Olefin polymerization catalysts bearing a thiazole or imidazole

A polymerization process comprising:

• polymerizing ethylene and one or more olefins in the presence of a catalyst system under olefin polymerization conditions to form an ethylene-based polymer, the catalyst system comprising a metal-ligand complex according to formula (I):
• where:
• M is a metal chosen from titanium, zirconium, or hafnium, the metal having a formal oxidation state of +2, +3, or +4;
• each X is a monodentate or bidentate ligand independently chosen from unsaturated (C2-C50) hydrocarbon, unsaturated (C2-C50) heterohydrocarbon, (C1-C50) hydrocarbyl, (C6-C50) aryl, (C6-C50) heteroaryl, cyclopentadienyl, substituted cyclopentadienyl, (C4-C12) diene, halogen, —N(RN)2, or —NCORC;
• m is 1 or 2;
• n is 2 or 3, provided m+n=4;
• each Z is NRN or S, wherein RN is (C1-C40) hydrocarbyl or (C1-C40) heterohydrocarbyl;
• each R1 is a (C1-C40) hydrocarbyl or (C1-C40) heterohydrocarbyl;
• each R2 and R3 is independently selected from the group consisting of (C1-C50) hydrocarbyl, (C1-C50) heterohydrocarbyl, (C6-C50) aryl, (C4-C50) heteroaryl, —Si(RC)3, halogen, and —H, wherein RC is independently selected from the group consisting of (C1-C20) hydrocarbyl, (C1-C20) heterohydrocarbyl, and —H;
• and
• optionally, R2 and R3 are covalently linked to form a ring.