Pub Date : 2026-01-08DOI: 10.1016/j.molstruc.2026.145292
Dong-Mei Liu , Xiuyu Chen , Jing Sun , Chao-Guo Yan
Here we revealed a convenient synthetic protocol for unique chromeno[2,3-b]pyridine scaffolds with excellent regioselectvity and diastereoselectivity. The functionalized chromeno[2,3-b]pyridines were successfully synthesized by oxa-Diels-Alder reaction of 5,6-unsubstituted 1,4-dihydropyridines with various electron-withdrawing group activated 2-vinylphenols such as 2-(2-nitrovinyl)phenols, 2-(o-hydroxyarylidene)-1,3-indanediones and 5-(o-hydroxyarylmethylene)barbituric acids under mild conditions. The features of this reaction included mild reaction conditions, widely variety of substrates, high functional group tolerance, high diastereoselectvity and significant atomic economy. The determination of three single crystal structures clearly showed that the unique chromeno[2,3-b]pyridines with diverse functionalized groups were efficiently formed.
{"title":"Convenient synthetic protocol for unique chromeno[2,3-b]pyridine scaffolds via oxa-Diels-Alder reaction","authors":"Dong-Mei Liu , Xiuyu Chen , Jing Sun , Chao-Guo Yan","doi":"10.1016/j.molstruc.2026.145292","DOIUrl":"10.1016/j.molstruc.2026.145292","url":null,"abstract":"<div><div>Here we revealed a convenient synthetic protocol for unique chromeno[2,3-<em>b</em>]pyridine scaffolds with excellent regioselectvity and diastereoselectivity. The functionalized chromeno[2,3-<em>b</em>]pyridines were successfully synthesized by <em>oxa-</em>Diels-Alder reaction of 5,6-unsubstituted 1,4-dihydropyridines with various electron-withdrawing group activated 2-vinylphenols such as 2-(2-nitrovinyl)phenols, 2-(<em>o</em>-hydroxyarylidene)-1,3-indanediones and 5-(<em>o</em>-hydroxyarylmethylene)barbituric acids under mild conditions. The features of this reaction included mild reaction conditions, widely variety of substrates, high functional group tolerance, high diastereoselectvity and significant atomic economy. The determination of three single crystal structures clearly showed that the unique chromeno[2,3-<em>b</em>]pyridines with diverse functionalized groups were efficiently formed.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145292"},"PeriodicalIF":4.7,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-08DOI: 10.1016/j.molstruc.2026.145301
Andrés Verde, Juan Carlos López, Susana Blanco
The structure of the ortho-, meta- and para-isomers of anisaldehyde, a common benzene derivative, has been investigated by means of their broadband rotational spectra. The conformational landscape of each system was evaluated with the aid of quantum chemical calculations, resulting in a different number of potential conformers for each isomer. The detection of heavy-atom isotopologues has enabled the accurate determination of the experimental gas-phase structure of one conformer of ortho-anisaldehyde, three conformers of meta-anisaldehyde, and two conformers of the para-isomer. The comparison of the molecular structures of the isomers reveals several noteworthy features, including the planar skeleton in all the detected conformers. This feature is directly connected to the antioxidant properties of anisaldehydes, which make them highly valuable in a wide range of applications. The results of this work provide valuable insights into the impact of ortho-, meta-, and para-isomerism on the conformational landscape, molecular structure, aromaticity, and molecular electrostatic potential of a disubstituted aromatic compound.
{"title":"Conformational panorama, experimental structure and molecular properties of the ortho-, meta- and para-isomers of anisaldehyde","authors":"Andrés Verde, Juan Carlos López, Susana Blanco","doi":"10.1016/j.molstruc.2026.145301","DOIUrl":"10.1016/j.molstruc.2026.145301","url":null,"abstract":"<div><div>The structure of the <em>ortho</em>-, <em>meta</em>- and <em>para</em>-isomers of anisaldehyde, a common benzene derivative, has been investigated by means of their broadband rotational spectra. The conformational landscape of each system was evaluated with the aid of quantum chemical calculations, resulting in a different number of potential conformers for each isomer. The detection of heavy-atom isotopologues has enabled the accurate determination of the experimental gas-phase structure of one conformer of <em>ortho</em>-anisaldehyde, three conformers of <em>meta</em>-anisaldehyde, and two conformers of the <em>para</em>-isomer. The comparison of the molecular structures of the isomers reveals several noteworthy features, including the planar skeleton in all the detected conformers. This feature is directly connected to the antioxidant properties of anisaldehydes, which make them highly valuable in a wide range of applications. The results of this work provide valuable insights into the impact of <em>ortho</em>-, <em>meta</em>-, and <em>para</em>-isomerism on the conformational landscape, molecular structure, aromaticity, and molecular electrostatic potential of a disubstituted aromatic compound.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145301"},"PeriodicalIF":4.7,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, the inhibitory action of the organic compound N,N-dimethyl-4-(1,4,5-triphenyl-1H-imidazol-2-yl)aniline (IM-N(CH3)2) and 2-(4-nitrophenyl)-1,4,5-triphenyl-1H-imidazole (IM-NO2) on the inhibition of mild steel corrosion in 1.0 M hydrochloric acid is studied through mass loss determination, potentiodynamic polarization curve analysis, and electrochemical impedance measurements. Among the tested compounds, IM-N(CH3)2 reduces the corrosion rate of steel in a 1.0 M HCl environment. The effect of inhibitor concentration and electrode immersion time on the corrosion rate of steel is also studied. Surface analysis techniques (SEM-EDX) and electrochemical procedures were used for examination. The study highlights the mixed nature of the inhibitor used. The study showed that this inhibitor acts by adsorption on the metal surface, and this adsorption follows the Langmuir isotherm. The influence of temperature was studied over a range of 298 to 328K. Results showed that both IM-NO2 and IM-N(CH3)2 significantly inhibit corrosion. Specifically, IM-NO2 achieved an inhibition efficiency of 94 % at a concentration of 10-3 M, while IM-N(CH3)2 demonstrated a slightly higher inhibition efficiency of 94.7 %. Additionally, density functional theory (DFT) and monte carlo (MC) simulation were used to explore the anticorrosion mechanism, confirming the experimental results.
{"title":"Inhibitory performance of imidazole compounds against mild steel corrosion in acidic media: Electrochemical techniques, surface characterization, and theoretical analysis","authors":"Redouane Lachhab , Otmane Kharbouch , Elhachmia Ech-chihbi , Zakia Aribou , Mohamed Rbaa , Moussa Ouakki , Mohamed Ebn Touhami","doi":"10.1016/j.molstruc.2026.145259","DOIUrl":"10.1016/j.molstruc.2026.145259","url":null,"abstract":"<div><div>In this work, the inhibitory action of the organic compound <em>N,N-dimethyl-4-(1,4,5-triphenyl-1H-imidazol-2-yl)aniline</em> (<strong>IM-N(CH<sub>3</sub>)<sub>2</sub></strong>) and <em>2-(4-nitrophenyl)-1,4,5-triphenyl-1H-imidazole</em> (<strong>IM-NO<sub>2</sub>)</strong> on the inhibition of mild steel corrosion in 1.0 M hydrochloric acid is studied through mass loss determination, potentiodynamic polarization curve analysis, and electrochemical impedance measurements. Among the tested compounds, <strong>IM-N(CH<sub>3</sub>)<sub>2</sub></strong> reduces the corrosion rate of steel in a 1.0 M HCl environment. The effect of inhibitor concentration and electrode immersion time on the corrosion rate of steel is also studied. Surface analysis techniques (SEM-EDX) and electrochemical procedures were used for examination. The study highlights the mixed nature of the inhibitor used. The study showed that this inhibitor acts by adsorption on the metal surface, and this adsorption follows the Langmuir isotherm. The influence of temperature was studied over a range of 298 to 328K. Results showed that both <strong>IM-NO<sub>2</sub></strong> and <strong>IM-N(CH<sub>3</sub>)<sub>2</sub></strong> significantly inhibit corrosion. Specifically, <strong>IM-NO<sub>2</sub></strong> achieved an inhibition efficiency of 94 % at a concentration of 10<sup>-3</sup> M, while <strong>IM-N(CH<sub>3</sub>)<sub>2</sub></strong> demonstrated a slightly higher inhibition efficiency of 94.7 %. Additionally, density functional theory (DFT) and monte carlo (MC) simulation were used to explore the anticorrosion mechanism, confirming the experimental results.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145259"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K2Pb8(PO4)6 rare-earth-substituted phosphors (RE3+) ions Dy3+, Eu3+, Sm3+, Tb3+, and Pr3+ were successfully prepared via a combustion method. The phase purity and hexagonal crystal structure of the prepared phosphors were confirmed through X-ray diffraction analysis, while their chromaticity, and luminescence properties were studied using CIE coordinates and photoluminescence (PL) measurements. The Dy3+-activated K2Pb8(PO4)6 phosphor exhibited two characteristic emission peaks at 470 nm (blue) and 573 nm (yellow), owing to the 4F9/2→ 6H15/2 and 4F9/2→ 6H13/2 transitions under 350 nm excitation. When excited at 394 nm, the Eu3+-activated sample showed strong orange and red emission peaks at 591 nm and 614 nm, corresponding to the 5D0→ 7F1 and 5D0→ 7F2 transitions, respectively. The Sm3+-doped samples, when excited at 403 nm, exhibited prominent orange-red emission centered at 599 nm, corresponding to the ⁴G5/2→ ⁶H7/2 transition. The Tb3+-doped phosphor displayed a characteristic green emission at 546 nm arising from the 5D4→ 7F5 transition under 378 nm excitation. For the Pr3+-doped sample, excitation at 447 nm produced an intense orange-red emission centered at 602 nm, attributed to the 3P0→ 3H6 transition. The prepared phosphors demonstrated excellent color purity based on their CIE coordinates, and optimal doping concentrations were determined to minimize concentration quenching. These results indicate that Dy3+, Eu3+, Sm3+, Tb3+, and Pr3+-activated K2Pb8(PO4)6 phosphor materials are promising candidates for n-UV-activated solid-state lighting and multi-color display applications.
{"title":"Multicolor emission and luminescence behaviour of novel K2Pb8(PO4)6:RE3+(RE3+= Dy, Eu, Sm, Tb, Pr) phosphors for n-UV-excited solid-state lighting","authors":"C.M. Nandanwar , A.N. Yerpude , P.M. Nandanwar , A.M. Uke , K.N. Shinde , N.S. Kokode","doi":"10.1016/j.molstruc.2026.145283","DOIUrl":"10.1016/j.molstruc.2026.145283","url":null,"abstract":"<div><div>K<sub>2</sub>Pb<sub>8</sub>(PO<sub>4</sub>)<sub>6</sub> rare-earth-substituted phosphors (RE<sup>3+</sup>) ions Dy<sup>3+</sup>, Eu<sup>3+</sup>, Sm<sup>3+</sup>, Tb<sup>3+</sup>, and Pr<sup>3+</sup> were successfully prepared via a combustion method. The phase purity and hexagonal crystal structure of the prepared phosphors were confirmed through X-ray diffraction analysis, while their chromaticity, and luminescence properties were studied using CIE coordinates and photoluminescence (PL) measurements. The Dy<sup>3+</sup>-activated K<sub>2</sub>Pb<sub>8</sub>(PO<sub>4</sub>)<sub>6</sub> phosphor exhibited two characteristic emission peaks at 470 nm (blue) and 573 nm (yellow), owing to the <sup>4</sup>F<sub>9/2</sub>→ <sup>6</sup>H<sub>15/2</sub> and <sup>4</sup>F<sub>9/2</sub>→ <sup>6</sup>H<sub>13/2</sub> transitions under 350 nm excitation. When excited at 394 nm, the Eu<sup>3+</sup>-activated sample showed strong orange and red emission peaks at 591 nm and 614 nm, corresponding to the <sup>5</sup>D<sub>0</sub>→ <sup>7</sup>F<sub>1</sub> and <sup>5</sup>D<sub>0</sub>→ <sup>7</sup>F<sub>2</sub> transitions, respectively. The Sm<sup>3+</sup>-doped samples, when excited at 403 nm, exhibited prominent orange-red emission centered at 599 nm, corresponding to the ⁴G<sub>5/2</sub>→ ⁶H<sub>7/2</sub> transition. The Tb<sup>3+</sup>-doped phosphor displayed a characteristic green emission at 546 nm arising from the <sup>5</sup>D<sub>4</sub>→ <sup>7</sup>F<sub>5</sub> transition under 378 nm excitation. For the Pr<sup>3+</sup>-doped sample, excitation at 447 nm produced an intense orange-red emission centered at 602 nm, attributed to the <sup>3</sup>P<sub>0</sub>→ <sup>3</sup>H<sub>6</sub> transition. The prepared phosphors demonstrated excellent color purity based on their CIE coordinates, and optimal doping concentrations were determined to minimize concentration quenching. These results indicate that Dy<sup>3+</sup>, Eu<sup>3+</sup>, Sm<sup>3+</sup>, Tb<sup>3+</sup>, and Pr<sup>3+</sup>-activated K<sub>2</sub>Pb<sub>8</sub>(PO<sub>4</sub>)<sub>6</sub> phosphor materials are promising candidates for n-UV-activated solid-state lighting and multi-color display applications.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1358 ","pages":"Article 145283"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145957710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.molstruc.2026.145280
Taisheng Wang , Zhenyang Li , Chao Bai , Yi Feng , Shiwei Chen , Bin Liu , Na Zhang
This work presents a novel ratiometric fluorescent sensor (SiPy), for the selective and sensitive detection of fluoride ions (F⁻) in aqueous media. SiPy was synthesized via a one-step silylation reaction using commercially available pyranine (Py), where the phenolic hydroxyl groups were protected by tert‑butyldimethylsilyl (TBDMS) groups. The existence of three sodium sulfonate groups endowed SiPy with excellent water solubility. In neutral aqueous solution, SiPy exhibited blue fluorescence (λem = 430 nm) due to suppression of intermolecular excited-state proton transfer (ESPT). Upon F- addition, desilication induced the cleavage of the Si-O bonds to regenerate Py. The liberated Py synergistically engaged in water-induced intermolecular ESPT, producing a distinct green emission (λem = 510 nm). This dual mechanism, desilication-triggered probe activation and subsequent water-mediated ESPT, enabled a significant ratiometric fluorescence response. The sensor achieved a low detection limit (LOD) of 74 nM and high sensitivity (1.22 × 105 M-1), with excellent selectivity for F⁻ over other anions (CN-, Cl⁻, Br⁻, CH3COO-, etc.). Critically, the response was exclusive to aqueous systems, as organic solvents (DMSO, DMF, and methanol) failed to induce fluorescence changes. The practicality of SiPy was validated by accurately quantifying F⁻ content in commercial toothpastes, yielding results consistent with labeled values.
{"title":"Desilication and water-induced intermolecular excited states proton transfer synergistically enable the ratiometric detection of fluoride ions in aqueous media","authors":"Taisheng Wang , Zhenyang Li , Chao Bai , Yi Feng , Shiwei Chen , Bin Liu , Na Zhang","doi":"10.1016/j.molstruc.2026.145280","DOIUrl":"10.1016/j.molstruc.2026.145280","url":null,"abstract":"<div><div>This work presents a novel ratiometric fluorescent sensor (SiPy), for the selective and sensitive detection of fluoride ions (F⁻) in aqueous media. SiPy was synthesized via a one-step silylation reaction using commercially available pyranine (Py), where the phenolic hydroxyl groups were protected by tert‑butyldimethylsilyl (TBDMS) groups. The existence of three sodium sulfonate groups endowed SiPy with excellent water solubility. In neutral aqueous solution, SiPy exhibited blue fluorescence (<em>λ</em><sub>em</sub> = 430 nm) due to suppression of intermolecular excited-state proton transfer (ESPT). Upon F<sup>-</sup> addition, desilication induced the cleavage of the Si-O bonds to regenerate Py. The liberated Py synergistically engaged in water-induced intermolecular ESPT, producing a distinct green emission (<em>λ</em><sub>em</sub> = 510 nm). This dual mechanism, desilication-triggered probe activation and subsequent water-mediated ESPT, enabled a significant ratiometric fluorescence response. The sensor achieved a low detection limit (LOD) of 74 nM and high sensitivity (1.22 × 10<sup>5</sup> M<sup>-1</sup>), with excellent selectivity for F⁻ over other anions (CN<sup>-</sup>, Cl⁻, Br⁻, CH<sub>3</sub>COO<sup>-</sup>, etc.). Critically, the response was exclusive to aqueous systems, as organic solvents (DMSO, DMF, and methanol) failed to induce fluorescence changes. The practicality of SiPy was validated by accurately quantifying F⁻ content in commercial toothpastes, yielding results consistent with labeled values.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145280"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study reports the synthesis of a new series of asymmetric coumarin–1,3,4-thiadiazole derivatives (T1a–T1g, T2a–T2c, T3a–T3b) targeting biochemical pathways relevant to Alzheimer’s disease. Three coumarin precursors (C1–C3) were employed, using a one-pot sequential addition followed by alkylation to afford alkylated coumarin intermediates. Subsequent condensation with thiosemicarbazide under mild basic conditions and intramolecular cyclization yielded previously unreported asymmetric coumarin–thiadiazole derivatives. Twelve compounds were obtained in high yields (>82%) and fully characterized by 1H and 13C NMR spectroscopy. Biological evaluation revealed significant antioxidant and anti-acetylcholinesterase (AChE) activities, supported by In Silico analyses. In the ABTS assay, compounds T1a, T1b, T1c, T1d, T1f, and T2b exhibited strong radical scavenging activity (IC₅₀ = 24.32 ± 0.32–50.14 ± 0.17 μM), comparable to BHT (47.84 ± 0.22 μM). Phenanthroline reduction identified T1f, T3a, and T1d as the most potent reducing agents (A₀.₅ = 11.38–31.90 μM), approaching BHA (7.32 ± 0.83 μM). AChE inhibition was most pronounced for T1f and T1g (IC₅₀ = 38.90 ± 0.46 and 20.35 ± 0.06 μM, respectively), relative to galantamine (IC₅₀ = 4.14 ± 0.07 μM). Molecular docking confirmed strong binding within the AChE active site, while quantum chemical and ADMET analyses indicated favorable electronic properties, electron-donating substituent effects, and drug-like pharmacokinetic profiles. T1f, T1g, T1c, and T3a emerged as multifunctional lead candidates combining antioxidant and AChE inhibitory activities, highlighting the coumarin–thiadiazole scaffold as a promising platform for the development of therapeutics targeting oxidative stress-associated neurodegenerative disorders.
{"title":"Coumarin 1,3,4-thiadiazole derivatives: Synthesis, bioactivity, and In Silico evaluation as Alzheimer’s Disease inhibitors","authors":"Fathi Benkonissa , Amar Djemoui , Mokhtar Boualem Lahrech , Salma Kaoutar Abdelali , Souli Lahcene , Ahmed Souadia , Mohammed Messaoudi , Chawki Bensouici , Dems Mohamed Abdesselem , Hatem Majdoub , Khadija Benarous , Mohamed Yousfi , Ahmed Barhoum","doi":"10.1016/j.molstruc.2025.145176","DOIUrl":"10.1016/j.molstruc.2025.145176","url":null,"abstract":"<div><div>This study reports the synthesis of a new series of asymmetric coumarin–1,3,4-thiadiazole derivatives (T1a–T1g, T2a–T2c, T3a–T3b) targeting biochemical pathways relevant to Alzheimer’s disease. Three coumarin precursors (C1–C3) were employed, using a one-pot sequential addition followed by alkylation to afford alkylated coumarin intermediates. Subsequent condensation with thiosemicarbazide under mild basic conditions and intramolecular cyclization yielded previously unreported asymmetric coumarin–thiadiazole derivatives. Twelve compounds were obtained in high yields (>82%) and fully characterized by 1H and 13C NMR spectroscopy. Biological evaluation revealed significant antioxidant and anti-acetylcholinesterase (AChE) activities, supported by <em>In Silico</em> analyses. In the ABTS assay, compounds T1a, T1b, T1c, T1d, T1f, and T2b exhibited strong radical scavenging activity (IC₅₀ = 24.32 ± 0.32–50.14 ± 0.17 μM), comparable to BHT (47.84 ± 0.22 μM). Phenanthroline reduction identified T1f, T3a, and T1d as the most potent reducing agents (A₀.₅ = 11.38–31.90 μM), approaching BHA (7.32 ± 0.83 μM). AChE inhibition was most pronounced for T1f and T1g (IC₅₀ = 38.90 ± 0.46 and 20.35 ± 0.06 μM, respectively), relative to galantamine (IC₅₀ = 4.14 ± 0.07 μM). Molecular docking confirmed strong binding within the AChE active site, while quantum chemical and ADMET analyses indicated favorable electronic properties, electron-donating substituent effects, and drug-like pharmacokinetic profiles. T1f, T1g, T1c, and T3a emerged as multifunctional lead candidates combining antioxidant and AChE inhibitory activities, highlighting the coumarin–thiadiazole scaffold as a promising platform for the development of therapeutics targeting oxidative stress-associated neurodegenerative disorders.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145176"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Schiff base compounds (7) and (8) were synthesized and characterized using ¹H NMR, ¹³C NMR, FT-IR, mass spectrometry, and single-crystal X-ray diffraction (SC-XRD) methods. Non-classical intermolecular C22–H22···O21 hydrogen bonding significantly enhances the structural integrity of compound (7), thereby stabilizing the structure. The DFT calculations were performed using the Gaussian09 program. The HOMO-LUMO energy gap in compound (7) was; compound (8) was . Molecular docking and dynamics analysis were performed using the PfA-M1 (Plasmodium falciparum aminopeptidase) enzyme complexed with the 9b inhibitor, which was retrieved from the RCSB Protein Data Bank (PDB ID: 4ZW3). Amino acids Ala461 and Tyr580 formed hydrogen bonds with the hydroxyl group of the ligand.
{"title":"Synthesis and theoretical investigations of Schiff base derivatives targeting antimalarial activity","authors":"Sanjeev Kumar , Gaurav Joshi , Shakti , Y. Khajuria , Alka Agarwal","doi":"10.1016/j.molstruc.2026.145279","DOIUrl":"10.1016/j.molstruc.2026.145279","url":null,"abstract":"<div><div>Schiff base compounds <strong>(7)</strong> and <strong>(8)</strong> were synthesized and characterized using ¹H NMR, ¹³C NMR, FT-IR, mass spectrometry, and single-crystal X-ray diffraction (SC-XRD) methods. Non-classical intermolecular C22–H22···O21 hydrogen bonding significantly enhances the structural integrity of compound <strong>(7),</strong> thereby stabilizing the structure. The DFT calculations were performed using the Gaussian09 program. The HOMO-LUMO energy gap in compound (<strong>7)</strong> was<span><math><mrow><mspace></mspace><mn>3.7295</mn><mrow><mspace></mspace><mtext>eV</mtext></mrow></mrow></math></span>; compound <strong>(8)</strong> was <span><math><mrow><mn>3.8433</mn><mspace></mspace><mtext>eV</mtext></mrow></math></span>. Molecular docking and dynamics analysis were performed using the PfA-M1 (<em>Plasmodium falciparum</em> aminopeptidase) enzyme complexed with the 9b inhibitor, which was retrieved from the RCSB Protein Data Bank (PDB ID: <span><span>4ZW3</span><svg><path></path></svg></span>). Amino acids Ala461 and Tyr580 formed hydrogen bonds with the hydroxyl group of the ligand.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1358 ","pages":"Article 145279"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Crystalline chelate Tb(ASA)3Phen and amorphous chelate Tb(LAA)3Phen embedded in polyvinyl alcohol (PVA) at varying concentrations were prepared using a chemical synthesis approach. Their structural and optical properties were investigated with X-ray diffraction and photoluminescence spectroscopy. Under ultraviolet (UV) excitation (λexc = 367 nm), the Tb3+ ions dispersed in a PVA matrix exhibit weak luminescence primarily due to the low absorption coefficient of the 4f-4f transitions of Tb3+. However, the emission intensities increase substantially when Tb3+ ions are substituted with the Tb3+-based chelates, particularly Tb(ASA)3Phen. The luminescence intensity of the Tb3+ ions depends strongly on their local environment, with the crystalline chelate exhibiting a notably higher enhancement than the amorphous one. A detailed discussion on the role of the bidentate ligands containing carboxylic and non-carboxylic groups is presented, further supported by the lifetime measurement of the 5D4 excited state of Tb3+ions. These luminescent polymeric materials act as efficient UV-to-visible energy converters and hold significant potential for applications in light-converting molecular devices and luminescent solar concentrators.
{"title":"Intense green emission from Tb(ASA)3Phen embedded in PVA film: The study of local environmental effect on 5D4→7FJ transitions of Tb3+ ion","authors":"Muskan Sahu , Charu Dubey , A.K. Singh , R.K. Verma","doi":"10.1016/j.molstruc.2026.145281","DOIUrl":"10.1016/j.molstruc.2026.145281","url":null,"abstract":"<div><div>Crystalline chelate Tb(ASA)<sub>3</sub>Phen and amorphous chelate Tb(LAA)<sub>3</sub>Phen embedded in polyvinyl alcohol (PVA) at varying concentrations were prepared using a chemical synthesis approach. Their structural and optical properties were investigated with X-ray diffraction and photoluminescence spectroscopy. Under ultraviolet (UV) excitation (λ<sub>exc</sub> = 367 nm), the Tb<sup>3+</sup> ions dispersed in a PVA matrix exhibit weak luminescence primarily due to the low absorption coefficient of the 4f-4f transitions of Tb<sup>3+</sup>. However, the emission intensities increase substantially when Tb<sup>3+</sup> ions are substituted with the Tb<sup>3+</sup>-based chelates, particularly Tb(ASA)<sub>3</sub>Phen. The luminescence intensity of the Tb<sup>3+</sup> ions depends strongly on their local environment, with the crystalline chelate exhibiting a notably higher enhancement than the amorphous one. A detailed discussion on the role of the bidentate ligands containing carboxylic and non-carboxylic groups is presented, further supported by the lifetime measurement of the <sup>5</sup>D<sub>4</sub> excited state of Tb<sup>3+</sup>ions. These luminescent polymeric materials act as efficient UV-to-visible energy converters and hold significant potential for applications in light-converting molecular devices and luminescent solar concentrators.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1357 ","pages":"Article 145281"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.molstruc.2026.145282
Aadil Ahmad Bhat, Vijay Singh
Lead halide perovskites exhibit excellent optoelectronic properties; however, their stability and toxicity pose certain challenges. The Cs2SnCl6 double perovskite is environmentally friendly and has a wide bandgap (∼4 eV), rendering it stable and inert across the ultraviolet, visible, and short-wave infrared regions. The octahedrally coordinated Bi3+ lattice site shows potential for the effective doping of the Cs2SnCl6 double perovskite. Therefore, we propose a solvothermal method for synthesizing Bi3+ doped Cs2SnCl6 perovskites. Both the pristine Cs2SnCl6 and Bi3+ doped Cs2SnCl6 perovskites exhibited a cubic crystal arrangement with Fmm space symmetry. Upon doping, the X-ray diffraction results confirmed the formation of a secondary crystalline phase, revealing anisotropic growth that resulted in large micron-sized octahedral morphology (<10 µm). This result was also confirmed using scanning electron microscopy. Bi3+ doping induced highly efficient light-blue emission at 450 nm in Cs2SnCl6, which showed no detectable photoluminescence in its pristine form, accompanied by a significant Stokes shift of 100 nm and a maximum photoluminescence quantum yield (PLQY) of ∼35%. The observed photoluminescence (PL) excitation peak was attributed to the 1S0→3P1 transition, and the intense light-blue PL is attributed to the spin-orbit coupled 3P1→1S0 transition of the Bi3+ ions, corresponding to 450 nm. Notably, the highest PL intensity was observed when the Bi3+ doping concentration was 5%. Exceeding this threshold resulted in concentration quenching, thereby reducing PL intensity. This study highlights the critical balance in doping effects and enhances our understanding of Bi3+-doped Cs2SnCl6 PL characteristics. Moreover, it supports the concept of tailoring bandgap engineering in perovskite materials.
{"title":"Bi3+ doped Cs2SnCl6 perovskites: solvothermal synthesis, structural modulation, and light-blue photoluminescence using bandgap engineering","authors":"Aadil Ahmad Bhat, Vijay Singh","doi":"10.1016/j.molstruc.2026.145282","DOIUrl":"10.1016/j.molstruc.2026.145282","url":null,"abstract":"<div><div>Lead halide perovskites exhibit excellent optoelectronic properties; however, their stability and toxicity pose certain challenges. The Cs<sub>2</sub>SnCl<sub>6</sub> double perovskite is environmentally friendly and has a wide bandgap (∼4 eV), rendering it stable and inert across the ultraviolet, visible, and short-wave infrared regions. The octahedrally coordinated Bi<sup>3+</sup> lattice site shows potential for the effective doping of the Cs<sub>2</sub>SnCl<sub>6</sub> double perovskite. Therefore, we propose a solvothermal method for synthesizing Bi<sup>3+</sup> doped Cs<sub>2</sub>SnCl<sub>6</sub> perovskites. Both the pristine Cs<sub>2</sub>SnCl<sub>6</sub> and Bi<sup>3+</sup> doped Cs<sub>2</sub>SnCl<sub>6</sub> perovskites exhibited a cubic crystal arrangement with Fm<span><math><mover><mn>3</mn><mo>¯</mo></mover></math></span>m space symmetry. Upon doping, the X-ray diffraction results confirmed the formation of a secondary crystalline phase, revealing anisotropic growth that resulted in large micron-sized octahedral morphology (<10 µm). This result was also confirmed using scanning electron microscopy. Bi<sup>3+</sup> doping induced highly efficient light-blue emission at 450 nm in Cs<sub>2</sub>SnCl<sub>6,</sub> which showed no detectable photoluminescence in its pristine form, accompanied by a significant Stokes shift of 100 nm and a maximum photoluminescence quantum yield (PLQY) of ∼35%. The observed photoluminescence (PL) excitation peak was attributed to the <sup>1</sup>S<sub>0</sub>→<sup>3</sup>P<sub>1</sub> transition, and the intense light-blue PL is attributed to the spin-orbit coupled <sup>3</sup>P<sub>1</sub>→<sup>1</sup>S<sub>0</sub> transition of the Bi<sup>3+</sup> ions, corresponding to 450 nm. Notably, the highest PL intensity was observed when the Bi<sup>3+</sup> doping concentration was 5%. Exceeding this threshold resulted in concentration quenching, thereby reducing PL intensity. This study highlights the critical balance in doping effects and enhances our understanding of Bi<sup>3+</sup>-doped Cs<sub>2</sub>SnCl<sub>6</sub> PL characteristics. Moreover, it supports the concept of tailoring bandgap engineering in perovskite materials.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1358 ","pages":"Article 145282"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-07DOI: 10.1016/j.molstruc.2026.145285
Samir Y. Abbas
Several simple and efficient methods for the synthesis of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives in excellent yields were developed. Usually, the synthesizing of various benzo[4,5]imidazo[1,2-a]pyrimidine derivatives is based on 2-aminobenzimidazole. Generally, there are two methods to obtain benzo[4,5]imidazo[1,2-a]pyrimidine derivatives: the first method is one-pot, multi-component reactions of 2-aminobenzimidazole, active methylene derivatives, and carbonyl compounds. Through this method, the benzo[4,5]imidazo[1,2-a]pyrimidine derivatives were synthesized in high yield and high purity with short reaction times. The second method is the reaction of 2-aminobenzimidazole with bifunctional agents. The most widely common bifunctional agents are unsaturated carbonyl derivatives. This review provides all known methods for synthesizing benzo[4,5]imidazo[1,2-a]pyrimidine derivatives. We briefly discussed the synthetic pathways of each methodology, as well as the highlighted variation of yields from different perspectives. This review serves as a guide for the synthetic strategies of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives.
{"title":"Efficient syntheses of benzo[4,5]imidazo[1,2-a]pyrimidine derivatives based on 2-aminobenzimidazole","authors":"Samir Y. Abbas","doi":"10.1016/j.molstruc.2026.145285","DOIUrl":"10.1016/j.molstruc.2026.145285","url":null,"abstract":"<div><div>Several simple and efficient methods for the synthesis of benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives in excellent yields were developed. Usually, the synthesizing of various benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives is based on 2-aminobenzimidazole. Generally, there are two methods to obtain benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives: the first method is one-pot, multi-component reactions of 2-aminobenzimidazole, active methylene derivatives, and carbonyl compounds. Through this method, the benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives were synthesized in high yield and high purity with short reaction times. The second method is the reaction of 2-aminobenzimidazole with bifunctional agents. The most widely common bifunctional agents are unsaturated carbonyl derivatives. This review provides all known methods for synthesizing benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives. We briefly discussed the synthetic pathways of each methodology, as well as the highlighted variation of yields from different perspectives. This review serves as a guide for the synthetic strategies of benzo[4,5]imidazo[1,2-<em>a</em>]pyrimidine derivatives.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1358 ","pages":"Article 145285"},"PeriodicalIF":4.7,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145957713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号