Formation of platinum allyl and propargyl complexes from protonation of platinum enyne and diyne complexes

Article abstract of DOI:10.1016/s0020-1693(97)05640-5

Protonation of (Ph₃P)₂Pt[η²-HC=CC(CH₃) =CH₂] (2a) with excess HBF₄·Et₂O produced the π-allyl complex (Ph₃P)₂Pt[η³-H₂C=CC(CH ₃)=CH₂] ⁺BF₄^- (3a-BF₄) instead of a π-propargyl complex. Reaction of excess CF3CO₂H with 2a initially produced the analogous π-allyl complex 3a-CF₃CO₂ which then added CF₃CO₂H across the vinylidene unit of 3a-CF₃CO₂ to give the π-allyl complex (Ph₃P)₂Pt[η³-CH₃C(CF ₃CO₂)C(CH₃)CH₂]⁺CF ₃CO₂^- (5a). Protonation of the platinum diyne complex [(p-CH₃-C₆H₄)₃P] ₂Pt(η²-CH₃C≡CC≡CCH₃) (7b) with HBF₄·Et₂O at -73°C initially produced the platinum hydride complex trans-[(p-CH₃-C₆H₄)₃P] ₂-PtH(η²-CH₃C ≡ CC ≡ CCH₃) ⁺BF₄^- (9), which rearranged to the platinum π-propargyl complex [(p-CH₃-C₆H₄)₃P] ₂Pt[η³-(CH₃CH=)-CC ≡ CCH₃]⁺BF₄^- (11) at -28°C.