US Patent 7863214 Catalysts for polymerizing cyclic olefin

Provided is a metal catalyst complex for preparing a cyclic olefin-based polymer by addition polymerization of a cyclic olefin-based monomer, which is represented by Formula 1 below:[M(L1)x(L′2)y(L3)z]a[Ani]b  <Formula 1>wherein M is a Group X metal; [M(L1)x(L′2)y(L3)z] is a cationic precatalyst; L1 is an anionic hydrocarbyl-containing ligand; L′2 is a neutral ligand; L3 is an N-heterocyclic carbene ligand; [Ani] is an anion capable of weakly coordinating with the metal M; x is 1 or 2; y is 0 to 4; z is 1 or 2; 2≦x+y+z≦6; a and b are each 1 to 10.