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The ultrafast proton transfer and the following dynamics for aromatic Schiff bases N,N′-bis(salicylidene)ethylenediamine (salen) and N,N′-bis(salicylidene)-1,4-butylenediamine (salbn) were investigated with experimental and theoretical methods. A dual emission property with a large Stokes shift in salen and salbn indicates that excited state intramolecular proton transfer occurs with photoexcitation. An efficient single proton transfer was confirmed within 200 fs for both molecules. Subsequently, a fast twisted motion of the keto moiety carries cis-keto to a relaxed stable geometry in the S1 state. Following the twisted motion, the phenol ring at keto moiety further rotates to a conical intersection with the ground state and a cis–trans isomerization occurs. The isomerization rate is high, which dominates the competition with the radiative transition, resulting in weak emission intensity. It is confirmed that the length of alkyl chain affects the direction of phenol ring twisting and rotation during the whole subsequent relaxation of excited cis-keto tautomer. Compared with polar solvent acetonitrile, the barrier of isomerization is higher and the hydrogen bond on keto moiety is stronger in nonpolar solvent toluene. It makes fluorescence radiation channels competing with isomerism more likely to occur, contributing to the observed difference of enol/keto emission ratios of salen and salbn in toluene and acetonitrile. [ABSTRACT FROM AUTHOR]

This study investigates novel zinc and indium phthalocyanines with Schiff base and sulphur moieties, focusing on their potential for cancer therapy and antimicrobial applications. It explores the effectiveness of photochemical and sono-photochemical methods to enhance singlet oxygen production, which is crucial for photodynamic therapy. The synthesized complexes in this study demonstrated high singlet oxygen quantum yields, with D3 (ZnPc) and D4 (InPc) showing ΦΔPDT values of 0.71 and 0.75, and ΦΔSPDT values of 0.91 and 0.94, respectively. Furthermore, the evaluation for biological properties revealed that both D3 and D4 exhibit significant antidiabetic properties, DPPH radical scavenging activity, DNA cleavage, antimicrobial activity, biofilm inhibition, and microbial cell viability impacts, both with and without photodynamic therapy. Notably, D3 and D4 achieved antimicrobial cell viability inhibition rates of 84.67 ± 4.67% and 98.32 ± 5.96%, respectively, showcasing their effectiveness in photodynamic antimicrobial therapy. Overall, the study highlights the potential of these phthalocyanine complexes as advanced photosensitizers, with strong singlet oxygen generation and promising biological activities, paving the way for future therapeutic applications. [ABSTRACT FROM AUTHOR]

Cellulose-based hydrogels have attracted considerable attention in biomedical engineering. However, existing cellulose-based adhesive hydrogels have several limitations, including poor wet adhesion, average antimicrobial activity and a lack of benign on-demand detachment. Using a dual-crosslinked design strategy, we created a cellulose-based hydrogel (ACCPFM) by combining polymerisable allyl cellulose, carboxymethyl chitosan and the aldehyde-cation copolymer P(FPMA-co-META). Covalent (Schiff base) and non-covalent (electrostatic interaction and hydrogen bonding) crosslinking enhance the mechanical performance of the prepared hydrogel. The introduction of P(FPMA-co-META) into the cellulose network architecture endowed the ACCPFM hydrogel with an impressive antibacterial capacity (bacterial reduction: > 95%). The ACCPFM hydrogel used the hygroscopicity of the hydroxy, carboxyl and cationic moieties to remove interfacial water on the tissue surface and then formed physical and dynamic covalent cross-links with the tissue (shear strength: > 50 kPa, tensile strength: > 70 kPa and interfacial toughness: > 110 J m−2). Notably, due to the dominance of physical and dynamic covalent crosslinking, which transforms timescale-dependent, on-demand detachment was achieved by applying a tailored benign solution (sodium bicarbonate/glycine) at different stages, providing a wider time window and fault-tolerance for the adhesion process. Given the ACCPFM hydrogel's strong wet adhesion, excellent antimicrobial capability and cytocompatibility, and benign on-demand detachment from tissues, cellulose-based hydrogels are expected to have potential applications in the biomedical field. [ABSTRACT FROM AUTHOR]

In this study, new Schiff base derivatives of α‐naphthalene acetic acid containing alkyl phenyl ether fragment have been effectively synthesized through multistep reaction process, characterized by 1H‐NMR and 13C‐NMR spectroscopy. These derivatives have been tested for their in vitro α‐amylase and α‐glucosidase inhibitory activities. In the series, 8 compounds (2j, 2f, 2e, 2m, 2a, 2b, 2l, and 2c) exhibited promising α‐amylase inhibition with IC50 values from 5.38 ± 0.36 to 14.59 ± 0.64 µg/mL. Similarly, in the case of α‐glucosidase inhibitory activity, 10 derivatives (2e, 2f, 2j, 2m, 2b, 2c, 2i, 2d, 2a, and 2l) exhibited excellent activity having IC50 values from 6.96 ± 0.39 to 16.27 ± 0.31 µg/mL, wheras the remaining derivatives exhibited good‐to‐least antidiabetic potential. The ADME properties were calculated for all Schiff base derivatives using Swiss‐ADME web tool. Furthermore, the docking studies identified the binding modes of the compounds. [ABSTRACT FROM AUTHOR]

Six Schiff bases with general name 5-(diethylamino)-2-(((halophenyl)imino)methyl)phenol (where halo = 4-fluoro (H1), 2-fluoro (H2), 2-bromo (H3), 4-bromo (H4), 4-chloro (H5) and 3-chloro-4-fluoro (H6)) were prepared by the condensation reaction between 4-(diethylamino)salicylaldehyde and suitable halogenated aromatic amines. The six halogenated Schiff bases were elucidated using different spectroscopic techniques and the structure of H3 and H6 were confirmed using single-crystal X-ray crystallography. The bond lengths of C7–N1, C7–C8 and C8–C9 obtained from structural analysis for both compounds depicted their enol-tautomeric characteristic form. The Hirshfeld analysis revealed that H‧‧‧H intermolecular contacts contributed most towards the Hirshfeld surfaces of both H3 (47.6%) and H6 (39.9%). Quantum chemical calculation studies showed that H1 and H2 have the highest and lowest energy band gap (∆E = 3.80 eV for H1 and ∆E = 3.73 eV for H2), depicting H2 and H1 as the most and least chemically reactive respectively among all the compounds. α-Amylase and α-glucosidase assay were used to evaluate the antidiabetes prowess of the synthesized compounds. All the compounds exhibited lower IC50 values than acarbose (reference drug) in α-amylase assay experiments and H5 with lowest IC50 value of 63.54 μM could be suggested to have the highest α-amylase inhibitory potential among the test samples. For α-glucosidase assay, H1–H6 displayed good antidiabetic potential. However, none of the compounds outshined acarbose with H6 having highest α-glucosidase inhibitory potential when compared to others i.e., IC50 of H6 = 60.89 μM and IC50 of acarbose = 51.42 μM. We measured the antioxidant potential of H1–H6 exploring 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric reducing ability power (FRAP) assays. The DPPH as well as NO radical scavenging assay showed that all the compounds exhibited excellent antioxidant results with some of the compounds surpassing catechin (reference drug). Compound H5 with IC50 values of 30.32 mM and 31.73 mM outshined catechin with IC50 values of 31.17 mM and 140.62 mM for DPPH and NO assays respectively. All the compounds fell within the threshold of Lipinski's Ro5 projecting them as orally bioavailable and less toxic future therapeutics. [ABSTRACT FROM AUTHOR]

Schiff bases possess a range of unique physical, chemical and medicinal properties, which contribute to their potency as biological agents. A Schiff base was synthesized, which consisted of 4-chloro aniline and vanillin. The successful formation of the compound was confirmed by their comparable FTIR, UV–Vis, 1HNMR and 13CNMR spectra. The compound was analyzed using X-ray crystallography, which revealed that it crystallizes in the monoclinic system with the space group P21/c. The Hirshfeld surface analysis revealed valuable information about the intermolecular interactions present in the crystal lattice. The most common contacts observed were between hydrogen and hydrogen, as well as carbon and hydrogen. The obtained fluorescence values of 375 nm and 412 nm at excitation wavelength 322 nm strongly indicated the luminescent nature of the compound. The thermal stability of the compound was assessed through thermogravimetric analysis (TGA). DFT was used to optimize the geometry using the B3LYP/cc-pVDZ basis set. The compound exhibited an energy gap of 2.35 electron volts (eV). According to the analysis of molecular electrostatic potential, C and O atoms were found to be electrophilic. According to Mulliken charge analysis, C atoms possess both positive and negative charges, hydrogen atoms exclusively carry positive charges, and Cl, O and N atoms exclusively carry negative charges. Upon analysis of the molecule, the electron localization function discovered that the atoms of carbon, nitrogen and chlorine exhibited delocalized electron density. Also, the localized orbital locator identified the localized orbital positions in the hydrogen atoms. The reduced density gradient (RDG) maps exhibit a wide range of noncovalent interactions. In comparison to the standard amoxicillin, the synthesized compound demonstrated moderate antimicrobial efficacy against the gram-positive bacteria Klebsiella pneumoniae and the fungi Candida albicans. The compound’s concentration-dependent antioxidant and anti-inflammatory properties were demonstrated through in vitro biological evaluation using 2,2-diphenyl-1-picrylhydrazyl and human red blood cell (HRBC) methods. The compound was docked using the proteins 7BYE and 4LEB were chosen from both organisms. The lowest binding attractions obtained were -3.40 kcal/mol for 7BYE and -4.51 kcal/mol for 4LEB. To investigate the stability of the protein–ligand complex, molecular dynamic simulation was employed. The ligands in silico toxicity potentialities were analyzed using seven toxicity models and the results indicated that the ligand is biocompatible. [ABSTRACT FROM AUTHOR]

Hydrogels are regarded as ideal tissue scaffold materials owing to their unique advantages, but problems such as low strength and easy cracking have become bottlenecks that limit their practical applicability. Constructing reinforced hydrogels is a widely studied approach for performance enhancement. Therefore, herein, cellulose nanocrystals were introduced as reinforcement into a thermally responsive hydrogel matrix through a Schiff base, achieving a cellulose nanocrystal-reinforced thermally responsive dynamic hydrogel. The CNC-reinforced hydrogel was characterized in detail, and the influence of CNCs on hydrogel properties was systematically investigated. Moreover, the thermally responsive and dynamic properties of the resulting hydrogels were tested to evaluate their mechanical performance. This work provides a feasible solution for the design of hydrogel-based tissue scaffold materials with long service life. [ABSTRACT FROM AUTHOR]

This study reports the development of new probes RR1 ((1E)-1-(1-(6-bromo-2-oxo-2H-chromen-3-yl)ethylidene)ethyl thiosemicarbazone) and RR2 ((1E)-1-(1-(6-bromo-2-oxo-2H-chromen-3-yl)ethylidene)phenyl thiosemicarbazone), which selectively showed fluorescence turn 'OFF' response towards Cu2+ and Al3+. Further, complexes of RR1-Cu2+ and RR2-Al3+ acted as chemosensors for the detection of L -amino acids. RR1-Cu2+ selectively detected L -arginine (fluorescence turn 'ON'), and RR2-Al3+ selectively detected L -glutamic acid (fluorescence turn 'ON'). The existence of the fluorophore–quencher complexes RR1-Cu2+ and RR2-Al3+ was confirmed by theoretical studies. Further, the chemosensors RR1-Cu2+ and RR2-Al3+ have three possible structural isomers (RR1-Cu2+- L -arginine – A, B and C) and (R2-Al3+- L -glutamic acid – D, E and F), as confirmed by theoretical studies. In vitro bio-imaging of the probes (RR1 and RR2), complexes (RR1-Cu2+ and RR2-Al3+) and complexes associated with L -arginine (RR1-Cu2+- L -arginine) and L -glutamic acid (R2-Al3+- L -glutamic acid) was performed in the MDA-MB-231 cell line using their IC50 concentrations. In addition, in vivo live cell imaging studies were conducted using C. elegans as the model organism. [ABSTRACT FROM AUTHOR]

Four new Ni16 molecular wheels with the general formula [L4Ni16(RCOO)16(H2O)x(MeOH)12‐x] (where H4L=1,4‐bis((E)‐((2'‐hydroxybenzyl)imino)methyl)‐2,3‐naphthalenediol, and R=H or Me) have been isolated and structurally characterised. Complexes C1−C3 (R=Me) were formed using nickel (II) acetate and presented as polymorphs with the same formulation of charged components. The same wheel‐like architecture was observed in C4 (R=H), which was prepared using nickel (II) formate, demonstrating the potential for further versatility of the system. In contrast to similar four‐fold symmetric Ni(II) wheel clusters, measurements of the static magnetic properties of C1 indicated the presence of dominant antiferromagnetic interactions and an S=0 ground state. [ABSTRACT FROM AUTHOR]

The identification of perilous metal ions and the treatment of diseases induced by microorganisms are critical areas requiring attention. We report herein the design and development of an acetylene‐functionalized Schiff base compound 4, using a low‐cost and straightforward approach. This compound 4 exhibits dual functions in the detection of harmful metal ions, particularly Al(III), as well as in the prevention of disorders caused by bacteria, specifically Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis). It was well characterized through the utilization of diverse spectroscopic techniques, such as NMR (1H and 13C), FT‐IR, and mass spectrometry. Furthermore, the complete structure clarification of the Schiff base compound 4 was revealed through the utilization of X‐ray crystallography. The limit of detection (LOD) for Al(III) is 35.5 × 10−8 M, surpassing the WHO drinking water standard of 26.7 µM, underscoring the high sensitivity of compound 4. The antibacterial activity of compound 4 has also been effectively evaluated on Gram‐positive (S. aureus and B. subtilis) bacteria. Furthermore, compound 4 was docked to S. aureus and B. subtilis proteins, which represents outstanding outcomes with binding energies of −7.31 kcal/mol and −7.87 kcal/mol, respectively. The antibacterial activity of the compound 4 in both in vitro and docking studies suggests that it possesses the potential to serve as an antibacterial agent in the future. [ABSTRACT FROM AUTHOR]

In recent developments, graphene quantum dots (GQDs) have emerged as valuable tools for imaging and biosensing. Various modifications on the GQDs with any desired functionality and attachment of organic molecules and/or nanostructures allow tuning their photophysical properties as well as charge transfer dynamics for bioimaging applications. This study focuses on synthesizing and characterizing of polyethyleneimine‐functionalized nitrogen‐doped GQDs (NC1), Schiff base‐ functionalized nitrogen‐doped GQDs (NC2), and silver nanocomposites of these Schiff base‐functionalized nitrogen‐doped GQDs (NC3). We explore their absorption and emission properties to understand their interactions in the ground state. Furthermore, ultrafast transient absorption spectroscopy measurements reveal that the presence of NC3 shortens the excited state lifetime of NC1 due to charge transfer, resulting in reduced fluorescence intensity. Both experimental and DFT results suggest the potential of NC3 for bioimaging and sensing applications, making them promising candidates for phototheranostic purposes. [ABSTRACT FROM AUTHOR]

This study successfully prepared three environmentally friendly Schiff base network (SNW) polymers, SNW‐1, SNW‐2, and SNW‐3, using melamine and aldehyde compounds as raw materials through a microwave‐assisted synthesis method. The SNW materials were applied to catalyze the copolymerization reaction of SO2 and epoxides. Through detailed analysis of the chemical structure and properties of SNW‐1, SNW‐2, and SNW‐3, their catalytic efficiency was thoroughly investigated. Three thermal degradation kinetic models, Flynn–Wall–Ozawa (FWO), Kissinger, and Coats–Redfern, were employed to calculate the kinetic parameters of the thermal degradation of poly(cyclohexene sulfite) (PCS). Potential thermal degradation mechanisms were speculated. Additionally, the Kissinger model accurately described the thermal degradation kinetics features of PCS. Based on experimental results and kinetic analysis, this paper elucidates the potential mechanism of the copolymerization reaction of SO2 and epoxides. The study indicates that microwave‐assisted synthesis exhibits convenience and high efficiency in preparing efficient catalysts, demonstrating significant potential across various application domains. [ABSTRACT FROM AUTHOR]

One of the central focuses in self‐assembly is precisely controlling the self‐assembly pathway so that the target molecules can be produced exclusively. Trans‐1,2‐cyclohexanediamine contains two amino units that form a 60° angle when projected on a plane. This angle naturally favors the formation of triangular products in most cases when trans‐1,2‐cyclohexanediamine is used as a bisamino building block in the synthesis of macrocycles and tubes. Here, we synthesized a slightly bent tetraformyl precursor bearing a central dibenzothiophene moiety, whose 3,7‐positions are functionalized with two m‐phthalaldehyde units. We observed that combining this tetraformyl building block with trans‐1,2‐cyclohexanediamine yielded a quadrangular tube when the concentrations of the precursors were relatively high. Both experimental measurements and theoretical calculations indicate that the formation of this unlikely occurring quadrangular product was driven by the intramolecular C−H⋅⋅⋅π interactions between the dibenzothiophene building blocks within the tube framework. This driving force, however, was disturbed in the triangular tube, a smaller counterpart whose formation was considered previously much more thermodynamically favored. These results improved our fundamental understanding on how to create those products whose syntheses are considered difficult or impossible, by modulating the intramolecular driving forces. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel indole‐containing pyridine‐based Schiff base, (E)‐2‐({[bis(pyridin‐2‐yl)methylidene]hydrazin‐1‐ylidene}methyl)‐1H‐indole, C20H15N5 (2‐DPHI), and its cadmium(II) complex poly[[2‐({[bis(pyridin‐2‐yl)methylidene]hydrazin‐1‐ylidene}methyl)‐1H‐indole]di‐μ‐chlorido‐cadmium(II)], [CdCl2(C20H15N5)]n (pCd2), as potential anticancer agents. The Schiff base was synthesized by reacting dipyridylmethanone hydrazone with indole‐2‐formaldehyde, while the cadmium complex was prepared by combining CdCl2 and 2‐DPHI in methanol at room temperature. Both compounds were evaluated for their cytotoxicity against three human cancer cell lines (A375, A549 and HeLa) and a normal cell line (HFF‐1). The ligand 2‐DPHI exhibited notable antitumour activity, with an IC50 value of 12.22 µM against A375 and 15.17 µM against A549 after 48 h, while the pCd2 complex showed an even stronger inhibition of A375 cells, with an IC50 value of 4.88 µM, outperforming both 2‐DPHI and CdCl2. Both compounds demonstrated lower toxicity towards normal cells compared to cancer cells. The structures of 2‐DPHI and pCd2 were fully characterized using single‐crystal X‐ray diffraction, elemental analysis, high‐resolution mass spectrometry and FT–IR, 1H NMR, 13C NMR and UV–Vis spectroscopy. [ABSTRACT FROM AUTHOR]

Three dinuclear zinc(II) acetate complexes of the general formula [Zn{Ln}(AcO)]2, namely, di‐μ‐acetato‐κ4O:O′‐bis[({2‐[(pyridin‐2‐ylmethylidene)amino]phenyl}sulfanido‐κ3N,N′,S)zinc(II)], [Zn2(C12H9N2S)2(C2H3O2)2] (n = 1), 4, μ‐acetato‐1:2κ2O:O′‐acetato‐2κO‐[μ‐(2‐{[1‐(pyridin‐2‐yl)ethylidene]amino}phenyl)sulfanido‐1κS:2κ3N,N′,S][(2‐{[1‐(pyridin‐2‐yl)ethylidene]amino}phenyl)sulfanido‐1κ3N,N′,S]dizinc(II), [Zn2(C13H11N2S)2(C2H3O2)2] (n = 2), 5, and μ‐acetato‐1:2κ2O:O′‐acetato‐2κO‐[μ‐(2‐{[phenyl(pyridin‐2‐yl)methylidene]amino}phenyl)sulfanido‐1κS:2κ3N,N′,S][(2‐{[phenyl(pyridin‐2‐yl)methylidene]amino}phenyl)sulfanido‐1κ3N,N′,S]dizinc(II)–bis(2‐aminophenyl) disulfide (2/1), [Zn2(C18H13N2S)2(C2H3O2)2]·0.5C12H12N2S2 (n = 3), 6·0.5(2‐APS)2, were obtained from the reaction of 2‐R‐(pyridin‐2‐yl)benzothiazoline precursors (R = H, 1; R = Me, 2; R = Ph, 3) with zinc acetate dihydrate in a 1:1 ratio. All the complexes crystallized as dinuclear species and complex 6 cocrystallized with one molecule of bis(2‐aminophenyl) disulfide (2‐APS)2. The anionic Schiff base ligands {Ln}− displayed a κ2N,κS‐tridentate coordination mode with the formation of two five‐membered chelate rings. In 4, 5 and 6·0.5(2‐APS)2, both ZnII ions are pentacoordinated and the coordination sphere of 4 was different with respect to those in 5 and 6·0.5(2‐APS)2. For 4, the X‐ray diffraction study showed a dinuclear complex containing two bridging acetate ligands linked to both ZnII ions. For 5 and 6·0.5(2‐APS)2, the dinuclear complexes displayed one bridging acetate ligand linked to both ZnII ions, where the first ZnII ion includes a dative bond with one S atom from an adjacent anionic Schiff base {Ln}−, while the second ZnII ion is coordinated to one terminal acetate ligand. In each dinuclear complex, the geometry is the same for both ZnII metal centres. The local geometry of the ZnII cation in 4 is halfway between trigonal bipyramidal and square pyramidal local geometries; in 5 and 6, the local geometries are described as distorted square pyramidal. Hirshfeld surface analysis of 5 and 6 showed the predominance of H...H interactions, as well as the contribution of C—H...C, C—H...O and C—H...S noncovalent interactions to the cohesion of the crystalline network of the ZnII complexes. [ABSTRACT FROM AUTHOR]

Purpose: The main purpose of the present study is to introduce new Schiff bases as corrosion inhibitor for carbon steel in 1 M HCl. The inhibitory activity of Schiff base was also assessed. Design/methodology/approach: 2,2′-((1Z,1′Z)-((2,2-dimethylpropane-1,3-diyl)bis(azanylylidene))bis(methanylylidene))diphenol was synthesized and it's performance as an inhibitor was then investigated in 1 M HCl. The inhibition of this compound was studied and evaluated by the chemical methods of electrochemical impedance spectroscopy, electrochemical potential dynamic polarization and Atomic Force microscopy (AFM) method. The thermodynamics parameters were investigated for corrosion of carbon steel in both the absence and presence of Schiff base. Findings: The results of the tests showed that this compound has a good performance as an inhibitor and the percentage of inhibition on steel corrosion will increase with increasing concentration and it will reach 70% in the presence of 2 × 10−3 M of this inhibitor. Polarization tests indicated that this compound will act as a mixed inhibitor. Nyquist curves showed that the addition of this substance to the solution increased the charge transfer resistance and decreased the capacity of the double layer. The absorption of the new Schiff base on steel follows Langmuir adsorption isotherm, and the amount of free energy of adsorption indicates the spontaneous adsorption of this inhibitor. Using AFM investigations, the results of electrochemical methods were confirmed. Originality/value: Incorporation of a new Schiff base into 1 M HCl is a promising approach for protecting the carbon steel against corrosive solution. [ABSTRACT FROM AUTHOR]

Vilsmeier–Haack formylation of 3-aminothiazolotriazolopyridine-7,9-dicarbonitrile 3 afforded the corresponding aldehyde derivative 4 in a 65% yield. Some Schiff bases 5-7 were efficiently synthesized by reacting substrate 4 with some primary amines. Reaction of substrate 4 with some active methylene nitriles produced 2-amino-3-substituted-pyridotriazolothiazolopyridines 8–12. Substrate 4 was utilized as a key intermediate for a diversity of pyridotriazolothiazolopyrazolopyridines 13–15, through the Friedlander reaction with pyrazolidine-3,5-dione, 5-amino-2,4-dihydro-3H-pyrazol-3-one, and 5-phenyl-2,4-dihydro-3H-pyrazol-3-one. Further, the reaction of substrate 4 with 5-amino-3-methyl-1H-pyrazole and 6-aminouracil, as cyclic enamines, produced pyridotriazolothiazolopyrazolopyridine 16 and pyridotriazolothiazolopyridopyrimidine 17, respectively. The antimicrobial efficiency was assessed for the synthesized products, and some of them showed notable activity. The structures of the synthesized products were confirmed using analytical and spectroscopic data. [ABSTRACT FROM AUTHOR]

In this study, oleogels were produced with the emulsion template method utilizing seven phenolic aldehyde fragrances (PAFs) crosslinked with chitosan, and the physical and chemical characteristics of oleogels prepared by different crosslinking factors were comparatively investigated. XRD and ATR-FTIR results showed that chitosan was crosslinked with the PAFs to generate Schiff bases and that the Schiff base reaction was the main contributing factor to the construction of the oleogels. Macroscopic characterization showed that all the oleogels had good Oil binding capacity (> 90%) and high gel hardness (> 55.46 g). The rheological properties showed that all the oleogels had high thermal stability and gel strength (G'>G"), as well as good thixotropic recovery (among them, CS-ISA had the largest thixotropic recovery of 24.05%), which indicated the elasticity and structural stability of the gel network formed by crosslinking of PAF and chitosan.Additionally, lower oxidation rates were observed for the peroxide value (POV) and thiobarbituric acid reactive substance (TBARS) values of all oleogels in accelerated oxidation experiments, all indicating good oxidative stability. [ABSTRACT FROM AUTHOR]

The current investigation involved the synthesis and detailed characterization of novel mixed‐ligand complexes of Mn(II) (MnDPPNPH) and Cu(II) (CuDPPNPH). These complexes incorporate 2,6‐di(1H‐pyrazol‐1‐yl)pyridine (DPP) and a Schiff base derived from 2‐hydroxy naphthaldehyde (NPH). The synthesized complexes revealed a stoichiometric ratio of 1:1:1 (metal:DPP:NPH), indicative of an octahedral coordination geometry around the Mn(II) and Cu(II) centers, as represented by the chemical formula [M (DPP)(NPH)(Cl)]. To elucidate their structural and electronic properties, theoretical calculations were performed. These calculations facilitated the optimization of the geometrical structures and provided insights into the molecular orbital characteristics of the complexes. The MnDPPNPH and CuDPPNPH complexes demonstrated potential phenoxazinone synthase mimicking activity by catalyzing aerial coupling of o‐aminophenol (OAPh) to form phenoxazine‐2‐one (phenox). The mimicking activity of these complexes was quantitatively assessed using Michaelis–Menten enzymatic kinetics. Various enzyme kinetics plots were employed to determine several kinetic parameters, including the specificity constant and turnover number (kcat), which are crucial for understanding the efficiency of the catalytic cycles. Remarkably, the synthesized MnDPPNPH and CuDPPNPH complexes exhibited significantly higher turnover numbers (kcat) compared to previously reported complexes. This finding suggests that these new complexes possess superior catalytic activity, highlighting their potential as effective catalysts for reactions mimicking the function of phenoxazinone synthase. [ABSTRACT FROM AUTHOR]

Novel compounds with pharmacological activity were synthesized from Pd(II), Fe(III), Cr(III), Ni(II), and Cu(II) ions with 1‐cyclopropyl‐6‐fluoro‐4‐(2‐hydroxy‐phenylimino)‐7‐piperazin‐1‐yl‐1,4‐dihydro‐quinoline‐3‐carboxylic acid (CFAP). The ligand's NH and OH groups allowed it to interact with the metals as a neutral tridentate. The investigated novel compounds were described using 1H and 13C NMR spectra, FT‐IR spectrums, TGA and UV–Vis (conductance of molecules), and CHN‐analysis. Additionally, the pH profile of the CFAP complexes indicated great stability, and the complexes' stability constant was discovered in the solution. To extract important properties for CFAP and its complexes, computational research was used, CFAPCu, CFAPCr, CFAPNi, and CFAPFe have octahedral geometry, while CFAPPd has square planar geometry. To investigate the molecular geometry, density functional theory calculations (DFT) were carried out. The molar ratio and continuous fluctuation data confirmed that the (M:L) ratio was (1:1). In vitro tests were conducted to evaluate Schiff base's antimicrobial action ligand and its metal chelates against fungal and bacterial infections. The findings showed that the antimicrobial efficacy is as follows: When CFAPPd is compared to fluconazol and ofloxacin as reference medications, it is the highly inhibitor complex. The novel CFAP ligand and its complexes were investigated for In vitro carcinogenic potential against Hep‐G2, MCF‐7, and HCT‐116 cell lines. As compared to the medication vinblastine, the results once again demonstrated that CFAPPd is the most active agent. Moreover, the complexes demnstrated strong reactivity in capturing free radicals when their antioxidant activity was investigated. Viscosity, spectral investigations, and gel electrophoreses were used to identify the interaction between metal chelates and DNA. Every examined compound is shown to be an enthusiastic DNA binder by viscosity and spectrophotometric titration investigations. The heightened hydrophobic and electrostatic interactions between aromatic rings could be the cause of this. Ultimately, these compounds could be regarded as promising bioactive substances. [ABSTRACT FROM AUTHOR]

Salamo‐type ligand H2L was designed and synthesized and reacted with Cu (II) and Zn (II) acetate, respectively, to obtain two binuclear Cu (II) and Zn (II) complexes: [Cu2(L)2]·2CH3OH (1) and [Zn2(L)2] (2) having the same coordination number but distinct geometries. Complex 1 is a Cu (II) complex containing two crystalline ethanol molecules, where two Cu (II) atoms are surrounded by two utterly deprotonated (L)2− parts, forming slightly twisted tetragonal pyramidal configurations of pentacoordinate. In complex 2, two utterly deprotonated (L)2− parts surround two Zn (II) atoms, forming pentadentate twisted triangular bipyramidal configurations. The complexes were elucidated via IR analyses and ultraviolet spectroscopy. Using DFT theoretical calculation, MEPs, IRI, and Hirshfeld surface analysis to investigate further the molecular interactions and reaction sites. Ultimately, the fluorescence characteristics of H2L and its complexes 1 and 2 were discussed. [ABSTRACT FROM AUTHOR]

This study investigates organotin (IV) complexes derived from the recently synthesized quinazoline Schiff base ligand (L). The research involves synthesizing and characterizing these complexes, including elemental analysis, UV–visible, FT‐IR, mass spectra, and conductometric measurements. Advanced studies such as density functional theory (DFT) are employed to gain insights into the stable electronic configuration. Specifically, the study explores the proposed geometry, revealing a distorted octahedral structure for the complexes. The findings contribute as critical molecular characteristics of these newly synthesized complexes, paving the way for potential applications in diverse fields, including medicinal chemistry. Through an investigation into the antimicrobial properties, the efficacy of the synthesized compounds was assessed against a diverse range of bacterial and fungal strains. Remarkably, the complexes demonstrated significant antimicrobial activities, showing potential applications in combating various microbial infections. In an extended exploration of their medical utility, the compounds were examined for their antibiotic properties against Helicobacter pylori. The Schiff base and its metal complexes emerged as promising antibiotics with notable efficacy against H. pylori, suggesting their potential in addressing infections associated with this bacterium. Furthermore, the antitumor potential of the synthesized complexes was investigated, focusing on their impact on MCF‐7 (Breast carcinoma) cells. The organotin (IV) Schiff base complexes in this research showed remarkable efficacy, evidenced by their notably low IC50 values (9, 10, 11 μg/mL) in comparison with cisplatin. In addition to their potent antitumor effects, these complexes exhibited reduced cytotoxicity toward normal cells (VERO cells) compared with cisplatin. The investigation extends to molecular docking, where this approach aims to elucidate their interactions with specific protein structures, including (2JFZ, 1SC7, and 6W41). The primary objective is to clarify the potential properties of these compounds, focusing on their antibiotic efficacy, anti‐H. pylori activity, antitumor potential, and anti‐COVID‐19 properties. [ABSTRACT FROM AUTHOR]

Three new Zn(II) Schiff base complexes, [ZnLCl2] (1), [ZnLBr2] (2) and [ZnL(SCN)2] (3), have been synthesized by adding Zn(II) salts of chloride and bromide to a compartmental ligand with NNO donor prepared through the simple condensation of pyridine‐2‐carboxaldehyde and a substituted aniline. The complexes have been identified using standard physicochemical methods, and their solid‐state structures have been determined through single‐crystal X‐ray analysis. The phosphatase‐like activity of all three complexes has been investigated using 4‐NPP as the model substrate in a DMSO/water medium. Complex 1 exhibits the highest level of phosphatase activity. The reactivity trend shows that complex 1 > complex 2 > complex 3. A plausible mechanism and the causes underlying the activity trend have been explored through DFT study, ESI‐mass spectra and 31P experiments. Complex 1 shows promising potential for use in gene‐targeted therapeutics due to its remarkable performance in DNA digestion. The excellent DNA cleavage result of complex 1 has led to the investigation of its molecular docking interaction with the liver cancer 2 receptor to study its anti‐liver cancer activity. Furthermore, in vitro anticancer activity of complex 1 also shows excellent antiproliferative activity against hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

[Display omitted] In emergencies, uncontrolled severe bleeding can result in undesired complications and even death of the injured. Designing advanced hemostatic agents is a potential solution for emergency hemostasis, yet it remains challenging to realize the persistent adhesion in a wet wound environment. In this study, based on dynamic reversible Schiff base bond and photo-initiated double-bond polymerization, a novel injectable hemostatic hydrogel (L -COC) consisting of methacrylated carboxymethyl chitosan (CMCSMA), oxidized konjac glucomannan (OKGM) and (+)-catechin hydrate (CH) was synthesized for emergency hemostasis. To our delight, the incorporated CH imparted enhanced blood procoagulantion to the L -COC hydrogel by intensifying the hydrogel-red blood cell interactions. As a result, the hemostatic effect of the engineered L -COC hydrogel was significantly superior to that of fluid gelatin SurgifloTM for liver bleeding wounds in rats (Blood loss: 0.62 ± 0.11 g (L -COC), 0.90 ± 0.08 g (SurgifloTM); hemostasis time: 69.0 ± 2.9 s (L -COC), 84.0 ± 2.2 s (SurgifloTM)). With the favorable antioxidant and antibacterial activities, as well as multifunctional properties, the bio-adhesive L -COC hydrogel and the underlying design principles may facilitate further development of practical hemostatic hydrogels. [ABSTRACT FROM AUTHOR]

Background: This study reports the preparation of 2‐hydroxy‐3‐(4‐(((2‐((2‐(((E)‐4‐(2‐hydroxy‐3‐(trimethylammonio)propoxy)‐3‐methoxybenzylidene)amino)ethyl)amino)ethyl)imino)methyl)‐2‐methoxyphenoxy)‐N,N,N‐trimethylpropan‐1‐aminium (HYM/QA). The adsorbent was employed to extract and concentrate vanadium from its solutions and boiler ash samples. Results: The impact of initial dosage, pH, reaction time and temperature on the sorption behavior of V(V) was examined. Under optimal conditions (pH 5, 0.08 g dose, 45 min at room temperature), a sorption capacity of 392.25 mg g−1 was achieved. The uptake of V(V) on HYM/QA was effectively reversed using 1 mol L−1 NaOH, regenerating the material. After six cycles of sorption and elution, the sorption capability remained at 91.4% of its initial value. The efficiency and selectivity of HYM/QA toward V5+ ions were assessed using the separation factor parameter, revealing limited interference from heavy metals such as Mn2+, Cr3+, Pb2+, Si4+, Al3+, NO32−, HCO3− and Zn2+. The uptake process of HYM/QA for V(V) conformed to the Langmuir and Dubinin–Radushkevich isotherm models and the pseudo‐second‐order kinetic model. HYM/QA was characterized by infrared, Brunauer–Emmett–Teller surface area, 1H NMR, 13C NMR and gas chromatography–mass spectrometry analyses, confirming successful preparation. Thermodynamic assessments suggested that the sorption process is endothermic, spontaneous and becoming more favorable with rising temperature. Conclusion: The optimized conditions were used to adsorb vanadium from boiler ash samples, and the obtained vanadium pentaoxide was analyzed and confirmed using various tools, demonstrating the material's effectiveness for vanadium extraction. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

New Schiff base ligand: 4-methoxy salicaldhyde-2-2-phenyl-hydrazono acetaldehíyde prepared by facile method. The molecular structures characterized by elemental analysis and proton magnetic resonance spectra (1H-NMR spectra). This spectra at the chemical shifts (3.5–10.39 ppm) confirmed the types and the numbers of protons. The sharp melting point at the range 110–112 °C confirmed purity. New optically active metal (samarium, terbium and gadolinium) complexes of the Schiff base synthesized in a one pot reaction. Vibrational IR spectra confirmed functional groups. Scanning electron microscopy micrographs confirmed that the modified microstructure of the metal complexes differed in morphology than the ligand. Powder X-ray diffraction patterns confirmed good crystalline structure. The optically activity of the solid metal complexes confirmed from electronic absorption spectra. The UV absorbance band at the wavelength range 280–390 nm and the intense phosphorescence bands up to 830 nm enabled application in photo dynamic therapy for apoptosis cancer cells by conversion triplet oxygen in the tissues into reactive singlet oxygen. Low charge transfer energy: 2.59–2.61 eV, high molar extinction coefficients (ε) at the order of magnitude M− 1 cm− 1 and the intense phosphorescence bands reflected good photodynamic activity. The metal complexes are thermally stable. [ABSTRACT FROM AUTHOR]

ABSTRACT The current study involved production, comprehensive structural analysis, and physicochemical characterizing of two distinctive complexes namely, Cu(TBH) and Zn(TBH); TBH donor ligand: N′‐(1‐(3,6‐dihydro‐4‐hydroxy‐2,6‐dioxo‐2H‐1,3‐thiazin‐5‐yl)ethylidene)‐2‐hydroxybenzohydrazide) using a wide range of analytical methods, including elemental analysis, UV–Vis, FT‐IR, and 1HNMR spectrometry, molar conductivity and magnetic susceptibility measurements, and thermal analysis. According to the findings, chelation can occur through O, N, and O donor atoms of monoanionic chelator for generating mono‐nuclear chelates with tetrahedral geometry for Cu (II) and octahedral geometry for Zn (II). The anticarcinogenic ability of TBH chelator and its coordinated compounds against human liver cancer (HepG‐2) was investigated. The Cu(TBH) complex was found to have selective and promising anticancer activity against a liver cancer cell line, with lower IC50 (liver carcinoma cell line) and higher IC50 (normal human cell line) values than other produced compounds and standard drugs. Utilizing DFT computations, the molecular structures of the TBH and its complexes were verified, offering a detailed understanding of their quantum chemical characteristics. A quantitative structure–activity relationship (QSAR) model, which illustrates the association between DFT‐computed descriptors and biological activities pIC50, was also created using multiple linear regression (MLR) on the synthesized compounds as anticancer medicines. Additionally, there are no issues with the produced compounds' oral bioavailability according to (ROF) Lipinski's rule of five. Furthermore, docking studies of the synthesized TBH chelator and its chelates with CDK2 kinase have been performed to validate the biological findings. According to our findings, the novel Cu(TBH) nanodrug exhibits considerable cytotoxic activity, prompting further study into its pharmacological profile and exploring its potential in drug development. [ABSTRACT FROM AUTHOR]

Schiff bases have proven to be beneficial in medicine and have interesting complexation capabilities with transition metals. The +4, +5, and +6 oxidation states of schiff base metal complexes have been the subject of recent review, which have highlighted their notable cytotoxic effects against various colon cancer cell lines (HT-29, HCT-116, SW-480, Coco-2, CT-26, LT-174, LoVo). Extensive research has focused on schiff base metal complexes in the +4 and +6 oxidation states, exhibiting distinct geometries and significant thermodynamic stability. These studies provide IC50 values for these complexes in colon cancer cell lines along with comprehensive structural representations that shed light on how different substituents affect cytotoxicity. When compared to schiff base ligands alone, metal complexes of schiff bases have been shown to significantly reduce colon cancer cell invasion and proliferation. The studied literature emphasizes schiff base metal complexe’s potential in biological applications and suggests that more study may be necessary to fully comprehend their biology. To enable more sophisticated multidisciplinary study in this field, future investigations should focus on synthesizing novel complexes with enhanced bioavailability, solubility, and low toxicity. [ABSTRACT FROM AUTHOR]

ABSTRACT This article explains the synthesis of three Schiff base Cu(II) complexes derived from 3‐hydroxybenzaldehyde and ethylenediamine using three distinct copper anionic salts, and it explores the effects of those salts on the properties of the complexes. Elemental analysis, electronic spectra, FT‐IR, ESR, molar conductance, magnetic measurement, thermogravimetric analysis and PXRD were used to characterize the compounds. The anionic salt has been demonstrated to exhibit distinctive characteristics on Gram‐positive and Gram‐negative bacteria in terms of structure, DNA binding, cell viability, DNA breakage and activity. Furthermore, this ligand L1 and its derivatives indicated positive antifungal efficacy against Aspergillus niger and Trichophyton tonsurans. The study elucidates the manner in which distinct anion salts impacted the properties of complexes and their antifungal, anticancer and antibacterial outcomes. [ABSTRACT FROM AUTHOR]

ABSTRACT This research focused on the design and comprehensive characterization of two novel transition metal complexes derived from the symmetrical Schiff base 2‐[(2‐chloroquinolin‐3‐yl)methylidene]aminobenzenethiol (CQAT), coordinated with nickel(II) (NiCQAT) and copper(II) (CuCQAT) ions. The structural elucidation of these complexes was achieved through a range of advanced analytical techniques. Thermal analysis revealed the stability and decomposition patterns of the complexes, supporting the identification of their coordination geometries. The collective data indicated that both NiCQAT and CuCQAT complexes adopt octahedral coordination, with the specific formulas [Ni(CQAT)2(H2O)2] and [Cu(CQAT)2(H2O)2], respectively. To complement the experimental findings, density functional theory (DFT) calculations were employed. These theoretical calculations confirmed the proposed molecular structures and provided detailed insights into key quantum chemical parameters, such as HOMO–LUMO energies, molecular orbitals, and electronic distributions, which are crucial for understanding the complexes' reactivity and stability. Furthermore, extensive in vitro biological evaluations were conducted to assess the anti‐inflammatory and antioxidant properties of the synthesized complexes. These assays demonstrated that both NiCQAT and CuCQAT exhibited significantly enhanced bioactivity compared to the free CQAT ligand, suggesting a synergistic effect of metal coordination on the ligand's biological efficacy. To further explore the mode of action, molecular docking studies were performed targeting two key proteins—human cyclooxygenase‐2 (PDB ID: 5IKT) and human peroxiredoxin 2 (PDB ID: 5IJT). The docking simulations provided valuable insights into the binding affinities, interaction energies, and key amino acid residues involved in the binding process, offering a molecular‐level understanding of their potential biological mechanisms. The findings from these multidisciplinary studies highlight the therapeutic potential of CQAT and its nickel and copper complexes, positioning them as promising candidates for further development in the field of medicinal chemistry. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Dalton Transactions: An International Journal of Inorganic Chemistry," published by The Royal Society of Chemistry. It includes various articles on topics such as NHC aluminum chemistry, catalytic functionalization of ferrocenes, and energetic coordination polymers. The journal covers a wide range of research on inorganic chemistry, showcasing recent advances and studies in the field. [Extracted from the article]

Novel asymmetrical Fe(III) Schiff base coordination complexes, with the N4O2 coordination environment, exhibiting abrupt spin crossover (SCO) behaviour with a wide hysteresis loop of 27 K, have been synthesised from an ethylenediamine based asymmetrical Schiff base ligand viz. N-(2-aminoethyl)salicylaldimine (saen) and characterised via single crystal XRD measurements, variable temperature magnetic studies and Mössbauer measurements. The single crystal XRD measurements prove that the compound is a mixture of two fractions, one with methanol and the other without methanol, viz, [Fe(saen)2]NO3·CH3OH at 299 K (1–299) and at 173 K (1–173) and [Fe(saen)2]NO3 at 173 K (2–173), confirming that the Fe(III) centre has a distorted octahedral coordination geometry having two deprotonated asymmetrical tridentate saen ligands, counterbalanced by a nitrate anion and methanol solvent molecule in 1 while 2 has a non-solvate form. An extended hydrogen bonding network between the amino hydrogen atoms of the saen ligand, nitrate counteranion, and methanol solvate molecule is observed in fraction 1, while an extended zig-zag hydrogen bonding between the nitrate anion and amino hydrogens of saen is observed in fraction 2. Furthermore, the complex has been characterised by variable temperature magnetic susceptibility measurements and 57Fe Mössbauer spectroscopy, confirming the SCO nature. [ABSTRACT FROM AUTHOR]

In recent years, compounds from the Schiff base group have been intensively studied for their biological activities. Accordingly, a series of Schiff bases were synthesized from substituted aromatic aldehydes (5-chlorosalicylaldehyde) and differently substituted aromatic amines and their antimicrobial activities were evaluated. The molecular identity of compounds was confirmed using various spectroscopic techniques, such as IR and NMR spectroscopy and elemental analysis, and the molecular structure of compound 3k was determined by single-crystal X-ray analysis. The antimicrobial activity of 3a–3k compounds was examined in sixteen microorganisms (five species of bacteria and eleven species of fungi) using the microdilution method. Regarding antibacterial activity, a remarkable MIC value (0.0098 mg mL−1) and, therefore, the best activity was displayed against Proteus mirabilis for 3e, which is even stronger than the most frequently used antibiotic medications. 3f showed the best antifungal activity against Microsporum gypseum, which is stronger than standard antimycotic fluconazole, and is also an important result considering that Microsporum gypseum can cause dermatophytosis in both humans and animals. [ABSTRACT FROM AUTHOR]

A new multifunctional Schiff base probe AnQn containing dual fluorophores (anthracene-quinoline) has been synthesised via a facile one-pot reaction. This probe demonstrated the ability to selectively discriminate group IIIA metal ions (Al3+ and Ga3+) via a dual-mode fluorescent turn-on response. Upon excitation at the same wavelength (λex 320 nm), AnQn displayed two distinct emission bands for Al3+ (λem = 410 nm) and Ga3+ (λem = 487 nm) in acetonitrile solutions. The detection limits calculated for Al3+ and Ga3+ were found to be as low as 9.2 nM and 230 nM, respectively. A 1 : 1 complexation between AnQn and Al3+/Ga3+ has been established using Job's plot, FT-IR, ESI-MS, 1H NMR and DFT analyses. The practical applicability of the probe was assessed through logic gate analysis, low-cost paper strip experiments and real water sample analysis. Intriguingly, AnQn exhibited an aggregation-induced-emission (AIE) behaviour in a semi-aqueous (CH3CN : H2O) medium, resulting in the formation of highly fluorescent green aggregates, which could be clearly evidenced by SEM images and time-resolved fluorescence (TRF) analyses. Interestingly, the resultant AnQn aggregates were further utilized as a viable fluorescent platform to selectively recognize heavy Pd2+ ions as well as highly explosive picric acid with excellent limit of detection. [ABSTRACT FROM AUTHOR]

Biopotent hybrid diorganotin(IV) complexes, derived from salicylaldehyde Schiff bases having general formula R2SnL, where LH = (OH)C6H4HC: NCR′(R″)CHR‴OH] [where R = Me or Bu], were logically designed, generated, and characterized using spectroscopic techniques, single‐crystal X‐ray investigations, and DFT studies. Different diorganotin(IV) complexes were synthesized because of interaction between diorganotin(IV) dichloride and sodium salts of Schiff bases of salicylaldehyde ligand in anhydrous refluxing THF at 1:1 and 1:2 molar ratio (Product A and B). The chelating property of Schiff bases replaces organo group from diorganotin(IV) dichloride. It creates an O2SnL type of complex when diorganotin(IV) dichloride and ligand interact in 1:2 ratio, which is this study's most fascinating aspect. The characterization of these complexes is aided by physicochemical and spectroscopic investigations, including IR and NMR (1H, 13C, and 119Sn). Single‐crystal X‐ray investigations, mass spectrum studies, and DFT investigations suggest the dimeric structure of these compounds. These diorganotin(IV) complexes have a dimeric structure containing hexacoordinated central tin atom. Two µ2─O atoms bridge the gap between two Sn(IV) atoms in the dimeric dimethyltin(IV) complexes. The DPPH assay results for radical scavenging activity and IC50 values demonstrate the antioxidative potential of diorganotin(IV). [ABSTRACT FROM AUTHOR]

The utilization of biologically active metal complexes in medicine is gaining recognition as an alternative approach to traditional biologically active organic molecules, which often exhibit undesirable side effects. This study focuses on the synthesis and characterization of a Co(II) complex derived from the (E)‐2‐((2‐hydroxybenzylidene)amino)‐5‐methylbenzonitrile ligand system (HL) and cobalt(II) acetate tetrahydrate in a dichloromethane/methanol solution. A comprehensive characterization strategy was employed, involving proton and carbon nuclear magnetic resonance, infrared, electronic spectra, PXRD, SEM‐EDX, and mass spectroscopies, as well as elemental analysis (CHN and Co), TGA, and molar conductance, to confirm the chemical structures of the ligand and its complex. The infrared spectral data revealed the ligand as a bidentate ligand, chelating the Co(II) ion through the oxygen and nitrogen atoms of the phenolate and imine groups. Additionally, PXRD and SEM analyses indicated crystalline and amorphous properties for the ligand and complex, respectively. Assessment of antimicrobial potential using a modified disc diffusion method, with streptomycin as the positive control, demonstrated the complex's enhanced antibacterial activity compared to the ligand against all tested bacteria, showing a concentration‐dependent response. Similarly, antioxidant studies revealed promising results, with the complex exhibiting superior DPPH radical scavenging activity (IC50 values: ligand 64.5 μg.mL−1, complex 43.1 μg.mL−1). Theoretical analysis through DFT calculations and molecular docking provided insights into the electronic properties and binding affinity of the ligand and complex, supporting the experimental findings and affirming the biological activities exhibited by the compounds. Overall, this research showcases the synthesis, characterization, and biological evaluation of a promising Co(II) complex, highlighting its potential as an effective antimicrobial and antioxidant agent. [ABSTRACT FROM AUTHOR]

Efficient and selective fluorescence sensors based on katiragum dialdehyde‐ amino acid Schiff's base is developed for fluorometric sensing to detect vanillin, Cu2+ ions and 4‐nitrophenol (4NP) in their aqueous solution. Two Schiff bases namely katiragum dialdehyde‐ arginine (KGDR) and katiragum dialdehyde‐ tryptophan (KGDT) are developed in the author's laboratory between which KGDR can detect vanillin with a detection limit of 60.29 nM whereas KGDT can detect both Cu2+ ion and 4NP with a detection limit of 72.6 nM and 97.83 nM respectively. KGDR and KGDT show significant quantum yields of 0.47 % and 0.25 % compared to a standard known substance fluorescein (0.97 %). The detection limit of vanillin, Cu2+ ions and 4NP are lower than other reported sensors. The developed Schiff base KGDR and KGDT show excellent recovery percentage and relative standard deviation (RSD) values in real sample analysis. [ABSTRACT FROM AUTHOR]

Compound 4, a Schiff base‐containing pyrimidine moiety, was synthesized from the reaction of N‐amino pyrimidine derivative with 4‐fluorobenzaldehyde. The molecular and crystallographic structure of 4 was determined by the SC‐XRD method. According to these results, compound 4 crystallized in the triclinic P‐1 space group, and the stability of its crystal structure was ensured through intermolecular C−H⋅⋅⋅π and π⋅⋅⋅π interactions. In addition to the antibacterial effects of the molecule on some Gram‐positive and Gram‐negative bacteria, the inhibition of biofilm formation in P. aeruginosa PAO1 and the production of violacein pigment in Chromobacterium violaceum (C. violaceum) 12472 were studied. The results demonstrated that compound 4 had strong effectiveness in preventing the formation of biofilms produced by PAO1 with an inhibition rate of 69 %. Extensive theoretical calculation studies of molecule have been conducted and the molecular structure of 4 has been optimized in the ground state using density functional theory (DFT). The investigated compound's frontier molecular orbitals, chemical parameters, and molecular electrostatic potential surfaces were examined. Molecular docking studies were performed to explain the binding interaction 4 with the high inhibitory effect against C. violaceum phenylalanine hydroxylase D139A (PDB ID: 4Q3Y), D139E (PDB ID: 4Q3W), D139K (PDB ID: 4Q3Z), and D139N (PDB ID: 4Q3X) mutations. [ABSTRACT FROM AUTHOR]

This work focuses on the rapid synthesis of Schiff bases with green protocols, where P2CA (Pyridine‐2‐carboxylic acid) is utilized as a catalyst. The condensation reaction of aldehydes and anilines, facilitated by P2CA, resulted in the production of Schiff bases in good to excellent yield within a remarkably short time of up to 15 min. The electronic effect of the various substituents on aldehyde and aniline, in combination with the catalytic effect of P2CA, accelerated the reactions under mild conditions. The reusability of the catalyst was thoroughly examined, and the catalyst was characterized over every cycle. Importantly, this approach is not only green and sustainable, but also cost‐effective, harmless, and environmentally friendly, thanks to the affordability and benign nature of P2CA. [ABSTRACT FROM AUTHOR]

Ambroxol hydrochloride is a pharmaceutical compound that is primarily used to treat respiratory disorders characterized by excessive mucus production. It is a mucolytic agent used in treating various respiratory conditions, including bronchitis, asthma, COPD (Chronic Obstructive Pulmonary Disease), and cystic fibrosis. The standard industrial‐scale synthesis involves Schiff's base formation followed by reduction; this method is widely adopted due to its efficiency and cost‐effectiveness. Apart from this, various patented methodologies have emerged recently, along with novel therapeutic applications, where it is used for treating Parkinson's and Alzheimer's diseases, including anti‐inflammatory and antioxidant properties. These findings open new avenues for its use in various medical treatments. The current review aims to assess the industrial scale processes in the current market, examine its pharmacological action, and explore recently evaluated therapeutic applications, offering a comprehensive overview of its potential in modern medicine. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks designed as chromatic sensors offer opportunities to probe biological interfaces, particularly when combined with biocompatible matrices. Particularly compelling is the prospect of chemical tomography – or the 3D spatial mapping of chemical detail within the complex environment of living systems. Herein, we demonstrate a chromic Covalent Organic Framework (COF) integrated within silk fibroin (SF) microneedles that probe plant vasculature, sense the alkalization of vascular fluid as a biomarker for drought stress, and provide a 3D in-vivo mapping of chemical gradients using smartphone technology. A series of Schiff base COFs with tunable pKa ranging from 5.6 to 7.6 enable conical, optically transparent SF microneedles with COF coatings of 120 to 950 nm to probe vascular fluid and the surrounding tissues of tobacco and tomato plants. The conical design allows for 3D mapping of the chemical environment (such as pH) at standoff distances from the plant, enabling in-vivo chemical tomography. Chromatic COF sensors of this type will enable multidimensional chemical mapping of previously inaccessible and complex environments. It is promising but elusive to use covalent organic frameworks (COFs)-based chromatic sensors for chemical tomography – or the 3D spatial mapping of chemical details within living systems. Here, the authors report a COF-silk fibroin microneedle interface capable of 3D mapping of the chemical environment at standoff distances from the plant, enabling in-vivo chemical tomography. [ABSTRACT FROM AUTHOR]

Polysaccharide‐based hydrogels are promising for biomedical applications such as drug delivery owing to their biocompatibility, biodegradability, and bioactivities. In particular, there is a need for hydrogels with injectability for minimally invasive therapies and controlled sustained release for sustained drug effect. Hydrogels made from carboxymethyl chitosan (CMC) and tannic acid (TA) (CMC‐TA) contain dynamic covalent bonds owing to autoxidation between CMC and TA, and interact with proteins via TA, elucidation of the detailed mechanism of dynamic covalent bonding in CMC‐TA hydrogels will facilitate stable loading and zero‐order release of proteins. Herein, the physical properties of oxidized CMC‐TA (Oxi‐CMC‐TA) prepared for the encapsulation and sustained release of proteins are explored. Following incubation at 37 °C for 24 h, CMC‐TA undergoes secondary crosslinking by autoxidation to produce Oxi‐CMC‐TA. Notably, CMC‐TA is viscoelastic and shear‐thinning, allowing for injection and 3D bioprinting. Indeed, CMC‐TA can be 3D‐printed with green fluorescent protein (GFP) encapsulated in its matrix. Oxi‐CMC‐TA also exhibits an affinity for protein owing to its gallol groups, enabling Oxi‐CMC‐TA to collect GFP in aqueous solutions against a concentration gradient. Moreover, Oxi‐CMC‐TA releases GFP over 15 days. Injectable, 3D‐printable, protein‐collecting, and zero‐order sustained‐releasing Oxi‐CMC‐TA has the potential to make a significant contribution to drug delivery. [ABSTRACT FROM AUTHOR]

ABSTRACT The novel Schiff base, (Z)‐2‐(1‐((3‐methylpyridin‐2‐yl)imino)ethyl)phenol (HL), was synthesized by reacting 1‐(2‐hydroxyphenyl)ethanone with 3‐methylpyridin‐2‐amine. Metal complexes [M (L)n (H2O)2] (M = Co and Cu, n = 2) were synthesized and characterized utilizing various analytical techniques including UV–visible spectroscopy, FTIR, elemental analysis, molar conductance, 1H NMR, thermal analysis, and magnetic moment measurement. The findings indicated that the Co+2 and Cu+2 complexes exhibited octahedral geometries. In vitro biological activity testing was conducted to evaluate the antimicrobial potential of the complexes against Bacillus subtilis (B. subtilis) and Escherichia coli (E. coli) bacteria strains. Similarly, molecular docking was conducted to elucidate the interactions between the active sites of protein–metal complexes and dihydrofolate reductase as well as ferrochelatase. [ABSTRACT FROM AUTHOR]

Despite the continued dominance of detrimental formaldehyde‐based binders in the wood reconstituted products, there is a growing push to develop more environmentally friendly alternatives. Cellulose‐based biomass adhesives have been extensively researched and documented. However, their industrial application is limited due to inadequate water resistance and suboptimal coating ability. In this study, a cellulose‐derived wood binder with a hyperbranched entangling structure was synthesized by covalently cross‐linking branched polyethylenimine and oxycellulose through Schiff base formation. The dry/wet bonding strength of the prepared plywood was 2.07 and 1.52 MPa, respectively, exhibiting a remarkable increase and breakthrough compared to that of pure oxidized cellulose binder. This can be attributed to the formation of a water‐resistant Schiff base tangle network, which enhances the toughness of the adhesive. Notably, the pure cellulose adhesive tends to agglomerate on the wood surface, whereas the hyperbranched modified cellulose adhesive exhibits a more uniform coating ability. This study further demonstrates the reliable potential of tangle structures based on Schiff base reactions in the development of biomass‐based adhesives. Highlights: A high bonding strength cellulose‐based wood adhesive was prepared.The Schiff base reactions have been used to construct cross‐linked structures.The cross‐linked network structure provides excellent water resistance.The cured cellulose‐based adhesive has excellent dry/wet bonding strength. [ABSTRACT FROM AUTHOR]

Precise control of the crystal field and local symmetry around the paramagnetic spin center is crucial for the design and synthesis of single-molecule magnets (SMMs). Herein, three mononuclear Dy(III)-based complexes, [Dy(LN6)(CH3COO)2](BPh4)(CH2Cl2) (1), [Dy(LN6)(2,6-Cl-4-NO2-PhO)(H2O)2]2(PF6)2(H2O)(2,6-Cl-4-NO2-PhO)2 (2) and [Dy(LN6)(2,6-Cl-4-NO2-PhO)2](BPh4)(CH2Cl2)2 (3) (LN6 = N6-hexagonal plane accomplished by a neutral Schiff base ligand formed from 2,6-diacetylpyridine and ethylenediamine), are successfully isolated. In these complexes, the Dy(III) centers are coordinated with six neutral N atoms from a nonrigid equatorial ligand, while different oxygen-bearing ligands are arranged at the axial positions of the central ions by gradual regularization of the axial ligands. As a result, Dy(III) ions in the three complexes exhibit various coordination geometries, forming a ten-coordinate tetradecahedron for 1, a nine-coordinate muffin configuration for 2 and a distorted eight-coordinate hexagonal bipyramid for 3. Magnetic studies reveal that all complexes exhibit no SIM behaviour under zero dc field, due to the predominant quantum tunneling of magnetization (QTM), which can be effectively suppressed by additional dc fields. Experiments, coupled with theoretical calculations, demonstrate that varying local symmetries and coordination geometries are synergistically responsible for the disparities of QTM and uniaxial anisotropy, resulting in notably different magnetic properties. [ABSTRACT FROM AUTHOR]

The anthracene‐appended Schiff base N1‐(anthracene‐9‐methylene)benzene‐1,2‐diamine and its Cu(II) complex has been synthesized and anchored on MCM‐41 support (MCM@CP@AnL@Cu 1). The synthesized catalyst was characterized by various analytical techniques including single crystal X‐ray. Malononitrile, 1,3‐dione, and aromatic aldehydes with various substituents were used in one‐pot, three‐component synthesis of 2‐amino‐3‐cyano‐4H‐pyran/chromene derivatives using above catalyst 1. All the products of the catalytic reaction were characterized by 1H and 13C NMR spectra. We have also proposed a probable reaction mechanism involved in the catalytic reaction. The present catalyst has several advantages like works in mild reaction conditions, that is, at 80 °C, gives higher yields up to 97%, has thermal stability up to 295 °C, and can be reused up to 5 cycles. The immobilized material did not show any considerable leaching or deterioration throughout the catalytic reactions, confirming that it possesses a practical benefit over homogeneous catalysis. The MCM@CP@AnL@Cu (1) is believed to be a good solid heterogeneous catalyst and meets the need of green chemistry for sustainable environment. To the best of our knowledge, this is first example of anthracene‐based Cu (II)‐Schiff base complexes immobilized on modified MCM‐41 surfaces for the multicomponent synthesis of 4H‐pyrans. [ABSTRACT FROM AUTHOR]

AbstractIn this work, Schiff bases of 4-methoxybenzyl amine and hydrazide derivatives containing succinic (BMSHE), oxalyl (BMOHE), and phenylaceto (BMPHE) have been synthesized and applied for corrosion inhibition of mild steel (MS) in 1.0 M HCl. The synthesized compounds are characterized by Fourier-transform infrared (FTIR) and H1 nuclear magnetic resonance (NMR) spectroscopy. The FTIR and H1 NMR results have confirmed their formation through the presence of functional groups and hydrogen associated with them. Corrosion mitigation examination is done by polarization measurements (PM), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) equipped with energy dispersive X-rays (EDX), and atomic force microscopy (AFM). All inhibitors demonstrated notable efficacy in preventing MS in HCl (BMSHE-88%, BMOHE-84%, and BMPHE-72%). As per corrosion potentials, BMOHE and BMPHE have been found to be mixed types of inhibitors, and BMSHE is noticed as a cathodic inhibitor. The SEM results demonstrated how these hydrazide derivatives prevented corrosion by covering the MS surface. The EDX analysis of the surfaces has revealed that the inhibited MS contains lower amounts of O and Cl, which indicate that the inhibitors prevent MS in HCl. AFM analysis shows that the surfaces of MS in the presence of the inhibitors are damaged less than in their absence, which reveals the same facts as told above. The inhibition of MS by BMSHE, BMOHE, and BMPHE is also explained with a reason after analyzing the results. [ABSTRACT FROM AUTHOR]

The MHC class I-related 1 (MR1) molecule is a non-polymorphic antigen-presenting molecule that presents several metabolites to MR1-restricted T cells, including mucosal-associated invariant T (MAIT) cells. MR1 ligands bind to MR1 molecules by forming a Schiff base with the K43 residue of MR1, which induces the folding of MR1 and its reach to the cell surface. An antagonistic MR1 ligand, Ac-6-FP, and the K43A mutation of MR1 are known to inhibit the responses of MR1-restricted T cells. In this study, we analyzed MR1-restricted TCRs obtained from tumor-infiltrating lymphocytes (TILs) from breast cancer patients. They responded to two breast cancer cell lines independently from microbial infection and did not respond to other cancer cell lines or normal breast cells. Interestingly, the reactivity of these TCRs was not inhibited by Ac-6-FP, while it was attenuated by the K43A mutation of MR1. Our findings suggest the existence of a novel class of MR1-restricted TCRs whose antigen is expressed in some breast cancer cells and binds to MR1 depending on the K43 residue of MR1 but without being influenced by Ac-6-FP. This work provides new insight into the physiological roles of MR1 and MR1-restricted T cells. [ABSTRACT FROM AUTHOR]

Gossypol and its derivatives arouse interest due to their broad spectrum of biological activities. Despite its wide potential application, there is no reported example of gossypol derivatives bearing stable radical functional groups. The first gossypol nitroxide hybrid compound was prepared here via formation of a Schiff base. By this approach, synthesis of a gossypol nitroxide conjugate was performed by condensation of gossypol with a 4-amino-TEMPO (4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl) free radical, which afforded the target product in high yield. Its structure was proven by a combination of NMR and EPR spectroscopy, infrared spectroscopy, mass spectrometry, and high-resolution mass spectrometry. In addition, the structure of the gossypol nitroxide was determined by single-crystal X-ray diffraction measurements. In crystals, the paramagnetic Schiff base exists in an enamine–enamine tautomeric form. The tautomer is strongly stabilized by the intra- and intermolecular hydrogen bonds promoted by the resonance of π-electrons in the aromatic system. NMR analyses of the gossypol derivative proved that in solutions, the enamine–enamine tautomeric form prevailed. The gossypol nitroxide at micromolar concentrations suppressed the growth of tumor cells; however, compared to gossypol, the cytotoxicity of the obtained conjugate was substantially lower. [ABSTRACT FROM AUTHOR]

Designing and developing small organic molecules for use as urease inhibitors is challenging due to the need for ecosystem sustainability and the requirement to prevent health risks related to the human stomach and urinary tract. Moreover, imaging analysis is widely utilized for tracking infections in intracellular and in vivo systems, which requires drug molecules with emissive potential, specifically in the low-energy region. This study comprises the synthesis of a Schiff base ligand and its selected transition metals to evaluate their UV/fluorescence properties, inhibitory activity against urease, and molecular docking. Screening of the symmetrical cage-like ligand and its metal complexes with various eco-friendly transition metals revealed significant urease inhibition potential. The IC50 value of the ligand for urease inhibition was 21.80 ± 1.88 µM, comparable to that of thiourea. Notably, upon coordination with transition metals, the ligand–nickel and ligand–copper complexes exhibited even greater potency than the reference compound, with IC50 values of 11.8 ± 1.14 and 9.31 ± 1.31 µM, respectively. The ligand–cobalt complex exhibited an enzyme inhibitory potential comparable with thiourea, while the zinc and iron complexes demonstrated the least activity, which might be due to weaker interactions with the investigated protein. Meanwhile, all the metal complexes demonstrated a pronounced optical response, which could be utilized for fluorescence-guided targeted drug delivery applications in the future. Molecular docking analysis and IC50 values from in vitro urease inhibition screening showed a trend of increasing activity from compounds 7d to 7c to 7b. Enzyme kinetics studies using the Lineweaver–Burk plot indicated mixed-type inhibition against 7c and non-competitive inhibition against 7d. [ABSTRACT FROM AUTHOR]