Nickel-Mediated Trifluoromethylation of Phenol Derivatives by Aryl C-O Bond Activation.

The increasing pharmaceutical importance of trifluoromethylarenes has stimulated the development of more efficient trifluoromethylation reactions. Tremendous efforts have focused on copper- and palladium-mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel-mediated trifluoromethylation of phenol derivatives with readily available trimethyl(trifluoromethyl)silane (TMSCF3 ). The strategy relies on PMe3 -promoted oxidative addition and transmetalation, and CCl3 CN-induced reductive elimination. The broad utility of this transformation has been demonstrated through the direct incorporation of trifluoromethyl into aromatic and heteroaromatic systems, including biorelevant compounds.

Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes.

Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm-2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.

Reduced graphene oxide anchoring CoFe2O4 nanoparticles as an effective catalyst for non-aqueous lithium-oxygen batteries.

CoFe2O4 nanoparticles were uniformly anchored on reduced graphene oxide by a facile solvothermal method. The obtained CoFe2O4/reduced graphene oxide (CoFe2O4/rGO) hybrid was employed as catalyst for Li-O2 batteries. It could effectively lower the ORR (oxygen reduction reaction) and OER (oxygen evolution reaction) overpotentials of the batteries and deliver a large capacity of 12 235 mA h grGO(-1) (2116 mA h ghybrid(-1)). It also exhibited high cyclic stability.