Bypassing a highly unstable frustrated Lewis pair: dihydrogen cleavage by a thermally robust silylium–phosphine adduct

Abstract

The thermally robust silylium complex [iPr₃Si–PtBu₃]⁺[B(C₆F₅)₄]⁻ (1) activates H₂/D₂ at 90 °C (PhCl); no evidence for dissociation into the separated Lewis pair is found. DFT calculations show H₂ cleavage proceeds via Si–P bond elongation to form an encounter complex directly from the adduct, thus avoiding the non-isolable iPr₃Si⁺–PtBu₃ FLP.