Macrocyclic polyaza dichelates linked through ring nitrogens via an amide or ester functionality

Abstract

This invention relates to dichelants, in particular compounds having two macrocyclic chelant groups linked by a bridge containing an ester or amide bond, especially compounds of formula Vb ##STR1## (wherein each X which may be the same or different is NZ, O or S, at least two Xs being NZ; each Z is a group R.sup.1 or a group CR.sup.1.sub.2 Y, at least one Z, and preferably 2 or 3 Zs, on each macrocyclic ring being a group CR.sup.1.sub.2 Y; each Y is a group CO.sub.2 H, PO.sub.3 H, SO.sub.3 H, CONR.sup.1.sub.2, CON(OR.sup.1)R.sup.1, CNS or CONR.sup.1 NR.sup.1.sub.2, preferably COOH; m is 0 or 1 or 2, preferably 1; each n is 2 or 3, preferably 2; q is 1 or 2, preferably 1; each R.sup.1 which may be the same or different is a hydrogen atom or an alkyl group optionally substituted by one or more hydroxy and/or alkoxy groups; and D is a bridging group having a molecular weight of less than 1000, preferably less than 500, joining two macrocyclic rings via at least one amide or ester bond) and salts and metal chelates thereof.

Dependencies are inferred from the claim text.