Genesis of electron deficient Pt1(0) in PDMS-PEG aggregates

Abstract

While numerous single atoms stabilized by support surfaces have been reported, the synthesis of in-situ reduced discrete metal atoms weakly coordinated and stabilized in liquid media is a more challenging goal. We report the genesis of mononuclear electron deficient Pt₁(0) by reducing H₂PtCl₆ in liquid polydimethylsiloxane-polyethylene glycol (PDMS-PEG) (Pt₁@PDMS-PEG). UV–Vis, far-IR, and X-ray photoelectron spectroscopies evidence the reduction of H₂PtCl₆. CO infrared, and ¹⁹⁵Pt and ¹³C NMR spectroscopies provide strong evidence of Pt₁(0), existing as a pseudo-octahedral structure of (R¹OR²)₂Pt(0)Cl₂H₂ (R¹ and R² are H, C, or Si groups accordingly). The weakly coordinated (R¹OR²)₂Pt(0)Cl₂H₂ structure and electron deficient Pt₁(0) have been validated by comparing experimental and DFT calculated ¹⁹⁵Pt NMR spectra. The H⁺ in protic state and the Cl⁻ together resemble HCl as the weak coordination. Neutralization by a base causes the formation of Pt nanoparticles. The Pt₁@PDMS-PEG shows ultrahigh activity in olefin hydrosilylation with excellent terminal adducts selectivity.

Synthesis of discrete reduced metal atoms weakly coordinated and stabilized in liquid media remains challenging. Here, the authors report the genesis of mononuclear electron deficient Pt1(0) in polydimethylsiloxane-polyethylene glycol aggregates, and its ultrahigh activity in olefin hydrosilylation with excellent terminal adducts selectivity.