Lithium bis(diisopropylphosphino)amide LiN[P(i-Pr) 2 ] 2 reacts with SnCl 2 or GeCl 2 •dioxane in the presence of excess n-BuLi to produce the bicyclic compounds {MN[P(i-Pr) 2 ] 2 } 2 (M = Sn, Ge) which feature Sn 2 2+ or Ge 2 2+ units bridged by phosphorus. When paired with B(C 6 F 5) 3 in THF, the Lewis-basic M 2 2+ complexes participate in a THF ring-opening reaction. Quite surprisingly, in the absence of THF one para-F atom from B(C 6 F 5) 3 is activated and displaced to B while a new M-C bond is formed. Each of these complexes, as well as Cl 2 Sn{N[P(i-Pr) 2 ] 2 } 2 and {ClSnN[P(i-Pr) 2 ] 2 } 2 were characterized by a combination of multinuclear NMR spectroscopy and single-crystal X-ray diffraction.
Five different coordination motifs were observed upon reaction of the simple group 13 Lewis acids MCl (M = In, Ga, Al, B) or BF·EtO with the ambidentate bis(diisopropylphosphino)amine ligand HN[P(i-Pr)]. In a 1:1 reaction mixture, the softer Lewis acids InCl, GaCl and BCl coordinate to one of the two P atoms of the ligand. In contrast, AlCl and BF prefer coordination to the harder N atom. In all cases, the acidic N-H proton is shifted to P upon complexation with a metal. By altering the reaction stoichiometry, 2:1 metal-ligand complexes could be isolated for three of the combinations. BCl gives a bis-adduct via the two P atoms. GaCl produces a salt consisting of a [GaCl] anion and a P,P-chelated [LGaCl] cation. Most unexpectedly, the reaction with InCl in methanol resulted in solvent deprotonation by the ligand to give two symmetric [(i-PrPH)N] cations in which all the basic P sites are coordinated to H rather than the group 13 Lewis acid. These cations are balanced by the unique complex dianion [(MeO)InCl·2MeOH]. All complexes were characterized with a combination of multinuclear NMR spectroscopy and single-crystal X-ray diffraction.
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