Platinum allenylidene complexes and formation of platinum and palladium acetonitrile alkynyl complexes

► Oxidative addition of bromoalkynes to [Pt(PPh3)4] is solvent-dependent. ► Reaction of [Br(PPh3)2PtCCC(O)R] with MeOTf is strongly R-dependent. ► For R=NR∗2 alkylation with MeOTf/CH2Cl2 gives allenylidene complexes. ► For R = OMenthyl reaction with MeOTf/MeCN gives trans-alkynyl-MeCN complexes.