Catalyst system for the polymerization of olefins

1. A catalyst system for the polymerization of olefins comprising the product obtained by contacting:

(A) at least one transition metal organometallic compound, pirrolydil bis(η-cyclopentadienyl)methylzirconium being excluded, and

(B) an organometallic compound obtainable by contacting:

a) a Lewis base having formula (I):

 wherein R a , R b , R c and R d , equal to or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated, C 1 -C 10 alkyl, C 6 -C 20 aryl, C 7 -C 20 arylalkyl and C 7 -C 20 alkylaryl groups, optionally containing O, S, N, P, Si or halogen atoms, or two or more adjacent substituents R a , R b , R c and R d form one or more C 4 -C 7 rings, optionally containing O, S, N, P or Si atoms, that can bear substituents; with

b) a Lewis acid of formula (II)

MtR 1 3   (II)

 wherein Mt is a metal belonging to Group 13 of the Periodic Table of the Elements; R 1 , equal to or different from each other, are selected from the group consisting of halogen, halogenated C 6 -C 20 aryl and halogenated C 7 -C 20 alkylaryl groups; two R 1 groups optionally form with the metal Mt one condensed ring; and

(C) optionally an alkylating agent.

2. The catalyst system according to claim 1 , wherein the organometallic compound (B) has formula (III):

 wherein Mt is a metal belonging to Group 13 of the Periodic Table of the Elements; R 1 , eqaul to or different from each other, are selected from the group consisting of halogen, halogenated C 6 -C 20 aryl and halogenated C 7 -C 20 alkylaryl groups; two R 1 groups optionally form with the metal Mt one condensed ring;

and the substituents R 5 , R 4 , R 3 and R 2 ,eqaul to or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated C 1 -C 10 alkyl, C 6 -C 20 aryl, C 7 -C 20 arylalkyl and C 7 -C 20 arylalkyl groups, optionally containing O, S, N, P, Si or halogen atoms, or two or more adjacent substituents R 2 -R 5 from one or more C 4 -C 7 rings, optionally containing O, S, N, P or Si atoms; with the proviso that at least one of the substituents R 5 , R 4 , R 3 and R 2 is different from hydrogen.

3. The catalyst system according to claim 1 , wherein the organometallic compound (B) has formula (IV):

 wherein Mt is a metal belonging to Group 13 of the Periodic Table of the Elements; R 1 , eqaul to or different from each other, are selected from the group consisting of halogen, halogenated C 6 -C 20 aryl and halogenated C 7 -C 20 alkylaryl groups; two R 1 groups optionally form with the metal Mt one condensed ring; the substituents R 2 ′, R 3 ′, R 4 ′ and R 5 ′, equal to or different from each other, are selected from the group consisting of hydrogen, halogen, linear or branched, saturated or unsaturated C 1 -C 10 alkyl, C 6 -C 20 aryl, C 7 -C 20 arylalkyl and C 7 -C 20 arylalkyl groups, optionally containing O, S, N, P, Si or halogen atoms, or two or more adjacent substituents R 2 ′, R 3 ′, R 4 ′ and R 5 ′ form one or more C 4 -C 7 rings optionally containing O, S, N, P or Si atoms, that can bear substituents; said rings are aliphatic and optionally contain double bonds, with the proviso that said rings are not aromatic.

4. The catalyst system according to claim 1 , wherein the transition metal organometallic catalyst compound has the following formula (VIII):

(Cp)(ZR 7 m ) n (A) r ML p   (VIII)

wherein (ZR 7 m ) n is a divalent group bridging Cp and A; Z being C, Si, Ge, N or P, and the R 7 groups, equal to or different from each other, being hydrogen or linear or branched, saturated or unsaturated C 1 -C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl or C 7 -C 20 arylalkyl groups or two R 7 form an aliphatic or aromatic C 4 -C 7 ring;

Cp is a substituted or unsubstituted cyclopentadienyl group, optionally condensed to one or more substituted or unsubstituted, saturated, unsaturated or aromatic rings, containing from 4 to 6 carbon atoms, optionally containing one or more heteroatoms;

A is O, S, NR 8 PR 8 , wherein R 8 is hydrogen, a linear or branched, saturated or unsaturated C 1 -C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl or C 7 -C 20 arylalkyl, or A has the same meaning of Cp;

M is a transition metal belonging to group 3, 4, 5, 6 or to the lanthanide or actinide groups of the Periodic Table of the Elements:

the substituents L, equal to or different from each other, are monoanionic sigma ligands selected from the group consisting of hydrogen, halogen, R 9 , OR 9 , OCOR 9 , SR 9 , NR 9 2 and PR 9 2 , wherein R 9 is a linear or branched, saturated or unsaturated C 1 -C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl or C 7 -C 20 arylalkyl group, optionally containing one or more Si or Ge atoms;

m is 1 or 2, being when Z is N or P, and being 2 when Z is C, Si or Ge;

n is an integer ranging from 0 to 4;

r is 0, 1 or 2; n is 0 when r is 0;

p is an integer equal to the oxidation state of the metal M minus r+1.

5. The catalyst system according to claim 1 , wherein the transition metal organometallic catalyst compound has the following formulas (IX) or (X):

L a M a A a   (X)

wherein M a is a metal belonging to Group 8, 9, 10 or 11 of the Periodic Table of the Elements;

L a is a bidentate or tridentate ligand of formula (XI):

wherein:

B is a C 1 -C 50 bridging group linking E 1 and E 2 , optionally containing one or more atoms belonging to Groups 13-17 of the Periodic Table;

E 1 and E 2 , the same or different from each other, are elements belonging to Group 15 or 16 of the Periodic Table and are bonded to said metal M a ;

the substituents R a1 , equal to or different from each other, are selected from the group consisting of hydrogen, linear or branched, saturated or unsaturated C 1 -C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl and C 7 -C 20 arylalkyl radicals, optionally containing one or more atoms belonging to groups 13-17 of the Periodic Table of the Elements; or two R a1 substituents attached to the same atom E 1 or E 2 form a saturated, unsaturated or aromatic C 4 -C 7 ring, having from 4 to 20 carbon atoms; m a and n a are independently 0, 1 or 2, depending on the valence of E 1 and E 2 , so to satisfy the valence number of E 1 and E 2 ; q a is the charge of the bidentate or tridentate ligand so that the oxidation state of M a X a p , or M a A a is satisfied, and the compound (IX) or (X) is overall neutral;

X a , the same or different from each other, are monoanionic sigma ligands selected from the group consisting of hydrogen, halogen, R a , OR a , OSO 2 CF 3 , OCOR a , SR a , —NR a 2 and PR a 2 groups, wherein the R a substituents are linear or branched, saturated or unsaturated, C 1 -C 20 alkyl, C 3 -C 20 cycloalkyl, C 6 -C 20 aryl, C 7 -C 20 alkylaryl or C 7 -C 20 arylalkyl radicals, optionally containing one or more atoms belonging to groups 13-17 of the Periodic Table of the Elements; or two X a groups form a metallacycle ring containing from 3 to 20 carbon atoms;

p a is an integer ranging from 0 to 3, so that the final compound (IX) or (X) is overall neutral; and

A a is a π-allyl or a π-benzyl group.