Synthesis and characterization of group 13 dichloride (M = Ga, In), dimethyl (M = Al) and cationic methyl aluminum complexes supported by monoanionic NNN-pincer ligands

Abstract

A series of group 13 dichloride species, supported by monoanionic NNN-pincer ligands, LMCl₂ (L = 2,5-(ⁱPr₂PNAr)₂N(C₄H₂); Ar = 4-ⁱPrC₆H₄ (L^Pipp), 2,4,6-Me₃C₆H₂ (L^Mes), 2,6-ⁱPr₂C₆H₃ (L^Dipp); M = Ga (1), In (2)), were prepared via the reaction of NaL with MCl₃ and characterized by multinuclear NMR spectroscopy, elemental analysis and X-ray crystallography. Related organoaluminum complexes, LAlMe₂ (3), were synthesized by addition of AlMe₃ to L. Treatment with the Lewis acid B(C₆F₅)₃ afforded well-defined cationic aluminum methyl species, [LAlMe]⁺[MeB(C₆F₅)₃]⁻ (4), which were found to be thermally stable in both solid and solution state for days.