Patent ID: 8519070

Claim:
A pro-ligand of general formula I: wherein R 1 , R 3 , R 4 , R 5 , R 6 and R 7 are each independently selected from hydrogen, unsubstituted or substituted hydrocarbyl, or inert functional group, wherein two or more of said groups can be linked together to form one or more rings, wherein Z′ is O, S, or N═N and n is 0 or wherein n is 1 and Z′ is N, Z is an atom selected from group 14 of the Periodic Table, and R 2 is a substituted or unsubstituted aryl group having at most 8 carbon atoms with the restriction that Z(R 2 ) 3 is a bulky group, at least as bulky as tertio-butyl.