| Abstract
| - Calculations indicate cationic aluminum amidinates should not polymerize ethene because chain transfer to monomer is easier, even with bulky substituents on the ligand. For neutral aluminum alkyls, a modest preference for propagation is predicted.
- The effect of substituent variation on olefin insertion and chain transfer in cationicaluminum amidinate alkyls [R1C(NR2)2AlEt]+ was studied by theoretical methods. Introduction of bulky substituents at C (t-Bu) and N (i-Pr) favors insertion more than chain transfer,but the system still keeps a clear preference for chain transfer, and even the full system[t-BuC(Ni-Pr)2AlEt]+ is predicted not to polymerize ethene. Changing to a neutral analogue(as in H2C(NH)2AlEt) and relieving the geometric constraints (in Me2AlEt) favor insertioneven more, so that trialkylaluminum is finally predicted to have a clear preference foroligomerization.
|
