Patent ID: 7597878

Claim:
A compound of the formula: wherein Cat + is a cation; r is an integer equal to 1, 2 or 3; X and Y are each independently O, S, Se, or (CH 3 ) 2 C; and R 8 and R 13 are each independently alkyl, L—R 25 or L—B; wherein at least one of R 8 and R 13 is L—B; R 25 is a member selected from the group consisting of optionally substituted alkyl, hydroxyl, thioacetyl and sulfanato; L is a linker; B is a ligand; n is 0, 1, 2 or 3; R 11 and R 12 are each independently F, H, sulfonato, or together with the atoms to which they are bonded form an aromatic ring; and R 16 and R 17 are each independently H, sulfonato, or together with the atoms to which they are bonded form an aromatic ring.