Novel cyanide supramolecular fluorescent chemosensor constructed from a quinoline hydrazone functionalized-pillar[5]arene

Herein, we report a simple and novel approach for the design of fluorescent chemosensor through the self-assembly of functionalized monomer molecules. According to these approach, a novel supramolecular fluorescent chemosensor (SPMS) was successfully constructed by self-assembly of a quinoline hydrazone functionalized pillar[5]arene monomer PM. Interestingly, upon the addition of CN^-, the solution of SPMS instantly shows dramatic fluorescent enhancement and emitting bright blue emission. Meanwhile, the fluorescence quantum yields show distinct increase from 0.0582 of SPMS to 0.3952 of SPMS + CN^-. The detection limit (LOD) of SPMS for CN^- is 9.70 × 10^-8 M, which indicated high sensitivity. Moreover, the SPMS is selective for CN^- even in the presence of other anions, the fluorescent detection process of SPMS for CN^- was not interfered by other competitive anions (F^-, Cl^-, Br^-, I^-, N₃^-, OH^-, SCN^-, HSO₄^-, AcO^-, H₂PO₄^- and ClO₄^-). Notably, in the CN^- sensing process, the self-assembly structure of the supramolecular chemosensor SPMS didn't show any disassembly. This work provides a novel approach for instant detection of CN^- through a self-assembled supramolecular fluorescent chemosensor in aqueous system. Moreover, the test strips based on SPMS were fabricated, which could serve as convenient and efficient CN^- test kits.

Low Band Gap Donor⁻Acceptor Type Polymers Containing 2,3-Bis(4-(decyloxy)phenyl)pyrido[4,3-b]pyrazine as Acceptor and Different Thiophene Derivatives as Donors

Four donor–acceptor type conducting polymers, namely poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-thiophen-2-yl)pyrido[4,3-b]pyrazine) (P1), poly(2,3-bis(4-decyloxy)phenyl)-5,8-bis(4-butylthiophen-2-yl)pyrido[4,3-b]pyrazine) (P2), poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(4-hexyloxythiophen-2-yl)pyrido[4,3-b]pyrazine) (P3) and poly(2,3-bis(4-(decyloxy)phenyl)-5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)pyrido[4,3-b]pyrazine) (P4), containing thiophene or its derivative as the donor and pyrido[4,3-b]pyrazine as the acceptor were prepared and characterized by cyclic voltammetry, scanning electron microscopy, and UV-Vis spectroscopy to detect the influence of the donor units’ strength on the electrochromic performances. The results demonstrated that all of the polymers could be reversibly reduced and oxidized by p-type doping and n-type doping, and showed near-infrared activities and different color changes in p-type doping process. Especially, P3 and P4 showed lower optical band gap than P1 and P2 due to the strong electron-donating hexyloxythiophen group of P3 and ethylenedioxythiophene group of P4. Besides, P3 and P4 displayed the saturated green color at the neutral state and the desirable transparency at the oxidized state. All the polymers displayed desirable optical contrasts, satisfactory coloration efficiency, excellent stability and short switching time, which made the polymers fascinating candidates in the electrochromic device applications.

The utilization of post-synthetic modification in opto-electronic polymers: an effective complementary approach but not a competitive one to the traditional direct polymerization process

By presenting some typical examples, the recent progress of opto-electronic polymers is reviewed, which were only accessible from the post-synthetic modification strategy.

Near-infrared thermochromic diazapentalene dyes

A series of 2,5-diazapentalene containing dyes with tunable energy gaps are visible and near-infrared halochromic towards various acids and their protonated counterparts represent a new class of thermochromic materials with the near-infrared absorption being switched on at room temperature and off above 50 °C.