Patent ID: 7666886

Claim:
A compound of formula I: wherein R 1 -R 8 are selected from the group consisting of hydrogen, deuterium, tritium, fluoride, chloride, bromide, iodide, hydroxide, amino, methylamino, dimethylamino, trimethylammonium, methyl, ethyl, methoxy, ethoxy, fluoromethyl, difluoromethyl, trifluoromethyl, wherein at least one of R 5 -R 8 and one of R 1 -R 4 is H; and P is selected from wherein m is an integer between 1 and 20; q is an integer between 1 and 20; R 9 -R 16 are selected from the group consisting of hydrogen, deuterium, tritium, fluoride, chloride, bromide, iodide, hydroxide, amino, methylamino, dimethylamino, trimethylammonium, methyl, ethyl, methoxy, ethoxy, fluoromethyl, difluoromethyl, trifluoromethyl, wherein at least one of R 9 -R 12 and one of R 13 -R 16 is H; and X is hydrogen, methyl, or ethyl.