Patent ID: 7601666

Claim:
A composition represented by the formula: where M is hafnium or zirconium; each R 1 is methyl; each R 2 is independently selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl and the isomers thereof, provided that when R 3 and R 6 and or R 12 and R 15 form a 5 carbon ring, then each R 2 is independently selected from the group consisting of ethyl, propyl, butyl, pentyl, hexyl and the isomers thereof; R 3 is carbon; R 4 is CH 2 ; a is 1; R 5 is CH 2 ; b is 1; R 6 is carbon; and R 3 , R 4 , R 5 and R 6 are bound together to form a ring; each R 7 is hydrogen; each R 8 is hydrogen; each R 9 is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and a functional group, and two R 9 groups may be linked together to form a ring, R 9 and R 8 may be linked together to form a ring, R 9 and R 16 may be linked together to form a ring, R 9 and R 11 may be linked together to form a ring; c is 0; R 10 is -M 2 (R 16 ) h — where M 2 is Si, h is an integer from 1 to 2, such that the valence of M 2 is filled, and R 16 is hydrogen, hydrocarbyl, substituted hydrocarbyl or a functional group, and two R 16 groups may be linked together to form a ring; d is 1; each R 11 is independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and a functional group, and two R 11 groups may be linked together to form a ring R 11 and R 8 may be linked together to form a ring R 11 and R 16 may be linked together to form a ring; e is 1; where the sum of c, d, and e is 2; R 12 is carbon; R 13 is CH 2 ; f is 1; R 14 is CH 2 ; g is 1; and R 15 is carbon.