Electrophilic attack on [Cp*Cl(PPh3)Ru(CCHR)]:: Carbyne formation vs chloride abstraction

The course of electrophilic addition to the ruthenium(II) chloro vinylidenes [Cp*Cl(PPh3)Ru(CCHR)] is influenced by the steric properties of the electrophile and ruthenium complex. Thus, H+ selectively adds to C-beta of the vinylidene ligand to yield the ruthenium(IV) carbynes [Cp*Cl(PPh3)Ru(CCH2R)][A] (A = BF4-, BAr4f-), while the comparably larger Me+ (from MeOTf) abstracts Cl- to yield, after anion coordination, [Cp*(OTf)(PPh3)Ru(CCHR)] and MeCl.