Diazenido-complexes of molybdenum and tungsten

Abstract

The diazenido-complexes [MX(N₂H)(dppe)₂](M = Mo or W: X = F, Cl, or Br; dppe = Ph₂PCH₂CH₂PPh₂) have been prepared by treatment of the corresponding diarene, [MX₂(NH:NH)(dppe)₂], or hydrazido(2–), [MF(N-NH₂)(dppe)₂][BF₄], complexes with triethylamine or aqueous potassium carbonate. With 1 mol of anhydrous acid they regenerate the parent diazeneor hydrazido(2–) complexes. The complex [WBr(N₂H)(dppe)₂] reacts with organic bromides to give the known complexes [WBr₂(N₂HR)(dppe)₂](R = Me or MeCO). The N₂H ligand is not displaced by trialkylphosphines but nitrogen mono-oxide displaces it quantitatively to give the nitrosyl complexes [MX(NO)(dppe)₂]. Spectroscopic data for these complexes and their ¹⁵N and ²H derivatives are described.