| abstract |
PROBLEM TO BE SOLVED: To provide a catalyst capable of efficiently and inexpensively polymerizing a conjugated diene or copolymerizing a conjugated diene with an aromatic vinyl compound. SOLUTION: This is a polymerization catalyst such as a conjugated diene, which comprises a metallocene-type cation complex of a gadolinium compound, for example, a general formula (I): R a GdX b (where Gd represents gadolinium; A pentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a fluorenyl group, or a substituted fluorenyl group; X represents an anion; a represents an integer of 1 or 2; Which is a metallocene-type cation complex of a trivalent gadolinium compound represented by the following formula: [Selection diagram] Fig. 1 |