Patent ID: 8907107

Claim:
A compound of formula (I) in which each A, which may be the same or different, is a halide selected from fluoride, chloride, bromide and iodide, or is O-Y, wherein Y is a substituted or unsubstituted, saturated or unsaturated, straight or branched chain alkyl moiety; R 1 , R 2 , R 3 , R 6 , R 7 , and R 8 are each independently H, OH, NO 2 or O-L-X, wherein L is a spacer group, and X is a conjugation group or a water-solubilizing group; with the proviso that at least one of R 1 , R 2 , R 3 is OH or O-L-X and at least one of R 6 , R 7 , and R 8 is OH or O-L-X; and each of R 4 and R 5 is phenyl.