Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 33. Reactions of [W(![[triple bond, length half m-dash]](https://www.rsc.org/images/entities/char_e007.gif)
CMe)(CO)2(η-C5H5)] with the dimetal compounds [MRh(µ-CO)2(η-C5Me5)2](M = Co or Rh); X-ray crystal structure of [Rh2W(µ-CO)(µ3-CMe)(CO)2(η-C5H5)(η-C5Me5)2]
Abstract
The compound [W(CMe)(CO)2(η-C5H5)] reacts with [Rh2(µ-CO)2(η-C5Me5)2] in tetrahydrofuran (thf) at room temperature to give two crystalline products, red [Rh2W(µ-CO)(µ3-CO){µ3-C(O)CMe}(CO)(η-C5H5)(η-C5Me5)2](1) and green [Rh2W(µ-CO)(µ3-CMe)(CO)2(η-C5H5)(η-C5Me5)2](2a). The structures of both species are assigned on the basis of spectroscopic data (i.r. and n.m.r.), with that of the latter confirmed by a single-crystal X-ray diffraction study. The methylmethylidyne ligand symmetrically bridges the metal atom triangle [µ3-C–Rh 2.026(7), µ3-C–W 2.030(12), Rh–Rh 2.639(1), Rh–W 2.836(1)Å]. One CO ligand symmetrically bridges the Rh–Rh vector, while the remaining two CO groups bonded to tungsten asymmetrically bridge the Rh–W edges of the triangle [W–C–O 167.4(9)°]. Compound (1) in solution releases CO irreversibly to give (2a). The µ3-C(O)CMe ligand in (1) may be protonated or methylated, affording dirhodiumtungsten salts containing bridging alkyne ligands [Rh2W(µ-CO){µ3-C(OR)CMe}(CO)2(η-C5H5)(η-C5Me5)2][X](R = H, X = BF4 or CF3CO2; R = Me, X = CF3SO3). Treatment of [CoRh(µ-CO)2(η-C5Me5)2] with [W(CMe)(CO)2(η-C5H5)] in thf at room temperature gives a mixture of the dimetal compound [RhW(µ-CMe)(CO)3(η-C5H5)(η-C5Me5)] and the trimetal complex [CoRhW(µ-CO)(µ3-CMe)(CO)2–(η-C5H5)(η-C5Me5)2]. Protonation (HBF4·Et2O) of the latter affords the salt [CoRhW(µ-H)(µ-CO)(µ3-CMe)(CO)2(η-C5H5)(η-C5Me5)2][BF4](two isomers). The related salts [Rh2W(µ-H)(µ-CO)(µ3-CR)(CO)2(η-C5H5)(η-C5Me5)2][BF4](R = Me or C6H4Me-4) have also been prepared. The 1H and 13C-{1H} n.m.r. spectra of the new compounds are reported and discussed.
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![[triple bond, length half m-dash]](https://www.rsc.org/images/entities/h2_char_e007.gif)
CMe)(CO)2(η-C5H5)] with the dimetal compounds [MRh(µ-CO)2(η-C5Me5)2](M = Co or Rh); X-ray crystal structure of [Rh2W(µ-CO)(µ3-CMe)(CO)2(η-C5H5)(η-C5Me5)2]