Synthesis and structures of lithium N-trimethylsilyl- and -neopentyl-anilides and their Et2O and tmen adducts; crystal structures of [(Li{μ-N(Ph)R}-trans)2(μ-tmen)]∞ (R = SiMe3 1 or CH2But 2) and [Li{μ-N(Ph)CH2But}(OEt2)]2

Abstract

Treatment of N-trimethylsilyl- or -neopentyl-aniline successively with n-butyllithium and tmen in hexane yielded the crystalline polymeric lithium amides [(Li{μ-N(Ph)R}-trans)₂(μ-tmen)]_∞ (R = SiMe₃1 or CH₂Bu^t2), which contain the rare bridging, rather than chelating, tmen ligands. Details are also provided of: (i) the preparation of crystalline [Li{N(Ph)SiMe₃}]₄, hydrocarbon-insoluble [Li{N(Ph)CH₂Bu^t}]_n, and diethyl ether adducts [Li{μ-N(Ph)R-trans}(OEt₂)]₂ (R = SiMe₃ or CH₂Bu^t); (ii) variable temperature multinuclear NMR spectra in toluene-d₈ and (iii) three crystal structures.