Patent ID: 7598385

Claim:
A fluorescent dye comprising a compound having the following general structural formula I: wherein n is 1, 2 or 3; X is chosen from: C(CH 3 ) 2 , O, S or Se; R 1 and R 2 are each independently chosen from H, C 1-18 alkyl, —C 1-6 alkyl-OR 5 or halogen; R 3 is independently chosen from: H, C 1-18 alkyl, OR 5 , —C 1-6 alkyl-OR 5 , COOR 5 , NO 2 , CN or halogen; R 4 is C 1-18 alkyl, —C 1-6 alkyl-OR 5 , benzyl or halogen, said benzyl optionally substituted with one or more substituents independently chosen from: halogen, hydroxyl, sulfhydryl, cyano, nitro, alkyl, aryl, alkoxy, heterocyclyl, haloalkyl, amino, alkylamino, amido, or carboxyl; R 5 is H or C 1-18 alkyl; and Y − is a counter ion; or derivatives and conjugates thereof.