Provided is a catalyst for the polymerization of olefins of general formula:
wherein X is an hetero-atom ligand with one or two lone pair electrons selected
from the elements of Group VA or VIA which can be substituted or non-substituted:
(C4RmC5C4Rn)
is a symmetrically substituted, 3,6-substituted fluorenyl; R is hydrogen
or hydrocarbyl radical having from 1-20 carbon atoms, a halogen, an alkoxy, an
alkoxy alkyl or an alkylamino or alkylsilylo radical, each R may be the
same or different and m and n independently are 1, 2 3 or 4, with the proviso that
the bilateral symmetry is maintained; R is a structural bridge between
X and the (C4RmC5C4Rn)
ring to impart stereorigidity; Q is a hydrocarbyl radical having 1-20 carbon atoms
or is a halogen; Me is a Group IIIB, IVB, VB, or VIB metal as positioned in the
Periodic Table of Elements; and Me can be in any of its theoretically possible
oxidation states.
Also provided are olefin monomers (particularly propylene) polymerized using
these catalysts to form syndiotactic/atactic block polymers of high molecular weight
and comprising at least 70% of syndiotactic triads.
