Patent ID: 7030257

Claim:
A compound having the formula (I): wherein: M is a transition metal selected from Groups 4 to 10 (IUPAC, 1990); R a is H or C1 to C6 alkyl, optionally substituted; y is an integer of 1 or 2; R b is H, or a vinyl group having the formula (II): or the formula (IIA): or the formula (IIB): wherein R c is H or C1 to C6 alkyl, optionally substituted; R 1 and R 2 are independently selected from C1 to C6 alkyl, optionally substituted; R 3 and R 4 are independently selected from H or C1 to C6 alkyl, optionally substituted; and n is an integer of 2 or 3.