Efficient Nitrate-to-Ammonia Electroreduction at Cobalt Phosphide Nanoshuttles.

The nitrate electroreduction reaction (NO3--ERR) is an efficient and green approach for nitrate remediation, which requires a highly active and selective electrocatalyst. In this work, porous and amorphous cobalt phosphide nanoshuttles (CoP PANSs) are successfully synthesized by using Mg2+ ion-doped calcium carbonate nanoshuttles (Mg-CaCO3 NSs) as the initial reaction precursor via precipitation transformation and a high-temperature phosphidation strategy. Various physical characterizations show that CoP PANSs have porous architecture, amorphous crystal structure, and big surface area. Electrochemical measurements reveal for the first time that CoP PANSs have outstanding electroactivity for NO3--ERR in a neutral electrolyte. At an applied potential of -0.5 V vs reversible hydrogen electrode, CoP PANSs can achieve a high Faraday efficiency (94.24 ± 2.8%) and high yield rate (19.28 ± 0.53 mg h-1 mgcat-1) for ammonia production, which exceeds most reported values at various electrocatalysts for NO3--ERR. Thus, the present result indicates that cobalt phosphide nanomaterials have promising application for NO3--ERR.

Secondary phosphine oxides stabilized Au/Pd nanoalloys: metal components-controlled regioselective hydrogenation toward phosphinyl (Z)-[3]dendralenes.

A series of gold/palladium nanoalloys stabilized by secondary phosphine oxides have been prepared for the first time. The nanocatalysts exhibit excellent regio- and chemo-selectivity in the hydrogenation of conjugated enynes, providing a mild and highly efficient way to access phosphinyl (Z) and (Z,Z)-[3]dendralenes.

Cascade Alkynylation and Highly Selective Hydrogenation Catalyzed by Binaphthyl-Palladium Nanoparticles Accessing Phosphinyl (Z)-[3]Dendralenes.

A cascade alkynylation and selective hydrogenation catalyzed by covalent binaphthyl-stabilized palladium nanoparticles has been established, providing a novel and highly efficient methodology for accessing Z and Z,Z-selective phosphinyl [3]dendralenes with broad functional group tolerance and good yields. This strategy achieves the first cascade reactions of alkynylation and hydrogenation with chemoselectivity modulated by catalyst loading.

tert-Butyl nitrite-mediated radical cyclization of tetrazole amines and alkynes toward tetrazolo[1,5-a]quinolines.

A general and efficient radical cyclization of 1H-tetrazol-5-amines and alkynes toward tetrazolo[1,5-a]quinolines is established for the first time. The annulation mediated by tert-butyl nitrite takes place expeditiously within 10 minutes under mild conditions. Without using external additives or excitation, the tetrazolo[1,5-a]quinoline derivatives are obtained in moderate to good yields, along with high regioselectivities for unsymmetrical alkynes and broad functional tolerance features. The reaction is exemplified to occur via a radical process, with aryl radicals synergistically generated from tert-butyl nitrite, water and tetrazolate-diazonium salts.