Alkylaluminum Complexes Containing Pyridyl Amido Ligands. Syntheses, Structures, and NMR Spectroscopic Studies of [Al(CH3)2(NHCH2-2-Py)]2, [Al(CH3)2(NHCH2-4-Py)]2, [Al(CH3)2(HNCH2-4-Py)Al(CH3)3]2, and Al(CH3)3(NH2CH2-4-Py)Al(CH3)3

Abstract

The reactions of Al(CH3)3 with 2-(aminomethyl)pyridine and 4-(aminomethyl)pyridine have been investigated. The reaction of Al(CH3)3 with 2-(aminomethyl)pyridine in a 1:1 ratio in toluene yields a cis dinuclear compound [Al(CH3)2(NHCH2-2-Py)]2 (1), where the aluminum center is five-coordinate. The reaction of Al(CH3)3 with 4-(aminomethyl)pyridine in a 1:1 ratio in toluene yields a four-coordinate dinuclear compound [Al(CH3)2(NHCH2-4-Py)]2 (2), while the reaction in a 2:1 ratio yields the adduct Al(CH3)3(NH2CH2-4-Py)Al(CH3)3 (4) initially which changes to the tetranuclear compound [Al(CH3)2(HNCH2-4-Py)Al(CH3)3]2 (3) in solution and in the solid state. Compound 3 can also be obtained by the reaction of Al(CH3)3 with 2 in a 2:1 ratio in toluene. Both cis and trans isomers are present in solution for compounds 2 and 3, but only the crystals of the trans products were obtained. The structures of compound 1 and the trans products of 2 and 3 were determined by X-ray diffraction analyses.