Patent ID: 7323566

Claim:
A compound having the structural formula: where R 1 is H, C 1 -C 30 alkyl, or C 1 -C 30 alkyl having a substituent of C 6 -C 18 aryl, or a heteroatom containing group where the heteroatom is oxygen, nitrogen, or sulfur; R 2 is H, X, or Sn(C 1 -C 6 alkyl) 3 ; X is F, Cl, Br, or I; R 3 is H, X or Sn(C 1 -C 6 alkyl) 3 ; R 4 , R 5 and R 6 are each independently H, nitro, amino, hydroxyl, X, or C 1 -C 30 alkyl having a substituent of C 6 -C 18 aryl; or Sn(C 1 -C 6 alkyl) 3 with the proviso that at least one of R 4 , R 5 and R 6 is nitro, amino, hydroxyl, X or Sn(C 1 -C 6 alkyl) 3 ; and when R 5 is NH 2 , OH or X; R 4 is H; and R 6 is H; then at least one of R 2 and R 3 is X; R 7 and R 8 are each independently H, C 1 -C 6 alkyl group, a C 1 -C 6 alkyl group having a substituent of C 6 -C 18 aryl; where R 7 and R 8 are optionally fused to form a ring structure, the ring structure optionally having a heteroatom therein and optionally having pendent groups therefrom, the pendent groups each independently selected from H, C 1 -C 8 alkyl, or a C 1 -C 8 alkyl group having a substituent of hydroxyl, amine, sulfonate, thiol, carboxyl, substituted amine or quaternary amine; wherein at least one of R 2 -R 6 is X and wherein X in at least one occurrence is a radioisotope.