Catalysts, catalyst systems, and methods for using the same

A catalyst represented by formula (Ia):

• wherein:
• each M is a group 4 metal;
• E is N;
• each of X1, X2, X3, and X4 is independently hydrogen, halogen, hydroxyl, —N(C1-C40 hydrocarbyl)2, C1-C40 hydrocarbyl, or substituted C1-C40 hydrocarbyl;
• each of R1, R2, and R3 is independently hydrogen, halogen, C1-C40 hydrocarbyl, substituted C1-C40 hydrocarbyl, C6-C10 aryl, substituted C6-C10 aryl, —NR′2, —SR′, —OR′, —OSiR′3, or —PR′2, wherein each R′ is hydrogen, halogen, C1-C10 alkyl, or C6-C10 aryl or one or both of R1 and R2 or R2 and R3 are joined to form a saturated ring, unsaturated ring, substituted saturated ring, or substituted unsaturated ring;
• each of R4, R5, 105 and 106 is independently hydrogen or Ci-C40 hydrocarbyl;
• and
• each of R6, R7, R8, R9, R10, R11, R12, R13, R14, R17, R18, R19, R20, R21, R22, R23, R24, and R25 is independently hydrogen, halogen, C1-C40 hydrocarbyl, substituted C1-C40 hydrocarbyl, C6-C10 aryl, substituted C6-C10 aryl, —NR′2, —SR′, —OR′, —OSiR′3, or —PR′2, wherein each R′ is hydrogen, halogen, C1-C10 alkyl, or C6-C10 aryl aryl, or one or more of R6 and R7, R7 and R8, R8 and R9, R10 and R11, R11 and R12, R12 and R13, R13 and R14, R17 and R18, R18 and R19, R17 and R20, R21 and R22, R22 and R23, R23 and R24, R24 and R25, and R21 and R25 are joined to form a saturated ring, unsaturated ring, substituted saturated ring, or substituted unsaturated ring.