Patent ID: 6951947

Claim:
A fluorescent compound of the formula: wherein: each m is 1; n is an integer ranging from 0 to 2; R 8 , R 11 and R 12 are separately CO, SO 2 , C═C(CN) 2 , S, O or C(CH 3 ) 2 ; each R 13 , is hydrogen, or an alkyl or branched alkyl substituted with charged groups to enhance water solubility and enhance photostability, each R 9 and R 10 is separately hydrogen, a charged group or an alkyl chain that can be substituted with charged groups to enhance water solubility or with reactive groups for conjugation to other molecules; wherein at least one R 9 is a charged group or a reactive group, or at least one R 9 alkyl chain chain is substituted with a charged group; and wherein each of said charged groups or reactive groups is separately SO 3 − , amide, ether, —NH—(C═O)—CH 2 -halide, amine maleimide, —N═C═S, acyl halide, succinimidyl ester, sulfosuccinimidyl ester, sulfonyl halide, sulfonyl azide, alcohol, thiol, semicarbazide hydrazine, hydroxylamine, or COO-Rx, wherein Rx is phenol or naphtol.