Patent ID: 7625621

Claim:
An antipyrine azo ligand of the formula (I) wherein A is cyano, C 1-4 alkoxy, carbamyl, —N—C 1-4 alkylcarbamyl, wherein the alkyl is unsubstituted or substituted by C 1-4 alkoxy; N-Phenylcarbamyl, wherein the phenyl is unsubstituted or substituted by C 1-4 alkyl or C 1- alkoxy; acetyl, benzoyl, 4-nitrophenyl or 4-cyanophenyl; R 1 and R 10 are independently selected from the group consisting of hydrogen, C 1-8 alkyl, phenyl and benzyl; R 2 , R 3 and R 4 independently are selected from the group consisting of hydrogen, —CH 3 , —C 2 H 5 , —CH(CH 3 ) 2 , phenyl, —CN, —Cl, —Br, —CN, and —CF 3 ; R 5 to R 9 independently are selected from the group consisting of hydrogen, —Cl, —CN, —Br, —CF 3 , C 1-4 alkyl, chloromethyl, C 1-4 -alkoxymethyl, phenoxymethyl, NO 2 and sulfonamide group.