Redox-potential–structure relationships in metal complexes. Part 4. Electron-poor dinitrogen complexes of rhenium(I)

Abstract

The systematic syntheses of some new electron-poor Re^I(N₂) complexes are described. The oxidation potentials of these complexes vary essentially linearly with ν(N₂) whilst only those with E_½^ox > ca. +0.8 V versus the saturated calomel electrode react with LiMe. In general, the nature of the product(s) of reaction of these complexes with LiR (R = alkyl or aryl) depend upon R. For example, [ReCl(CO)₂(N₂)(PPh₃)₂] reacts with LiMe–H⁺ to give [ReCl{C(OH)Me}(CO)(N₂)(PPh₃)₂], but with LiPh–H⁺ gives the five-co-ordinate [ReCl(CO)₂(PPh₃)₂]. We have not observed attack by LiR upon N₂ in any of the complexes. The apparent selectivity of the site of attack by LiR is discussed.