Reactivity of a 1-Azavinylidene-Bridged Triruthenium Carbonyl Cluster with Alkynes. Synthesis of Binuclear Derivatives Containing New C−H or C−N and C−C Bonds Formed by Alkyne Insertion into M−H or M−N and M−C Bonds

Abstract

Treatment of the 1-azavinylidene cluster complex [Ru3(μ-H)(μ-NCPh2)(CO)10] (1) with an excess of diphenylacetylene or 1-phenyl-1-propyne, in 1,2-dichloroethane at reflux temperature, gives the metallacyclic derivatives [Ru2{μ-PhCCR−CPhCR−NCPh(C6H4)}(μ-CO)(CO)4] (2, R = Ph; 3, R = Me). These reactions represent the first examples of insertion of weakly electrophilic alkynes into metal−nitrogen bonds, since compounds 2 and 3 contain novel ligands that result from the orthometalation of a phenyl group of the original 1-azavinylidene ligand, the insertion of the corresponding alkyne molecule into a ruthenium−nitrogen bond, and the insertion of a second alkyne molecule into a ruthenium−carbon bond. At lower temperature (THF under reflux), the reactions of compound 1 with the same alkynes or with 3-hexyne, acetylene, phenylacetylene, p-tolylacetylene, or tertbutylacetylene proceed via cluster fragmentation and insertion of the corresponding alkyne into a ruthenium−hydrogen bond, resulting in the binuclear alken...