The reactions of triethylaluminum with a series of 13 secondary amines (RH=HNMe2, HNEt2, HNPr2n, HNPr2i, HNBu2n, HNBu2i, HNBu2s, HNC4H8, HNC5H10, HNC6H12, HN(c-C6H11)2, HN(CH2Ph)2, and HNC4H8NMe) afford room-temperature stable, clear, colorless liquid complexes. These complexes were characterized by 1H and 13C NMR, IR and elemental analyses. Trends in the NMR chemical shift data are compared with data previously reported for the analogous trimethylaluminum, -gallium, and -indium compounds in terms of the steric properties of the amines. Subsequent thermolysis of these complexes yields dimeric aminoalanes via 1,2-elimination of ethane in all cases. The dimers were characterized by 1H and 13C NMR, IR, melting point, cryoscopic molecular weight determinations, and elemental analyses. The NMR chemical shift data are compared with known data for the [Me2AlR]2 and [Me2GaR]2 series. The molecular structures of [Et2AlN(c-C6H11)2]2 and [Et2AlNC4H8NCH3]2, obtained from X-ray crystal data, are presented and discussed in terms of the correlations between the structural parameters of the Al2N2 ring and the nature of the Al and N substituents. © Elsevier Science Ltd.