| 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 (V) (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 R1 or a group CR12Y, at least one Z, and preferably 2 or 3 Zs, on each macrocyclic ring being a group CR12Y; each Y is a group CO2H, PO3H, SO3H, CONR12, CON(OR1)R1, CNS or CONR1NR12, 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 R1 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, other than an unsubstituted carbonylaminoethylaminocarbonyl 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. |