The doubly-bonded ditungsten anion [W2Cp2(μ-PPh2)(NO)2]−: an entry to the chemistry of unsaturated nitrosyl complexes

Abstract

Complex [W₂Cp₂(μ-I)(μ-PPh₂)(NO)₂] was prepared by reacting [W₂Cp₂(μ-I)(μ-PPh₂)(CO)₂] with NO at 233 K followed by decarbonylation in refluxing toluene. It was reduced by Na(Hg) in acetonitrile to give Na[W₂Cp₂(μ-PPh₂)(NO)₂], the first anionic nitrosyl complex featuring a metal–metal double bond (computed W–W = 2.580 Å). Reactions of the latter anion with (NH₄)PF₆ and [AuCl{P(p-tol)₃}] gave the hydride [W₂Cp₂(μ-H)(μ-PPh₂)(NO)₂] and the cluster [AuW₂Cp₂(μ-PPh₂)(NO)₂{P(p-tol)₃}] respectively, also featuring multiple W–W bonding (experimental W–W ca. 2.75 Å), and its reaction with S₈ yielded the electron-precise derivative Na[W₂Cp₂(μ-PPh₂)(μ-S)(NO)₂], which was methylated by Me₂SO₄ to give the thiolate complex [W₂Cp₂(μ-PPh₂)(μ-SMe)(NO)₂].