Patent ID: 8030096

Claim:
A rhodamine dye or a salt thereof, comprising a rhodamine-type parent xanthene ring having attached to the xanthene C9 carbon a phenyl group that is further substituted with an ortho carboxy or ortho sulfonate group or a salt thereof, one to three substituted or unsubstituted aminopyridinium groups and a substituted or unsubstituted alkylthio, arylthio or heteroarylthio group, wherein the rhodamine dye comprises the structure: wherein: n is an integer selected from the group consisting of 1, 2, and 3; Y is a rhodamine-type parent xanthene ring attached to the illustrated phenyl group at the xanthene C9 carbon; each R is independently selected from the group consisting of a (C 1 -C 6 ) alkyl or heteroalkyl, a (C 5 -C 20 ) aryl or heteroaryl, a (C 6 -C 26 ) arylalkyl or heteroalkyl and a (C 5 -C 20 ) arylalkyl or heteroaryl-heteroalkyl, or when taken together, both R form a moiety selected from the group consisting of a (C 4 -C 10 ) alkyldiyl, a (C 4 -C 10 ) alkyleno, a heteroalkyldiyl and a heteroalkyleno; S is sulfur; Z is selected from the group consisting of a (C 1 -C 12 ) alkyl, a (C 1 -C 12 ) alkyl substituted with one or more of the same or different W 1 groups, a (C 5 -C 20 ) aryl or heteroaryl and a (C 5 -C 20 ) aryl or heteroaryl substituted with one or more of the same or different W 2 groups; W 1 is selected from the group consisting of —X, —R, ═O, —OR, —SR, ═S, —NRR, ═NR, —CX 3 , —CN, —OCN, —SCN, —NCO, —NCS, —NO, —NO 2 , ═N 2 , —N 3 , —S(O) 2 O − , —S(O) 2 OH, —S(O) 2 R, —C(O)R, —C(O)X, —C(S)R, —C(S)X, —C(O)OR, —C(O)O − , —C(S)OR, —C(O)SR, —C(S)SR, —C(O)NRR, —C(S)NRR and —C(NR)NRR; W 2 is selected from the group consisting of —R, —OR, —SR, —NRR, —S(O) 2 O − , —S(O) 2 OH, —S(O) 2 R, —C(O)R, —C(O)X, —C(S)R, —C(S)X, —C(O)OR, —C(O)O − , —C(S)OR, —C(O)SR, —C(S)SR, —C(O)NRR, —C(S)NRR and —C(NR)NRR; each X is independently a halogen; and Y or Z is optionally substituted with L, wherein L is a bond or a linker selected from the group consisting of a hydrophobic moiety, a charged group, a member of a pair of specific binding molecules, a photo-activatable group and a reactive functional group.