Reactions of Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11 with disubstituted alkynes C2R2 (R = Me, Ph)
Abstract
Reaction of the dicarbon-containing complex Ru5(µ5-C2)(µ-SMe)2(µ-PPh2)2(CO)11 1 with diphenylethyne gave as major products Ru5(µ5-CCCPhCPh)(µ-SMe)2(µ-PPh2)2(CO)10 2 and Ru5(µ5-CCPhCPh)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9 3. The only product from the reaction between 1 and but-2-yne was identified as Ru5(µ5-CCCMeCMe)(µ3-SMe)(µ-SMe)(µ-PPh2)2(CO)9 4. Pyrolysis of 2 gave 3. Carbonylation of 3 yields the complex Ru5(CCCPhCPh)(µ-SMe)2(µ-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 Ru5 clusters in both complexes adopt the open-envelope conformation, the Ru4 rhombus being planar in 2, but bent across the Ru(3)· · ·
Ru(5) diagonal by 39.6° in 3. The organic ligand is formed by coupling of the C2 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 Ru4 rhombus. In 3, atoms C(1,2,3,4) have an η4 interaction with Ru(4).