Improved electrochemical properties of polypyrrole with cucurbit[6]uril via supramolecular interactions.

A supramolecular polymer was developed through the encapsulation of polypyrrole by cucurbit[6]uril (PPy@Q[6]), which was employed as the electrode material to improve the capacitor ability of conductive polypyrrole. In the optimized ratio of 2 : 1 (CPPy : CQ[6]), the capacitor properties of the supramolecular material were evaluated, and a high specific capacitance of 414 F g-1 at 10 mV s-1 was obtained, which was 3.1 times higher than that of pure polypyrrole (132 F g-1). A comprehensive analysis suggested that the capacitance performances should be relevant to the component, surface area, and pore volume of the materials. The addition of 0.4 M Fe2(SO4)3 into the electrolyte provided a surprising specific capacitance of 3530 F g-1 on the cucurbituril-encapsulated polypyrrole electrode material, with a high energy density of 707 W h kg-1 at a power density of 32 000 W kg-1 and a current density of 8 A g-1. The 81.6% capacitance retention maintained after 1000 cycles revealed the acceptable cycling capacity of the proposed supramolecular supercapacitor system, which demonstrated good performance even at a low temperature of -20 °C.

A high-sensitive sensor with HEPES-enhanced electrochemiluminescence of benzo[3]uril for Fe3+ and its application in human serum.

An electrochemiluminescence (ECL) sensor based on a benzo[3]uril-modified glassy carbon electrode with sensitized luminescence, with the coexistence of 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as the coreactant, was successfully constructed. The sensitization mechanism was proposed by analyzing the results of the control experiments for establishing the relationship of the luminescence effect with the concentration of HEPES. Under the optimized conditions, the fabricated sensor system was applied for the detection of Fe3+ in an aqueous solution with good sensitivity and selectivity. A low detection limit of 0.41 nM was achieved, indicating superior sensor performance over the previous analytical methods. The ECL sensor system was employed for the detection of Fe3+ in human serum samples to produce excellent recoveries ranging from 96.17% to 101.81%.

A fluorescence-enhanced chemosensor based on multifarene[2,2] and its recognition of metal cations.

A selective and sensitive fluorescent chemosensor based on an anthracene-functionalized triazole-linked multifarene[2,2] was successfully synthesized and investigated with regard to the recognition of metal ions using fluorescence spectroscopy, 1H NMR titration, and IR spectroscopy. The proposed sensor exhibited desirable properties for potential fluorescence enhanced chemosensor applications, including selective affinity and low Zn2+ and Cd2+ detection limits compared with other metal ions. Quantum chemical calculations described the synthesized chemosensor's static structure and its coordination to Zn2+ and Cd2+. Frontier molecular orbital distribution and energy changes suggested a possible mechanism for increased receptor fluorescence intensity with Zn2+ and Cd2+ addition.

Recent Breakthroughs in Supercapacitors Boosted by Macrocycles.

Supercapacitors are essential for electrochemical energy storage because of their high-power density, good cycle stability, fast charging and discharging rates, and low maintenance cost. Macrocycles, including cucurbiturils, calixarene, and cyclodextrins, are cage-like organic compounds (with a nanocavity that contains O and N heteroatoms) with unique potential in supercapacitors. Here, we review the applications of macrocycles in supercapacitor systems, and we illustrate the merits of organic macrocycles in electrodes and electrolytes for improving the electrochemical double-layer capacitors and pseudocapacitance via supramolecular strategies. Then, the observed relationships between electrochemical performance and macrocyclic structures are introduced. This comprehensive review describes recent progress on macrocycle-block supercapacitors for researchers.