This invention further relates to a novel olefin polymerization systems comprising an activator and one or more catalysts represented by the of the following formulae: wherein R1 to R5 may be independently hydrogen, a heteroatom containing group or a C1 to C100 group provided that one of R2 to R5 is a group containing a heteroatom (R5 and/or R1 also may or may not be bound to the metal M), and fur