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-[Ru=C=CHR(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 [Ru=C=C=CRR'(Cl)(dippe)(2) ](+), which were also isolated as [BPh4](-) salts. The reaction of trans-[RuC1(C=CPh)(dippe)(2)], formed by deprotonation of [Ru=C=CHPh(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)(mu-Cl)(3)(sigma, eta(2)-C=CPh)(2)(Ag-2(mu-dippe))](+), isolated as the [BPh4](-) salt, in which two sigma-alkynyl ligands attached to ruthenium are bridged by a [Ag-2(mu-dippe)](2+) fragment. To understand better the coordination modes of dippe to silver, the complex [(Ag(dippe))(2)(mu-dippe)][BPh4](2) was synthesized. The P-3l(H-1) NMR spectra of silver-containing derivatives, which display complex second-order patterns, have been analyzed in detail, and the X-ray crystal structures of trans-[Ru=C=CH2(Cl)(dippe)(2)][BPh4], [(Ru(dippe))(2)(mu-Cl)(3)(sigma, eta(2)-C=CPh)(2)(Ag-2(mu-dippe))][BPh4], and [(Ag(dippe))(2)(mu-dippe)(2)][BPh4](2) are reported.