ALUMINUM ORGANYLS WITH PENTACOORDINATE AL UMINUM - SYNTHESES AND MOLECULAR-STRUCTURES OF [ALX2(2,6-(NET2CH2)(2)C6H3)] (X = CL, ET, H)

The reaction of [Li{2,6-(NEt2CH2)(2)C6H3}](2) with AlCl3 or Et2AlCl gi ves [AlX2{2,6-(NEt2CH2)(2)C6H3}] [X = Cl (1), Et (2)] in good yield. 1 reacts with NaH in toluene to give [AlH2{2,6-(NEt2CH2)(2)C6H3}] (3). 1-3 were characterised spectroscopically (H-1, C-13, Al-27 n.m.r., i.r ., mass spectroscopy). In solution at room temperature 13 exhibit dyna mic behaviour. For 1 and 3 this can be frozen out below 278 K (H-1 n.m .r.), indicating the presence of monomeric molecules with pentacoordin ate Al at low temperature. Such species are also observed in the solid state as shown by an X-ray structure determination on 1 (monoclinic s pace group P2(1)/n, a = 9.7325(14), b = 13.552(5), c = 28.858(7) A, be ta = 99.57(2)degrees, V = 3753(2) Angstrom(3) Z = 8, at 223(2)K) and 2 (monoclinic space group C2/c, a = 15.0045(12), b = 9.2986(8),c = 14.9 955(12) Angstrom, beta = 99.512(1)degrees, Z = 4, at 223(2) K).