Reactions of a Trinuclear Ruthenium Complex Derived from 3-(2-Pyridyl)indene with Diphenylacetylene and Phenylacetylene: Insertion of Alkynes into the Ru−C bond

Thermal treatment of the trinuclear ruthenium complex {μ 2 -η 5:η 1 -(C 5 H 4 N)(C 9 H 5 )}Ru 3 (CO) 9 ( 1 ) with 1 equiv of diphenylacetylene gave the trinuclear complex {μ 3 -η 1:η 2:η 5 -(C 5 H 4 N)(C 9 H 5 )(PhC═CPh)}Ru 3 (CO) 7 ( 2 ) via the insertion of an alkyne into the Ru−C(η 1 ) bond of 1 . Complex 2 could be transformed into the dinuclear and trinuclear complexes {μ 2 -η 1:η 5 -(C 5 H 4 N)(C 9 H 5 )(PhC═CPh)}Ru 2 (CO) 2 (μ 2 -η 2:η 4 -CPh═CPhCPh═CPh) ( 3 ), {μ 3 -η 2:η 3:η 5 -(C 5 H 4 N)(C 9 H 5 )(CPhCPh═CPhCPh)}Ru 3 (CO) 6 ( 4 ), and {μ 2 -η 1:η 5 -(C 5 H 4 N)(C 9 H 5 )(PhC═CPh)}Ru 3 (CO) 4 (μ 3 -η 2 -PhC═CPh) 2 ( 5 ) in the presence of excess diphenylacetylene. Similarly, reaction of 1 with 1 equiv of phenylacetylene gave the alkyne-inserted product {μ 3 -η 1:η 2:η 5 -(C 5 H 4 N)(C 9 H 5 )(HC═CPh)}Ru 3 (CO) 7 ( 6 ), which could also react with excess phenylacetylene to give the complexes {μ 3 -η 2:η 4:η 5 -(C 5 H 4 N)(C 9 H 5 )(C═CPhCH═CPh)}(μ 2 -H)Ru 3 (CO) 6 ( 7 ) and {μ 2 -η 2:η 4 -(C 5 H 4 N)(C 9 H 6 )(C═CPhCH═CPh)}Ru 2 (CO) 4 (μ 2 -CO) ( 8 ). Complex 7 could be transformed slowly into 8 in refluxing toluene. The reactions of 3-(2-pyridyl)indene with internal alkynes catalyzed by Ru 3 (CO) 12 and 1 were also tested, obtaining several C−H/alkyne coupling products, while the reaction with phenylacetylene did not work under the same conditions. The molecular structures of 2 − 8 were determined by X-ray diffraction.