A comparison of the NMR, mass spectral, and molecular structure data for [R 2AlN(CH 2Ph) 2] 2, where R=Me, Et, Pr n, Bu n, and Bu i

Abstract

Aminoalane dimers of the formula [R 2AlN(CH 2Ph) 2] 2, where R=Pr n , Bu n , and Bu i , were synthesized by thermolysis of the corresponding 1:1 mixtures of the trialkylaluminum and dibenzylamine at 120 °C. The 1H and 13C NMR spectra of the series [R 2AlN(CH 2Ph) 2] 2, where R=Me ( 1), Et ( 2), Pr n ( 3), Bu n ( 4), and Bu i ( 5), were fully assigned using a combination of 1-D and 2-D NMR techniques. This series was also characterized by electron impact (EI) mass spectrometry and fragmentation patterns are discussed. The single-crystal X-ray structural data of [Et 2AlN(CH 2Ph) 2] 2 and [Bu n 2AlN(CH 2Ph) 2] 2 were determined and the data compared with those of [Me 2AlN(CH 2Ph) 2] 2 to identify any structural trends in the series with respect to R. The structural data for these three compounds are also compared with data for [MeAlN(H)CH 2Ph] 2, [RAlN(CH 2Ph)-μ-(CH 2C 6H 4)] 2, and Me 3Al·HN(CH 2Ph) 2. Finally, the molecular structure data of [Me 2MN(CH 2Ph) 2] 2 and Me 3M·HN(CH 2Ph) 2, where M=Al, Ga and In, are discussed in terms of the influence of the Group 13 metal.