Patent ID: 8637691

Claim:
An ansa-metallocene comprising a compound having the formula: wherein: M 1 is zirconium or hafnium; X′ and X″ are independently F, Cl, Br, I, H, BH 4 , methyl, phenyl, benzyl, neopentyl, trimethylsilylmethyl, CH 2 CMe 2 Ph, CH 2 SiMe 2 Ph, CH 2 CMe 2 CH 2 Ph, or CH 2 SiMe 2 CH 2 Ph; E is C or Si; R 1 and R 2 are independently an alkyl group, an aryl group, or hydrogen; R 3A and R 3B are independently a hydrocarbyl group, a trihydrocarbylsilyl group, or hydrogen; n is an integer from 0 to 10, inclusive; and R 4A and R 4B are independently a hydrocarbyl group.