The preparation and oxidation, substitution, and protonation reactions of trans-bis(dinitrogen)tetrakis(methyldiphenylphosphine)tungsten

Abstract

The complex trans-[W(N₂)₂(PMePh₂)₄] has been prepared. It gives trans-[W(N₂)₂(PMePh₂)₄][FeCl₄] with an excess of FeCl₃ in ethanol, and [W(N₂)₂(PMePh₂)₃L](L = NC₅H₅, NC₅H₄Me-3, NC₅H₄Me-4, or NC₅H₄CO₂H-4) on treatment with L in tetrahydrofuran (thf). With dppe (Ph₂PCH₂CH₂PPh₂) in thf, trans-[M(N₂)₂(PMePh₂)₄](M = Mo or W) give [M(N₂)₂(PMePh₂)₂(dppe)]. Treatment of [W(N₂)₂(PMePh₂)₄] with hydrogen chloride in dichloromethane gives dinitrogen (1 mol) and [WCl₃(NHNH₂)(PMePh₂)₂], which with H₂SO₄ in methanol gives hydrazine (0.28 mol) and ammonia (0.23 mol), but mainly ammonia (0.76 mol) and a little hydrazine (0.08 mol) on treatment with 40% aqueous potassium hydroxide.