A composition having the formula I where R1 and R2 are independently hydrogen, C1 to C12 linear and branched alkyl, C3 to C12 cycloalkyl, aryl, C1 to C12 alkoxy, F, Cl, SO3, C1 to C12 perfluoroalkyl, and N(CH3)2, R3 is independently selected from the group consisting of hydrogen, C1 to C12 linear and branched alkyl, C3 to C12 cycloalkyl, aryl, and 2,2,2-trifluoroethyl, A is —C(R4)—, —(CH2)x—, —(CH2)xNH(CH2)x—, or —CY2CY2—, where R4 is a hydrocarbyl, halosubstituted hydrocarbyl, or alkoxy group of from 1 to 12 carbon atoms, x is an integer from 1 to 12, and Y is halogen, and X is halogen, triflate, acetate, trifluoroacetate, hydride, or tetrafluoroborate. When combined with an activating co-catalyst is useful in polymerizing olefinic monomers.