Fluorogenic cyanine compounds for detecting nucleic acids

A cyanine compound having Formula 1a or 1b:

• wherein:
• each HBG is independently a hydrogen bonding group;
• Y and Z are each independently an optionally substituted monocyclic or multicyclic fused ring system;
• n is 0, 1, 2, or 3;
• X is O, S, NH, NR10, Se, C(R20)R21, Si(R20)R21, PH, PR20, or P(═O)R20;
• R1-R3 are independently selected from hydrogen, halogen, cyano, carboxy, optionally substituted alkyl, optionally substituted alkoxy, optionally substituted aryloxy, optionally substituted aryl, optionally substituted heteroaryl, SR10, NHR10, NR10R11, -L1-HBG, and -L2-HBG;
• R5 and R6 are independently selected from hydrogen, optionally substituted alkyl, halogen, carboxy, optionally substituted alkoxy, optionally substituted aryloxy, thiol, optionally substituted alkylthiol, optionally substituted arylthiol, azido, nitro, nitroso, cyano, amino, OH, a phosphonyl, a sulfonyl, a carbonyl, a boronyl, optionally substituted aryl, optionally substituted heteroaryl, -L1-HBG, and -L2-HBG, or R5 and R6 are cyclically linked to provide an optionally substituted monocyclic or bicyclic fused ring system;
• R7, R8, R10, R11, R20 and R21 are each independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, optionally substituted heteroaryl, -L1-HBG, and -L2-HBG;
• and
• L1 and L2 are each independently a linker;
• and
• W is an optional counterion;
• wherein each HBG moiety is independently connected to one of R1-R21, X, Y and Z through the linker L1 or L2.