Dilithium diamides [{Li(OC4H8)}2{C20H12(NR)2}](R = SiMe3or CH2But) derived from R-, S- or R,S-2,2′-diamino-1,1′-binaphthyl derivatives

Abstract
The dilithium diamides [{Li(thf)}2{C20H12(NR)2}](R = SiMe31 or CH2But2, thf = tetrahydrofuran) were prepared from R,S-2,2′-diamino-1,1′-binaphthyl, C20H12(NH2)2, via C20H12[N(H)SiMe3]2 or C20H12[NHC(O)But]2 and C20H12[N(H)CH2But]2, respectively, and were transformed into SiCl2[C20H12(NR)2] by treatment with SiCl4. The crystal structures of 1 and 2 were determined. They are monomers, having a Li(1)N(1)Li(2)N(2) buckled ring, with Li(1)–N(2)ca. 0.2 Å shorter than Li(1)–N(1), the two groups R cis to one another, and N(1)–C(1)η2 bonded to Li(1). The R and S enantiomers were similarly prepared and their optical stability was demonstrated by their hydrolysis to R- and S-C20H12(NH2)2, respectively. Evidence is provided for the structures of [M{[graphic omitted](SiMe3)]2}](M = Ge or Sn), obtained by conversion of the stannylene into the crystallographically characterised [{Sn[([graphic omitted]20H12](µ-O)}3].

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