Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I).

##STR00001##

Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I).

##STR00001##

Embodiments of the present disclosure are directed towards metal complexes that can be utilized to form polymers. As an example, the present disclosure provides a metal complex of Formula (I) wherein M is Zr, Hf, or Ti; each Het is independently a heterocyclic; each L is independently a bridging group; each X is independently Cl, Br, I, or alkyl; each R.sup.1 is independently selected from the group including hydrogen, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, aromatic rings, fused aromatic rings, and combinations thereof; and each n is independently an integer having a value of one to five. ##STR00001##

Embodiments of the present disclosure are directed towards metal complexes that can be utilized to form polymers. As an example, the present disclosure provides a metal complex of Formula (I) wherein M is Zr, Hf, or Ti; each Het is independently a heterocyclic; each L is independently a bridging group; each X is independently Cl, Br, I, or alkyl; each R.sup.1 is independently selected from the group including hydrogen, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, aromatic rings, fused aromatic rings, and combinations thereof; and each n is independently an integer having a value of one to five. ##STR00001##

Catalyst compositions and polymerization systems include at least one thiourea complex according to Formula (I): MQ.sub.aX.sub.4-a (I) in which M is Ti, Zr, or Hf; a is 1 or 2; each group Q of the thiourea complex is a bidentate thiourea ligand bound to the metal center and having Formula (Ia), Formula (Ib), or Formula (Ic): (Formulas should be inserted here). In Formulas (Ia), (Ib), and (Ic), each group R.sup.1, R.sup.2, and R.sup.3 is independently chosen from alkyl groups or aryl groups; each group Z.sup.1 or Z.sup.2 is independently chosen from alkylene groups. If a=2, groups R.sup.1 of the two groups Q are optionally linked, or groups R.sup.3 of the two groups Q are optionally linked. Each X is covalently bonded or coordinated to the metal center and is independently chosen from alkyl groups or halides. The polymerization systems may be configured to copolymerize ethylene and -olefins.

##STR00001##

Catalyst compositions and polymerization systems include at least one thiourea complex according to Formula (I): MQ.sub.aX.sub.4-a (I) in which M is Ti, Zr, or Hf; a is 1 or 2; each group Q of the thiourea complex is a bidentate thiourea ligand bound to the metal center and having Formula (Ia), Formula (Ib), or Formula (Ic): (Formulas should be inserted here). In Formulas (Ia), (Ib), and (Ic), each group R.sup.1, R.sup.2, and R.sup.3 is independently chosen from alkyl groups or aryl groups; each group Z.sup.1 or Z.sup.2 is independently chosen from alkylene groups. If a=2, groups R.sup.1 of the two groups Q are optionally linked, or groups R.sup.3 of the two groups Q are optionally linked. Each X is covalently bonded or coordinated to the metal center and is independently chosen from alkyl groups or halides. The polymerization systems may be configured to copolymerize ethylene and -olefins.

##STR00001##

Embodiments of the present disclosure are directed towards metal complexes that can be utilized to form polymers. As an example, the present disclosure provides a metal complex of Formula (I) wherein M is Zr, Hf, or Ti; each Het is independently a heterocyclic; each L is independently a bridging group; each X is independently Cl, Br, I, or alkyl; each R.sup.1 is independently selected from the group including hydrogen, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, aromatic rings, fused aromatic rings, and combinations thereof; and each n is independently an integer having a value of one to five.

##STR00001##

Embodiments of the present disclosure are directed towards metal complexes that can be utilized to form polymers. As an example, the present disclosure provides a metal complex of Formula (I) wherein M is Zr, Hf, or Ti; each Het is independently a heterocyclic; each L is independently a bridging group; each X is independently Cl, Br, I, or alkyl; each R.sup.1 is independently selected from the group including hydrogen, alkyls, alkenyls, alkynyls, cycloalkyls, aryls, acyls, aroyls, alkoxys, aryloxys, alkylthiols, dialkylamines, alkylamidos, alkoxycarbonyls, aryloxycarbonyls, carbomoyls, alkyl- and dialkyl-carbamoyls, acyloxys, acylaminos, aroylaminos, aromatic rings, fused aromatic rings, and combinations thereof; and each n is independently an integer having a value of one to five.

##STR00001##

Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I). ##STR00001##

Processes of polymerizing olefins include contacting ethylene, a (C.sub.3-C.sub.40)alpha-olefin comonomer, and a solvent in the presence of a chain transfer agent and a catalyst system, the catalyst system comprising a metal-ligand complex according to formula (I). ##STR00001##