4-Aminonaphthalimide

Electron donor groups in the 4-position of naphthalimides increase electron transfer to the electron-withdrawing carbonyl groups in the 1,8-positions, giving products that are strongly fluorescent. Commercially the most important products are based on N-substituted-4-aminonaphthalimides (3.6), as illustrated by Cl Disperse Yellow 11 (3.6a) and Cl Solvent Yellow 43 (3.6b). 

Naphthalimide Dyes. Derivatives of 4-aminonaphthalimide were used initially to dye acetate fibers. For polyesters, condensation products of 1,8-naphthalenedicar-boxylic acid (e.g., 19) or 1,4,5,8-naphthalenetetracarboxylic acid [128-97-2] with 1,2-diaminobenzenes are used. 

The 4-aminonaphthalimides and their /V-alkylatcd derivatives are brilliant greenish yellow fluorescent dyes. A cylation of the amino group at the 4-position of the naphthalimide ring shifts the fluorescence toward blue [111], yielding compounds suitable for use as optical brighteners, such as 4-acetylamino-7V-(//-butyl)naph-thalimide [3353-99-9] [112],... 

Recently, proton sponge was used as a fluorescent indicator for protons257. By incorporating the residue of 1 into the structure of the known fluorophore, 4-aminonaphthalimide, the researchers designed the fluorescent switch 274, whose synthesis was conducted in 5 steps with overall yield ca 10%. 

The photophysical properties of polyacene molecules depend markedly on the number of rings and the fluorescence behaviour of hexacene has now been compared with that of earlier members of the series. A similar comparison has been made of the photophysical properties of catacondensed aromatic poly-cycles. Fluorescence from an upper-excited singlet state has been described for benz[a]azulene derivatives while the fluorescence properties of some antiaromatic molecules have been described in detail. Several thiopyrylium and pyrylium salts have been studied and the effects of various substituents attached to the heterocycle have been examined in terms of the triplet yield. A full evaluation of the photophysical properties of 4-aminonaphthalimide, and its... 

One Lucifer Yellow derivative is available for labeling sulfhydryl-containing molecules. Lucifer Yellow iodoacetamide is a 4-ethyliodoacetamide derivative of the basic disulfonate aminonaphthalimide fluorophore structure (Molecular Probes). The io-doacetyl groups react with —SH groups in proteins and other molecules to form stable thioether linkages (Fig. 240). 

Tian, Chen, and their team at the East China University of Science and Technology, Shanghai, also exploit the special features of aminonaphthalimide-... 

Compound 1 is poorly fluorescent because the emission has to compete with photoinduced electron transfer (PET)45 7 from the yV-arylaza-15-crown-5 ether receptor to the aminonaphthalimide fluorophore across the dimelhy-lene spacer. This receptor" successfully binds Na+ at the concentrations found in normal blood and is sufficiently selective against other ions like K" " and H" "." ... 

Another excellent example is Qian s 9 [46] with high selectivity in sensing. This was from a 2,6-bis(aminomethyl)pyridine receptor and also functions in neutral aqueous solution. Two aminonaphthalimide fluorophores are incorporated within this classic PET system. 

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