Facile access to mid-valent Group 5 and 6 metal synthons

Abstract

Group 5 and 6 metal chlorides, MCl_x (M = Nb, Ta, Mo, W) are easily and controllably reduced, in a stepwise fashion, by stoichiometric PhMe₂SiH, yielding only PhMe₂SiCl, a useful reagent, and H₂ as the byproducts. Addition of n moles of PhMe₂SiH to toluene solutions of MCl_x yields stepwise uncoordinated reduction products of the form MCl_x−n (M = Nb, Ta, Mo, W; x = 5 for Nb, Ta, Mo, x = 6 for W; n = 1 for Nb and Ta, n = 1, 2 for Mo and W). The reactions proceed cleanly furnishing quantitative, analytically pure yields of the desired mid-valent binary chlorides. The obtained products are very reactive and can be further derivatized with coordinating ethers or phosphines for the on-demand preparation of desired inorganic synthons.