Catalysts compositions for the polymerization and copolymerization of alpha-olefins

A bridged metallocene compound containing two substituted indenyl ligands joined by a ridging group and complexed to a metal atom of formula (I):

• wherein:
• M is a transition metal atom selected from the group consisting of the atoms of Group 4 of the Periodic Table;
• R1 is an indenyl ligand;
• Q is a divalent group of formula ═SiR4R5 or —CH R4—CH R5—;
• wherein R4 and R5 are, independently, hydrogen atoms or monovalent radicals selected from halogen, C1-C20 alkyl, C6-C20 aryl, C2-C20 alkenyl, C7-C20 arylalkyl and C7-C20 alkylaryl, optionally containing oxygen and/or silicon atoms as substituents;
• R2 and R3 bonded to R1 at position 3 are, independently, hydrogen or a radical Ra, wherein Ra is a monovalent organic radical selected from C1-C20 alkyl, C2-C20 alkenyl and C7-C20 alkylaryl, said monovalent organic radical optionally containing oxygen and/or silicon atoms as substituents which are not bonded directly to the cyclopentadienyl ring moiety;
• R2′ and R3′ bonded to R1 at position 2 are, independently, hydrogen or a radical Ra, wherein Ra is as defined above;
• wherein at least one of R2 and R3is Ra, and
• when R2 is Ra, then R2′ is H, or
• when R3 is Ra, then R3′ is H, and
• when R2 and R3 independently are both Ra, then R2′ and R3′ are simultaneously H, with the proviso that
• when R2′ and R3′ are simultaneously hydrogen, then R2 and R3 are not simultaneously methyl (Me), iso-propyl (i-Pr) or tert-butyl (t-Bu) for rac isomer;
• or
• when R2′ and R3′ are simultaneously hydrogen, M is Zr or Hf, X1 and X2 are both Cl and Q is ═SiMe2, then R2 and R3 are not simultaneously pentenyl for rac and meso isomers;
• or when R2′ and R3′ are simultaneously hydrogen, M is Zr, X1 and X2 are both Cl and Q is ═SiMe2, then R2 and R3 are not simultaneously para-tolyl for rac and meso isomers;
• or when R2 is H then R3 is not Me, or when R2 is Me then R3 is not H for rac and meso isomers;
• or when R2, R2′, R3′ are H, M is Zr, X1 and X2 are both Cl and Q is ═SiMe2, then R3 is not benzyl, or when R2 is benzyl, R2′ and R3′ are both H, M is Zr, X1 and X2 are both Cl and Q is ═SiMe2, then R3 is not H for rac and meso isomers;
• and
• X1 and X2 are, independently, monovalent ligands selected from hydrogen, halogen, C1-C20 alkyl, C6-C20 aryl, C7-C20 alkylaryl, C7-C20 arylalkyl, C1-C20 hydrocarbyloxy, C6-C20 aryloxy, C1-C20 di(alkyl)amido and carboxylate;
• its racemic or meso stereoisomers and mixtures thereof.