Direct Observation of β-Methyl Elimination in Cationic Neopentyl Complexes: Ligand Effects on the Reversible Elimination of Isobutene

Abstract

β-Me elimination from cationic neopentyl complexes, [Cp‘2Zr(CH2CMe3)]+, has been demonstrated. The more crowded complex (Cp‘ = C5Me5) eliminates isobutene instantaneously at −75 °C, whereas the less crowded analogue (Cp‘ = C5H5) is stable in solution at 0 °C but undegoes reversible β-Me elimination at 25 °C; strong anion or Lewis base coordination suppresses β-Me elimination, consistent with involvement of a 14-electron species.