Water soluble fluorescent compounds

A fluorescent compound comprising a structure according to Formula I:

• wherein
• the dotted lines encircling X and Y are each independently selected from atoms necessary for the formation of one ring to three fused rings having 4 to 7 atoms in each ring;
• and
• at least one atom in the ring comprising Ca is a nitrogen;
• at least one atom in the ring comprising Cb is a nitrogen;
• w and z are integers independently selected from 0 to the number of atoms necessary for the formation of X or Y
• wherein
• w and z cannot both be 0;
• each R3 is a member independently selected from H, OR30, SR30, NR30R30, halogen, CN, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and a reactive functional group
• wherein
• two R3 groups, together with the atoms to which they are attached, can be optionally joined to form a ring;
• n is an integer selected from 0 to 4;
• R1 and R2 are members independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, halogen, reactive functional group, NO2, CN, P(O)(OR4)(OR5), D1R6, NR7R8 and C(D2)R9
• wherein
• at least one of R1 and R2 is P(O)(OR30)(OR30);
• D1 is a member selected from O and S;
• D2 is a member selected from O, S and NH;
• R4 and R5 are members independently selected from H, substituted or unsubstituted C1-C4 alkyl, substituted or unsubstituted C1-C4 heteroalkyl
• R6, R7 and R8 are members independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl and a reactive functional group;
• wherein
• R7 and R8, together with the nitrogen to which they are attached, can be optionally joined to form a member selected from a reactive functional group, —NHNH2, —N═N═N, —N═C═S and —N═C═O;
• R9 is a member selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, a reactive functional group, NR10R11 and OR12
• wherein
• R10 and R11 are members independently selected from H, substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl;
• R12 is a member selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl and C(O)R13
• wherein
• R13 is a member selected from substituted or unsubstituted alkyl and substituted or unsubstituted heteroalkyl
• wherein each R30 is independently selected from H, a negative charge, and a salt counterion.