A metal complex comprising actinium and a compound represented by Formula I wherein: A is (CHR 1) m or C; W is -C -(CH 2) p -; -C [-CH 2 -CH 2 -O] n -, -[CH 2 -CH 2 -O] n -(CH 2) 2 -, -C -[CH(R 3) t] q -, -(CH 2) m -O-(CH 2) n -, -(CH 2) m -S-(CH 2) n -, -(CH 2) m -S -(CH 2) n -, -(CH 2) m -S 2 -(CH 2) n -, or -(CH 2) m -NR a -(CH 2) n -, Y is-NH-, -NR 2 -, or X is -(C 1 -C 10)alkylene-(C 3 -C 10)arylene, -(C 3 -C 10)arylene, -(C 3 -C 10)arylene-(C 1 -C 10)alkylene-, phenylene, -(C 1 -C 10)alkylene-(C 3 -C 10)cycloalkylene, -(C 3 -C 10)cycloalkylene, or -(C 3 -C 10)cycloalkylene-(C 1 -C 10)alkylene-; R 1 and R 2 are each independently H, -(C 1 -C 10)alkyl, -C -(C 1 -C 10)alkyl, benzyl, -(C 3 -C 10)cycloalkyl, or -(C 3 -C 10)aryl; R a and R b are each independently H, -OH, -(C 1 -C 10)alkyl, -[CH 2 -CH 2 -O] n -(CH 2) 2 -T, -C -(C 1 -C 10)alkyl, -(C 1 -C 10)alkylene-C -, -(C 1 -C 10)alkylene-C -Z, benzyl, -(C 3 -C 10)cycloalkyl, -(C 3 -C 10)aryl-(C 1 -C 10)alkylene, -(C 3 -C 10)aryl, halo-(Ci-Cio)alkyl, hydroxy-(Ci-C 10)alkyl, -NH-(C 1 -C 10)alkyl, or -(C 1 -C 10)alkylene-NR d R e -, or R a and R b together with the nitrogen to which they are bonded form a (C 3 -C 6)-heteroaryl or (C 3 -C 6)-heterocycloalkyl; Z is-OH, -O(C 1 -C 10)alkyl, or R c is -OH, -O(C 1 -C 10)alkyl, -Obenzyl, -O(C 3 -C 10)cycloalkyl, -O(C 3 -C 10)aryl, -O-(C 1 -C 10)alkylene-(C 3 -C 10)aryl, or -O-(C 1 -C 10)alkylene-(C 3 -C 10)cycloalkyl, R 3 is H, halogen, -OH, -NH 2, -(CH 2) p -COOH, or -(CH 2) p - NH 2; T is-H, -OH, -COOH, or -NR d R e; R d and R e are each independently H, bond, -OH, -(C 1 -C 10)alkyl, or -(C 3 -C 10)heteroaryl-(C 1 -C 10)alkylene; m, n, p, q, t and r are each independently 0, 1, 2, 3, 4, 5, 6, 7, 8 9, or 10; and D is wherein any alkyl, alkylene, aryl, arylene, heteroaryl, heteroarylene, cycloalkyl, cycloalkylene, heterocycloalkyl, or heterocycloalkylene is optionally substituted with 1, 2, or 3 substituent groups selected from the group consisting of -(C 1 -C 10)alkyl, -(C 1 -C 10)haloalkyl,-(C 1 -C 10) aminoalkyl, -(C 1 -C 10)alkylene-COOH, -(C 1 -C 10)hydroxyalkyl, -OH, halogen, -NH 2, -COOH, -C -(C 1 -C 10)alkyl, -(C 1 -C 10)alkylene-C -, -(C 1 -C 10)alkylene-C -X,-NH-(C 1 -C 10)alkyl, and -(C 1 -C 10)alkylene-NR d R e -, and -NR d R e. A is (CHR 1) m or C; W is -C -(CH 2) p -; -C [-CH 2 -CH 2 -O] n -, -[CH 2 -CH 2 -O] n -(CH 2) 2 -, -C -[CH(R 3) t] q -, -(CH 2) m -O-(CH 2) n -, -(CH 2) m -S-(CH 2) n -, -(CH 2) m -S -(CH 2) n -, -(CH 2) m -S 2 -(CH 2) n -, or -(CH 2) m -NR a -(CH 2) n -, Y is-NH-, -NR 2 -, or X is -(C 1 -C 10)alkylene-(C 3 -C 10)arylene, -(C 3 -C 10)arylene, -(C 3 -C 10)arylene-(C 1 -C 10)alkylene-, phenylene, -(C 1 -C 10)alkylene-(C 3 -C 10)cycloalkylene, -(C 3 -C 10)cycloalkylene, or -(C 3 -C 10)cycloalkylene-(C 1 -C 10)alkylene-; R 1 and R 2 are each independently H, -(C 1 -C 10)alkyl, -C -(C 1 -C 10)alkyl, benzyl, -(C 3 -C 10)cycloalkyl, or -(C 3 -C 10)aryl; R a and R b are each independently H, -OH, -(C 1 -C 10)alkyl, -[CH 2 -CH 2 -O] n -(CH 2) 2 -T, -C -(C 1 -C 10)alkyl, -(C 1 -C 10)alkylene-C -, -(C 1 -C 10)alkylene-C -Z, benzyl, -(C 3 -C 10)cycloalkyl, -(C 3 -C 10)aryl-(C 1 -C 10)alkylene, -(C 3 -C 10)aryl, halo-(Ci-Cio)alkyl, hydroxy-(Ci-C 10)alkyl, -NH-(C 1 -C 10)alkyl, or -(C 1 -C 10)alkylene-NR d R e -, or R a and R b together with the nitrogen to which they are bonded form a (C 3 -C 6)-heteroaryl or (C 3 -C 6)-heterocycloalkyl; Z is-OH, -O(C 1 -C 10)alkyl, or R c is -OH, -O(C 1 -C 10)alkyl, -Obenzyl, -O(C 3 -C 10)cycloalkyl, -O(C 3 -C 10)aryl, -O-(C 1 -C 10)alkylene-(C 3 -C 10)aryl, or -O-(C 1 -C 10)alkylene-(C 3 -C 10)cycloalkyl, R 3 is H, halogen, -OH, -NH 2, -(CH 2) p -COOH, or -(CH 2) p - NH 2; T is-H, -OH, -COOH, or -NR d R e; R d and R e are each independently H, bond, -OH, -(C 1 -C 10)alkyl, or -(C 3 -C 10)heteroaryl-(C 1 -C 10)alkylene; m, n, p, q, t and r are each independently 0, 1, 2, 3, 4, 5, 6, 7, 8 9, or 10; and D is wherein any alkyl, alkylene, aryl, arylene, heteroaryl, heteroarylene, cycloalkyl, cycloalkylene, heterocycloalkyl, or heterocycloalkylene is optionally substituted with 1, 2, or 3 substituent groups selected from the group consisting of -(C 1 -C 10)alkyl, -(C 1 -C 10)haloalkyl,-(C 1 -C 10) aminoalkyl, -(C 1 -C 10)alkylene-COOH, -(C 1 -C 10)hydroxyalkyl, -OH, halogen, -NH 2, -COOH, -C -(C 1 -C 10)alkyl, -(C 1 -C 10)alkylene-C -, -(C 1 -C 10)alkylene-C -X,-NH-(C 1 -C 10)alkyl, and -(C 1 -C 10)alkylene-NR d R e -, and -NR d R e.