Electrophilic Attack on [Cp*Cl(PPh<INF>3</INF>)Ru(CCHR)]:  Carbyne Formation vs Chloride Abstraction

The course of electrophilic addition to the ruthenium(II) chloro vinylidenes [Cp*Cl(PPh<INF>3</INF>)Ru(CCHR)] is influenced by the steric properties of the electrophile and ruthenium complex. Thus, H⁺ selectively adds to C<INF>β</INF> of the vinylidene ligand to yield the ruthenium(IV) carbynes [Cp*Cl(PPh<INF>3</INF>)Ru(CCH<INF>2</INF>R)][A] (A = BF<INF>4</INF>^-, BAr^f<INF>4</INF>^-), while the comparably larger Me⁺ (from MeOTf) abstracts Cl^- to yield, after anion coordination, [Cp*(OTf)(PPh<INF>3</INF>)Ru(CCHR)] and MeCl.