Decamethylzirconocene-Chalcogenide-Hydride Complexes

Stoichiometric reaction of [(C5Me5)2ZrH3]Li (1) with diphenylphosphine sulfide or selenide yields the bimetallic species [(C5Me5)2ZrH]2(μ-E) (E = S 2, Se 3). These reactions are proposed to proceed via an intermediate of the form [(C5Me5)2ZrH2(EPPh2)]- with concurrent loss of dihydrogen. Subsequent β-elimination of Ph2PH affords 2 and 3 via dimerization and loss of Li2E. The initial synthetic strategy to trap an anionic intermediate involved treatment of 1 with diphenylphosphine oxide. This approach failed, affording instead the tetrameric species [Ph2POLi(THF)]4 (4) and Cp*2ZrH2. An alternative, successful approach to an oxide anion involved the reaction of 1 with Me3NO. The resulting species [(C5Me5)2ZrH(OLi(THF))]2 (5) was isolated, and the species 2−5 have been structurally characterized. These results are presented and the implications discussed.