Patent ID: 8822818

Claim:
A 4,4′-dicarboxy-2,2′-bipyridine derived tridentate ligand represented by formula (I): wherein Y 1 and Y 2 are independently selected from a group consisting of hydrogen and a C 1 -C 8 straight or branched chain alkyl group; and R is selected from a group consisting of wherein R 1 and R 4 are independently selected from a group consisting of hydrogen, a halogen atom, trifluoromethyl, a carboxylic group, and a C 1 -C 12 straight or branched chain alkyl group; and one of R 2 and R 3 is hydrogen, and the other of R 2 and R 3 is selected from a group consisting of a C 1 -C 12 straight or branched chain alkyl group, an alkoxyl, wherein R 21 and R 22 are independently selected from a group consisting of a C 1 -C 12 straight or branched chain alkyl group, an alkoxy group, an alkylsulfenyl group, and wherein R 23 and R 24 are independently selected from a group consisting of hydrogen, a C 1 -C 12 straight or branched chain alkyl group, an alkoxy group, and an alkylsulfenyl group.