Catalytic systems for the polymerization and copolymerization of alpha-olefins

Metallocene compounds according to the following formulas:

• 21
• wherein:
• L, equal to or different from each other, is selected from the group comprising:
• cyclopentadienyl, indenyl, tetrahydroindenyl, fluorenyl, octahydrofluorenyl and benzoindenyl;
• each R is independently selected from hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, C7-C20 arylalkyl, C7-C20 alkylaryl, C8-C20 arylalkenyl, linear or branched, optionally substituted by 1 to 10 halogen atoms, or a group SiRII3;
• each RI, equal to or different from each other, is a divalent aliphatic or aromatic hydrocarbon group containing from 1 to 20 carbon atoms, optionally containing from 1 to 5 heteroatoms of groups 14 to 16 of the periodic table of the elements and boron;
• preferably it is:
• C1-C20 alkylene, C3-C20cycloalkylene, C6-C20 arylene, C7-C20 alkenyl, C7-C20 arylalkylene, or alkylarylene, linear or branched, or a group SiRII2;
• each RII is independently selected from C1-C20 alkyl , C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, C7-C20 arylalkyl, C8-C20 arylalkenyl or C7-C20 alkylaryl, linear or branched;
• preferably RII is methyl, ethyl or isopropyl;
• each Q is independently selected from B, C, Si, Ge, Sn;
• M is a metal of group 3, 4 or 10 of the Periodic Table, Lanthanide or Actinide;
• preferably it is titanium, zirconium or hafnium;
• each X is independently selected from:
• hydrogen, chlorine, bromine, ORII, NRII2, C1-C20 alkyl or C6-C20 aryl;
• L′ is N or O
• when L is cyclopentadienyl k is equal to 5, when L is indenyl k is equal to 7, when L is fluorenyl or benzoindenyl k is equal to 9, when L is tetrahydroindenyl k is equal to 11 and when L is octahydrofluorenyl, k is equal to 17;
• z is equal to 0, 1 or 2;
• x is equal to 1, 2 or 3;
• y is equal to 1, 2 or 3;
• x+y+z is equal to the valence of M;
• m is an integer which can assume the values 1, 2, 3 or 4;
• a and b are integers whose value ranges from 0 to k-1;
• f is an integer whose value ranges from 1 to k;
• g is an integer whose value ranges from 0 to 1;
• c and e are equal to 0 or 1;
• a+b+c is at least 1;
• a+g+c is at least 1;
• d is equal to 0, 1 or 2;
• when Q is B then c+d=1;
• when Q is C, Si, Ge or Sn, then c+d=2;
• when L is N, then g+e=1;
• when L′ is O, then g=0 and e=0.
• characterized in that at least one L is a fluorenyl, benzoindenyl or octahydrofluorenyl ring, optionally substituted by C1-C20 alkyl , C3-C20 cycloalkyl, C6-C20 aryl, C3-C20 alkenyl, C7-C20 arylalkyl, C8-C20 arylalkenyl or C7-C20 alkylaryl.