Rare earth metal complex, polymerization catalyst, and process for producing polymer

Abstract

A rare earth metal complex represented by the formula (1): in which A represents a Group 14 element of the periodic table, Cp represents a group having a substituted or unsubstituted cyclopentadienyl anion moiety, Ln represents a Group 3 metal atom or a lanthanoid metal atom, Rto Rare the same or different, and represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a silyl group substituted with a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, Rrepresents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, Xs represent a monoanionic ligand, Ys represent a neutral ligand, m represents an integer of 1 to 3, and n represents an integer of 0 to 3. The rare earth metal complex is useful as, for example, a catalyst for polymerization reaction of olefins. A polar monomer such as a lactone can be polymerized using the rare earth metal complex as a catalyst.