Synthesis of amino- and amido-aluminium derivatives and investigation of their dynamics in solution

The salts Li[Al(C4H8N)(4)].nC(4)H(8)NH (n = 1, 2; C4H8NH = pyrrolidine) have been prepared and characterised in solution by H-1-, C-13-, Li-7- and Al-27-NMR spectroscopy. Their reaction with AlCl3 (Cl/Li molar ratio = 3) affords the binary amido derivative [Al(C4H8N)(3)](2), which, on turn, is reactive towards AlX3, yielding [AlX2(C4H8N)](2) (X = Cl, CH3). The binuclear derivatives [AlY2(C4H8N)](2) ( Y = Cl, CH3, C4H8N) react with [NH2Et2] Cl affording the amine complexes AlY2Cl(C4H8NH)(n) (Y = CH3, n = 1; Y = Cl, n = 1, 2). Alternatively, the monochloro species Al(CH3)(2)Cl( C4H8NH) results from the reaction of Al(CH3)(3)(C4H8NH) and AlCl3(C4H8NH) (CH3/Cl molar ratio = 2). The dichloro-methyl derivative Al(CH3)Cl-2(C4H8NH) is obtained by reacting Al(CH3)(3)(C4H8NH) and AlCl3(C4H8NH) (Cl/CH3 molar ratio = 2). The Lewis adducts AlCl3(amine)(n) ( amine = pyrrolidine, n = 1, 2; amine = N, N, N'- trimethylpropanediamine, n = 1) have been isolated when AlCl3 was contacted with the stoichiometric amount of the amine. At variance with N, N, N'-trimethylpropanediamine, N, N, N'-trimethylethylenediamine and N, N, N', N'-tetramethylethylenediamine react with AlCl3 yielding the salt derivatives [AlCl2(amine)(2)][AlCl4]. The dynamic processes of the coordinated amine ligands of AlCl3( amine) n ( amine = pyrrolidine, n = 1, 2; amine = N, N, N'-trimethylpropanediamine, n = 1) and [AlCl2(amine)(2)][AlCl4] (amine = N, N, N', N'-tetramethylethylenediamine) have been investigated in solution by NMR spectroscopy.