Functionalized polyamine chelants and radioactive rhodium complexes thereof for conjugation to antibodies

A rhodium complex which comprises rhodium, in which at least a portion of the rhodium is radioactive rhodium, complexed with a compound of the formula:

• ##STR6## wherein:
• each R independently represents a straight-chained or branched alkylene group of 2 to 10 carbon atoms inclusive, with the proviso that for any two adjacent nitrogens connected by an R group the R group must provide at least three single bonds between the nitrogens it connects;
• each R.sup.1 independently represents hydrogen or a straight-chained or branched alkylene group of 1 to 10 carbon atoms inclusive;
• X an X.sup.1 represent H, or X and X.sup.1 taken together complete a bridging straight-chained or branched alkylene group of 2 to 10 carbon atoms inclusive or a bridging aralkylene group wherein the alkylene is a straight-chained or branched alkylene group of 2 to 10 carbon atoms inclusive, with the proviso that when X and X.sup.1 are taken together the group it represents must provide at least three single bonds between the adjacent nitrogens it connects;
• n is an integer of 0 or 1, provided that when the :
• group is bonded to the same nitrogen atom, n must be 0, otherwise n must be 1;
• y is an integer of 1 through 3 inclusive;
• and
• L is a linker/spacer group covalently bonded to, and replaces one hydrogen atom of, any one of the nitrogen or carbon atoms, said linker/spacer group being represented by the formula ##STR7## wherein:
• s represents an integer of 1;
• t represents an integer of 0 through 20 inclusive;
• R.sup.2 represents an electrophilic or nucleophilic moiety which allows for covalent attachment to an antibody or nucleophilic moiety which allows for covalent attachment to an antibody or fragment thereof, or a synthetic linker which can be attached to an antibody or fragment thereof;
• and
• .sup.Cyc represents an aromatic moiety, aliphatic heterocyclic moiety, or aromatic heterocyclic moiety, each of said moieties optionally substituted with one or more groups which do not interfere with binding to an antibody or antibody fragment.