Pub Date : 2026-02-01DOI: 10.1016/j.molstruc.2026.145554
R. Pradeep Kumar , RO.MU. Jauhar , V. Viswanathan , S. Priyadharshini , K. Anitha , V. Siva , R. Subramaniyan Raja
Single crystals of bis(4-aminopyridinium) hexafluorosilicate monohydrate was synthesised and characterized to explore their structural and optical features towards the applications in the fields of photonic and nonlinear optical (NLO) devices. Single crystals were effectively grown adopting slow solvent evaporation technique at room temperature. Subsequent analysis with single-crystal X-ray diffraction revealed the monoclinic crystal structure with C2/c space group. Here the asymmetric unit consists of two (SiF₆)2⁻halves, two 4-aminopyridinium cations, and a water molecule. Further the crystal structure of the title material is reported for the first time in the literature. The functional groups and intermolecular interactions within the lattice of the grown crystals were confirmed from the FTIR spectroscopy. The optical transmittance spectrum revealed that the grown crystal is transparent in the entire visible region with lower cutoff wavelength to be 286 nm indicating the materials suitability for optoelectronic applications. Thermal stability of the sample was found to be 99 °C as investigated through the TG-DTA Analysis. Further the stability around 99 °C confirms the presence of water molecule in the lattice. The Computational studies were performed under gaseous condition by employing the Gaussian 16 software and DFT computations through the B3LYP method. The nonlinear optical applications were carried out by the Z-scan characterization, including the nonlinear refractive index (n₂), two-photon absorption coefficient (β), and third-order nonlinear susceptibility (χ3). The cumulative results reveal that the title material is suitable for the photonic, laser, and nonlinear optical applications.
{"title":"Three dimensional framework of a semi-organic bis(4-aminopyridinium) hexafluorosilicate monohydrate single crystals with quantum chemical insights for nonlinear optical applications","authors":"R. Pradeep Kumar , RO.MU. Jauhar , V. Viswanathan , S. Priyadharshini , K. Anitha , V. Siva , R. Subramaniyan Raja","doi":"10.1016/j.molstruc.2026.145554","DOIUrl":"10.1016/j.molstruc.2026.145554","url":null,"abstract":"<div><div>Single crystals of bis(4-aminopyridinium) hexafluorosilicate monohydrate was synthesised and characterized to explore their structural and optical features towards the applications in the fields of photonic and nonlinear optical (NLO) devices. Single crystals were effectively grown adopting slow solvent evaporation technique at room temperature. Subsequent analysis with single-crystal X-ray diffraction revealed the monoclinic crystal structure with C2/c space group. Here the asymmetric unit consists of two (SiF₆)<sup>2⁻</sup>halves, two 4-aminopyridinium cations, and a water molecule. Further the crystal structure of the title material is reported for the first time in the literature. The functional groups and intermolecular interactions within the lattice of the grown crystals were confirmed from the FTIR spectroscopy. The optical transmittance spectrum revealed that the grown crystal is transparent in the entire visible region with lower cutoff wavelength to be 286 nm indicating the materials suitability for optoelectronic applications. Thermal stability of the sample was found to be 99 °C as investigated through the TG-DTA Analysis. Further the stability around 99 °C confirms the presence of water molecule in the lattice. The Computational studies were performed under gaseous condition by employing the Gaussian 16 software and DFT computations through the B3LYP method. The nonlinear optical applications were carried out by the Z-scan characterization, including the nonlinear refractive index (n₂), two-photon absorption coefficient (β), and third-order nonlinear susceptibility (χ3). The cumulative results reveal that the title material is suitable for the photonic, laser, and nonlinear optical applications.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145554"},"PeriodicalIF":4.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191421","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 : 2026-02-01DOI: 10.1016/j.molstruc.2026.145538
Sonia Rani , Vijay Luxami , Shweta Goyal
Hydroxy-aryl benzimidazole (HABI) organic molecule has been synthesised and explored as a corrosion sensor and inhibitor for steel in different corrosive environments (acidic and basic). The sensing behaviour of the molecule was studied by UV-Vis and fluorescence spectroscopy, and corrosion inhibition efficiency was investigated through gravimetric, electrochemical measurements and theoretical studies. HABI fluorescence is turned off in the presence of Fe3+ due to the formation of the HABI-Fe3+ complex. In both acidic (97.4%) and basic (87.5%) environments, more than 85% corrosion inhibition efficiency at 1.0 mM was achieved through gravimetric and electrochemical studies. The inhibitor acts on both anodic and cathodic sites and the value of -37.7 (acidic) and -31.8 (basic) KJmol-1 proposed the adsorption of inhibitor on the steel surface through physio-chemisorption. The surface analysis used microscopic and spectroscopic techniques like FE-SEM, FTIR, and XPS, they suggest that inhibitor form protective layer on the steel surface. The binding mechanism of the HABI inhibitor with Fe3+ was investigated through DFT studies, providing HOMO-LUMO gap of 4.42 eV for inhibitor that reduces significantly to 1.80 eV upon binding with Fe3+ proving the efficient corrosion inhibition mechanism through charge transfer that agreed with experimental results. Practical application on the steel sample coated with HABI was done and obtained excellent corrosion inhibition (99%) efficiency.
{"title":"Experimental and theoretical aspects of Hydroxyarylbenzimidazole (HABI) as an effective corrosion sensor and inhibitor in different corrosive environments","authors":"Sonia Rani , Vijay Luxami , Shweta Goyal","doi":"10.1016/j.molstruc.2026.145538","DOIUrl":"10.1016/j.molstruc.2026.145538","url":null,"abstract":"<div><div>Hydroxy-aryl benzimidazole (<strong>HABI</strong>) organic molecule has been synthesised and explored as a corrosion sensor and inhibitor for steel in different corrosive environments (acidic and basic). The sensing behaviour of the molecule was studied by UV-Vis and fluorescence spectroscopy, and corrosion inhibition efficiency was investigated through gravimetric, electrochemical measurements and theoretical studies. <strong>HABI</strong> fluorescence is turned off in the presence of Fe<sup>3+</sup> due to the formation of the <strong>HABI</strong>-Fe<sup>3+</sup> complex. In both acidic (97.4%) and basic (87.5%) environments, more than 85% corrosion inhibition efficiency at <strong>1.0 mM</strong> was achieved through gravimetric and electrochemical studies. The inhibitor acts on both anodic and cathodic sites and the value of <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mi>G</mi><mrow><mi>a</mi><mi>d</mi><mi>s</mi></mrow><mn>0</mn></msubsup></mrow></math></span> -37.7 (acidic) and -31.8 (basic) KJmol<sup>-1</sup> proposed the adsorption of inhibitor on the steel surface through physio-chemisorption. The surface analysis used microscopic and spectroscopic techniques like FE-SEM, FTIR, and XPS, they suggest that inhibitor form protective layer on the steel surface. The binding mechanism of the <strong>HABI</strong> inhibitor with Fe<sup>3+</sup> was investigated through DFT studies, providing HOMO-LUMO gap of 4.42 eV for inhibitor that reduces significantly to 1.80 eV upon binding with Fe<sup>3+</sup> proving the efficient corrosion inhibition mechanism through charge transfer that agreed with experimental results. Practical application on the steel sample coated with <strong>HABI</strong> was done and obtained excellent corrosion inhibition (99%) efficiency.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145538"},"PeriodicalIF":4.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192405","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}
The escalating global health crisis of Antimicrobial Resistance (AMR) necessitates the rapid discovery of agents with novel structures and multi-targeted mechanisms of action. This study utilizes the Pharmacophore Hybridization Approach (PHA) to address this challenge by designing novel conjugates targeting essential bacterial pathways, specifically the Peptide Deformylase (PDF) enzyme. A virtual library of over 40 compounds, integrating the triazole linker with four established heterocyclic scaffolds (indoline-2,3‑dione, 4‑hydroxy-2H-chromen-2-one, 2-phenyl-1H-indole, and 2-hydroxybenzaldehyde), was generated. Eighteen lead molecules were rationally selected following in silico screening for drug-likeness (Lipinski’s Rule of Five) and preliminary ADMET profiles. These 18 leads were successfully synthesized via an optimized Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) reaction, utilizing a high-yield 1:1 THF/Water solvent system. The structures of all synthesized triazole derivatives were confirmed by a rigorous spectral assessment including 1H NMR, 13C-NMR and HRMS analyses. Molecular docking studies against Escherichia coli PDF (PDB ID: 1G2A) revealed potent binding affinities for several synthesized derivatives, significantly exceeding those of standard antibiotics. Structure-activity relationship (SAR) analysis highlighted the crucial role of specific substituents, particularly electron-withdrawing groups at R1 and a -NHCOCH3 group at R3, in enhancing binding affinity and predicted activity. Molecular dynamics simulations comparing a representative compound (Compound 3) to sulphamethoxazole indicated differences in dynamic behavior, with Compound 3 showing less conformational stability and higher flexibility, despite similar overall compactness. Experimental validation confirmed the successful synthesis of the target compounds and demonstrated promising antibacterial activity against a panel of Gram-positive and Gram-negative bacterial strains, correlating well with the predicted SAR. Cytotoxicity assessment in HEK293 cells showed dose-dependent, generally moderate effects. These integrated computational and experimental findings identify several triazole-based conjugates as promising lead candidates for further development in the fight against AMR.
{"title":"Design and synthesis of triazole-based conjugates: Biological assessment and computational analysis","authors":"Udit Kumar , Javeria , Kavya Singh , Preeti Jaiswal , Vishal Kumar Singh , Anuradha Singh","doi":"10.1016/j.molstruc.2026.145550","DOIUrl":"10.1016/j.molstruc.2026.145550","url":null,"abstract":"<div><div>The escalating global health crisis of Antimicrobial Resistance (AMR) necessitates the rapid discovery of agents with novel structures and multi-targeted mechanisms of action. This study utilizes the Pharmacophore Hybridization Approach (PHA) to address this challenge by designing novel conjugates targeting essential bacterial pathways, specifically the Peptide Deformylase (PDF) enzyme. A virtual library of over 40 compounds, integrating the triazole linker with four established heterocyclic scaffolds (<em>indoline-2,3‑dione, 4‑hydroxy-2H-chromen-2-one, 2-phenyl-1H-indole, and 2-hydroxybenzaldehyde</em>), was generated. Eighteen lead molecules were rationally selected following <em>in silico</em> screening for drug-likeness (Lipinski’s Rule of Five) and preliminary ADMET profiles. These 18 leads were successfully synthesized via an optimized Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) reaction, utilizing a high-yield 1:1 THF/Water solvent system. The structures of all synthesized triazole derivatives were confirmed by a rigorous spectral assessment including <sup>1</sup>H NMR, 13C-NMR and HRMS analyses. Molecular docking studies against <em>Escherichia coli</em> PDF (PDB ID: <span><span>1G2A</span><svg><path></path></svg></span>) revealed potent binding affinities for several synthesized derivatives, significantly exceeding those of standard antibiotics. Structure-activity relationship (SAR) analysis highlighted the crucial role of specific substituents, particularly electron-withdrawing groups at R<sub>1</sub> and a -NHCOCH<sub>3</sub> group at R<sub>3</sub>, in enhancing binding affinity and predicted activity. Molecular dynamics simulations comparing a representative compound (Compound <strong>3</strong>) to sulphamethoxazole indicated differences in dynamic behavior, with Compound <strong>3</strong> showing less conformational stability and higher flexibility, despite similar overall compactness. Experimental validation confirmed the successful synthesis of the target compounds and demonstrated promising antibacterial activity against a panel of Gram-positive and Gram-negative bacterial strains, correlating well with the predicted SAR. Cytotoxicity assessment in HEK293 cells showed dose-dependent, generally moderate effects. These integrated computational and experimental findings identify several triazole-based conjugates as promising lead candidates for further development in the fight against AMR.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1359 ","pages":"Article 145550"},"PeriodicalIF":4.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171011","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 : 2026-02-01DOI: 10.1016/j.molstruc.2026.145556
Juan Song , Liang Zhang , Jia-Mi Zhou , Yun-Long Zhou , Miao Wu , Bo-Feng Duan
Two novel cadmium(II) coordination polymers (CPs), [Cd(cpt)2(H2O)]ₙ (1), and [Cd(cpt)2]ₙ (2), are solvothermally synthesized. Structural analysis reveals that CP1 forms a 2D sql network, while CP2 adopts a 3D bey topology. Both water-stable CPs function as effective fluorescent sensors for tetracycline antibiotics (TCs), exhibiting significant quenching toward tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX). Specifically, for DOX, CP1 shows a KSV of 6.15 × 103 M-1 and an LOD of 4.31 μM; for CTC, CP2 exhibits a KSV of 6.02 × 103 M-1 and an LOD of 3.82 μM, with all detection limits falling within the low μM range. Furthermore, they are successfully applied to detect TCs in real milk samples. This work provides promising sensor materials and insights into structure-guided crystal engineering.
{"title":"From 2D to 3D: Condition-directed synthesis of topologically diverse Cd(II)-CPs for selective detection of tetracycline antibiotics","authors":"Juan Song , Liang Zhang , Jia-Mi Zhou , Yun-Long Zhou , Miao Wu , Bo-Feng Duan","doi":"10.1016/j.molstruc.2026.145556","DOIUrl":"10.1016/j.molstruc.2026.145556","url":null,"abstract":"<div><div>Two novel cadmium(II) coordination polymers (CPs), [Cd(cpt)<sub>2</sub>(H<sub>2</sub>O)]ₙ (1), and [Cd(cpt)<sub>2</sub>]ₙ (2), are solvothermally synthesized. Structural analysis reveals that CP1 forms a 2D sql network, while CP2 adopts a 3D bey topology. Both water-stable CPs function as effective fluorescent sensors for tetracycline antibiotics (TCs), exhibiting significant quenching toward tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX). Specifically, for DOX, CP1 shows a K<sub>SV</sub> of 6.15 × 10<sup>3</sup> M<sup>-1</sup> and an LOD of 4.31 μM; for CTC, CP2 exhibits a K<sub>SV</sub> of 6.02 × 10<sup>3</sup> M<sup>-1</sup> and an LOD of 3.82 μM, with all detection limits falling within the low μM range. Furthermore, they are successfully applied to detect TCs in real milk samples. This work provides promising sensor materials and insights into structure-guided crystal engineering.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1359 ","pages":"Article 145556"},"PeriodicalIF":4.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171137","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 : 2026-02-01DOI: 10.1016/j.molstruc.2026.145553
Xin Hao , Xuying Wang , Qianxi Jiang , Jingbiao Xia , Qiurui Song , Xiangyan Chen , Peng Qian , Zhongjie Wang , Changjin Zhu , Zhongfei Han
Poor blood glucose control and its resulting increased metabolism of glucose polyol pathway are the two main causes of diabetic complications. In the present study, a series of novel quinolin-4(1H)-one derivatives with hydroxyacetidine used as the bioisostere of N1-acetic acid were developed as bifunctional inhibitors of α-glucosidase and aldose reductase. The two enzymes relate to blood glucose level and anomalously elevated polyol pathway respectively. Most of these derivatives were found to be potent and selective for both enzymes with submicromolar IC50 values. Particularly, compounds 8e and 8f were the most active possessing a N1-hydroxyacetidine and phenolic hydroxyl substituted C3-phenoxy side chain. The introduction of phenolic hydroxyl was also proved to gain significant antioxidant activity, verifying the 3,5-dihydroxyphenoxy side chain as the key structure for alleviating oxidative stress. Additionally, all the hydroxyacetidine derivatives showed better permeability than the corresponding carboxylic acid. Therefore, the bioisosteric replacement of hydroxyacetidine is an effective strategy to optimize the physicochemical profile of carboxylic acid ARIs, and more suitable to construct potent dual inhibitors targeting aldose reductase/α-glucosidase for treatment of diabetic complications.
{"title":"Novel hydroxyacetimidamide derivatives of quinolin-4(1H)-one as dual inhibitor targeting AKR1B1/α-glucosidase for treatment of diabetic complications: Design, synthesis and biological evaluation","authors":"Xin Hao , Xuying Wang , Qianxi Jiang , Jingbiao Xia , Qiurui Song , Xiangyan Chen , Peng Qian , Zhongjie Wang , Changjin Zhu , Zhongfei Han","doi":"10.1016/j.molstruc.2026.145553","DOIUrl":"10.1016/j.molstruc.2026.145553","url":null,"abstract":"<div><div>Poor blood glucose control and its resulting increased metabolism of glucose polyol pathway are the two main causes of diabetic complications. In the present study, a series of novel quinolin-4(<em>1H</em>)-one derivatives with hydroxyacetidine used as the bioisostere of N1-acetic acid were developed as bifunctional inhibitors of α-glucosidase and aldose reductase. The two enzymes relate to blood glucose level and anomalously elevated polyol pathway respectively. Most of these derivatives were found to be potent and selective for both enzymes with submicromolar IC<sub>50</sub> values. Particularly, compounds <strong>8e</strong> and <strong>8f</strong> were the most active possessing a N1-hydroxyacetidine and phenolic hydroxyl substituted C3-phenoxy side chain. The introduction of phenolic hydroxyl was also proved to gain significant antioxidant activity, verifying the 3,5-dihydroxyphenoxy side chain as the key structure for alleviating oxidative stress. Additionally, all the hydroxyacetidine derivatives showed better permeability than the corresponding carboxylic acid. Therefore, the bioisosteric replacement of hydroxyacetidine is an effective strategy to optimize the physicochemical profile of carboxylic acid ARIs, and more suitable to construct potent dual inhibitors targeting aldose reductase/α-glucosidase for treatment of diabetic complications.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145553"},"PeriodicalIF":4.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192492","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 : 2026-01-31DOI: 10.1016/j.molstruc.2026.145535
Yuhan Zhang , Guangxuan Wang , Lin Tang , Wenxi Chen , Weiqiang Yuan , Jingjing Chen , Haohong Li , Huidong Zheng
The resolution of regioisomers in ionone synthesis to obtain high-purity α-/β-ionone products is highly significant for the perfume industry. In this work, co-crystallization method was applied firstly in highly efficient resolution of α-/β-ionone, which were the cyclization step raw products with different α-/β-ionone ratios. Bisphenol Z (BPZ) was screened as co-former for selective co-crystallization, which can be executed under wide scope of α-/β-ionone ratio (nα: nβ from 1:9 to 8:2). The co-crystal was structurally determined as β-ionone·2BPZ by X-ray single crystal diffraction. According to its structure analysis, the stronger H-bond accepting ability of carbonyl on β-ionone, the bis-hydrogen bond donators provided by phenol groups, and the C–H···π interaction endowed by cyclohexane ring are the reasons for the high co-crystallization selectivity in α-/β-ionone mixtures. The co-crystallization process has been optimized, based on which high separation efficiency (αX: 3.29 × 10–3 ∼ 6.91 × 10–3) can be achieved. The final yields/purities (α-ionone: 98.83%/90.21%; β-ionone: 98.19%/98.64%) were much higher than those from traditional methods. Co-former BPZ can also be recovered facilely with high yield and purity for next co-crystallization processes. The efficient α-/β-ionone resolution can pave a new avenue for high quality perfume production.
{"title":"High-efficiency resolution of ionone conformational isomers through selective co-crystallization: mechanism study and process optimization","authors":"Yuhan Zhang , Guangxuan Wang , Lin Tang , Wenxi Chen , Weiqiang Yuan , Jingjing Chen , Haohong Li , Huidong Zheng","doi":"10.1016/j.molstruc.2026.145535","DOIUrl":"10.1016/j.molstruc.2026.145535","url":null,"abstract":"<div><div>The resolution of regioisomers in ionone synthesis to obtain high-purity α-/β-ionone products is highly significant for the perfume industry. In this work, co-crystallization method was applied firstly in highly efficient resolution of α-/β-ionone, which were the cyclization step raw products with different α-/β-ionone ratios. Bisphenol Z (BPZ) was screened as co-former for selective co-crystallization, which can be executed under wide scope of α-/β-ionone ratio (n<sub>α</sub>: n<sub>β</sub> from 1:9 to 8:2). The co-crystal was structurally determined as β-ionone·2BPZ by X-ray single crystal diffraction. According to its structure analysis, the stronger H-bond accepting ability of carbonyl on β-ionone, the bis-hydrogen bond donators provided by phenol groups, and the C–H···π interaction endowed by cyclohexane ring are the reasons for the high co-crystallization selectivity in α-/β-ionone mixtures. The co-crystallization process has been optimized, based on which high separation efficiency (<em>α</em><sub>X:</sub> 3.29 × 10<sup>–3</sup> ∼ 6.91 × 10<sup>–3</sup>) can be achieved. The final yields/purities (α-ionone: 98.83%/90.21%; β-ionone: 98.19%/98.64%) were much higher than those from traditional methods. Co-former BPZ can also be recovered facilely with high yield and purity for next co-crystallization processes. The efficient α-/β-ionone resolution can pave a new avenue for high quality perfume production.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145535"},"PeriodicalIF":4.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192478","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 : 2026-01-31DOI: 10.1016/j.molstruc.2026.145534
Nafeesa Naeem , Charlene Marais , Marrigje Marianne Conradie , Mustafa S. Alluhaibi , Abdullah Yahya Abdullah Alzahrani , Amina Sadiq , Ernst H.G. Langner , Marthinus Rudi Swart , Nandisiwe GS Mateyise , Jeanet Conradie , Ehsan Ullah Mughal
Three hydrazone–chalcone hybrid compounds (1–3) were synthesized and investigated using spectroscopic, electrochemical, and computational methods. UV–Vis spectroscopy and TD-DFT calculations reveal two main absorption bands: a low-energy band at 480–500 nm arising from a hydrazone-localized HOMO → LUMO (π→π*) transition, and higher-energy bands (300–350 nm) associated with chalcone-centered excitations. Cyclic voltammetry shows a first diffusion-controlled reduction near –1.3 V vs. Fc/Fc⁺, significantly less negative than for simple chalcones, indicating hydrazone-based reduction, followed by a second chalcone-centered reduction at more negative potentials. The reduction potentials correlate inversely with DFT-calculated LUMO energies, consistent with sequential electron addition to hydrazone- and chalcone-centered orbitals. These results demonstrate that the hydrazone moiety governs the optical and redox behaviour of these hybrids, while chalcone substituents modulate higher-energy transitions.
{"title":"Azo Hydrazone–Chalcone Hybrids: DFT and experimental insights into spectroscopic and redox behavior","authors":"Nafeesa Naeem , Charlene Marais , Marrigje Marianne Conradie , Mustafa S. Alluhaibi , Abdullah Yahya Abdullah Alzahrani , Amina Sadiq , Ernst H.G. Langner , Marthinus Rudi Swart , Nandisiwe GS Mateyise , Jeanet Conradie , Ehsan Ullah Mughal","doi":"10.1016/j.molstruc.2026.145534","DOIUrl":"10.1016/j.molstruc.2026.145534","url":null,"abstract":"<div><div>Three hydrazone–chalcone hybrid compounds (<strong>1</strong>–<strong>3</strong>) were synthesized and investigated using spectroscopic, electrochemical, and computational methods. UV–Vis spectroscopy and TD-DFT calculations reveal two main absorption bands: a low-energy band at 480–500 nm arising from a hydrazone-localized HOMO → LUMO (π→π*) transition, and higher-energy bands (300–350 nm) associated with chalcone-centered excitations. Cyclic voltammetry shows a first diffusion-controlled reduction near –1.3 V vs. Fc/Fc⁺, significantly less negative than for simple chalcones, indicating hydrazone-based reduction, followed by a second chalcone-centered reduction at more negative potentials. The reduction potentials correlate inversely with DFT-calculated LUMO energies, consistent with sequential electron addition to hydrazone- and chalcone-centered orbitals. These results demonstrate that the hydrazone moiety governs the optical and redox behaviour of these hybrids, while chalcone substituents modulate higher-energy transitions.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145534"},"PeriodicalIF":4.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192449","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 : 2026-01-31DOI: 10.1016/j.molstruc.2026.145543
Tulasi Barik , M. Visalakshi , Vijay Sharma , N. Ramanathan
σ-stacking interactions play a pivotal role in the structural stabilization of alkyl-containing molecular systems and have far-reaching implications across multiple areas of modern chemistry. Although inherently weak, their cumulative effect significantly influences fundamental physical properties such as phase behaviour, solubility, and melting and boiling points. In this study, σ-stacking interactions in dimers of pentane structural isomers (n-pentane, isopentane, and neopentane) are explored through an integrated theoretical and experimental approach. High-level ab initio calculations reveal multiple low-energy σ-stacked configurations for n-pentane dimers: face-to-face, slip-stacked, parallel-displaced, T-shaped, sandwich-typed, slip-displaced and partial stacked-each stabilized primarily by C–H···H–C contacts. Similar C–H···H–C contacts with varying magnitude found to stabilize isopentane, and neopentane dimers. Complementary electronic structure analyses, including Quantum Theory of Atoms-in-Molecules (QTAIM) and Natural Bond Orbital (NBO), confirm the existence of weak yet distinct σ-type interactions, while Energy Decomposition Analysis (EDA) emphasizes the cooperative contributions of dispersion and electrostatic components to overall stabilization. Further topological examinations employing Non-Covalent Interaction (NCI), Independent Gradient Model (IGM) frameworks provide spatial insights into intermolecular interaction regions. Experimental validation for model n-pentane dimers was achieved using matrix isolation infrared spectroscopy at cryogenic temperatures, facilitated by molecular beam techniques with both effusive and supersonic nozzle sources in Ar and N2 matrices. The results deliver direct spectroscopic evidence for face-to-face and slip-stacked σ-stacked configurations, offering a detailed understanding of dispersion-driven interactions in simple alkane systems.
{"title":"Unveiling σ-stacking in pentane dimers using matrix isolation infrared spectroscopy and Ab initio computations: The hidden architecture of weak alkane interactions","authors":"Tulasi Barik , M. Visalakshi , Vijay Sharma , N. Ramanathan","doi":"10.1016/j.molstruc.2026.145543","DOIUrl":"10.1016/j.molstruc.2026.145543","url":null,"abstract":"<div><div>σ-stacking interactions play a pivotal role in the structural stabilization of alkyl-containing molecular systems and have far-reaching implications across multiple areas of modern chemistry. Although inherently weak, their cumulative effect significantly influences fundamental physical properties such as phase behaviour, solubility, and melting and boiling points. In this study, σ-stacking interactions in dimers of pentane structural isomers (<em>n</em>-pentane, isopentane, and neopentane) are explored through an integrated theoretical and experimental approach. High-level <em>ab initio</em> calculations reveal multiple low-energy σ-stacked configurations for <em>n</em>-pentane dimers: face-to-face, slip-stacked, parallel-displaced, T-shaped, sandwich-typed, slip-displaced and partial stacked-each stabilized primarily by C–H···H–C contacts. Similar C–H···H–C contacts with varying magnitude found to stabilize isopentane, and neopentane dimers. Complementary electronic structure analyses, including Quantum Theory of Atoms-in-Molecules (QTAIM) and Natural Bond Orbital (NBO), confirm the existence of weak yet distinct σ-type interactions, while Energy Decomposition Analysis (EDA) emphasizes the cooperative contributions of dispersion and electrostatic components to overall stabilization. Further topological examinations employing Non-Covalent Interaction (NCI), Independent Gradient Model (IGM) frameworks provide spatial insights into intermolecular interaction regions. Experimental validation for model <em>n</em>-pentane dimers was achieved using matrix isolation infrared spectroscopy at cryogenic temperatures, facilitated by molecular beam techniques with both effusive and supersonic nozzle sources in Ar and N<sub>2</sub> matrices. The results deliver direct spectroscopic evidence for face-to-face and slip-stacked σ-stacked configurations, offering a detailed understanding of dispersion-driven interactions in simple alkane systems.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1359 ","pages":"Article 145543"},"PeriodicalIF":4.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171095","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 : 2026-01-31DOI: 10.1016/j.molstruc.2026.145533
P. Ponlakshmi, V. Dharaniprabha, Kuppanagounder P. Elango
In the present study, three fluorene-based donor-π-acceptor (D-π-A) systems, PPL3-H, PPL3–OCH3, and PPL3-NO2 were designed and synthesized through a Knoevenagel condensation reaction between fluorene carboxaldehyde and phenyl acetonitrile derivatives bearing different substituents (-H, –OCH3, and -NO2) at the para position to evaluate their substituent effect on the optical characteristics and sensing capabilities. The fluorene core was incorporated as a donor unit, as it is strongly emissive upon extending its π-conjugation, attributed to its strong solid-state fluorescence. Optical and theoretical analysis of these derivatives highlights that a feasible intramolecular charge transfer (ICT) transition in PPL3-NO2 led to its application in the sensing field. Positive Solvatochromism is shown by PPL3-NO2, validating the existence of strong ICT. The nucleophilic addition of CN- at the electropositive carbon atom of PPL3-NO2 removes π-conjugation, leading to a drastic colour change and fluorescent enhancement. The results show that substituent tuning plays a decisive role in governing the probe's performance in cyanide ion detection. The fingerprint imaging showcases the effectiveness of PPL3-derivatives in crime scenes. The prepared test buds effectively change their colour in the presence of cyanide, and the good recoveries in real-water analysis prove the sensing efficacy of PPL3-NO2 in real-world situations.
{"title":"Substituent and solvent effects on photophysical and cyanide sensing properties of fluorene-based chemo-dosimeters: Spectral and TD-DFT studies","authors":"P. Ponlakshmi, V. Dharaniprabha, Kuppanagounder P. Elango","doi":"10.1016/j.molstruc.2026.145533","DOIUrl":"10.1016/j.molstruc.2026.145533","url":null,"abstract":"<div><div>In the present study, three fluorene-based donor-π-acceptor (D-π-A) systems, <strong>PPL3-H, PPL3–OCH<sub>3</sub></strong>, and <strong>PPL3-NO<sub>2</sub></strong> were designed and synthesized through a Knoevenagel condensation reaction between fluorene carboxaldehyde and phenyl acetonitrile derivatives bearing different substituents (-H, –OCH<sub>3,</sub> and -NO<sub>2</sub>) at the <em>para</em> position to evaluate their substituent effect on the optical characteristics and sensing capabilities. The fluorene core was incorporated as a donor unit, as it is strongly emissive upon extending its π-conjugation, attributed to its strong solid-state fluorescence. Optical and theoretical analysis of these derivatives highlights that a feasible intramolecular charge transfer (ICT) transition in <strong>PPL3-NO<sub>2</sub></strong> led to its application in the sensing field. Positive Solvatochromism is shown by <strong>PPL3-NO<sub>2</sub></strong><sub>,</sub> validating the existence of strong ICT. The nucleophilic addition of CN<sup>-</sup> at the electropositive carbon atom of <strong>PPL3-NO</strong><sub><strong>2</strong></sub> removes π-conjugation, leading to a drastic colour change and fluorescent enhancement. The results show that substituent tuning plays a decisive role in governing the probe's performance in cyanide ion detection. The fingerprint imaging showcases the effectiveness of <strong>PPL3</strong>-derivatives in crime scenes. The prepared test buds effectively change their colour in the presence of cyanide, and the good recoveries in real-water analysis prove the sensing efficacy of <strong>PPL3-NO<sub>2</sub></strong> in real-world situations.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1359 ","pages":"Article 145533"},"PeriodicalIF":4.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171013","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}
The study presents the synthesis and structural analysis of iridium(III) oxime complexes, denoted as [Ir(ppy)2(L)]+/0, where ppy stands for 2-phenylpyridine and L represents dimethyl glyoxime (H2dmg), 2-(hydroxyimino)-1,2-diphenylethan-1-one (dbm), and 10-(hydroxyimino)phenanthren-9(10H)-one (ptm). The structural characterisations of these three complexes were conducted through FT-IR, ¹H and ¹³C NMR, ESI-MS, electronic absorption-emission spectroscopy, and cyclic voltammetry studies. Additionally, the single-crystal structures of Ir1 and Ir2 were elucidated. It revealed the deoximation of one oxime function to the keto group of diphenyl glyoxime (H2dbd) and 9,10-phenanthrenequinone dioxime (H2ptd) ancillary ligands in complexes Ir2 and Ir3, while the coordination of dioxime groups (-N-OH) of dimethyl glyoxime (H2dmg) ligand to the iridium metal center was successfully achieved in Ir1. These complexes represent the first instances of selective generation of aromatic monoximes in H2dbd and H2ptd upon coordination with iridium. The potential of these complexes as cancer therapeutics was assessed against MCF-7 and MDA-MB-231 cells, but all the complexes showed inactivity in inhibiting the growth of cancer cells. Furthermore, the complexes exhibited low quantum yields and were very weakly luminescent.
{"title":"Unexpected transformation of aromatic dioximes to monoximes in cyclometallated Ir(III) complexes: Structural and cytotoxic insights","authors":"Madhusmita Jadab , Suvasmita Behera , Atanu Sahoo , Manas Kumar Santra , Swagatika Mallik , Jagadish Kumar , Satyanarayan Pal","doi":"10.1016/j.molstruc.2026.145540","DOIUrl":"10.1016/j.molstruc.2026.145540","url":null,"abstract":"<div><div>The study presents the synthesis and structural analysis of iridium(III) oxime complexes, denoted as [Ir(ppy)<sub>2</sub>(L)]<sup>+/0</sup>, where ppy stands for 2-phenylpyridine and L represents dimethyl glyoxime (<strong>H<sub>2</sub>dmg</strong>), 2-(hydroxyimino)-1,2-diphenylethan-1-one (<strong>dbm</strong>), and 10-(hydroxyimino)phenanthren-9(10H)-one (<strong>ptm</strong>). The structural characterisations of these three complexes were conducted through FT-IR, ¹H and ¹³C NMR, ESI-MS, electronic absorption-emission spectroscopy, and cyclic voltammetry studies. Additionally, the single-crystal structures of <strong>Ir1</strong> and <strong>Ir2</strong> were elucidated. It revealed the deoximation of one oxime function to the keto group of diphenyl glyoxime <strong>(H<sub>2</sub>dbd)</strong> and 9,10-phenanthrenequinone dioxime <strong>(H<sub>2</sub>ptd)</strong> ancillary ligands in complexes <strong>Ir2</strong> and <strong>Ir3,</strong> while the coordination of dioxime groups (-N-OH) of dimethyl glyoxime (<strong>H<sub>2</sub>dmg</strong>) ligand to the iridium metal center was successfully achieved in <strong>Ir1</strong>. These complexes represent the first instances of selective generation of aromatic monoximes in <strong>H<sub>2</sub>dbd</strong> and <strong>H<sub>2</sub>ptd</strong> upon coordination with iridium. The potential of these complexes as cancer therapeutics was assessed against MCF-7 and MDA-MB-231 cells, but all the complexes showed inactivity in inhibiting the growth of cancer cells. Furthermore, the complexes exhibited low quantum yields and were very weakly luminescent.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1360 ","pages":"Article 145540"},"PeriodicalIF":4.7,"publicationDate":"2026-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146192545","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}