The treatment of (tj5-C5H5)MH2 (M = Mo or W) with CH3Mn(CO)5 gives as principal products respectively the binuclear complexes (7)5-C5H5)(CO)M(u-(i)5:);1-C5H4))Mn(CO)4, where M = Mo (la) and M = W (lb), each accompanied by the evolution of methane and hydrogen; from (ij5-C5H5)2ReH and CH3Mn(CO)5 one obtains (7)5-C5H5)(H)Re^-())5:V-C5H4)) Mn(CO)4 (2), with evolution of methane and carbon monoxide. Studies with deuterium-labeled starting materials confirm that the methane in these reactions is formed from a hydrogen atom of a cyclopentadienyl ring of the metallocene hydride and the methyl group of CH3Mn(CO)5. The deuterium atom remaining in a sample of 2-d[t obtained from (j75-C5H5)2ReD and CD3Mn(CO)5, is found to be randomly distributed over all positions indicating an intramolecular hydrogen tautomerism in this bimolecular metalation product. With H2 at ambient temperatures, lb yields an unstable intermediate (t/5-C5H5)2(H)W-Mn(CO)5 which is converted at 80 °C in the presence of H2 to (ij5-C5H5)2WH2 and Mn2(CO)10; with D2 at 80 °C, the metallocene hydride obtained is found to contain extensive exchange of deuterium for hydrogen. The binuclear complex 2 is stable toward H2 up to 80 °C but shows exchange of deuterium for hydrogen when treated with D2 at that temperature. Treatment of lb with phosphorus-containing ligands gives substitution products with evolution of CO and no evidence of the formation of any acyl complexes.
The structure of the title compound, ( 5-05 5)(00) (µ-( ;5: 1-5 4)) (00)4, has been determined by a three-dimensional X-ray diffraction study. The compound crystallizes in the triclinic space group Pi with a = 8.056 (1) Á, b = 9.322 (3) A, c = 11.927 (2) Á, a = 98.44 (3)°, ß = 82.97 (3)°, and y = 123.39 (2)°. The density of 1.89 g cm'3 calculated on the basis of two molecules in the unit cell agrees with the measured density of 1.88 g cm"3. Diffraction data to 29max = 65°( Mo Ka radiation) were collected on a Picker four-circle automated diffractometer. The structure was solved by the heavy-atom method and refined by full-matrix least-squares procedures to a conventional discrepancy index R = 0.045 on the basis of 4900 unique reflections. The C5H4 ring has C-C bond distances of average value 1.424 Á and appears to be a cyclopentadienyl ring rather than a dienecarbenoid ring. One carbon atom in the C5H4 ring is rather close to the Mn atom, Mn-C = 2.005 (4) Á and Mo-Mn = 2.9605 (8) Á. The angle Mo-Mn-C involving these three atoms is 49°. Apart from this cis compression, the disposition of the four CO groups around Mn is approximately octahedral; i.e., angles involving CCo and Mn are approximately 90°. The configuration around Mo is very similar to that in ( 75-5 5)2 2.
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