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 Pt(1)(0) by reducing H(2)PtCl(6) in liquid polydimethylsiloxane-polyethylene glycol (PDMS-PEG) (Pt(1)@PDMS-PEG). UV-Vis, far-IR, and X-ray photoelectron spectroscopies evidence the reduction of H(2)PtCl(6). CO infrared, and (195)Pt and (13)C NMR spectroscopies provide strong evidence of Pt(1)(0), existing as a pseudo-octahedral structure of (R(1)OR(2))(2)Pt(0)Cl(2)H(2) (R(1) and R(2) are H, C, or Si groups accordingly). The weakly coordinated (R(1)OR(2))(2)Pt(0)Cl(2)H(2) structure and electron deficient Pt(1)(0) have been validated by comparing experimental and DFT calculated (195)Pt 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 Pt(1)@PDMS-PEG shows ultrahigh activity in olefin hydrosilylation with excellent terminal adducts selectivity.