Synthesis of Lewis Base Adducts of Barium Bis[bis(trimethylsilyl)amide

Abstract

Transmetalation of Sn{N(SiMe3)2}2 with barium metal in 1,2‐dimethoxyethane (DME) yields [(dme)2Ba{N(SiMe3)2}2] (1). The neutral ether ligand can be substituted by stronger Lewis bases such as tetramethylethylenediamine (tmeda) and pentamethyldiethylenetriamine (pmdeta) leading to the formation of [(tmeda)Ba{N(SiMe3)2}2] (2) and [(pmdeta)Ba{N(SiMe3)2}2] (3). The tetrahydropyran adduct [(thp)3Ba{N(SiMe3)2}2] (4) can be isolated after addition of tetrahydropyran (thp) to coligand‐free [Ba{N(SiMe3)2}{µ‐N(SiMe3)2}]2. The Ba–N bond lengths to the amido ligands are dictated by the coordination number of the metal atom. A comparitive analysis with alternative methods of preparation shows that the metathetical approach requires the use of exact stoichiometry because bariates form with any excess KN(SiMe3)2.