Rhodamine dyes and conjugates

1. A composition comprising a rhodamine dye or a salt thereof with the general structure of

having a single functional group wherein the R1, R2, R3, R4 and R5 groups are independently selected as follows:

R5 is independently H,

R4 is independently H,

R3 is independently H,

R2 is independently H or

and R1 is H,

wherein the rhodamine dye is capable of conjugating with another molecule via the functional group; and wherein the Ar on the substituent is an aryl group, the R6 R7 on the substituents form a spacer which contains a single functional group on either R6 or R7 suitable for conjugating with another molecule.

2. The composition of claim 1 wherein the functional group is selected from the group consisting of amines, alcohols, isocyanates, isothiocyanates, thiols, and carboxylic acids.

3. The composition of claim 1 wherein the other molecule is a macromolecule.

4. The composition of claim 3 wherein the macromolecule is selected from the group consisting of polymers, proteins, polysaccharides, polysaccharide derivatives, lipids and nucleic acids.

5. The composition of claim 4 wherein the protein is an antibody.

6. The composition of claim 4 wherein the nucleic acid is a DNA or an RNA.

7. The composition of claim 1 wherein the salt is selected from the group consisting of trifluoroacetate, chloride, hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, isonicotinate, acetate, lactate, salicylate, citrate, tartrate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, fortmate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzensulfonate and p-toluenesulfonate.

8. The composition of claim 1 wherein the salt is trifluoroacetate or chloride.

9. The composition of claim 1 wherein the salt is a pharmaceutically acceptable salt.

10. The composition of claim 1 wherein the spacer is selected from the group consisting of alkyl, aryl, amide, alkyl sulfonamide, alkyl ether, alkyl amine and alkyl amide.

11. The composition of claim 10 wherein the alkyl groups have a carbon chain length of 1 to 20.

12. The composition of claim 1 wherein R6 and R7 are connected to form a cyclic structure.

13. The composition of claim 12 wherein the cyclic structure is

14. The composition of claim 1 wherein R1, R2, R4 and R5 are H and R3 is

15. The composition of claim 14 undergoing a re-arrangement to form an isomer having the structure of

16. The composition of claim 15 wherein the rhodamine dye is a salt.

17. The composition of claim 16 wherein the salt is dichloride.

18. The composition of claim 15 wherein the rhodamine dye is capable of conjugating with another molecule via the amino functional group to form a single isomeric conjugation product.

19. The composition of claim 2 wherein the functional group is an amine.

20. The composition of claim 10 wherein the spacer is alkyl amine.

21. The composition of claim 4 wherein the polysaccharide is a dextran.

22. The composition of claim 4 wherein the polysaccharide derivative is carboxymethylated-dextran.

23. The composition of claim 1 wherein R1, R2, R4 and R5 are H and R3 is

24. The composition of claim 1 wherein R1, R2, R4 and R5 are H and R3 is

25. The composition of claim 24 wherein the other molecule is carboxymethylated-dextran.

26. The composition of claim 1 wherein R1, R2, R4 and R5 are H and R3 is

27. The composition of claim 26 wherein the other molecule is carboxymethylated-dextran.

28. The composition of claim 14 wherein the other molecule is carboxymethylated-dextran.

29. The composition of claim 1 wherein R1, R2, R3 and R4 are H, R5 is

one of R6 or R7 is

and the other of R6 or R7 is H.

30. The composition of claim 29 wherein the other molecule is carboxymethylated-dextran.