Patent ID: 7682601

Claim:
Chelating agent of the general formula: wherein m is 0 or 1; X is NR 4 or S; Y is SR 5 , NHR 6 or P(R 5 ) 2 ; R 1 and R 3 are the same or different and are selected from H, alkyl or aryl; R 2 is H, COOH, NHR 6 or (CH 2 ) n COOR 6 ; R 4 is H, alkyl, aryl, (CH 2 ) n COOR 6 or (CH 2 ) n OR 6 ; R 5 is H, alkyl, aryl, (CH 2 ) n COOR 6 or (CH 2 ) n OR 6 ; R 6 is H, alkyl or aryl; n is 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10; and wherein at least one of R 1 , R 3 , R 4 , R 5 , and R 6 is phenyl or benzyl.