Dealkylation of Zirconium(IV) by Borane: The Intimate Mechanism of an Alkyl Transfer Reaction

Article abstract of DOI:10.1021/ja00373a005

The reaction of Cp2ZrMe2 with BH3*THF ultimately yields Cp2Zr(BH4)2.The reaction is sequential in the sense that Cp2Zr(BH4)Me has also been detected.By use of 11B NMR spectroscopy, both for resolution of chemically distinct boron-containing species and as an aid to proton counting, it has been possible to show that these reactions proceed through intermediates containing coordinated BH3Me^- and BH2Me2^-, and thus the reaction is initially a formal insertion of BH3 into a Zr-CH3 bond.These intermediates react further with borane to produce a complex equilibrating mixture of alkyl diboranes, B2MenH6-n and Zr(BH4) groups.