Carborane trianion based catalyst

A Ziegler-Natta catalyst for olefin polymerization comprising a metal cation of Group 4 or 14 of the Periodic Table (IUPAC 1976), wherein the catalyst is represented by the general formula

• [(R1)n(Rd)mA(R2)E]MX (I),
• wherein:
• A is a C2B9H10-carborane dianion;
• R1 is methyl, ethyl or phenyl, and n is 0 or 1, said R1 being attached to a carbon atom of A;
• Rd is a halide, an O-alkyl or N-alkyl group, and m is 0 or an integer from 1 to 3, said Rd being attached to a boron atom of A;
• R2 is a bridge consisisting of a constrained chiral center enriched ring having two to four carbon atoms between A and E, at least one of which carbon atoms being chiral, said bridge having the formula (—WR2)n, wherein W is C or Si and may be same or different in the bridge, R may be same or different and is selected from H, halogen, methyl, ethyl, propyl, butyl or isomers thereof and n is an integer from 5 to 8;
• E is a heteroatom anion selected from [NR3]− or O−, which is bridged to A via R2, E being optionally substituted by R3 anion, wherein R3 is a C1–C12-hydrocarbyl aliphatic or aromatic group;
• M is a fourvalent metal cation selected from the group consisting of titanium, zirconium, hafnium and tin;
• and
• X is a valence group.

A Ziegler-Natta catalyst for olefin polymerization comprising a metal cation of Group 4 or 14 of the Periodic Table (IUPAC 1976), wherein the catalyst is represented by the general formula

• [(R1)n(Rd)mA(R2)E]MX (I),
• wherein:
• A is a C2B9-carborane dianion;
• R1 is methyl, ethyl or phenyl attached to a carbon atom of A;
• n is 1;
• m is 0;
• R2 is a cyclohexyl ring having two carbon atoms between A and E;
• E is —[NR3]— or —O−;
• wherein R3 is a C1–C12-hydrocarbyl aliphatic group, E being bridged to A via R2;
• M is a fourvalent metal cation selected from the group consisting of titanium and zirconium;
• and
• X is a valence group.

A process for preparing a Ziegler-Natta catalyst for olefin polymerization comprising:

• a) reacting [(R1)n(Rd)m(C2B9H11)] with an organic base, and an electrophilic compound comprising at least two backbone atoms;
• b) reacting the compound obtained in a) with an alkali metal hydroxide in the presence of a quaternary ammonium salt;
• and
• c) reacting the compound obtained in b) with an organic base and MXZ3;
• wherein R1 is selected from the group consisting of C1–C12-hydrocarbyl aliphatic group, C1–C12-aromatic group and a polymer chain, optionally linked to a support, preferably a polymer chain, said polymer chain comprising ethylene, propylene monomer units, said unit optionally being substituted by C1–C12-hydrocarbyl aliphatic or aromatic groups, said support serving to immobilize the ZN catalyst;
• Rd is selected from the group consisting of H, a C1–C12-hydrocarbyl aliphatic group, C1–C12-hydrocarbyl aromatic group, a halide, an O-alkyl group and N-alkyl group;
• at least one of the backbone atoms is a chiral center;
• M is a fourvalent metal cation of Group 4 or 14 of the Periodic Table (IUPAC 1976) and
• X is a valence group saturating the remaining coordination valence of the central metal atom;
• Z is a leaving group selected from halide, sulfonate, or NR′R″, wherein R′ is hydrogen, alkyl, aryl, alkylaryl or arylalkyl and R″ is alkyl, aryl, alkylazyl or arylakyl.

A method of polymerizing olefins comprising reacting olefin monomers or mixtures thereof in the presence of a Ziegler-Natta catalyst for olefin polymerization wherein the catalyst is represented by the general formula

• [(R1)n(Rd)mA(R2)E]MX (I)
• wherein:
• A is a carborane dianion;
• R1 is a H, C1–C12-hydrocarbyl aliphatic or aromatic group and n is 0 or 1, said R1 being attached to a carbon atom of A;
• Rd is H, a C1–C12-hydrocarbyl aliphatic or aromatic group, a halide, an O-alkyl or N-alkyl group and m is 0 or an integer from 1 to 5, said Rd being attached to a boron atom of A;
• R2 is a constrained chiral center enriched hydrocarbyl bridge comprising at least two carbon atoms, wherein at least one bridging carbon atom may be replaced by Si;
• E is a heteroatom anion of group 15 or 16 of the Periodic Table (IUPAC), which is bridged to A via R2;
• M is a fourvalent metal cation selected from the group consisting of titanium, zirconium, hafnium and tin;
• and
• X is a valence group saturating the remaining coordination valence of the central metal atom.

A method for preparing a Ziegler-Natta catalyst for olefin polymerizations, wherein the catalyst is represented by the general formula

• [(R1)n(Rd)mA(R2)E]MX
• comprising:
• a) reacting [(R1)n(Rd)mA] with an organic base, and an electrophilic compound comprising the moiety (R2)E;
• b) reacting the compound obtained in (a) with an alkali metal hydroxide in the presence of a quaternary ammonium salt;
• and
• c) reacting the compound obtained in (b) with an organic base and MXZ3;
• wherein
• A is a carborane dianion;
• R1 is H, a C1–C12-hydrocarbyl aliphatic or aromatic group and n is 0 or 1, said R1 being attached to a carbon atom of A;
• Rd is H, a C1–C12-hydrocarbyl aliphatic or aromatic group, a halide, an O-alkyl or a N-alkyl group and m is 0 or an integer from 1 to 5, said Rd being attached to a boron atom of A;
• R2 is a constrained chiral center enriched hydrocarbyl bridge comprising at least two carbon atoms, wherein at least one bridging carbon atom may be replaced by Si;
• E is a heteroatom anion of group 15 or 16 of the Periodic Table (IUPAC), which is bridged to A via R2;
• M is a fourvalent metal cation selected from the group consisting of titanium, zirconium, hafnium and tin;
• X is a valence group saturating the remaining coordination valence of the central metal atom;
• and
• Z is a leaving group selected from halide, sulfonate, and NR′R″, wherein R′ is H, alkyl, aryl, alkylaryl or arylalkyl and R″ is alkyl, aryl, alkylaryl or arylalkyl.