Some metallofluorescent derivatives of 2,2'-diamino-diphenyl-n,n,n',n'-tetraacetic acid

The N,N,N',N'-tetraacetic acid derivatives of five 4,4'-disubstituted 2,2'-diaminodiphenyls have been prepared and their fluorescent properties examined. 2,2'-Diaminodiphenyl-4,4'-dicarboxylic acid-N,N,N',N'-tetraacetic acid exhibits intense fluorescence in aqueous solution above pH 4, and forms stable non-fluorescent l:1 complexes with copper(II) and nickel(II) ions at pH 7.5. The quenching of the fluorescence of the compound by nickel(II) may be used in the fluorimetric determination of nickel.