Journal of Molecular Structure最新文献

{"title":"Design, synthesis, and computational studies of novel pyrazoline-based dual EGFR/HER-2 inhibitors with apoptotic antiproliferative activity","authors":"Lamya H. Al-Wahaibi ,&nbsp;Hani Mohamed Hafez ,&nbsp;Fadwa H. Edrees ,&nbsp;Hesham A. Abou-Zied ,&nbsp;Bahaa G.M. Youssif ,&nbsp;Stefan Bräse","doi":"10.1016/j.molstruc.2025.142364","DOIUrl":"10.1016/j.molstruc.2025.142364","url":null,"abstract":"<div><div>The simultaneous targeting of EGFR and HER2 constitutes a legitimate anticancer strategy for the treatment of solid tumors. In response, we developed and synthesized a new group of pyrazoline compounds that act as dual-target inhibitors for EGFR and HER-2. The structure of the newly synthesized compounds was validated with ¹H NMR, ¹³C NMR, and elemental analysis. The novel compounds' antiproliferative efficacy was evaluated against four cancer cell lines. All compounds showed GI₅₀ values ranging from 23 to 66 nM, with the breast cancer cell line (MCF-7) showing the highest sensitivity. Compounds <strong>7c, 7d, 7f, 7h, 7j</strong>, and <strong>7l</strong> had the strongest antiproliferative activity, with derivatives <strong>7d, 7h</strong>, and <strong>7j</strong> outperforming erlotinib in all tested cancer cell lines. The study revealed that compounds <strong>7d</strong> and <strong>7h</strong> are the most effective dual-target inhibitors of EGFR and HER-2, exceeding the reference EGFR inhibitor erlotinib and having comparable action to the clinically used HER-2 medication Lapatinib. We tested the apoptotic potential of <strong>7d</strong> and <strong>7h</strong> and found that both compounds cause apoptosis by turning on caspase-3, caspase-8, and Bax and decreasing the expression of Bcl-2, a protein that prevents apoptosis. Molecular docking studies revealed robust interactions of these compounds within the EGFR and HER-2 binding pockets, supported by molecular dynamics simulations that confirmed their stability. ADME profiling highlighted the pharmacokinetic advantages of these compounds, particularly <strong>7h</strong>, as orally bioavailable and effective inhibitors. These findings suggest that pyrazoline-based inhibitors could serve as a foundation for future development of dual-targeted therapies to overcome resistance in cancer treatment.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142364"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143864833","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}

{"title":"Synthesis & Optical properties Of ZnO / curcumin composite nanostructure","authors":"V.B. Pawade ,&nbsp;V.Y. Karadbhajne ,&nbsp;G.P. Lakhawat ,&nbsp;A.J. Agrawal ,&nbsp;K.S. Janbandhu","doi":"10.1016/j.molstruc.2025.142314","DOIUrl":"10.1016/j.molstruc.2025.142314","url":null,"abstract":"<div><div>ZnO/curcumin nanocomposites have been synthesized by the wet chemical and ultrasound sonochemical approach. Phase purity and crystallite size were examined by using XRD and TEM techniques. The presence of organic groups, bending, stretching, and vibration in curcumin and synthesized nanocomposites was investigated by FTIR techniques. Absorption wavelengths of the pure ZnO and ZnO/curcumin nanocomposites were studied by using UV-visible spectra. Further, the luminescence properties of curcumin nanoparticles that dispersed in water were examined by PL techniques, which show a blue emission band under NUV excitations. Diamond and hexagonal-shaped particles of the synthesized ZnO/curcumin nanocomposites were clearly observed in TEM images. Hence, this work focuses on the shape and size-dependent optical properties of the synthesized nanostructure and their potential scope in nanomedicine for targeted drug delivery system</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142314"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882706","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}

{"title":"Design, synthesis, in vitro, and in silico investigations of new barbituric acid-hydrazone-chalcone derivatives as promising urease inhibitors","authors":"Mehdi Asadi ,&nbsp;Mohammad Hosein Sayahi ,&nbsp;Meysam Talebi ,&nbsp;Navid Dastyafteh ,&nbsp;Maryam Esmkhani ,&nbsp;Maryam Mohammadi‐Khanaposhtani ,&nbsp;Asieh Hosseini ,&nbsp;Massoud Amanlou ,&nbsp;Homa Azizian ,&nbsp;Mohammad Mahdavi ,&nbsp;Fouzia Naz ,&nbsp;Khalid Mohammed Khan","doi":"10.1016/j.molstruc.2025.142307","DOIUrl":"10.1016/j.molstruc.2025.142307","url":null,"abstract":"<div><div>The present study focuses on the synthesis of a library of arylated hydrazones of barbituric acid, aiming to develop exceptionally potent urease inhibitors. A two-step synthesis was adopted; first, chalcone derivatives were synthesized by reacting 4-aminoacetophenone with variously substituted aldehydes under basic conditions, these derivatives were then treated with barbituric acid to afford barbituric acid hybrids <strong>5a-n</strong>. The FTIR, CHNS, ¹H NMR, and ¹³C NMR were structurally characterized. All compounds were examined for their potential against the urease enzyme and displayed remarkable results with IC₅₀ values ranging from 4.84 ± 0.62 to 13.36 ± 0.23 µM. The structure-activity relationship was also established, revealing that compound <strong>5n</strong> (IC₅₀ = 4.84 ± 0.62 µM) with -Cl and -NO₂ substitutions <em>para</em> to each other plays a major role in urease inhibition and is identified as the most potent analog of the library. Moreover, molecular docking investigations indicated the barbituric acid rings in all compounds align consistently, with the carbonyl group at C2 positioned toward the bi-nickel center atoms, resembling the orientation in AHA and thiourea. Chalcone and hydrazone subunits occupy a similar conformation near the active site's entrance. Compound <strong>5n</strong> is stabilized at the active site's bi-nickel center by the barbiturate moiety, which forms metal coordination bonds and hydrogen bonds with key residues like Asp633, His492, and Cys592. Additional interactions with His593, Arg439, and His594 contribute to its stability and influence the flexibility of the active site's mobile flap, ultimately inhibiting urease activity.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142307"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850419","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}

{"title":"New multicomponent crystals of nevirapine with improvement on solubility: preparation, characterization, calculation and analysis","authors":"Zhenjun Liu ,&nbsp;Fuhai Yu ,&nbsp;Haomin Sun ,&nbsp;Songgu Wu ,&nbsp;Hua Rong ,&nbsp;Haibin Song ,&nbsp;Yong Zhang ,&nbsp;Wei Chen ,&nbsp;Qiuxiang Yin","doi":"10.1016/j.molstruc.2025.142363","DOIUrl":"10.1016/j.molstruc.2025.142363","url":null,"abstract":"<div><div>The poor water solubility of nevirapine (NVP) significantly restricts its bioavailability. To address this challenge, this work proposes an efficient method for screening NVP multicomponent crystals using the full interaction map (FIM) and the Conductor-like screening model for real solvents (COSMO-RS) model. Two NVP salts and two NVP cocrystals with enhanced solubility were prepared using liquid-assisted grinding method and solvent evaporation method, namely nevirapine-5-sulfosalicylate (NVP-5SA), nevirapine-2,6-dihydroxybenzoate (NVP-2,6DBA), nevirapine-2,3-dihydroxybenzoic acid cocrystal (NVP-2,3DBA) and nevirapine-2,5-dihydroxyterephthalic acid cocrystal (NVP-2,5DTA). Systematic characterization, structural analysis, solubility measurement, dissolution evaluation and theoretical calculations were conducted on these multicomponent crystals. Notably, the solubility of NVP-5SA and NVP-2,6DBA increased to 5.32 and 3.90-fold respectively compared with NVP in phosphate buffer (pH = 6.8). The structures of four multicomponent crystals were characterized using single crystal X-ray diffraction. Quantum chemical calculations, including Hirshfeld surface analysis, atoms in molecules theory, independent gradient model based on Hirshfeld partitioning, and molecular electrostatic potentials surface, were employed to study molecular interactions at the microscopic level. The lattice energy (<em>E</em>_L) and hydration-free energy (<em>E</em>_HF) of NVP and its four multicomponent crystals were calculated, and the relationships between these parameters and the changes of melting point and dissolution behavior were analyzed. So, the variations and origins of these physicochemical properties were rationalized and explained on the atomic scale. Meanwhile, the efficiency of the novel combined coformers screening method was verified.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142363"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869161","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}

{"title":"Photoluminescence investigation of Tm3+/ Dy3+ co-doped LiNa5(PO4)2 phosphors for color tunable LED applications","authors":"A.V. Bharati ,&nbsp;Dattatraya B. Bharti ,&nbsp;Ashok Bharati","doi":"10.1016/j.molstruc.2025.142368","DOIUrl":"10.1016/j.molstruc.2025.142368","url":null,"abstract":"<div><div>One of the main areas of research at the present time is the production of luminous materials. Particularly, materials based on inorganic phosphor have been widely used for many different kinds of applications, such as white light emitting diodes (WLEDs), radiation dosimetry, field emission displays (FEDs), cathode ray tubes (CRTs), and lamp industries. In this research, we successfully synthesized single-host LiNa₅(PO₄)₂: Tm³⁺/Dy³⁺ by using the solid-state reaction method to achieve white light emission. The luminescence properties of the synthesized samples were analyzed under UV light. XRD analysis confirmed the phase purity of LiNa₅(PO₄)₂. SEM images showed that the phosphor materials tend to form agglomerates. Photoluminescence (PL) measurements of LiNa₅(PO₄)₂:Dy³⁺doped phosphors demonstrated efficient excitation at 349 nm, with prominent emission bands at 487 nm (blue) and 576 nm (yellow). For LiNa₅(PO₄)₂: Tm³⁺ doped phosphors, strong orange emissions were observed at 458 nm corresponding to the ¹D₂→³H₄ transitions in Tm³⁺ ions. Co-doping with these rare earths resulted in strong blue and yellow emissions. The color qualities of the luminous prepared samples were calculated using the CIE color coordinates. Therefore, these findings result suggest that Tm³⁺/Dy³⁺ co-doped LiNa₅(PO₄)₂ phosphors, when excited by UV LEDs could be suitable for producing white light emitting diodes and display devices.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142368"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838209","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}

{"title":"Benzimidazolone conjugated biscoumarins: Synthesis, molecular docking studies, urease, lipase, and acetylcholinesterase inhibitory activities","authors":"Okan Güven ,&nbsp;Emre Menteşe ,&nbsp;Bahar Bilgin Sökmen ,&nbsp;Mustafa Emirik ,&nbsp;Gülay Akyüz","doi":"10.1016/j.molstruc.2025.142362","DOIUrl":"10.1016/j.molstruc.2025.142362","url":null,"abstract":"<div><div>New biscoumarin molecules bridged benzimidazolone were synthesized and then screened for their urease, lipase, and acetylcholinesterase inhibition properties. In this series, the best urease inhibition value belongs to compound <strong>4f</strong> (IC₅₀: 0.05 ± 0.003 μM), the most effective lipase inhibition was shown by the compound <strong>4s</strong> (IC₅₀: 0.05 ± 0.014 μM). Although the inhibition value of all compounds against acetylcholinesterase is remarkable, compound <strong>4e</strong> showed the closest inhibition to tacrine (IC₅₀: 0.031 ± 0.013 μM) with an IC₅₀ value of 0.096 ± 0.018 μM. Molecular docking studies were performed using the Schrödinger Suite package using the IFD protocol to elucidate the interaction mode of the synthesized compounds with the binding site of urease, lipase and acetylcholine esterase enzymes. The molecular docking studies supported the in vitro inhibition results. It was shown that the compounds interacted with the important residues of the active site of the enzymes through hydrogen bonding, π–π stacking and hydrophobic interactions. 100 ns Molecular Dynamics (MD) simulations were performed on the top docking-scored complex to evaluate the stability of the ligand–protein interactions. The ADMET profiles of the most potent compounds were also evaluated to assess their pharmacokinetic and toxicity characteristics.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1338 ","pages":"Article 142362"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835339","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}

{"title":"One molecule, two switches: Synthesis and DFT studies of Oxalohydrazide-based photoswitches","authors":"Mazlum Turk,&nbsp;Dilek Yüksel,&nbsp;Nazan Tunoglu,&nbsp;Ayse Uzgoren-Baran","doi":"10.1016/j.molstruc.2025.142318","DOIUrl":"10.1016/j.molstruc.2025.142318","url":null,"abstract":"<div><div>In organic chemistry, compounds with hydrazone moiety have the potential for application in various fields. Many hydrazone compounds with different functional groups, which can be converted from one state or isomer to another by light or heat, are used as molecular photoswitches. The research on these intriguing functional molecules is rapidly advancing.</div><div>Herein, <em>N¹, N²-bis(-naphthalen-1-ylmethylene) oxalohydrazide</em> (<strong>2</strong>) containing the –CO–NH-N=CH– moiety as a photoswitch linker was designed and synthesized. The structures of the synthesized compound were characterized by proton nuclear magnetic resonance (1H NMR), carbon nuclear magnetic resonance (13C NMR), Mass spectrometry (MS), and the Fourier-transform infrared spectroscopy (FT-IR) spectra. Photoswitching of the obtained compound was carried out under UV–light (300–400 nm). As far as we know, this is the first study of photoswitching of oxalohydrazide compounds.</div><div>As a result of Ultraviolet-visible spectroscopy (UV–vis), 1H NMR spectra, and density functional theory calculations (DFT), it was found that compound <strong>2</strong> undergoes a characteristic E to Z photoisomerization after light irradiation. Fast <em>E/Z</em> response under UV–light illumination was observed. The thermally unstable Z isomer was found to be recovered to the E isomer by temperature, which refers to T–type photochromic switches. It is envisaged that the compound can be used as a possible photoswitch after further studies are completed.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142318"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869311","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}

{"title":"The effect of 1.5 mol % Zn substitution on the broadband THz optical parameters of stoichiometric LiNbO3 single crystal","authors":"Lalit Kumar ,&nbsp;Guruvandra Singh ,&nbsp;R. Bhatt ,&nbsp;Dibakar Roy Chowdhury ,&nbsp;M. Soharab ,&nbsp;Indranil Bhaumik ,&nbsp;Chitra Gautam ,&nbsp;Mukesh Jewariya","doi":"10.1016/j.molstruc.2025.142365","DOIUrl":"10.1016/j.molstruc.2025.142365","url":null,"abstract":"<div><div>Lithium Niobate (LiNbO₃, LN) crystals, recognized as a significant optical functional material, have gained extensive interest in terahertz (THz) photonics. This particular interest is prominently evident in the generation and detection of THz waves through difference frequency generation (DFG) or optical rectification (OR), as well as electro-optical (EO) detection. Moreover, these crystals are essential to the optical components employed for THz beam steering. The present work comprehensively investigates the THz optical properties of stoichiometric lithium niobate (SLN) and 1.5 mol % Zn-doped stoichiometric lithium niobate (Zn:SLN) z-oriented single crystals, which are grown from Li-rich melt using high temperature top seeded solution growth method. The phase purity and lattice structure were analyzed using PXRD measurements, while Raman spectroscopy was employed to investigate the existing lattice vibrational modes. Furthermore, the detailed characterization of the refractive index, absorption coefficient, and dielectric function of both crystals is performed by employing the terahertz time-domain spectroscopy (THz-TDS) in transmission mode within the frequency range of 0.4 to 1.6 THz. The experiment revealed that 1.5 mol % Zn doping resulted in a substantial enhancement of the THz optical parameters. Remarkably, the experimentally obtained results are aligned well with the theoretical Lorentz damped harmonic oscillator (DHO) model, which confirms that the dielectric response of undoped and Zn-doped SLN crystals is governed by the lowest transverse optical E(TO1) mode of vibration. Also, Zn-doping significantly alters the fitting parameters of the undoped SLN single crystal. This investigation provides invaluable information on tuning the THz response of LiNbO₃ through 1.5 mol % Zn doping, paving the way for its optimized use in next-generation THz photonics and applications such as THz radiation emitter and detector.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1339 ","pages":"Article 142365"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143838377","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}

{"title":"A study on the boosted activity of the Bi2O3CeO2 nanoparticles toward phenazopyridine photodegradation; A brief comparison of the effects of some coupling strategies","authors":"Hamid Shirzadi ,&nbsp;Alireza Nezamzadeh-Ejhieh ,&nbsp;Majid Kolahdoozan","doi":"10.1016/j.molstruc.2025.142367","DOIUrl":"10.1016/j.molstruc.2025.142367","url":null,"abstract":"<div><div>In the present study, some strategies were applied to fabricate binary coupled Bi₂O₃/CeO₂ systems and their roles in the boosted photocatalytic activity against the photodegradation of phenazopyridine. The individual Bi₂O₃ and CeO₂ nanoparticles (NPs) were mechanically mixed in agate mortar (MMix sample) in the first pathway. In the second pathway, the same prepared MMix sample was dispersed in n-hexane and ultrasonicated at 37 MHz for 15 min, and then the solvent evaporated (Ultra-MMix). In the third pathway, an ultrasonicated sample was prepared under the above-mentioned conditions on a mixture of Bi₂O₃ + CeO₂ NPs (Ultra-M sample). Finally, in the fourth sample, the binary catalyst was prepared via a precipitation procedure (Co-Pre). Some techniques like powder XRD, FTIR, SEM, and UV–Vis DRS were used to characterize the samples. Both Scherrer and Williamson-hall equations determined the crystallite size of the samples, conforming to the nano dimension for the crystals. DRS results showed a relative decrease in band gaps of the integrated systems compared to Bi₂O₃ alone. In the first initial steps of the photodegradation experiments, the activity of MMix and Co-Pre catalysts were evaluated against the PZP solution, revealing a boosted activity concerning the individual Bi₂O₃ and CeO₂ NPs. Due to the relatively higher activity of the MMix than the Co-Pre catalyst, the influences of the critical factors on its activity in the PZP photodegradation amount were optimized, and the optimal conditions of a Bi₂O₃:CeO₂ molar ratio of 1:1 for the coupled catalyst, C_PZP: 2 ppm, catalyst doe: 0.4 g/L, pH: 5, and illumination time of 90 min were reached. The pseudo-first-order kinetic model described the process kinetics. The effects of the scavenging reagents were also evaluated to estimate the relative role of the reactive species in PZP removal. Accordingly, the photoinduced holes and superoxide radicals showed higher relative roles in PZP photodegradation. A brief comparison on the effect of some fabrication roots in the photocatalytic activity of the coupled catalyst was applied.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1338 ","pages":"Article 142367"},"PeriodicalIF":4.0,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835338","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}

{"title":"Synthesis, characterization and study the mesogenic properties of a new class of asymmetrical calamitic mesogenic materials based on imidazo[2,1-b][1,3,4]thiadiazole","authors":"Nabih M. Abdulnabi,&nbsp;Ivan Hameed R. Tomi","doi":"10.1016/j.molstruc.2025.142328","DOIUrl":"10.1016/j.molstruc.2025.142328","url":null,"abstract":"<div><div>A new series of asymmetrical calamitic mesogens, 6-(4-methoxyphenyl)-2-(4-alkoxyphenyl)-imidazo[2,1-b][1,3,4]thiadiazole derivatives (M_n), has been successfully synthesized. This series is characterized by a coplanar imidazo[2,1-b][1,3,4]thiadiazole central core, featuring a methoxy‑terminal group on the imidazo side and alkoxy-terminated chains (OR = OC_nH_2n+1) on the thiadiazole side. The synthesis of the (M_n) series was achieved through a cyclization reaction between 2-amino-1,3,4-thiadiazole derivatives (N_n) and 4-methoxyphenacyl bromide. The chemical structures of the compounds were confirmed using various analytical techniques, including FT-IR, NMR (¹H &amp; ¹³C) spectroscopy, and mass spectrometry (EI-MS). The mesomorphic properties of these calamitic mesophases were investigated using polarizing optical microscopy (POM), differential scanning calorimetry (DSC) during both heating and cooling cycles and X-ray powder diffraction (XRPD) analyses. All mesogens (M_b–M_j, M_k) exhibited enantiotropic mesomorphic behavior. Notably, the second compound in the series, M_b (<em>n</em> = 2), displayed a nematic (N) mesophase during heating, while both nematic (N) and smectic A (SmA) phases appeared upon cooling. In contrast, other derivatives (M_c–M_g, M_i) (<em>n</em> = 3, 4, 5, 6, 7, 9) exhibited both nematic (N) and smectic A (SmA) mesophases during heating and cooling. The final members of the series, M_h, M_j, and M_k (<em>n</em> = 8, 10, 12), exclusively exhibited the smectic A (SmA) mesophase in both thermal cycles. The observed mesophase behavior, including the presence of smectogenic and nematogenic ranges, is attributed to the coplanarity and conjugation of the central fused imidazo[2,1-b][1,3,4]thiadiazole core. Furthermore, the methoxy (-OCH₃) terminal group and the gradual elongation of the flexible alkoxy tail play a crucial role in influencing the mesomorphic properties of these compounds.</div></div>","PeriodicalId":16414,"journal":{"name":"Journal of Molecular Structure","volume":"1338 ","pages":"Article 142328"},"PeriodicalIF":4.0,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143816531","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}