Constrained geometry addition polymerization catalysts

#The present invention relates to metal coordination complexes having constrained geometry. The invention also relates to certain novel addition polymerization catalysts comprising such metal complexes having constrained geometry. Furthermore, the invention relates to methods for the polymerization of addition polymerizable monomers and to the resulting polymers.

#Because of the unique exposure of the active metal site of the metal coordination complexes having constrained geometry, catalysts resulting therefrom have unique properties. Under certain conditions, the catalysts of the invention are capable of preparing novel olefin polymers having previously unknown properties due to their unique facile abilities to polymerize α-olefins, diolefins, hindered vinylidene aliphatic monomers, vinylidene aromatic monomers and mixtures thereof.

#Numerous metal coordination complexes are known in the art including such complexes involving monocyclopentadienyl groups and substituted monocyclopentadienyl groups. The present metal coordination complexes differ from those previously known in the art due to the fact that the metal is bound to a delocalized substituted π-bonded moiety in a manner so as to induce a constrained geometry about the metal. Preferably the metal is bound to a cyclopentadienyl, substituted cyclopentadienyl or similar group by both a η5-bond and a bridging linkage including other ligands of the metal. The complexes also preferably include metals having useful catalytic properties.

#FIGS. 1-5 are computer generated models of constrained geometry complexes of the invention based on single crystal X-ray data.

#FIGS. 6 and 7 are computer generated models of metal complexes based on single crystal X-ray data showing less constrain than those of FIGS. 1-5.

#FIGS. 8-13 illustrate calculated and observed distribution of styrene, ethylene and reversed styrene units in ethylene/styrene copolymers observing pseudo-random incorporation rules according to the invention.

#By use of the term “delocalized π-bonded moiety” is meant an unsaturated organic moiety, such as those comprising ethylenic or acetylenic functionality, wherein the π-electrons thereof are donated to the metal to form a bond. Examples include alkene-, alkenyl-, alkyne-, alkynyl-, allyl-, polyene-, and polyenyl moieties as well as unsaturated cyclic systems.

#By use of the term “constrained geometry” herein is meant that the metal atom is forced to greater exposure of the active metal site because of one or more substituents on the delocalized π-bonded moiety. Preferably the delocalized π-bonded moiety is a cyclopentadienyl or substituted cyclopentadienyl group forming a portion of a ring structure wherein the metal is both bonded to an adjacent covalent moiety and is held in association with the delocalized π-bonded moiety through η5 bonds. It is understood that each respective bond between the metal atom and the constituent atoms of the delocalized π-bonded moiety need not be equivalent. That is the metal may be symetrically or unsymetrically π-bound to the π-bonded moiety.

#The geometry of the active metal site is further defined as follows. The centroid of the π-bonded moiety may be defined as the average of the respective X, Y, and Z coordinates of the atomic centers forming the π-bonded moiety. The angle, Θ, formed at the metal center between the centroid of the π-bonded moiety and each other ligand of the metal complex may be easily calculated by standard techniques of single crystal X-ray diffraction. Each of these angles may increase or decrease depending on the molecular structure of the constrained geometry metal complex. Those complexes wherein one or more of the angles, Θ, is less than in a similar, comparative complex differing only in the fact that the constrain-inducing substituent is replaced by hydrogen have constrained geometry for purposes of the present invention. Preferably one or more of the above angles, Θ, decrease by at least 5% more preferably 7.5% compared to the comparative complex. Highly preferably, the average value of all bond angles, Θ, is also less than in the comparative complex. Most preferably the metal coordination complex having constrained geometry is in the form of a ring structure, i.e. the constrain-inducing substituent is part of a ring system which includes the metal.