UNEXPECTED FORMATION OF A TETRANUCLEAR HETEROBIMETALLIC COMPLEX BY REACTION OF A RUTHENIUM ALKYNYL WITH AGCF3SO3

[RuCl2(dippe)2] (dippe = 1,2-bis(diisopropylphosphino)ethane) reacts with HC⋮CR (R = Ph, H) in dichloromethane in the presence of [NH4][PF6] furnishing the corresponding cationic vinylidene complexes trans-[RuCCHR(Cl)(dippe)2]+, which were isolated as tetraphenylborate salts. In an analogous fashion, the reaction of [RuCl2(dippe)2] with substituted propargyl alcohols HC⋮CC(OH)RR‘ (R = R‘ = Me; R = Me, R‘ = Ph) yielded the allenylidene derivatives [RuCCCRR‘(Cl)(dippe)2]+, which were also isolated as [BPh4]- salts. The reaction of trans-[RuCl(C⋮CPh)(dippe)2], formed by deprotonation of [RuCCHPh(Cl)(dippe)2][BPh4] by KOBut, with AgCF3SO3 in the presence of HC⋮CPh was carried out in an attempt to generate a cationic alkynyl−vinylidene species. However, this reaction yielded instead the unexpected tetranuclear heterobimetallic complex [{Ru(dippe)}2(μ-Cl)3(σ,η2-C⋮CPh)2{Ag2(μ-dippe)}]+, isolated as the [BPh4]- salt, in which two σ-alkynyl ligands attached to ruthenium are bridged by a [Ag2(μ-dippe)]2+ fragment. ...