27Al NMR spectroscopy of ethylaluminum halides

Abstract 27 Al NMR data for the dimeric compounds of the (Et 3- n AlX n ) 2 type ( n = 0-3; X = Cl, Br and I) have been determined. A characteristic U-shaped relationship between the 27 Al NMR chemical shift and the value of n was found, together with a correlation between available 27 Al nuclear quardrupole coupling constants (NQCC) and the δ( 27 Al) NMR values for four-coordinate Al atoms. On the bases of this correlation, it is concluded that the U-shaped relationship arises principally from the changes in the groud-state charge-distribution at Al nucleus.