Bis(aminothiolato)nickel nanosheet as a redox switch for conductivity and an electrocatalyst for the hydrogen evolution reaction.

A π-conjugated coordination nanosheet comprising bis(aminothiolato)nickel ( NiAT ) moieties was synthesized by the reaction of Ni(acac)2 with 1,3,5-triaminobenzene-2,4,6-trithiol at liquid-liquid and gas-liquid interfaces. The sheet thickness could be controlled down to a single layer (0.6 nm). Selected area electron diffraction and grazing incidence X-ray diffraction analyses indicated the formation of a flat crystalline sheet with a kagome lattice stacked in a staggered alignment. NiAT was reversibly interconverted to a bis(iminothiolato)nickel ( NiIT ) nanosheet by the chemical 2H+ -2e- reaction, which was accompanied by a drastic change in electrical conductivity from 3 × 10-6 to 1 × 10-1 S cm-1 . This change in conductivity was explained by the difference in band structures between NiAT and NiIT . NiAT acted as an efficient electrocatalyst for the hydrogen evolution reaction, showing strong acid durability and an onset overpotential of -0.15 V.