Vinamidine chelates of aluminium and gallium

The vinamidine aluminum and gallium complexes C5H7R2AlCl2N2 (8) and C5H7R2C l2GaN2 (9) (R = Me, Pr-i, Bu-t) are obtained from the corresponding vinamid ines and ECl3 (E = Al, Ga) in moderate yields. Crystal structure analyses o f 8a, 8b, 9a and 9c reveal a minor influence of the alkyl subtituents on th e structure of the six membered rings. Ab initio calculations demonstrate p olar Al-N and Ga-N bonds without significant pi-interaction. The calculated C-13- and Al-27-NMR shifts are reported.