Porous poly(aryleneethynylene) networks have been prepared through alkyne metathesis and their porosities and adsorption properties towards common aromatic solvents have been investigated.
Two p-type phenoxazine-based COFs with high discharge potentials (up to 3.6 V vs. Li/Li+) were achieved as directly usable cathode materials with superior active-site accessibility, ultrafast redox kinetics, and remarkable cycling stability.
Pyrene‐4,5,9,10‐tetraone (PTO), a coal tar derivative with redox‐active ortho‐carbonyl groups, has been intensively explored for sustainable organic electrodes due to its remarkably high capacity, superior redox robustness, and versatile cation storage. However, PTO often suffers from poor cycling stability due to its being soluble in organic electrolytes, which results in a detrimental shuttle effect and self‐discharge behavior. Its low electrical conductivity also results in poor rate performance, limiting practical applications. Therefore, different strategies have recently been developed to inhibit the solubility of PTO. In this review, the latest progress in enhancing the performance of PTO‐based electrodes and their applications in various battery types is presented. Firstly, a brief discussion on the relationship between the structural characteristics of PTO and its electrochemical performance is provided. Then, approaches to inhibiting the shuttle effect of molecular PTO are outlined and compared. Furthermore, the design and synthesis of PTO‐based polymer electrode materials are discussed. Finally, some perspectives and challenges are put forward regarding the performance improvement of PTO‐based electrode materials, inspiring further development of not only PTO but also other organic electrode materials in electrochemical energy storage applications.
Abstract A series of triphenolsilane‐coordinated molybdenum(VI) propylidyne catalysts has been developed, which are resistant to small alkyne polymerization and compatible with various functional groups (including phenol substrates). The catalysts remain active in solution for days at room temperature (months at −30 °C). The catalysts are also compatible with 5 Å molecular sieves (small alkyne scavengers), and have enabled the homodimerization of small alkyne substrates at 40–70 °C in a closed system, with dimer products being obtained in 76–96% yields. A shape‐persistent aryleneethynylene macrocycle ( 11 ) was also prepared on a gram scale with 0.5 mol% catalyst loading, in almost quantitative yield.
Calix[6]arene (CX6) was found to be an efficient ion transmembrane channel, which could be blocked by methylene blue (MB) through host-guest interactions. The blocked CX6 channel could be reopened by 4-sulfonated calix[6]arene owing to its stronger affinity with MB, thereby achieving a reversible ON-OFF-ON type switch.
A novel type of ionic covalent organic framework (ICOF), which contains sp(3) hybridized boron anionic centers and tunable countercations, was constructed by formation of spiroborate linkages. These ICOFs exhibit high BET surface areas up to 1259 m(2) g(-1) and adsorb a significant amount of H2 (up to 3.11 wt %, 77 K, 1 bar) and CH4 (up to 4.62 wt %, 273 K, 1 bar). Importantly, the materials show good thermal stabilities and excellent resistance to hydrolysis, remaining nearly intact when immersed in water or basic solution for two days. The presence of permanently immobilized ion centers in ICOFs enables the transportation of lithium ions with room-temperature lithium-ion conductivity of 3.05×10(-5) S cm(-1) and an average Li(+) transference number value of 0.80±0.02. Our approach thus provides a convenient route to highly stable COFs with ionic linkages, which can potentially serve as absorbents for alternative energy sources such as H2, CH4, and also as solid lithium electrolytes/separators for the next-generation lithium batteries.
Novel polydiacetylenes (PDAs) bearing alkyl and phenyl substituents have been synthesized, for the first time, by solution polymerization using acyclic enediyne metathesis. The resulting polymers are soluble in common organic solvents and show distinct physical and photophysical properties both in solution and as thin films, caused by different steric and electronic effects from the side-groups. Bulk heterojunction solar cells employing these PDAs have been fabricated and evaluated.
This study successfully synthesized two distinct covalent organic frameworks (COFs): the rigid DAPO-TFPT-COF and the flexible DAPO-TFPC-COF. Both COFs boast high crystallinity, large specific surface area, and uniform pores. A...
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