Interfacial Transmetallation Synthesis of Platinadithiolene Nanosheet as a Potential 2D Topological Insulator

Weaving two-dimensional metal complex material is fascinating because of its structural and functional diversity. We have previously reported the synthesis of electroconductive nickelladithiolene (NiDT) and palladadithiolene (PdDT) nanosheets using benzenehexathiol (BHT). Down the group from Ni, Pd to Pt, there is a distinct positive shift in the reduction potential, as a result, synthetically, it becomes more challenging to stabilize Pt2+ than formation of metallic Pt(0) in the presence of BHT acting as a reducing agent. Here, we report the novel synthetic strategy for platinadithiolene nanosheet (PtDT) using a dibutyltin-protected BHT ligand, leading to transmetallation in the presence of dioxygen. Both free-standing stacked sheets and atomic layer sheets were obtained and characterized by microscopic techniques such as AFM, SEM, and TEM. To study the morphology of the sheets and determine their charge neutrality, X-ray photoelectron (XP) and infrared (IR) spectroscopic techniques were used. Powder X-ray diffraction analysis of multilayer PtDT indicates a half-way slipped hexagonal configuration in P3 @#x0305;1m space group. Band structure of this PtDT exhibits an existence of band gap at the Fermi level, which is different from NiDT in the staggered configuration, and an existence of Dirac gap indicating a possibility of 2D topological insulator at room temperature. PtDT is insulating but chemically activated by oxidation with I2 to increase the conductivity by more than 106 folds up to 0.39 S cm-1. MDT sheets exhibit electrocatalytic activity for hydrogen evolution reaction; the activity order is NiDT < PdDT < PtDT.