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.
本发明涉及二
螯合剂,特别是含有两个大环螯合基团的化合物,这些基团通过含有酯或酰胺键的桥连接,特别是公式Vb的化合物:##STR1## (其中每个X可能相同或不同,为NZ,O或S,至少两个X为NZ;每个Z为R.sup.1基团或CR.sup.1.sub.2Y基团,每个大环上至少一个Z,最好是2或3个Z为CR.sup.1.sub.2Y基团;每个Y为CO.sub.2H,PO.sub.3H,SO.sub.3H,CONR.sup.1.sub.2,CON(OR.sup.1)R.sup.1,CNS或CONR.sup.1NR.sup.1.sub.2基团,最好是COOH;m为0或1或2,最好为1;每个n为2或3,最好为2;q为1或2,最好为1;每个R.sup.1可能相同或不同,为氢原子或烷基基团,可选地被一个或多个羟基和/或烷氧基取代;D为桥连基团,其分子量小于1000,最好小于500,通过至少一个酰胺或酯键连接两个大环环)。以及其盐和
金属螯合物。