Bis(η2-cyclopentadienyl)zirconium(IV) alkyl chlorides and hydrides have been prepared and characterized. Hydrogenation of these species yields the corresponding alkane and zirconium hydride complexes, Cp2ZrHCl and Cp2ZrH2, respectively. Deuterium labeling experiments suggest that these d0 complexes activate H2 by heterolytic attack on that molecule. Qualitative rates for hydrogenation of a series of complexes were Cp2Zr(R)H > Cp2Zr(R)Cl ≃ Cp2ZrR2 > [(Cp2ZrCl)2-(μ-OCHR)] > Cp2Zr(COR)Cl. This rate trend is the same as that for carbonylation and suggests a conceptual link between mechanisms for hydrogenation and carbonylation of these unsaturated complexes. A possible relationship is noted between heterolytic activation and oxidative addition of H2 to transition-metal species.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry