Catalyst for olefin polymerization and polymerization method using same

A catalyst composition for olefin polymerization, comprising a main catalyst and a cocatalyst, wherein the main catalyst comprises a bisphenol metal complex represented by Formula Ia:

• wherein R1 and R1′ are each independently selected from hydrogen and substituted or unsubstituted C1-C20) hydrocarbyl;
• R3-R7 and R3′-R7′ are each independently selected from hydrogen and substituted or unsubstituted C1-C20 hydrocarbyl, and any two adjacent groups of R3-R7 are optionally joined to form a ring, and any two adjacent groups of R3′-R7′ are optionally joined to form a ring;
• R8 and R9 are each independently selected from hydrogen and substituted or unsubstituted C1-C20 hydrocarbyl;
• each R is independently selected from hydrogen and substituted or unsubstituted C1-C20 hydrocarbyl;
• M and M′ are each independently a Group 4 metal;
• each X is independently selected from hydrocarbyl having 1 to 20 carbon atoms, hydride, amido, alkoxide, alkyl sulfide, alkyl phophide, halide, diene, amine, phosphine, and ether;
• and
• m and n are independently an integer selected from 1, 2, 3, and 4;
• and
• wherein the cocatalyst comnprises an organoaluminum compound.