PtII−N‐Heterocyclic Carbene Complexes in Solvent‐Free Alkene Hydrosilylation

Herein, we report the catalytic activity of a series of platinum(II) pre‐catalysts, bearing N‐heterocyclic carbene (NHC) ligands, in the alkene hydrosilylation reaction. Their structural and electronic properties are fully investigated using X‐ray diffraction analysis and nuclear magnetic resonance spectroscopy (NMR). Next, our study presents a structure‐activity relationship within this group of pre‐catalysts and gives mechanistic insights into the catalyst activation step. An exceptional catalytic performance of one of the complexes is observed, reaching a turnover number (TON) of 970 000 and a turnover frequency (TOF) of 40 417 h−1 at 1 ppm catalyst loading. Finally, an attractive solvent‐free and open‐to‐air alkene hydrosilylation protocol, featuring efficient platinum removal (reduction of residual Pt from 582 ppm to 5.8 ppm), is disclosed. Pt(II)−NHC complexes are used in alkene hydrosilylation reactions. Some of the examined compounds display excellent catalytic activity, outperforming Pt(0)−NHC pre‐catalysts. Our study explores the catalyst structure‐activity relationship and provides new mechanistic insights into this industrially important transformation. A sustainable protocol, featuring efficient platinum removal, allows us to access a series of organosilanes in very good to excellent yields.