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The electronic structure of the molecule is significantly influenced by the number of conjugated C=C bonds. In this work, the influence of the conjugated C=C bonds of the SNCN derivatives on the excited state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT) properties are studied by density functional theory (DFT) and time-dependent density functional theory (TDDFT). The calculation level is proved to be reasonable by calculating electronic spectra. The hydrogen bond parameters, infrared vibrational frequency (IR), reduction density gradient (RDG) isosurface, topological analysis and potential energy curves of SNCN derivatives in ground state (S0) and the first excited state (S1) are analyzed. According to theoretical research results, ESIPT reaction has a higher likelihood of occurring in the S1 state. Moreover, the ESIPT reaction becomes more challenging to occur with the number of conjugated C=C bonds rising. Finally, the analyses of the frontier molecular orbitals (FMOs), dipole moment and charge transfer transition confirm that the ICT effect is aided by the increased number of conjugated C=C bonds. This work indicates that the number of conjugated C=C bonds can regulate the ESIPT and ICT processes, which provides guidance for the study of fluorescent groups with similar characteristics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This work investigates the different charge transfer characteristics and excited state intramolecular proton transfer process (ESIPT) of 2'-aminochalcones derivatives carrying different electron-withdrawing groups. Four new molecules are designed in the experiment and named as 2c, 3c, 4c and 5c, respectively. (Dyes and Pigments, 2022, 202.) Based on these four molecules, the effect of substituents on the ESIPT process and the charge transfer process are discussed in detail in our work. According to the study of the related parameters at the hydrogen bond site, infrared vibration spectrum, interaction region indicator isosurface (IRI) and scatter plots, it is concluded that the hydrogen bond interaction is enhanced under photoexcitation, and the descending order of the excited state hydrogen bond strength is 3c > 5c > 4c > 2c. The hydrogen bond energy is calculated by atoms in moleculs (AIM) topological analysis and core-valence bifurcation (CVB) index. The potential energy curve reveals the ESIPT mechanism. Frontier molecular orbital and electron-hole analyses explain the reasons for the changes in the ESIPT process at the electronic level. In addition, the ionization potentials (IPa and IPv), affinity energies (EAa and EAv) and reorganization energies are calculated to evaluate the potential application value of organic molecules in material transport field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Arsenic (As) is a widespread metalloid and human carcinogen found in the natural environment, and multiple toxic effects have been shown to be associated with As exposure. As can be accumulated in the spleen, the largest peripheral lymphatic organ, and long-term exposure to As can lead to splenic injury. In this study, a Sprague-Dawley (SD) rat model of As-poisoned was established, aiming to explore the molecular mechanism of As-induced immune injury through the combined analysis of proteomics and metabolomics of rats' spleen. After feeding the rats with As diet (50 mg/kg) for 90 days, the spleen tissue of the rats in the As-poisoned group was damaged, the level of As was significantly higher than that of the control group (P < 0.001), and the level of inflammatory cytokine interleukin-6 (IL-6) was decreased (P < 0.01). Proteomics and metabolomics results showed that a total of 134 differentially expressed proteins (DEPs) (P < 0.05 and fold change > 1.2) and 182 differentially expressed metabolites (DEMs) (VIP >1 and P < 0.05) were identified in the spleens of the As poisoned group compared to the control group (As/Ctrl). The proteomic results highlight the role of hypoxia-inducible factors (HIF), natural killer cell mediated cytotoxicity, and ribosomes. The major pathways of metabolic disruption included arachidonic acid (AA) metabolism, glycerophospholipid metabolism and folate single-carbon pool. The integrated analysis of these two omics suggested that Hmox1, Stat3, arachidonic acid, phosphatidylcholine and leukotriene B4 may play key roles in the mechanism of immune injury to the spleen by As exposure. The results indicate that As exposure can cause spleen damage in rats. Through proteomic and metabolomic analysis, the key proteins and metabolites and their associated mechanisms were obtained, which provided a basis for further understanding of the molecular mechanism of spleen immune damage caused by As exposure., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Arsenic (As) is a highly toxic environmental toxicant and a known human carcinogen. Long-term exposure to As can cause liver injury. Dictyophora polysaccharide (DIP) is a biologically active natural compound found in the Dictyophora with excellent antioxidation, anti-inflammation, and immune protection properties. In this study, the Sprague-Dawley (SD) rat model of As toxicity was established using a feeding method, followed by DIP treatment in rats with As-induced liver injury. The molecular mechanisms of As toxicity to the rat liver and the protective effect of DIP were investigated by proteomic studies. The results showed that 172, 328 and 191 differentially expressed proteins (DEPs) were identified between the As-exposed rats versus control rats (As/Ctrl), DIP treated rats versus As-exposed rats (DIP+As/As), and DIP treated rats versus control rats (DIP+As /Ctrl), respectively. Among them, the expression of 90 DEPs in the As/Ctrl groups was reversed by DIP treatment. As exposure caused dysregulation of metabolic pathways, mitochondria, oxidative stress, and apoptosis-related proteins in the rat liver. However, DIP treatment changed or restored the levels of these proteins, which attenuated the damage to the livers of rats caused by As exposure. The results provide new insights into the mechanisms of liver injury induced by As exposure and the treatment of DIP in As poisoning., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

4-Aminophthalimide is a highly fluorescent signaling unit with excellent photophysical properties and wide application foregrounds. Based on this, a range of theoretical investigations are conducted on the fluorescent probe (E)-5-((2-hydroxybenzylidene) amino) isoindoline-1, 3-dione (HID) with the core of 4-aminophthalimide using density functional theory (DFT) and time-containing density functional theory (TD-DFT) methods in this paper. The optimized configurations, vertical excitation and emission energies, electronic characteristics and excited-state intramolecular proton transfer (ESIPT) behaviors of the probe HID are discussed in detail. Furthermore, to enhance the luminescent properties of HID, five novel compounds have been designed based on the structure of HID by introducing amino, methoxy and naphthalene groups (-NH 2 , -OMe and C 10 H 8 ). Our work thoroughly explores how the property and position of substituents and conjugation affect photophysical characteristics and ESIPT processes. We find that the ESIPT dynamics can be modulated by the substitution and conjugation effects. Specifically, the introduction of amino and methoxy groups at the ortho-position and the introduction of the naphthalene group promote the ESIPT behavior of HID1, whereas the introduction of amino and methoxy groups at the meta-position exhibits the contrary impact. Therefore, we boldly infer that the introduction of electron-donating groups in the ortho-position and the introduction of the conjugated group make the ESIPT process more effortless to occur, whereas the introduction of substituents with opposing natures in the meta-position makes the ESIPT process more difficult to occur. In addition, the ionization potentials (IP), electron affinities (EA) and reorganization energies (λ h and λ e ) of molecules are calculated to assess their potential as luminescent materials. Our work not only reveals the luminescence and ESIPT mechanism of the probe HID1, but also proposes to modulate the ESIPT process through the substitution and conjugation effects. In particular, the designed molecules have better photoelectric properties as a result of their red-shifted absorption and fluorescence spectra, smaller energy gaps, larger transferred charges and greater charge transferred distances, which offers some valuable ideas for the experimental development of more efficient organic luminescent materials with ESIPT properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Recently, based on the mechanism of excited-state intramolecular proton transfer (ESIPT), a new fluorescent probe named 3-(benzo[d]thiazol-2-yl)-5-bromosalicylaldehyde- 4 N-phenyl thiosemicarbazone (BTT) was successfully synthesized [Analyst 146 (2021) 4348-4356.]. However, the importance of ESIPT processes of BTT probe and the mechanism of detecting Zn 2+ ions have not been studied in detail. In this study, the photochemical behavior of ESIPT-chromophore and the photophysical changes of detecting Zn 2+ ions were explained at the molecular level for the first time. The calculated spectral values were in agreement with the experiment. We not only confirmed the excited state hydrogen-bond strengthening by interaction region indicator (IRI), but also scanned the potential energy curves of BTT molecule in different electronic states, which confirmed that the hydrogen proton is easier to transfer in the first excited state. In addition, we had given the reasonable structure of the BTT-Zn 2+ complex (L1) by comparing the binding free energies. The hole-electron distribution and interfragment charge transfer (IFCT) methods proved the excitation type of intraligand charge transfer (ILCT). Finally, the photophysical phenomenon of BTT for detecting Zn 2+ ions is explained by calculating the electronic spectra and the energy gap (E gap ) between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)