Patent ID: 8183378

Claim:
A ligand of Formula I: wherein: a) R 1 , R 2 , R 3 and R 4 , are independently selected from the group consisting of hydrogen, halogen, hydroxy, C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 1 -C 10 alkoxy, C 1 -C 10 alkylthio, C(O)R 5 , C(O)OR 5 , C(O)NHR 5 , Si(R 5 ) 3 , benzyl and aryl; b) X is selected from the group consisting of Cl, Br, I, OR 6 , O-Prot, OPR 6 , P(R 6 ) 2 , NHR 6 , N(R 6 ) 2 , NHCSNHR 6 , NHCONHR 6 and SR 6 ; and c) R 5 and R 6 are independently selected from the group consisting of hydrogen, C 1-10 alkyl, C 2-10 alkenyl, C 2-10 alkynyl, C 1-10 alkoxy, phenyl, and aryl.