Discrimination of Anionic Polysaccharides via Monomer-Excimer Switching and Photo-Induced Colorimetric Reaction of 1-Methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium

Abstract

1-Methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium can be a discriminator for anionic polysaccharides via monomer-excimer switching and photo-induced colorimetric reaction. In the system, the excimer fluorescence increases remarkably in the presence of sulfated polysaccharides. The degree of enhancement depends on the number of sulfate groups in its structure. In contrast, the degree of excimer enhancement is not significant in the presence of carboxylated polysaccharides probably due to a different photo-induced decay pathway. The solutions containing carboxylated polysaccharides certainly become yellow via a photo-induced colorimetric reaction.

Advances in fluorescent and colorimetric sensors for anionic species

“…Saimoto and co-workers have previously reported the anion sensing properties of charged receptor 41 [95], and have since reimplemented the system as a novel polysaccharide sensor in aqueous solution [96]. The presence of sulfate-containing polysaccharides, such as 42, induced a change in the wavelength of maximum emission from the monomer peak (395 nm) to a new excimer peak (495nm), as shown in Fig.…”

Unique Photophysical Properties of 1,8-Naphthalimide Derivatives: Generation of Semi-stable Radical Anion Species by Photo-Induced Electron Transfer from a Carboxy Group

“…The 1,8-naphthalimide (NI) derivatives are attractive species for developing anion sensors because they have an electron-deficient naphthalene ring capable of ET and PET. ,− We previously reported the interesting photophysical property of 1-methyl-3-( N -(1,8-naphthalimidyl)­ethyl)­imidazolium (MNEI), which consists of the NI group as a chromophore, an imidazole group as an anion receptor, and an N -ethyl linker . The fluorescence intensities decreased as the electronegativity decreased owing to charge transfer from anion to MNEI. , In addition, MNEI underwent a photo-induced colorimetric reaction, in which the MNEI aqueous solution became yellow in the presence of carboxylate derivatives by UV light irradiation. , The yellow chemical species was unstable to O 2 , and the yellow color gradually disappeared under an ambient condition. The colorimetric reaction of MNEI proceeded especially readily in the presence of molecules having multiple carboxy groups, such as succinate, citrate, and polyacrylate, or amphiphilic carboxylate derivatives such as laurate and phenylacetate. , In contrast, the yellowing reaction was not observed in the presence of the same amount of acetate, but it was slightly observed in the presence of a ca.…”

“…The fluorescence intensities decreased as the electronegativity decreased owing to charge transfer from anion to MNEI. , In addition, MNEI underwent a photo-induced colorimetric reaction, in which the MNEI aqueous solution became yellow in the presence of carboxylate derivatives by UV light irradiation. , The yellow chemical species was unstable to O 2 , and the yellow color gradually disappeared under an ambient condition. The colorimetric reaction of MNEI proceeded especially readily in the presence of molecules having multiple carboxy groups, such as succinate, citrate, and polyacrylate, or amphiphilic carboxylate derivatives such as laurate and phenylacetate. , In contrast, the yellowing reaction was not observed in the presence of the same amount of acetate, but it was slightly observed in the presence of a ca. 30-fold higher amount of acetate.…”

Machine Learning Analysis for Photo-Induced Phenomena of 1-Methyl-3-(N-(1,8- Naphthalimidyl)ethyl)imidazolium Salts

“…[1][2][3] While showing a potential as the fluorescent molecular sensor, MNEI shows yellow coloration with anionic polysaccharides upon irradiation. 4 Although MNEI can interact with various anions, its photo-induced phenomena are different depending on the guest anions. Hence, to use MNEI as a molecular sensor, we need to elucidate the applicable limit of MNEI, that is, the factors that cause the MNEI-anion complex to show fluorescence or coloration.…”

“…Conventional experimental and computational approaches show that complex chemical phenomena, such as non-adiabatic transition and excimer formation, are involved in the photoinduced process of MNEI complexes. [1][2][3][4] Hence, much time is required to detect and identify the physical characteristics that allow MNEI to act as an anion sensor. Furthermore, because the number of experimentally available MNEI salt is only a degree of countable, predicting the properties of unidentified chemical compounds is impossible.…”