NMR-STUDIES ON THE REACTIVITY OF ALUMINUM COMPOUNDS WITH AN UNSATURATED ALCOHOL

The interaction of an unsaturated alcohol, 10-undecen-1-ol (CH2=CH(CH2 )(3)CH2OH), with aluminium compounds AlEt3 and MAO (30% toluene soluti on) has been studied. The reactions were investigated at room and elev ated temperatures and followed by H-1, C-13 and Al-27 NMR-spectroscopy . The alcohol end group of 10-undecen-1-ol reacts quantitatively with aluminium alkyls (AlEt3 as well as AlMe3 present in MAO), liberating a lkane gas and forming in the first step the dimeric complexes [R-2'AlO R](2) and [R'Al(OR)(2)](2) (R' = Me, Et; R = 10-undecen). In the prese nce of excess 10-undecen-1-ol the alkyl aluminium alkoxides are found to generate tetrameric aluminium compounds, Al-4(R')(n)(OR)(12-n) (n = 6,4) containing six-coordinated central aluminium surrounded by six o xygen atoms. The structural assignment is based on C-13 as well as Al- 27 NMR, where narrow resonances at 8.21 and 7.3 ppm are observed for A l4Me6(OR)(6) and Al4Et6(OR)(6), respectively. Besides the above reacti on between the alcohol moiety and AlR3 another effect was also visible in the reaction of 10-undecen-1-ol with MAO. Broad carbon resonances were observed in C-13 NMR at the downfield side of the normal olefinic and alkoxy carbon resonances, indicating some kind of interaction of methylaluminoxane with the corresponding carbon atoms.