Functionalized naphthalene fluorophores

A peptide or protein comprising a modified amino acid residue comprising a substituted naphthalene fluorophore,

• wherein the substituted naphthalene fluorophore has a structure:
• where R1 is a substituent selected from the group consisting of H, C1-C20 alkyl, C1-C20 alkoxy, an NMR active isotope or an alkyl or alkoxy group comprising an NMR active isotope, a substituted silyl, trialkylsilyl, diphenylalkylsilyl, triphenylalkylsilyl, a substituted phosphorous, dialkylphosphino, diphenylphosphino, phenyl, substituted phenyl, aryl, substituted aryl, heteroaryl, —S(O)R4, —S(O)2R4, P(O)(OR4)2, and —C(Y)R4 where Y is O, NR5, or S;
• each R2 is a halogen, an NMR active isotope or an alkyl or alkoxy group comprising an NMR active isotope, a substituted silyl, trialkylsilyl, diphenylalkylsilyl, triphenylalkylsilyl, a substituted phosphorous, dialkylphosphino, diphenylphosphino, or an electron donating group selected from —N(R6)2, —OR6, and —SR6;
• each R3 is H, C1-C20 alkyl, an NMR active isotope or an alkyl or alkoxy group comprising an NMR active isotope, a substituted silyl, trialkylsilyl, diphenylalkylsilyl, triphenylalkylsilyl, a substituted phosphorous, dialkylphosphino, diphenylphosphino, or combined as ═O;
• each R4, R5 and R6 is independently selected from H, C1-C20 alkyl, C1-C20 alkoxy, a substituted silyl, trialkylsilyl, diphenylalkylsilyl, triphenylalkylsilyl, a substituted phosphorous, dialkylphosphino, diphenylphosphino, an NMR active isotope or an alkyl or alkoxy group comprising an NMR active isotope, substituted or unsubstituted phenyl, aryl, heteroaryl, benzyl, or two R6 groups on an R2 group may come together to form a cyclic structure;
• X is CH2, C(R6)2, C(CO2Alkyl)2, O, NTs, NH, NCOR5 or NR5;
• n is an integer from 0 to 2;
• m is an integer from 1 to 4, provided that either R1 is one of —S(O)R4, —S(O)2R4, P(O)(OR4)2, and —C(Y)R4 or the R3 groups are combined as ═O, wherein one or R1, R2, and R3 has reacted with a residue on an amino acid to form the modified amino acid.