Intermolecular electron transfer states of 1-methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium iodide obtained by constrained density functional theory

Abstract

Electron transfer (ET) states of 1-methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium iodide are responsible for its photophysics. Investigation of an ET state based on constrained density functional theory (CDFT) revealed that nonradiative decay from the ET excited state is mediated by the interaction of the iodine atom with the 1,8-naphthalimide or the imidazolium group.

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

“…In the presence of I – or Br – , MNEI/TENI showed strong fluorescence quenching via PET (Figure S1). , In these cases, it can be considered that the generated MNEI/TENI radical anion rapidly deactivated via ET from the MNEI/TENI radical anion to the I radical cation. Therefore, the radical anion was not generated in the presence of I – and Br – even though PET occurred.…”

“…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.…”

“…17 The fluorescence intensities decreased as the electronegativity decreased owing to charge transfer from anion to MNEI. 18,19 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. 20,21 The yellow chemical species was unstable to O 2 , and the yellow color gradually disappeared under an ambient condition.…”

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

“…1A), a 1,8-naphthalimide derivative, is designed as a versatile molecular sensor that exhibits a high affinity for anions due to the positive charge on the imidazolium group, allowing the detection of the electronegativity of a guest anion by fluorescence intensity. [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.…”

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

“…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.…”