Organoaluminium and -gallium compounds with N,N-diisopropylaminomethyl groups

Abstract

The N,N-diisopropylaminomethyl aluminium compound [^tBu₂AlCH₂NⁱPr₂·LiCl]₂ (1) and the gallium compounds Li[^tBu₂Ga(CH₂NⁱPr₂)₂] (2) and [^tBu₂GaCH₂N(H)ⁱPr₂]Cl·^tBu₃Ga (3) were prepared by transmetallation of N,N-diisopropylaminomethyllithium LiCH₂NⁱPr₂ with di-tert-butylaluminium or -gallium chloride, and characterised by elemental analyses, multinuclear NMR spectroscopy (¹H, ¹³C, ²⁷Al, ⁷Li) and IR spectroscopy. The crystal structures have been determined by single crystal X-ray diffraction. Compound 1 aggregates as a centrosymmetric dimer, with two Al–C–N units connected by a frame of two LiCl molecules [Al–Cl 2.367(1), Cl–Li 2.339(4) and 2.374(4), Li–N 1.977(4) Å]. Compound 2 is a lithium organogallate with two weak Li⋯N bonds [1.965(7) and 1.937(7) Å]. Compound 3 contains two different moieties: ^tBu₃Ga and a [^tBu₂GaCH₂N(H)ⁱPr₂]⁺ cation, which are bridged by a Cl⁻ anion [Ga–Cl 2.445(1) and 2.579(1), H⋯Cl 2.362(3) Å].