Organometallic catalyst complex and polymerization method employing same

A process for providing a polymer, said process comprising contacting one or more ethylenically unsaturated hydrocarbon compounds with a catalyst composition that comprises a complex having the general formula

• where
• M represents a Group 3 metal atom;
• L represents a neutral Lewis base;
• z is an integer of from 0 to 2 inclusive;
• R1 is H or a monovalent organic group;
• each R2 is H, a halogen atom, or a monovalent organic group;
• each R3 independently is H, a halogen atom, a hydrocarbyl group, a hydrocarbyloxy group, a hydrocarbylthio group, a dihydrocarbylamino group, a disilylamino group, or a dihydrocarbylphosphino group;
• Q is a —N(CH3)2 group;
• and
• R4 is a divalent organic group,
• with the proviso that either or both of the following can be true:
• (1) two R2 groups can join so as to provide a substituted or unsubstituted hydrocarbylene group and (2) Rl can join with an R2 so as to provide a substituted or unsubstituted hydrocarbylene group, wherein said one or more ethylenically unsaturated hydrocarbon compounds comprise at least one polyene, said polymer constituting the polymerization product of said compounds.