| Autor: |
Adams, Harry, A. Bailey, Neil, J. Gill, Louise, J. Morris, Michael, D. Sadler, Nicholas |
| Zdroj: |
Journal of the Chemical Society, Dalton Transactions; January 1997, Vol. 1997 Issue: 17 p3041-3048, 8p |
| Abstrakt: |
The thermal reaction of the dimolybdenum–ruthenium vinylidene clusters [Mo2Ru(3-C&z.dbd;CHR)(CO)7 (η-C5H5)2] (R = H 1a, Me 1b, Ph 1c or CO2Me 1d) with the tertiary phosphine PPh2Me afforded the monosubstituted complexes [Mo2Ru(3-C&z.dbd;CHR)(CO)6 (PPh2Me)(η-C5H5)2] 2a–2d in excellent yields. The products exist as single isomers in which site-selective substitution of a CO ligand has occurred exclusively at the ruthenium atom. The crystal structure of 2b has been determined by X-ray diffraction; the geometry of the vinylidene ligand is identical to that previously found in the parent compound 1b, but a slightly different pattern of semi-bridging carbonyls is present. The reactions of 1a and 1b with diphenylphosphine are more complex. Depending on the stoichiometry and conditions employed, three different types of cluster have been isolated: the substitution product [Mo2Ru(3-C&z.dbd;CH2)(CO) 6(PPh2H)(η-C5H5)2 ] 2e; the 46-electron monophosphido compounds [Mo2Ru(3-CCH2R)( -PPh2)(CO)5(η-C5H 5)2] 3a, 3b and the saturated bis(phosphido) species [Mo2Ru(3-C&z.dbd;CHR)(- PPh2)2(CO)4(η-C5H 5)2] 4a, 4b. Separate experiments have established that these products are formed sequentially, thus demonstrating the conversion of the initial vinylidene into an alkylidyne ligand and then back to a vinylidene. The structures of 3b and 4a have been confirmed by X-ray diffraction, showing that the phosphido groups bridge one or both of the Mo–Ru edges respectively. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
