Abstract
Reaction of the ruthenium bis-acetate complex cis-Ru(k(2)-OAc)(2)(PPh3)(2) with a range of terminal alkynes HC CR (R = Ph, CO2Me, C{OH}Ph-2, C{OH}Me-2) results in the formation of the vinylidene complexes Ru(k(2)-OAc)(k(1)-OAc)(=C=CHR)(PPh3)(2). The acetate ligands in these species are fluxional and, in the case where R = Ph, are undergoing fast exchange on the NMR time scale even at 195 K. In the case of the hydroxy-substituted complex Ru(k(2)-OAc)(k(1)-OAc)(=C=CHC{OH}Ph-2)(PPh3)(2) a hydrogen bond exists between the OH group on the gamma-position of the vinylidene and the k(1)-OAc ligand. This hydrogen bond inhibits the exchange of the OAc ligands, which now becomes slow on the NMR time scale at 215 K. In addition, and in contrast to the Cl-substituted analogues, elimination of water from the hydroxy vinylidene complex does not readily occur, possibly due to the presence of this hydrogen-bonding interaction. Instead, a slow reaction to form Ru(k(2)-OAc)(k(1)-OAc)(CO)(PPh3)(2) is observed with the concomitant formation of H2C=CPh2. An analogous process with Ru(k(2)-OAc)(k(1)-OAc)(=C=CHC-{OH}Me-2)(PPh3)(2) affords H2C=CMe2 and Ru(k(2)-OAc)(k(1)-OAc)(CO)(PPh3)(2).
| Original language | English |
|---|---|
| Pages (from-to) | 1320-1328 |
| Number of pages | 9 |
| Journal | Organometallics |
| Volume | 28 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 9 Mar 2009 |
Keywords
- TRANSITION-METAL-COMPLEXES
- CYCLOPENTADIENYL-OSMIUM CHEMISTRY
- RAY CRYSTAL-STRUCTURES
- TERMINAL ALKYNES
- PHOSPHINE-LIGANDS
- STRUCTURAL-CHARACTERIZATION
- ORGANOMETALLIC CHEMISTRY
- ALLENYLIDENE COMPLEXES
- INDENYLIDENE COMPLEXES
- MOLECULAR-STRUCTURE