence (CPL) property was applied as a CPL-based probe for quantitative detection of achiral acid.…”

Dissymmetric Chiral Poly(diphenylacetylene)s: Secondary Structure Elucidation and Dynamic Luminescence

“…However, in the case of PPAs the emissive form of the helical scaffold is when the polyene backbone adopts just a cis-cisoidal configuration. [113] The CPL emission was gauged by the dissymmetric factor defined as j g lum j = 2(I L À I R )/(I L + I R ), being I L and I R the left-and right-handed luminescent emissions respectively. In both cases a maximum g lum value of ca.…”

Integration of Different Graphene Nanostructures with PDMS to Form Wearable Sensors

“…In recent times, conductive polymers have been used to lower the manufacturing cost of the thin films and minimize the limitations of the nanocomposite-based electrodes. Some of the common conductive polymers used to form the flexible sensors are PEDOT: PSS [ 46 , 47 , 48 ], polyaniline (PANI) [ 37 , 49 , 50 ], polyacetylene (PA) [ 51 , 52 , 53 ], and polypyrrole (PPy) [ 54 , 55 , 56 ]. Their conjugation assists in inducing additional functional groups that add material properties to the prototypes.…”