Gel electrolytes have attracted increasing attention for solid-state supercapacitors. An ideal gel electrolyte usually requires a combination of advantages of high ion migration rate, reasonable mechanical strength and robust water retention ability at the solid state for ensuring excellent work durability. Here we report a zwitterionic gel electrolyte that successfully brings the synergic advantages of robust water retention ability and ion migration channels, manifesting in superior electrochemical performance. When applying the zwitterionic gel electrolyte, our graphene-based solid-state supercapacitor reaches a volume capacitance of 300.8 F cm−3 at 0.8 A cm−3 with a rate capacity of only 14.9% capacitance loss as the current density increases from 0.8 to 20 A cm−3, representing the best value among the previously reported graphene-based solid-state supercapacitors, to the best of our knowledge. We anticipate that zwitterionic gel electrolyte may be developed as a gel electrolyte in solid-state supercapacitors.

The transition-metal-free hydroboration of various alkenes with pinacolborane (HBpin) initiated by tris[3,5-bis(trifluoromethyl)phenyl]borane (BAr ) is reported. The choice of the boron Lewis acid is crucial as the more prominent boron Lewis acid tris(pentafluorophenyl)borane (B(C F ) ) is reluctant to react. Unlike B(C F ) , BAr is found to engage in substituent redistribution with HBpin, resulting in the formation of Ar Bpin and the electron-deficient diboranes [H BAr ] and [(Ar )(H)B(μ-H) BAr ]. These in situ-generated hydroboranes undergo regioselective hydroboration of styrene derivatives as well as aliphatic alkenes with cis diastereoselectivity. Another ligand metathesis of these adducts with HBpin subsequently affords the corresponding HBpin-derived anti-Markovnikov adducts. The reactive hydroboranes are regenerated in this step, thereby closing the catalytic cycle.

In the electrophilic C-H borylation of electron-rich aromatic compounds with catecholborane, the catalytic generation of the boron electrophile is initiated by heterolysis of the B-H bond by various Lewis and Brønsted acids, with a boronium ion formed exclusively. After ligand dissociation, the corresponding borenium ion undergoes regioselective electrophilic aromatic substitution on aniline derivatives as well as nitrogen-containing heterocycles. The catalysis is optimized using B(C F ) as the initiator and proceeds without the addition of an external base or dihydrogen acceptor. Temperatures above 80 °C are generally required to secure efficient turnover in these Friedel-Crafts-type reactions. Mechanistic experiments reveal that regeneration of the boronium/borenium ion with dihydrogen release is rate-determining. This finding finally led to the discovery that, with added alkenes, catalytic C-H borylations can, for the first time, be carried out at room temperature.

A ruthenium/C-TunePhos catalytic system has been identified for highly efficient direct reductive amination of simple ketones. The strategy makes use of ammonium acetate as the amine source and H as the reductant and is a user-friendly and operatively simple access to industrially relevant primary amines. Excellent enantiocontrol (>90% ee for most cases) was achieved with a wide range of alkyl aryl ketones. The practicability of this methodology has been highlighted by scalable synthesis of key intermediates of three drug molecules. Moreover, an improved synthetic route to the optimal diphosphine ligand C-TunePhos is also presented.

The rarely used boron Lewis acid tris [3,5-bis-(trifluoromethyl)phenyl]borane (BAr F 3 ) is found to be an excellent catalyst for metal-free hydroboration of imines. In the presence of 1.0 mol % of BAr F 3 , several ketimines and aldimines undergo hydroboration with pinacolborane (HBpin) at room temperature without the aid of an external Lewis base. BAr F 3 is more reactive than other Lewis acidic boranes, including the often-used tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 ). The steric hindrance imparted by the six fluorine atoms ortho to the boron center in B(C 6 F 5 ) 3 accounts for this. Mechanistic control experiments indicate conventional Lewis acid catalysis involving imine activation and hydride transfer from HBpin.