Magnesium complexes supported by a dianionic double layer nitrogen–phosphorus ligand: a synthesis and reactivity study

Abstract

A heterobimetallic complex [MeN(CH₂CH₂NPⁱPr)₂MgLiCl(THF)]₂ (1) supported by a dianionic double layer nitrogen–phosphorus ligand was synthesized by the reaction of H₂L1 (H₂L1 = MeN(CH₂CH₂NHPⁱPr)₂) with MgCl₂ in the presence of n-BuLi. Reactions of complex 1 with 2 equivalents of CuI, AgI and AuCl·SMe₂ led to the formation of heterobimetallic clusters [MeN(CH₂CH₂NPⁱPr)₂MgCuI]₂ (2), [MeN(CH₂CH₂NPⁱPr)₂MgAgI]₂ (3) and [MeN(CH₂CH₂NPⁱPr)₂MgAuCl]₂ (4), respectively. X-ray single-crystal diffraction analysis revealed that these complexes are dimers, which are composed of two [MeN(CH₂CH₂NPⁱPr)₂Mg] units connected by coinage metals (i.e., Cu, Ag, and Au). The reactivity of 1 was further investigated and it was found that complex 1 could react with 4 equivalents of MeI, giving a complex [CH₃N(CH₂CH₂NPⁱPr₂Me)₂MgI]⁺[I]⁻ (5), which can be viewed as a magnesium complex supported by a neutral double layer nitrogen–phosphorus ligand (CH₃N(CH₂CH₂NPⁱPr₂Me)₂). Complex 1 could also react with 2 equivalents of NaNH₂, leading to the isolation of an amido anion bridged magnesium–sodium heterobimetallic cluster [MeN(CH₂CH₂NPⁱPr)₂MgNaNH₂]₂ (6).