Anthony KERMAGORET - THESES ET MEMOIRES DE L'UDS

Chapitre V
The catalytic results, presented in Table 5, showed that increasing the amount of cocatalyst
produced more active systems but less selective in C4 olefins and in 1-butene. Very active
system the isomerization of 1-butene in 2-butene and favored the reinsertion of 1-butene and
2-butene to form C6 oligomers. 76
Some tetrahedral iron(II) complexes have shown good activities in oligomerization and
polymerization of ethylene 72, 73 and it was therefore interesting to test 12 with different
cocatalysts and study its reactivity. However, activities of 12 with 200 equiv. of MAO or 6
equiv. of AlEtCl2 were very low and only traces of butenes were detected by gas
chromatography. The hexacoordinated mononuclear iron complexes 10 and 11 containing two
ligands around the metal centre showed no activity with MAO or AlEtCl2 as cocatalyst,
perhaps because the coordination sphere of the iron center in saturated which disfavors
ethylene coordination to the metal centre. A similar situation was observed with other inactive
77, 78
iron complexes containing two C,N,C pincer ligands.
Table 5. Comparative Catalytic Data for Complexes 6, 8 and 9 in the Oligomerization of Ethylene
a, b
with AlEtCl2 as Cocatalyst.
EADC
Selectivity (mass %)
(equiv) C4 C6 C8
Productivity
[g C2H4/(g Ni·h)]
TOF
[mol C2H4/(mol Ni·h)]
α-olefin (C4)
(mol %)
6 6 53 43 4 26400 55600 8 0.57
6 10 54 42 4 29500 61800 9 0.55
8 6 90 10