Synthesis, X-ray structure, and multinuclear NMR investigation of some intramolecularly nitrogen stabilized organoboron, -aluminum, and -gallium compounds

The intramolecularly nitrogen stabilized organo-aluminum- and organoboron c ompounds Me2Al(CH2)(3)NMe2 (1), Me2AlC10H6-8-NMe2 (2), (1)Pr2Al(CH2)(3)NEt2 (3), (CH2)(5)Al(CH2)(3)NMe2 (4), and (CH2)(5)B(CH2)(3)NMe2 (5) are synthes ized from Me2AlCl and the corresponding organolithium compounds and from Al CL3 or BCl3, the lithium alkyl and (PrMgCl)-Pr-1 or BrMg(CH2)(5)MgBr,respec tively. AlCl3 and GaC1(3) react with Li(CH2)(3)NMe2 Or LiCH2CHMeCH2NMe2 for ming Cl2AlCH2CHMeCH2NMe2 (6), Cl2Al(CH2)(3)NMe2 (8), and Cl2Ga(CH2)(3)NMe2 (9). The reaction of 6 and of 8 or 9 with BrMg(CH2)(5)MgBr and BrMg(CH2)(6) MgBr, respectively, yields (CH2)(5)AlCH2CHMeCH2NMe2 (7), (CH2)(6)Al(CH2)(3) NMe2 (10), and (CH2)(6)Ga(CH2)(3)NMe2 (11). MeAlCl2, made by the redistribu tion reaction of AlCl3 with Me2AlCl, reacts with 2 equivalents of Li(CH2)(3 )NMe2 yielding MeAl[(CH2)(3)NMe2](2) (12) and with MeN[(CH2)(3)MgCl](2) und er formation of MeAl[(CH2)(3)](2)NMe (13). MeAlCl2, MeGaCl2, or GaCl3 accor dingly react with one equivalent of organolithium reagent to give the intra molecularly nitrogen stabilized organoaluminum and organogallium chlorides MeClAl(CH2)(3)NMe2 (14), MeClGa(CH2)(3)NMe2 (15), MeClGaC6H4-2-CH2NMe2 (16) as well as Cl2GaC6H4-2-CHMeNMe2 (17). The compounds were characterized by elemental analyses, mass spectroscopy, H-1, B-11, C-13 and Al-27 NMR invest igations. Single crystal Xray structure analyses of 1, 2, 4, 5 and 17 revea l the monomeric molecular structures with intramolecular nitrogen coordinat ion.