Reactions of Ru5(μ5-C2)(μ-SMe)2(μ-PPh2)2(CO)11 with disubstituted alkynes C2R2 (R = Me, Ph)

Reaction of the dicarbon-containing complex Ru-5(mu(5)-C-2)(mu-SMe)(2)(mu-PPh2)(2)(CO)(11) 1 with diphenylethyne gave as major products Ru-5(mu(5)-CCCPhCPh)(mu-SMe)(2)(mu-PPh2)(2)(CO)(10) 2 and Ru-5(mu(5)-CCPhCPh)(mu(3)- SMe)(mu-SMe)(mu-PPh2)(2)(CO)(9) 3. The only product from the reaction between 1 and but-2-yne was identified as Ru-5(mu(5)-CCCMeCMe)(mu(3)-SMe)(mu-SMe)(mu-PPh2)(2)(CO)(9) 4. Pyrolysis of 2 gave 3. Carbonylation of 3 yields the complex Ru-5(CCCPhCPh)(mu-SMe)(2)(mu-PPh2)(2)(CO)(11) 5, further heating of which regenerated a mixture of 2 and 3. The structures of 2 and 3 were determined from single crystal X-ray studies. The Ru, clusters in both complexes adopt the open-envelope conformation, the Ru-4 rhombus being planar in 2, but bent across the Ru(3) Ru(5) diagonal by 39.6 degrees in 3. The organic ligand is formed by coupling of the C-2 group in 1 with the alkyne and is attached by three of the four carbons in 2 and by all four in 3, atom C(1) being strongly attached to the Ru-4 rhombus. In 3, atoms C(1,2,3,3) have an eta(4) interaction with Ru(4).