Organometallic complex, olefin polymerization catalyst system and polymerization process

A polymerization process comprising polymerizing ethylene optionally with one or more than one C3-C12 alpha-olefin in the presence of an olefin polymerization catalyst system comprising:

• i) an organometallic complex represented by formula I:
• wherein
• M is Ti, Zr or Hf;
• R1 and R2 are each independently selected from the group consisting of hydrogen and RX;
• or R1 and R2 together with the P atom to which they are attached form a 3-10 membered heterocyclic group which is unsubstituted or further substituted by one or more substituent selected from the group consisting of a halogen atom, a C1-20 alkyl group, a C1-20 alkoxy group, a C7-20 alkylaryl group, a C7-20 arylalkyl group, a C6-20 aryl group, a C6-20 aryloxy group, a C7-20 alkylaryloxy group, and a C7-20 arylalkyloxy group;
• each RX is independently selected from the group consisting of a halogen atom;
• a C1-30 hydrocarbyl group, which hydrocarbyl group is unsubstituted or further substituted by one or more than one halogen atom, C1-20 alkyl group, C1-20 alkoxy group, C7-20 alkylaryl group, C7-20 arylalkyl group, C6-20 aryl group, C6-20 aryloxy group, C7-20 alkylaryloxy group, and/or C7-20 arylalkyloxy group;
• an amido group of the formula —NR′2;
• a silyl group of the formula —Si(Ra)3;
• a germanyl group of the formula —Ge(Ra)3;
• and a phosphinimine group of the formula —N═P(Rb)(Rc)(Rd);
• wherein each R′ is independently selected from the group consisting of hydrogen, C1-20 alkyl group, and
• C6-20 aryl group;
• wherein each Ra is independently selected from the group consisting of hydrogen, C1-8 alkyl group, C1-8 alkoxy group, C6-20 aryloxy group and C6-20 aryl group;
• and Rb, Rc, Rd, are each independently a C1-20 alkyl group;
• each X1 is an activatable ligand;
• Cy is a cyclopentadienyl-type ligand covalently bound to L and coordinated to M via η-bonding;
• and
• L is a bridging group containing a contiguous chain of atoms connecting P with Cy, wherein the contiguous chain of atoms consists of 2 or 3 atoms;
• and
• ii) a catalyst activator.