Reactions of bis(dialkylamino)aminophosphines
Reactions of bis(dialkylamino)aminophosphines
Bis(dialkylamino)aminophosphines react with trialkylalanes R3Al (R = Me, Et, i-Bu, t-Bu) quantitatively to iminophosphorane-trialkylalane adducts (R2N)2P(H)=NH→AlR3, while with dialkylalanes R2AlH (R = Me, Et) heterocycles of the type [(R2N)2P(H)N(H)AlR2]2 were obtained by H2 elimination [1].
Figure 1: Reactions of bis(dialkylamino)aminophosphines with organoaluminium compounds
Rearrangement of an H-atom from N to P yields the thermodynamically stable, tautomeric P(H)-iminophosphorane form selectively, which was also observed in reactions with group 4-metal complexes. According to theoretical studies this is due to the strong Lewis acid character of the neighbouring Al center [2].
Figure 2: Molecular structures of (Cy2N)2P(H)=NH→AlMe3 and [(Cy2N)2P(H)N(H)AlMe2]
References
[1] S. Schulz, M. Raab, M. Nieger, E. Niecke, Organometallics 2000, 19, 2616.
[2] (a) M. Raab, A. Sundermann, G. Schick, A. Loew, M. Nieger, W. Schoeller, E. Niecke Organometallics 2001, 20, 1770. (b) M. Raab, J. Tirrée, M. Nieger, E. Niecke Z. Anorg. Allg. Chem. 2003, 629, 769