Synthesis and temperature-dependent NMR studies of monomeric and dimeric tris(dialkylamido)alanes

Abstract

After an introductory overview of all currently known tris(dialkylamido)alanes with the formula [Al(NR₂)₃]_n (n = 1, 2), a simplified synthetic method based on the usage of is presented. The simplification results from the fact that the ether adduct can already be obtained during the necessary synthesis of the alane moiety and that the use of trimethylamine is no longer required. Current conflicts regarding the experimental data of tris(diethylamido)alane and their interpretation have been resolved by means of single crystal structure analysis. The N-methylpiperazine derivative was described for the first time and characterised by various analytical methods. In temperature-dependent NMR measurements ranging from −35 °C to 90 °C coalescence phenomena of ¹³C and ¹H NMR signals of tris(N-methylpiperazino)alane as well as thermal migration of ¹H NMR signals of tris(diethylamido)alane were observed.