Catalyst systems and methods for making and using the same. A catalyst system can include a non-metallocene catalyst having the structure: wherein M is a group 4 element, each of R13-R20 are independently a hydrogen or a methyl group, wherein at least one of R13-R20 is a methyl group, Ar is an aryl group or a substituted aryl group, Ar′ is an aryl group or a substituted aryl group, and each X is, independently, a hydride group, an amide, a benzyl group, a methyl group, a chloro group, a fluoro group, or a hydrocarbyl group.