TRINUCLEAR OSMIUM CLUSTERS AS MODELS FOR INTERMEDIATES IN CO REDUCTION CHEMISTRY - 2. CONVERSION OF A METHYLENE INTO A KETENE LIGAND ON A TRIOSMIUM CLUSTER FACE.

Article abstract of DOI:10.1021/ja00329a023

The bridging methylene complex Os//3(CO)//1//1( mu -CH//2) (3) reacts with CO to give the new ketene complex Os//3-(CO)//1//2( eta **2-(C,C), mu //2-CH//2CO) (4) in high yield. Complex 4 has been spectroscopically as well as structurally characterized. It crystallizes in the space group P2//1/n, with a equals 9. 414 (2) A, b equals 15. 369 (3) A, c equals 13. 940 (4) A, beta equals 107. 9 (2) degree , V equals 1918. 6 (7) A,**3 and Z equals 4. Least-squares refinement of the 3015 reflections with (F//o)**2 greater than 3 sigma (F//o)**2 converged to R equals 0. 033 and R//w equals 0. 034. The ketene ligand is incorporated into a triosmacyclopentanone ring and bridges between two Os atoms that are not joined by a metal-metal bond. Bond angles imply sp**3 and sp**2 hybridization for the CH//2 and CO carbon atoms, respectively. Complex 4 reacts with H//2O and CH//3OH to yield CH//3COOH and CH//3COOCH//3, respectively, along with Os//3(CO)//1//2.