Angewandte Chemie International Edition · 2017 · 15 citations · 69 references
Complex [PtMe<sub>2</sub> (PMe<sub>2</sub> ArDipp2 )] (1), which contains a tethered terphenyl phosphine (ArDipp2 =2,6-(2,6-<sup>i</sup> Pr<sub>2</sub> C<sub>6</sub> H<sub>3</sub> )<sub>2</sub> C<sub>6</sub> H<sub>3</sub> ), reacts with [H(Et<sub>2</sub> O)<sub>2</sub> ]BAr<sub>F</sub> (BAr<sub>F</sub><sup>-</sup> =B[3,5-(CF<sub>3</sub> )<sub>2</sub> C<sub>6</sub> H<sub>3</sub> ]<sub>4</sub><sup>-</sup> ) to give the solvent (S) complex [PtMe(S)(PMe<sub>2</sub> ArDipp2 )]<sup>+</sup> (2⋅S). Although the solvent molecule is easily displaced by a Lewis base (e.g., CO or C<sub>2</sub> H<sub>4</sub> ) to afford the corresponding adducts, treatment of 2⋅S with C<sub>2</sub> H<sub>2</sub> yielded instead the allyl complex [Pt(η<sup>3</sup> -C<sub>3</sub> H<sub>5</sub> )(PMe<sub>2</sub> ArDipp2 )]<sup>+</sup> (6) via the alkyne intermediate [PtMe(η<sup>2</sup> -C<sub>2</sub> H<sub>2</sub> )(PMe<sub>2</sub> ArDipp2 )]<sup>+</sup> (5). Deuteration experiments with C<sub>2</sub> D<sub>2</sub> , and kinetic and theoretical investigations demonstrated that the conversion of 5 into 6 involves a Pt<sup>II</sup> -promoted HC≡CH to :C=CH<sub>2</sub> tautomerization in preference over acetylene migratory insertion into the Pt-Me bond.
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