Bifunctional isothiocyanate derived thiocarbonyls as ligands for metal binding

A chelating agent of the formula:

• ##STR12## in which the NHCSNHR groups are in the 2,4- or 3,5-positions;
• and R is hydrogen or a substituent of the general formula:
• R=--(NH).sub.a (CH.sub.2).sub.b CY(NH).sub.d (CH.sub.2).sub.e --Z
• in which
• a=0 or 1;
• b=0-10;
• CY is C.dbd.S, C.dbd.O or CH.sub.2 ;
• d=0-2;
• e=1-10;
• Z=is H, N(R').sub.3.sup.+ X.sup.-, SO.sub.3 H, CO.sub.2 H, OH, H.sub.2 PO.sub.3 ;
• in which X.sup.- is a counterion such as a halide or an acid melt and R' is a C.sub.1 to C.sub.4 lower alkyl;
• and
• L comprises a reactive linker group selected from the group consisting of a primary amine, hydrazide, acid hydrazide, thioacid hydrazide, semicarbazide, thiosemicarbazide, reactive disulfide group, p-mercuribenzoate group, maleimide group, carboxylic acid, a carboxylic acid ester, an isothiocyanate, and succinate.

The chelating agent of claim 39 in which R is:

• --(NH).sub.a CY(CH.sub.2).sub.e Z
• in which
• a=0-2,
• e=0-10,
• CY is C.dbd.S, C.dbd.O or CH.sub.2 ;
• and
• Z is H, N(R').sub.3.sup.+ X.sup.-, SO.sub.3 H, CO.sub.2 H, OH, H.sub.2 PO.sub.3 ;
• in which X.sup.- is a counterion such as a halide or an acid salt and R' is a C.sub.1 to C.sub.4 lower alkyl.