220056-87-1Relevant academic research and scientific papers
A Study of the Mechanism of Platinum(II)/Tin(II) Dichloride Mediated Hydrogenation of Alkynes and Alkenes Employing Parahydrogen-Induced Polarization
Deibele, Christina,Permin, Alexei B.,Petrosyan, Valery S.,Bargon, Joachim
, p. 1915 - 1923 (1998)
The mechanism of hydrogenation of alkynes catalyzed by the [(PR3)2PtHX]/SnX2 system (PR3 = PPh3, PMePh2; X = Cl, Br) has been studied by means of parahydrogen-induced polarization of 1H spectra (PHIP). Dihydride intermediates confirming the stepwise hydrogenation at room temperature were observed when the reaction was run in acetone. The obtained 1H-PHIP spectra, together with NMR data for related species, are consistent with the formulation of these intermediates as cis-[H2Pt(PR3)(SnX 3)(σ-alkenyl)(acetone)], where the σ-alkenyl ligand originates from an insertion reaction of the alkyne (1-phenyl-1-propyne, 1-phenyl-1-butyne, diphenylacetylene, 3,3-dimethylbutyne). At elevated temperatures, the hydrogenation in acetone proceeds as a cis-synchronous transfer of the two hydrogen atoms of parahydrogen to the substrate molecule. A mechanism for this synchronous hydrogenation is suggested.
