C–H and P–C(Ph) activation competitive processes caused by interaction with the solvate [cis-Pt(C6F5)2(thf)2]

Abstract

The study of the reaction between the ethylene [Pt(η²-H₂CCH₂)(PPh₃)₂] or alkyne [Pt(η²-HC≡CR)(PPh₃)₂] (R = SiMe₃1, Bu^t2) complexes with [cis-Pt(C₆F₅)₂(thf)₂] (thf = tetrahydrofuran) has enabled us to observe the existence of competitive processes between the activation of a P–C(Ph) bond on the PPh₃ ligand, to give the binuclear derivative [cis-(C₆F₅)₂Pt(µ-Ph)(µ-PPh₂)Pt(PPh₃)] 3, and the activation of a C–H bond of the unsaturated group, to give the corresponding (µ-hydride)(µ-vinyl) [cis,cis-(PPh₃)₂Pt(µ-H)(µ-1κC^α:η²-CHCH₂)Pt(C₆F₅)₂] 4 or (µ-hydride)(µ-alkynyl) [cis,cis-(PPh₃)₂Pt(µ-H)(µ-1κC^α:η²-C≡CR)Pt(C₆F₅)₂] (R = SiMe₃5, Bu^t6) compounds, respectively. The monitoring of these reactions by NMR spectroscopy has allowed us to detect several intermediates, and to propose a mechanism for the C–H bond activation. In addition, the structures of the (µ-hydride)(µ-alkynyl) complex 5 and the unprecedented (µ-hydride)(µ-vinyl) derivative 4 have been obtained by X-ray crystallographic analyses.