Russian-Doll-Like Porous Carbon as Anode Materials for High-Performance Potassium-Ion Hybrid Capacitors.

Pore-structure design with the sophisticated and pragmatic nanostructures still remains a great challenge. In this work, porous carbon with Russian-doll-like pores rather than traditional single modal is fabricated via a boiling carbonization approach, accompanied by K+ -pre-intercalation. The most important internal factor is that alkali can penetrate into the stereoscopic space of layered Malonic acid dihydrazide and the confinement effect leads to the in-depth development of different dimensional pore structures. The oxygenated and nitrogenated surface guarantees the K+ intercalation behavior. Benefiting from their open framework and enlarged interlayer spacing, K+ -pre-intercalated porous carbon with Russian-doll-like pores (denoted as KPCRPs) as anode material exhibits promising potassium storage performance. The assembled KPCRP//activated carbon potassium-ion hybrid supercapacitor in 30 m CH3 COOK displays a high energy density of 157.29 Wh kg-1 , an ultrahigh power output of 14 kW kg-1 , and a long cycling life (99.58% capacity retention after 10000 cycles), highlighting the superiority of Russian-doll-like pore structure. This work sheds light on the designing of 3D pores structure, especially for multimodal pore architectures.

[4 + 2] Annulation of 3-Nitroindoles with Alkylidene Malononitriles: Entry to Substituted Carbazol-4-amine Derivatives.

A general and transition-metal-free method for the construction of the carbazol-4-amine motif via a vinylogous Michael addition/cyclization/isomerization/elimination reaction of 3-nitroindoles with alkylidene malononitriles has been developed. This novel methodology allows the facile synthesis of a series of di- and trisubstituted carbazol-4-amine derivatives in moderate to good yields. A gram-scale experiment was successfully performed, highlighting the practicability of this method. Moreover, this strategy is also applicable to 3-nitrobenzothiophene, affording the corresponding dibenzo[ b, d]thiophen-1-amine derivatives in moderate yields.

One-Pot Synthesis of Benzene-Fused Medium-Ring Ketones: Gold Catalysis-Enabled Enolate Umpolung Reactivity.

Enolate umpolung reactivities offer valuable and potentially unique alternatives over the enolate counterparts for the construction of ubiquitous carbonyl compounds. We disclose here that N-alkenoxypyridinium salts, generated readily upon gold-catalyzed additions of protonated pyridine N-oxide to C-C triple bonds of unactivated terminal alkynes, display versatile enolate umpolung chemistry upon heating and react with tethered arene nucleophiles in an SN2' manner. In a synthetically efficient one-pot, two-step process, this chemistry enables expedient preparation of valuable benzo-fused seven-/eight-membered cyclic ketones, including those of O-/N-heterocycles, from easily accessible aryl-substituted linear alkyne substrates. The reaction yields can be up to 87%.

DABCO-based ionic liquids: recyclable catalysts for aza-Michael addition of α,ß-unsaturated amides under solvent-free conditions.

An array of novel 1,4-diazobicyclo[2.2.2]octane (DABCO) based ionic liquids were developed and used as recyclable catalysts for the aza-Michael addition at room temperature without any organic solvent. [DABCO-PDO][OAc] was found to be the most efficient catalyst, and the amount of catalyst was only 10 mol %. Various amines reacted with a wide range of α,ß-unsaturated amides, smoothly affording target products in good to excellent yields within hours. Moreover, the catalyst could be reused up to eight times, still maintaining a high catalytic activity. Finally, a plausible mechanism was proposed. FTIR and computational chemistry were used to verify the catalytic mechanism.

An environmentally benign protocol for aqueous synthesis of tetrahydrobenzo[b]pyrans catalyzed by cost-effective ionic liquid.

A mild, efficient, and environmentally benign protocol for the synthesis of tetrahydrobenzo[b]pyran derivatives in the presence of readily accessible, biodegradable, and choline hydroxide based ionic liquid as catalyst has been established. The key features of the reported methodology include good to excellent yields of desired products, simple work-up procedure and good recyclability of catalysts, which may be a practical alternative to the existing conventional processes for the preparation of 4-H pyrans to cater to the requirements of academia as well as industry.

Fabrication of core-shell-like structured polymeric ionic liquid hybrid catalysts for aqueous reactions.

Core-shell-like structured polymeric ionic liquid hybrid nanoreactors with "internal hydrophobic-external hydrophilic" characteristics were successfully synthesized through the Stöber method and reversible addition-fragmentation chain transfer (RAFT) polymerization. Firstly, we introduced hydrophobic organosilicon as an inner core and fixed Pd nanoparticles (∼0.69 mmol g-1) in the pore and finally constructed a hydrophilic shell, which not only ensured the dispersity of the catalyst in water but also effectively prevented the leaching of Pd species. The structure and properties of nMIE@Pd/SiNP-CPDB were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption, ICP-OES, thermogravimetric analysis (TGA) and ultraviolet and visible spectrophotometry (UV-vis) characterization methods. The adsorption enthalpy of the best catalyst for styrene was calculated using the Clausius-Clapeyron equation and the value was -12.765 kJ mol-1, which strongly verified that the prepared catalyst could effectively promote mass transfer and the adsorption of reactants or products. Furthermore, the as-prepared nanoreactors exhibit distinguished catalytic activity for aqueous hydrogenation reactions and even after 7 cycles, the catalysts still maintain their superior catalytic activity, showing almost no leaching of palladium species.

Investigation of the mechanism of small size effect in carbon-based supercapacitors.

A small size effect could be conducive to enhancing the electrochemical performance, while the mechanism by which they also increase the capacitance for carbon electrode materials has not been established. Here, ultrasmall polyacrylonitrile particles with controllable sizes are supported on poly(ionic liquid)s microspheres (PILMs/PAN) by epitaxial polymerization growth strategy. Unlike traditional subtraction formulas in developing a porous architecture, we report on the synthesis of creating numerous micro/mesopores in carbon materials by addition theorem, and thus making for the perfection of packing density, which has not been reported yet. As an example, PILMC/PAN-L with a well-balanced specific surface area of 875.38 m2 g-1 and packing density of 1.05 g cm-3 demonstrated gravimetric and volumetric capacitances of 309 F g-1 and 324.45 F cm-3 at 0.5 A g-1, showing good rate performance and stable cyclability. Moreover, the underlying mechanism is thoroughly developed using multiple electrochemical methods. On this basis, this work would afford avenues to further enhancing the electrochemical performance, especially in exploring advanced carbon materials.