The preparation and properties of some diphosphines R2PCH2CH2PR2(R = alkyl or aryl) and of their rhenium(I) dinitrogen derivatives

Abstract

The synthesis of a range of diphosphines R₂PCH₂CH₂PR₂ from Cl₂PCH₂CH₂PCl₂ is described. The properties of a series of complexes [ReCl(N₂)(R₂PCH₂CH₂PR₂)₂] derived from them are discussed. The relationship between the values of E_½ ^ox and ν(N₂) for the complexes suggests that electron-withdrawing substituents on the diphosphine upset the usual balance of σ and π effects in rhenium–dinitrogen bonding.