Cyclooctatetraene-Embedded Carbon Nanorings.

With the prosperity of the development of carbon nanorings, certain topologically or functionally unique units-embedded carbon nanorings have sprung up in the past decade. Herein, we report the facile and efficient synthesis of three cyclooctatetraene-embedded carbon nanorings (COTCNRs) that contain three (COTCNR1 and COTCNR2) and four (COTCNR3) COT units in a one-pot Yamamoto coupling. These nanorings feature hoop-shaped segments of Gyroid (G-), Diamond (D-), and Primitive (P-) type carbon schwarzites. The conformations of the trimeric nanorings COTCNR1 and COTCNR2 are shape-persistent, whereas the tetrameric COTCNR3 possesses a flexible carbon skeleton which undergoes conformational changes upon forming host-guest complexes with fullerenes (C60 and C70), whose co-crystals may potentially serve as fullerene-based semiconducting supramolecular wires with electrical conductivities on the order of 10-7 S cm-1 (for C60⊂COTCNR3) and 10-8 S cm-1 (for C70⊂COTCNR3) under ambient conditions. This research not only describes highly efficient one-step syntheses of three cyclooctatetraene-embedded carbon nanorings which feature hoop-shaped segments of distinctive topological carbon schwarzites, but also demonstrates the potential application in electronics of the one-dimensional fullerene arrays secured by COTCNR3.

Soluble and Processable Single-Crystalline Cationic Polymers.

Single-crystal-to-single-crystal (SCSC) polymerization offers an effective protocol for the environmentally friendly preparation of polymer single crystals (PSCs) with extremely high crystallinity and very large molecular weights. Single-crystal X-ray diffraction (SCXRD) serves as a powerful technique for the in-depth characterization of their structures at a molecular level. Hence, a fundamental understanding of the structure-property relationships of PSCs is within our reach. Most of the reported PSCs, however, suffer from poor solubility, a property which hampers their post-functionalization and solution processability when it comes to practical applications. Here, we report soluble and processable PSCs with rigid polycationic backbones by taking advantage of an ultraviolet-induced topochemical polymerization from an elaborately designed monomer that results in a multitude of photoinduced [2 + 2] cycloadditions. The high crystallinity and excellent solubility of the resulting polymeric crystals enable their characterization both in the solid state by X-ray crystallography and electron microscopy and in the solution phase by NMR spectroscopy. The topochemical polymerization follows first-order reaction kinetics to a first approximation. Post-functionalization of the PSCs by anion exchange renders them super-hydrophobic materials for water purification. Solution processability endows PSCs with excellent gel-like rheological properties. This research represents a major step towards the controlled synthesis and full characterization of soluble single-crystalline polymers, which may find application in the fabrication of PSCs with many different functions.

Tremella-like Hydrated Vanadium Oxide Cathode with an Architectural Design Strategy toward Ultralong Lifespan Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising systems for energy storage due to their operational safety, low cost, and environmental friendliness. However, the development of suitable cathode materials is plagued by the sluggish dynamics of Zn2+ with strong electrostatic interaction. Herein, an Al3+-doped tremella-like layered Al0.15V2O5·1.01H2O (A-VOH) cathode material with a large pore diameter and high specific surface area is demonstrated to greatly boost electrochemical performance as ZIB cathodes. Resultant ZIBs with a 3 M Zn(CF3SO3)2 electrolyte deliver a high specific discharge capacity of 510.5 mAh g-1 (0.05 A g-1), and an excellent energy storage performance is well maintained with a specific capacity of 144 mAh g-1 (10 A g-1) even after ultralong 10,000 cycles. The decent electrochemical performance roots in the novel tremella-like structure and the interlayer of Al3+ ions and water molecules, which could improve the electrochemical reaction kinetics and structural long cycle stability. Furthermore, the assembled coin-type cells could power a light-emitting diode (LED) lamp for 2 days. We believed that the design philosophy of unique morphology with abundant active sites for Zn2+ storage will boost the development of competitive cathodes for high-performance aqueous batteries.