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In 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]

AbstractThree chlorinated metal complexes [Ni2(HL)2(C2H5OH)2Cl2]·2C2H5OH (complex 1), [Co(HL)(L)] (complex 2), and [Zn2(HL)2(CH3COO)2] (complex 3) derived from 5-chlorosalicylaldehyde and 2-(2-aminophenyl)-1H-benzimidazole Schiff base ligand (H2L). The crystal structures of the three complexes were characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis, X-ray single-crystal diffraction, and UV-visible absorption spectrum. The in vitro cytotoxicity of chlorinated ligand and its metal complexes were evaluated on four different tumor cell lines (A-549 lung cancer, SMMC-7721 liver cancer, MDA-MB-231 breast cancer, and CNE-2Z nasopharyngeal carcinoma), and normal ovarian epithelial cell (IOSE 80) was determined by MTT assay. The results indicated that chloro-benzimidazole Schiff base Co (III) complex (complex 2) displayed higher cytotoxicity against MDA-MB-231 cell line than cisplatin, while the cytotoxicity on IOSE 80 was lower than that of cisplatin. The results of further study of MDA-MB-231 cells by complex 2 showed that complex 2 could inhibit MDA-MB-231 cells in the G0/G1 phase, inhibit cell proliferation and migration, promote cell apoptosis, and increase intracellular ROS level. The Western blot analysis demonstrated that complex 2 could increase Bax protein expression and decrease Bcl-2 protein expression in MDA-MB-231 cells. [ABSTRACT FROM AUTHOR]

AbstractOne new sulfoxide-containing Schiff base, (E)-4-chloro-2-((2-(methylsulfinyl phenyl)imino)methyl) phenol (HL) was coordinated with ruthenium and rhodium, affording five ruthenium(II) complexes [RuCl(L)(CO)2] (1), [RuCl(L)(dmso)2] (dmso = dimethylsulfoxide, 2), [RuCl(L)(PPh3)(CH3CN)] (3), [RuCl(L)(CO)(PPh3)] (4), [RuCl(NOS-LH2)(CO)(PPh3)] (5) and one rhodium(IV) complex [RhCl3(L)] (6). Molecular structures of HL and complexes 1–6 were established by single crystal X-ray diffraction analysis. Moreover, the free ligand HL and its complexes 1–6 were characterized by infrared, NMR, UV-vis, and fluorescence spectroscopies, and their electrochemical properties were also investigated. The ruthenium complexes showed good catalytic activity for the cyclopropylation of styrene. [ABSTRACT FROM AUTHOR]

AbstractThis article presents a new and facile method for the synthesis of Schiff base compounds with a benzimidazole group using a low-cost and reusable calcium aluminate nanophosphorus catalyst (CaAl2O4). This approach avoids harmful solvents and reactants, supporting a more environmentally friendly synthesis process. The catalyst maintained its activity and heterogeneity over four cycles with minimal loss of efficiency. The synthesis process was straightforward and eliminated the need for column chromatography. The Schiff base ligand (HL=(E)-N-((6-(thiophen-2-yl)pyridin-2-yl)methylene)-1H-benzo[d]imidazol-2-amine)) was synthesized by the reaction of 6-(thiophen-2-yl)pyridine-2-carbaldehyde with 1H-benzimidazole-2-amine. Subsequently, metal(II) complexes of Co(II), Ni(II), and Cu(II) were prepared using this ligand. Structural analysis of both the ligand and its metal complexes was carried out using various physicochemical and spectroscopic methods. Ni(II) and Co(II) complexes were found to adopt an octahedral geometry, while the Cu(II) complex exhibited a square-planar structure. Binding studies with calf thymus DNA (CT-DNA) at pH 7.2 were performed using UV-visible spectroscopy, viscosity measurements, and thermal denaturation studies and showed that the metal complexes intercalate into the DNA and produced a distinct binding pattern. Molecular docking simulations with AutoDock Vina provided insights into the interaction of these complexes with the B-DNA dodecamer. Furthermore, the ligand and its metal complexes showed UV-visible photonuclease activity against pUC19 DNA. Agarose gel electrophoresis showed that the metal complexes exhibit photoinduced nuclease activity, confirming their ability to cleave DNA upon exposure to light. [ABSTRACT FROM AUTHOR]

N4-donor Schiff base copper(II) nanoparticles were easily prepared through surface modification of silica-coated magnetite nanoparticles (Fe3O4@SiO2) with pyrrole 2-carbaldehyde Schiff base and a subsequent reaction with Cu(CH3COO)2.H2O in ethanolic solution. This nanocatalyst was characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and magnetization. Efficient oxidation of alkenes and alcohols was carried out over the Schiff base copper(II) nanoparticles. Catalytic tests showed that the catalyst was particularly effective for the oxidation of α-methyl styrene, norbornene, benzyl alcohol, and benzohydrol. The results showed that acetophenone, 2-norbornanone, benzoic acid, and benzophenone with selectivity values of 88, 100, 100, and 100, respectively, were obtained. The heterogeneous catalyst of N4-donor Schiff base copper(II) offers advantages such as ease of product separation, catalyst recycling, and ease of preparation. Antibacterial tests against two gram-positive and two gram-negative bacterial species found that the bacteria stopped growing in the catalyst medium. HIGHLIGHTS: A novel nanomagnetic heterogeneous catalyst of N4-donor Schiff base copper(II) immobilized on superparamagnetic Fe3O4@SiO2 was Synthesized. Catalyst was characterized by TGA, XRD, FT-IR, TEM, and magnetization. Fe3O4@SiO2@APTMS@PYC@Cu was used as an efficient nanocatalyst for oxidation of alkenes and alcohols. Nano-catalyst antibacterial studies were performed. The catalyst has high catalytic capability, excellent magnetic separately, and reusability. [ABSTRACT FROM AUTHOR]

A simple salicylaldehyde-based Schiff base 2,2'-((1,3-phenylenebis(azanylylidine))bis(methanylylidene))dipehnol (PAMD) was synthesised by condensation reaction between salicylaldehyde and benzene-1,3-diamine (2:1 ratio) and characterised by spectral techniques such as NMR, FTIR and HRMS, followed by investigation for its spectroscopic behaviour towards diverse metal ions using UV and fluorescence studies. PAMD was found to exhibit sensitivity towards Cu2+ only. The receptor PAMD was then explored for its electrochemical behaviour using cyclic voltammetry, which displayed an irreversible anodic peak at 1.00 V due to imine group. Furthermore, PAMD was subjected to differential pulse voltammetry, which exhibited a sensitive response for Cu2+ in the linear range of 0–3.8 μM with lowest detection limit of 0.03 μM. The complexation between PAMD and Cu2+ was also supported by large values of binding constant (1.3 × 105 M−1) and negative free energy change (ΔG∘ = -29.2 kJmol−1) obtained from Benesi–Hildebrand equation. The carbon paste electrode (CPE) modified with PAMD displayed a Nernstian response to Cu2+ in the concentration range from 1.0 × 10−6 to 1.0 × 10−1 M and lowest detection limit of 4.0 × 10−7 M. The PAMD-CPE was successfully applied for determination of Cu2+ content in real samples such as groundwater, soil, and food grains (wheat and rice). [ABSTRACT FROM AUTHOR]

Dihydroxy derivative of vanillin-based diaminotriazole core monomer (DTV) has been synthesized using sustainable vanillin (V) and 3,5-diamino-1,2,4-triazole (DT) under appropriate experimental conditions and characterized with a view to develop Schiff base core nitrogen-rich benzoxazines capable of exhibiting excellent optical and anti-microbial properties. The monomer DTV has been subsequently converted into benzoxazines separately using six structurally varied amino compounds, viz. aniline (a), 1-(−2-aminoethyl)piperazine (aep), furfurylamine (ffa), 4-H-1,2,4-triazoal-4-amine (ta), 3-aminopyrazol (apy) and 1-(3-aminopropyl)imidazole (api) with paraformaldehyde through Mannich condensation. The corresponding Schiff base based benzoxazines, viz. DTV-a, DTV-aep, DTV-ffa, DTV-ta, DTV-apy and DTV-api were synthesized and characterized for their molecular structure, thermal stability, optical, hydrophobic and anti-microbial properties using different analytical techniques and methods. Data obtained from different analyses for DTV based benzoxazines can be used for wide range of industrial and engineering applications. [ABSTRACT FROM AUTHOR]

Cu(II) complexes of three Schiff bases were synthesized and characterized via X-ray diffraction, Fourier transform infrared, and UV–vis spectroscopies. The Schiff bases act as bidentate ligands, chelating Cu(II) ions in seesaw coordination geometry. Changing the substituent types and positions creates various non-covalent interactions within the crystal packings, yielding notable topological differences. GC–MS analysis reveals that Cu(II) complexes induce 1.38%–11.43% efficacy in Suzuki–Miyaura cross-coupling reactions. The biological activity of complexes correlates with substituent type and position in the aromatic ring. The one with ethoxy exhibits antimicrobial effects solely against Candida parapsilosis, while those with fluorine enhance the activity, particularly in the meta position. [ABSTRACT FROM AUTHOR]

A green and efficient ultrasound-mediated protocol was developed for the synthesis of a series of novel Schiff bases derived from quinoline-4-one. The synthetic strategy involved the condensation of 4-oxo-1,4-dihydro-quinoline-3-carboxaldehyde with diverse anilines and heteroaryl amines. The synthesized compounds were characterized using spectroscopic techniques. A comprehensive in vitro cytotoxicity evaluation against HCT116 and HT-29 human colon cancer cell lines revealed that several compounds exhibited potent anticancer activity. Notably, compounds 3c and 3e demonstrated superior cytotoxicity compared to the clinical standard doxorubicin. Mechanistic studies indicated that these lead compounds induced apoptosis, necrosis, and cell cycle arrest at G1 and G2 phases. Furthermore, autophagy induction was observed. In silico ADMET predictions support the potential of compounds 3c and 3e as promising anticancer drug candidates. The molecular docking studies revealed that the Schiff bases 3c and 3e displayed good interaction with VEGFR-2 receptor. These findings underscore the quinoline-4-one scaffold as a valuable template for the development of novel antitumor agents. [ABSTRACT FROM AUTHOR]

Isoxazole Schiff bases play an important role in medicinal chemistry, pharmacy, coordination chemistry, and industrial chemistry, therefore, finding easier and more reliable procedures for their synthesis is still in process. The present work deals with a single-step condensation reaction between 3-amino-5-methylisoxazole and various aromatic aldehydes to furnish a Schiff base scaffold of isoxazole (including one new compound) with excellent yields in a short time. The procedure is a solvent-free condition using DMEA as a green catalyst. The products were evaluated for their antibacterial efficacy against gram-positive and gram-negative bacteria including Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Salmonella abony. The antioxidant activity of the products was tested and the ascorbic acid and quercetin were used as standards. The produced Schiff bases exhibited the ability to scavenge the free radicals from the DPPH. This means that the products can be used as antioxidants. Two of the synthesized compounds were evaluated for their anticancer activity by testing their cytotoxic potency, which showed diminishing toxicity of cell lines against human breast cancer cell lines and gastric adenocarcinoma cell lines. Therefore, the products can be utilized as anticancer agents. [ABSTRACT FROM AUTHOR]

Different Schiff base complexes were prepared by immobilizing three aldehydes (4-Hydroxybenzaldehyde, 2-hydroxybenzaldehyde, and 2-Pyridinecarboxaldehyde) on graphene oxide and were fully characterized using multiple techniques such as FTIR, XRD, TGA, BET, SEM-EDS, and TEM. Then efficient heterogeneous catalysts were checked out in the selective catalytic oxidation of benzylic alcohols. The effects of different parameters, such as reaction time and temperature, were examined to obtain optimum reaction conditions. The solvent-free oxidation reaction of benzylic alcohols showed a conversion above 70% and selectivity higher than 95% in the presence of cobalt (II) Schiff base catalysts using H2O2 as an oxidant after 40 min of reaction. The reusability experiment results specified that the prepared catalysts could maintain high catalytic activity in the oxidation of benzylic alcohols (>80%) and selectivity (>96%) even after being used for three cycles. [ABSTRACT FROM AUTHOR]

Cobalt, nickel, copper and zinc metal complexes with a novel Schiff base (HL) have been synthesized and characterized by different physicochemical analyses (1H-NMR, IR, UV–Vis, fluorescence, mass spectrometry, cyclic voltammetry, TGA, and ESR). The Schiff base 3-methyl-1-phenyl-5-(naphthylidene) amino)-pyrazole was synthesized by condensing 5-amino-3-methyl-1-phenylpyrazole with 2-hydroxynaphthaldehyde. These compounds were evaluated for their fluorescence emission and the complexes show higher fluorescence intensity than their parent Schiff base. The structure determined for the copper complexes was square planar whereas the other complexes were octahedral. Using TGA, the presence of coordinated water was determined. The compounds were checked for their antibacterial and antifungal activity and the metal complexes appeared to be more active towards microorganisms than the parent Schiff base. [ABSTRACT FROM AUTHOR]

A new synthesized Schiff base, N-((anthracen-9-yl) methylene-2-methyl benzenamine) (AMMB), was prepared from o-toluidine and 9-anthracenecarboxaldehyde. The structure of the compound was confirmed by single crystal X-ray diffraction and characterized through various analytical tools such as high resolution mass, 1H and 13C NMR, infrared, UV-vis and elemental composition analysis. The molecular geometries of AMMB were optimized by means of DFT/B3LYP/6311-G++ (d,p) basis set. The optimized geometric parameters of the compound were concordant with the single crystal structure. The optimized structure was utilized in comparison of experimental FT-IR with calculated frequency calculation. TD-DFT analysis was performed to compute the electronic absorption of the compound. SCF-GIAO was employed to compute 1H and 13C NMR, which was consistent with the experimental results. Additionally, NLO, NBO, MEP and global reactivity parameters were also computed using the same level of theory. Hirshfield surface analysis, fingerprint plot and energy frameworks were presented to explore the intermolecular interactions within the crystal. Molecular docking study was carried out to predict the probable binding site of AMMB into lipid bilayers such as DMPC, DPPC, POPC, DLPE, DOPC and POPE. The molecular docking analysis of AMMB showed complex formation with binding affinity energy ranging from −9.3 to −3.4 kcal/mol. [ABSTRACT FROM AUTHOR]

Chitosan (CS) is lack of applications in pharmaceutical industry due to its lower compression density and instability during tablet process. This study mainly focus on the synthesis of ethyl vanillin incorporated CS(EV/CS) via Schiff base reaction and the evaluation of application as pharmaceutic excipient. Results of FT-IR showed that there is a typical amide peak in EV/CS that the 1640 cm−1 can be attributed to –C = N– bond and 1518 cm−1 can be attributed to backbone of benzene but not in CS raw material. Compared with the control, XRD of EV/CS have additional 2θ angle of 44°, 64° and 77° diffraction peaks except that the 2θ = 20° of EV is still existed. More slower weight loss of EV/CS than that of CS in the range of 248–760 °C is also demonstrated by TGA analysis. 1H NMR indicated there are intrinsic 7.5 and 7.1 ppm as well as emerging 4.2 ppm of chemical shift in EV/CS. The physical finger spectra from twelve indexes of EV/CS powder denotes quite differences in compressibility, fluidity and stability with that of CS. 5% content EV/CS of designed formulation can at most decrease the friability and disintegration time of the compressed tablet. In conclusion, the developed EV/CS is inclined to suitable for tablet as an excipient. [ABSTRACT FROM AUTHOR]

A series of Co(II), Ni(II), Cu(II), Zn(II) complexes have been synthesized with a benzothiazole azo dye containing tridentate (NNO) donor ligand 4-(((6-nitrobenzo[d]thiazol-2-yl)imino)methyl)benzene-1,3-diol derived from 2-amino-6-nitrobenzothiazole and 2,4-dihydroxybenzaldehyde. The structures of the novel ligand and metal complexes were identified and confirmed via various spectroscopic techniques (FT-IR,1H NMR,13C NMR, UV-Vis, mass spectrometry), TGA-DTA, powder X-ray diffraction, and DFT calculations. The optimal structural parameters and chemical reactivity of the ligand and metal complexes have been investigated using Density Functional Theory calculations (DFT/B3LYP,6-31G** and LanL2DZ basis sets) to provide insight about their frontier molecular orbitals (FMO) and molecular electrostatic potential (MESP). In vitro DPPH radical scavenging techniques have been used to assess the antioxidant activity of the ligand and complexes, indicating good antioxidant activity. The Ni(II) complex was the most potent with the lowest IC50 values. The in vitro antibacterial activities have been explored by screening against bacteria (Bacillus subtilis) and bacteria (E. coli) exhibiting significant activity against the tested strains of bacteria with Zn(II) complex as most potent with the lowest MIC value against E. coli and B. subtilis) and highest zone of inhibition against E. coli and B. subtilis at 1000 μg/mL concentration). The antifungal activity of complexes against Aspergillus niger and Candida albicans indicate that the Co(II) complex is most active for C. albicans and Zn(II) complex for A. niger. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSA new Schiff base inhibitor known as “N, N’ carbonyl- Bis (para-hydroxy benzaldehyde imine)” has been synthesized and characterized by FTIR, NMR, and UV-Visible spectroscopy, the molecule was then assessed for its ability to prevent copper from corroding in a solution of 0.5 M H2SO4 using potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy SEM combined with energy dispersion spectroscopy EDX, and atomic force microscopy AFM. The tested inhibitor exhibits good copper corrosion inhibition performance in a 0.5 M H2SO4 solution. As inhibitor concentration rises, inhibition performance also rises, reaching a maximum inhibitory efficacy of around 84.76 ± 0.69% at 5.10−4 M. The inhibitor was adsorbable to the metal surface and followed the Langmuir isotherm. It has been done such that the addition of KI increased the inhibitory effectiveness, the mixed additives worked together. There is good agreement between the conclusions drawn from theoretical calculations using DFT and MD simulation and actual observations.A new Schiff base inhibitor has been synthesized.The inhibitory efficiency increase with increasing inhibitor concentration.The investigated molecule adsorbs on the copper surface through active centers like N and O.The synthesized molecule has good inhibitory effectiveness with respect to copper corrosion in an acidic medium.A new Schiff base inhibitor has been synthesized.The inhibitory efficiency increase with increasing inhibitor concentration.The investigated molecule adsorbs on the copper surface through active centers like N and O.The synthesized molecule has good inhibitory effectiveness with respect to copper corrosion in an acidic medium. [ABSTRACT FROM AUTHOR]

Fluorescent probes incorporating the excited-state intramolecular proton transfer (ESIPT) phenomenon have emerged as versatile tools in scientific research. These probes exhibit dual emission, resulting from the unique transfer of a proton within the molecule upon excitation. This property makes ESIPT-based Schiff bases highly attractive for metal detection, cell imaging, and sensing biologically important molecules. In metal detection, the spectral changes of ESIPT-based Schiff bases upon interaction with metal ions enable the development of sensitive and selective sensors. For cell imaging, their photophysical properties make them ideal for labeling cellular components and facilitating multicolor imaging. In sensing biomolecules, ESIPT-based Schiff bases offer selective detection of interactions and enzymatic activities. Integration of these probes holds great promise for applications in environmental monitoring, biomedical research, and healthcare. This review focuses on the photoluminescent properties and application of ESIPT dual emission Schiff bases for sensing of metal ions, biologically relevant molecules and cell imaging. [ABSTRACT FROM AUTHOR]

In the present study, six mononuclear Zinc(II) complexes, [Zn(L1)(6-Methyl-2,2′-bpy)] (1), [Zn(L1)(1,10-Phen)] (2), [Zn(L1)(5-Amino-1,10-Phen)] (3), [Zn(L2)(6-Methyl-2,2′-bpy)] (4), [Zn(L2)(4,4′-Di-tert-butyl-2,2′-bpy)] (5), and [Zn(L2)(1,10-Phen)] (6) formed from Schiff bases, 2-methyl-1-phenyl-1-(pyridin-2-ylmethylimino)propan-2-ol (L1) and 4-chloro-5-methyl-2-(1-(pyridin-2-ylmethylimino)ethyl)phenol (L2) were synthesized. The synthesized Schiff base ligands and metal complexes were characterized by different spectroscopic techniques such as FTIR, UV–Visible, 1H & 13C NMR spectroscopy, in addition to Powder X-ray diffraction and cyclic voltammetry. Further, the synthesized metal complexes (1–6) and their parental Schiff bases (L1, L2) were evaluated for antibacterial, antifungal, and antioxidant activities. Of those, Complex 1 was shown to have significant antibacterial activity against all of the evaluated microorganisms. Schiff base ligands, L1 and L2, complexes 1, 4, and 5 were shown to have superior antifungal activity against Aspergillus niger than the standard drug, fluconazole. In addition, the synthesized compounds achieved good antioxidant activities when compared to the standard Ascorbic acid. [ABSTRACT FROM AUTHOR]

In this study, a series of new chelating copolymers containing 20% azomethine groups, poly(N-vinylpyrrolidone-co-vinylsalicylideneimine) (poly[VP-co-VSalI]), poly(N-vinylpyrrolidone-co-vinylpicolinideneimine) (poly[VP-co-VPicI]), poly(N-vinylpyrrolidone-co-vinylpyridoxylideneimine) (poly[VP-co-VPyrI]) with M = 63000 Da and their vanadium(IV) complexes – poly(VP-co-VSalI)-VO, poly(VP-co-VPicI)-VO, poly(VP-co-VPyrI)-VO, were designed and synthesized. These are intended for the delivery and pH-dependent release of vanadium species in the intestine environment. The chelating polymers were obtained from poly(N-vinylpyrrolidone-co-N-vinylamine) (poly[VP-VAm]) by polymer-analogous transformations with the corresponding aldehydes. The vanadium content, determined by ICP-AES and spectrophotometric methods, was 5.36%, 4.99%, and 9.1% of the dry mass for poly(VP-co-VSalI)-VO, poly(VP-co-VPyrI)-VO, and poly(VP-co-VPicI)-VO, respectively. XPS data confirmed that only vanadium(IV) is presented in the complexes. All complexes demonstrated a pH-dependent release of low molecular weight vanadium species, making them promising candidates for the development of vanadium-containing systems for oral administration. These systems protect the main vanadium content in the stomach but can release biologically active ions in the intestine. [ABSTRACT FROM AUTHOR]

Schiff bases with pyrene, anthracene or naphthalene groups can act as simple, sensitive, and selective sensors for the detection of trace explosives. We have prepared three new types of Schiff bases with fluorescent properties as fluorescent probes for use in the fluorescence detection of explosives. The detection properties of the synthesized compounds of photophysical and fluorescent explosives were investigated. Spectroscopic methods were used for the structural characterization of the compounds. Within the scope of the study, compounds (A, B and C) were used as fluorescent probes in the detection of some explosives and the data obtained were recorded. Instead of the quenching effect expected by the explosives on the emissions of the compounds, it was observed in some experiments that the emission intensity due to aggregation increased. In addition, the color measurements (CIE standards) and Color temperature (CCT) of the compounds were calculated. [ABSTRACT FROM AUTHOR]

In this study, synthesis, characterization, optical, and in silico medicinal properties of a Schiff base compound, 4-((4,5-difluoro-2-hydroxybenzylidene)amino)-1,5-dimethyl-2-phenyl-2,3-dihydro-1H-pyrazol-3-ol, were reported. X-ray, FTIR, and UV-vis spectra, including computational and experimental data, were used to characterize the Schiff base molecule. Pharmacophore analysis of the molecular structure was performed to investigate the active interaction centers that can interact with macromolecular biological targets. Since the synthesized Schiff base is not centrosymmetric, the NLO material potential was evaluated using the DFT approach, and it showed higher NLO efficacy compared to the reference molecule urea. Potential biological targets of the title compound were investigated using a web server (LigTMap). Top twelve candidate targets, including transferase, hydrolase, and kinase targets, were identified. According to the docking scores, the most potent target of the title compound was determined as vascular endothelial growth factor receptor 2 (PDB: 3VO3). [ABSTRACT FROM AUTHOR]

Schiff bases are produced through condensation reactions between aldehydes or ketones and molecules containing an amine group. Given their multifaceted uses across diverse domains, they have gained prominence. Numerous studies have been conducted in this field due to the uncomplicated methods of manufacturing and the abundant range of applications. Investigations into DNA binding are essential for understanding the many interactions between drugs and DNA. DNA binding can be investigated via UV-binding, fluorescence quenching, and viscosity investigations. This study aims to offer several research papers on the DNA binding activity of Schiff base metal complexes and compare them. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of a small molecule quinoline Schiff-base "turn-on" fluorescence probe L, denoted as (2-NC9H6)C(H)=N(C6H4OCH3-p), utilizing 4-aminoanisole and quinoline-2-carboxaldehyde as precursors. The synthesized probe was comprehensively characterized through EA,1H/13C NMR, FT-IR, and ESI-MS spectral analysis. In a CH3CN/H2O solution (1/1, v/v, 0.01 M PBS buffer, pH = 7.30), probe L responded to Hg(II) with high sensitivity (LOD = 2.98 × 10−7 M) and selectivity. Upon binding to Hg(II), the fluorescence of the probe shifted from being initially off to a distinct blue emission. The probe L to Hg(II) binding ratio was 1:1 and the binding constant was 1.955 × 104 M−1. The detection mechanism of Hg(II) by probe L is due to the complex formation between the metal ion and imine nitrogen (–CH = N), thus causing chelation-enhanced fluorescence. TD-DFT studies at the B3LYP/6-31G(d) level of theory further confirmed that the complexation of L and Hg(II) occurred. Finally, probe L could reversibly identify Hg(II) upon adding EDTA, thus developing a molecular logic gate. In addition, this probe was successfully used to detect Hg(II) in actual water samples. : [ABSTRACT FROM AUTHOR]

Pursuing our recent interest concerning the catalytic activity of half-sandwich RuII complexes containing Schiff base ligands (L1 and L2), in this study new Schiff bases and their half-sandwich RuII complexes were prepared. The structures of these compounds were confirmed by a variety of spectral and physical methods such as microanalysis, FT-IR, electronic spectra, proton and carbon NMR, TGA and mass spectra. The catalytic activities of the RuII complexes toward the transfer hydrogenation of ketones to their corresponding alcohols were investigated using i-PrOH as a hydrogen source and solvent. The complexes showed high catalytic activities at catalyst concentrations of 0.01 mmol and were able to carry out transfer hydrogenation (TH) to a wide range of ketones in the presence of KOH. In general, Schiff bases recognition, the coordination chemistry, and the ketone substrates were found to influence the catalytic performance of these complexes. [ABSTRACT FROM AUTHOR]

The incidence of multi-resistant infections has sharply increased. One of the best strategies for developing new drugs is re-engineering existing drugs to enhance their bioavailability and antimicrobial activities. The latest systems focus on designing bioinorganic platforms to develop antimicrobial agents to target drug-resistant microbial strains. Various literature reports highlight metal-based antimicrobial agents unveiling an innovative strategy to tackle microbial agents. One of the significant mechanisms of antibiotic resistance in bacteria is the impermeability of its cell membrane towards antibiotics. Antibiotic-based Schiff base complexes are prime candidates for drug design with minor side effects in this scenario. The enhanced activity of antibiotic Schiff base complexes over their parent compound plays a key role in the emergence of innovative antimicrobials. In this review, we highlight the biological potential aspects of some selected antibiotic-based Schiff base complexes of penicillin, cephalosporins, quinolones, and sulfonamides. Some of the bacteria, especially P. aeruginosa, remain resistant to most of the commercially available antibiotics. Here, the review highlights that Schiff base complexes mediated by antibiotics demonstrate bactericidal activity against these resistant strains. Additionally, their mode of action on the bacterial cell is highlighted. The increased activity of copper, zinc, and silver complexes of different Schiff bases is attributed to their inherent redox chemistry. [ABSTRACT FROM AUTHOR]

With the ultimate goal of discovering new anticancer agents, this study involved the design and synthesis of fifteen novel Schiff bases 4a,b, 5, 6a–d, 7a–e, and 8–10 which contain 3-(2-oxo-2H-chromen-3-yl)-1-(4-phenylthiazol-2-yl)-1H-pyrazole moiety. The synthetic method depended on reaction of 3-(2-oxo-2H-chromen-3-yl)-1-(4-phenylthiazol-2-yl)-1H-pyrazole-4-carboxaldehyde (3) with a series of aromatic and heteroaryl amines under ultrasound irradiation to explore the influence of aromatic and heteroaryl rings on biological activity. The chemical structures of these Schiff bases were fully elucidated using various spectral and elemental analyses. The antiproliferative activities of the Schiff bases were studied by the standard SRB method. Among the new 15 Schiff bases, derivatives 4a,b, 5, and 7b have significant cytotoxic effects against PC3, HepG2, and HCT116 cancer cell lines. These four bioactive Schiff bases significantly increased the late apoptosis of all studied tumor cells. Also, both products 4a and 4b arrested the cell cycle at the G1 phase, while both compounds 5 and 7b arrested the S and G2 phases against PC3 cells. In addition, the products 4a, 4b, 5, and 7b have promising high abilities to arrest the cell cycle at the G2 phase against HepG2 and HCT116 cells. The different substitutions on the aryl ring were the basis for the structure–activity relationship study. The molecular docking study confirmed good binding interactions of these compounds with Cyclin-dependent kinase 8 (CDK-8) receptor, while the absorption, distribution, metabolism, excretion, and toxicity (ADMET) prediction supported that these bioactive products can be promising anticancer agents. [ABSTRACT FROM AUTHOR]

In the current study, one new series of symmetrical liquid crystalline homologous series of dimers with a rigid aromatic core with azo and azomethine group were synthesized using an ether-linking group. Several spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR and elemental analysis, were used to describe the synthesised dimers. The differential scanning calorimetry (DSC) and polarised optical microscopy (POM) were used to assess their mesomorphic properties. The results showed that the number of methylene spacers significantly affected the thermal properties of the synthesized dimers. To ascertain photophysical behaviour, UV-visible spectroscopy was employed. All the dimers of the present series show excellent enantiotropic nematic mesophase. The relationships between structure and its mesogenic property, the effects of various flexible spacers, the mesophase ranges, and the photo-isomerization of liquid crystalline dimers were all investigated. DFT study was carried out to gain a better understanding of structural features. [ABSTRACT FROM AUTHOR]

Two new homologous series of mesogenic compounds, alkanoic acid 4-{[4-(6-chloro-benzooxazol-2-yl)-phenylimino]-methyl}-3-hydroxy-phenyl ester (3a-c) and alkcanoic acid 4-(6-chloro-benzooxazol-2-yl)-3-hydroxy-phenyl ester (5a-b) incorporating benzoxazole heterocyclic have been prepared and FT-IR, NMR, and MS spectrometry have been used to study the molecular structures. The mesogenic behaviour was examined using POM, DSC, and PXRD (variable temperature) techniques. To evaluate its impact on thermal behaviour and mesomorphic properties, the imine linking group of derivatives was modified and investigated. Enantiotropic SmA is observed by the members of Series-I, while those of series-II show monotropic SmA mesomorphism. These compounds were also examined for their absorption and fluorescent properties. The absorption and photoluminescence spectra of compounds 3a-c occurred at 345 nm and 410 nm, whereas in the case of 5a-b occurred at 325 nm and 370 nm respectively. The GAUSSIAN-09 programme has been utilised to perform DFT calculations at B3LYP level for the purpose of obtaining the stable electronic structures of 3a and 5a. [ABSTRACT FROM AUTHOR]

Environmental concerns arising from industrial activities and population growth have encouraged the development of green chemistry, a sustainable approach to synthesis. Researchers have explored various techniques for the eco-friendly synthesis of Schiff bases, including microwave irradiation, ultrasound irradiation, grinding, and natural acids. These versatile compounds, known for their unique chemical properties, have found diverse applications in various fields. Recently, the use of Schiff bases as dyes in dye-sensitized solar cells (DSSCs) has drawn the attention of researchers. DSSCs have advantages over silicon-based solar cells, such as a low cost of fabrication and the ability to operate under low light conditions. Schiff bases can be used as adsorbents to remove toxic metals from water. By embracing sustainable synthetic methods, researchers have reduced the environmental impact associated with Schiff base production and employed these compounds to promote environmental sustainability. This review describes the green synthesis of Schiff bases and their potential applications for environmental protection. [ABSTRACT FROM AUTHOR]

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), [Ni3L2(NO3)2(CH3OH)2]·2CH3OH (1), [Cu3Br2L2] (2), [Zn3L2(NCS)2(CH3OH)2]·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, [MoO2L] (4), have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition. [ABSTRACT FROM AUTHOR]

Chromium occurs in the environment primarily in two valence states, trivalent Cr3+ and hexavalent Cr6+, which have different physicochemical and biochemical properties. However, the higher concentration of Cr3+/6+ can cause various adverse effects on human health. Therefore, detecting Cr3+/6+ ions is important in various samples. Colorimetric and fluorescent chemosensors are the most powerful tools for the detection of Cr3+/6+ ions. These chemosensors have excellent bioimaging capability and significant sensitivity and selectivity. In this article, different colorimetric and fluorescent chemosensors based on organic compounds, including Schiff base, antipyrine, diarylethene, pyrene, crown ether, dansyl, pyridine, thiazole, coumarin, boradiazaindacene, rhodamine, imidazole, hydrazone, and other functional groups for detection of Cr3+/6+ ions have been reviewed, classified them according to different fluorophore and recognition mode. I hope this article will help the readers for the future design of highly effective, sensitive, and selective chemosensors for the detection and determination of Cr3+/6+ ions. [ABSTRACT FROM AUTHOR]

The Schiff base was synthesized and characterized with Infrared, Raman, UV, fluorescence, and NMR studies. The present work is theoretically investigated using DFT/WB97XD/cc-pVTZ basis set. The local energy decomposition (LED) has been performed using PBE0-D3/deft-TZVP basis set and DLPNO-CCSD(T) coupled cluster level. The DFT was used to define the molecular structure and geometry of the compound. To identify the primary binding sites and weak interactions, compound was subjected to a series of topological analyses, including ELF, LOL, ALIE, and RDG. The UV-Visible spectrum was analyzed using the TD-SCF method. The DFT/WB97XD/cc-pVTZ was used to measure the HOMO-LUMO, MEP, and NLO. The NBO calculations investigate the intermolecular and intramolecular movement of charges, as well as the molecule stability. To determine whether the 4CLBDA molecule has the potential to become a drug, computational drug-likeness studies were conducted. The docking study done against the 6X7Q protein is performed and reported. [ABSTRACT FROM AUTHOR]

In this work, we designed and synthesized a novel, simple, low-cost, and effective chromone–based Schiff base ligand (HL) and its application as a chemosensor for Fe3+ detection. The structure of the synthesized sensor bears carboxylic, azomethine, and carbonyl groups which act as chelating sites for the detection of Fe3+ ions. The chemosensor HL exhibited highly selective detection of Fe3+via a significant colour change from yellow to brown. The colour change is due to the ligand-to-metal charge-transfer (LMCT) mechanism. The sensor (HL) was characterized using UV-Vis, FTIR, NMR (1H- and 13C), and mass spectroscopy. The ligand solubility, detection condition, and sensitivity assessment suggested optimal use of DMF-water (9:1 v/v) as a working solvent at pH 7.0. Among a list of 15 metal ions screened, HL was highly selective, with instant response, towards Fe3+ ions without significant interferences with the other metal ions. The complexation ratio and association constants of HL to Fe3+ was determined by Job's plot and Benesi–Hildebrand methods, and were 2:1 and 2.24 × 103 M−1, respectively, with a detection limit of 2.86 μM. The HL probe was also applied to detect Fe3+ in real samples with acceptable performance. The simple test strips have been successfully developed and applied to the visual monitoring of Fe3+ ions with a detection limit of 68 µM. The DFT was used to examine the best interaction mode of HL with Fe metal to be Fe(III)–L or Fe(III)–2L. The chemical-reactivity and molecular electrostatic optional were figured to predict the interaction behaviour of the tested compounds. [ABSTRACT FROM AUTHOR]

Three new copper(II) and cadmium(II) complexes, [Cu(L1)2] (1), [CuL2(N3)] (2), and [Cd(L3)2] (3), where L1 = 2-bromo-4-chloro-6-cyclohexylaminomethylphenolate, L2 = 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenolate, and L3 = 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropylimino)methyl]phenolate, have been prepared and structurally characterized by X-ray crystallography. The Cu atom in complex 1 is in tetrahedrally distorted square planar geometry. The Cu atom in complex 2 is in square planar geometry. The Cd atom in complex 3 is in octahedral geometry. The complexes exhibited effective activities against B. subtilis, S. aureus and E. coli. [ABSTRACT FROM AUTHOR]

Two sulfoxide-containing Schiff bases, (E)-(((2-(methylsulfinyl phenyl) imino)methyl)-4-nitrophenol (HL1) and (E)-3,5-dibromo-2-(((2-(methylsulfinyl phenyl)imino)methyl)phenol (HL2), were prepared by condensation and subsequent oxidation reactions. In the presence of triethylamine, reactions of HL1 with 0.5 equivalent of copper acetate, cobalt acetate, nickel acetate and zinc acetate in ethanol afforded four metal complexes: (η2-N,O-L1)Cu(η3-O,N,O-L1) (1) and (η3-O,N,O-L1)2M (M = Co, 2; Ni, 3; Zn, 4), respectively. Similarly, treatment of HL2 with 0.5 equivalent of cobalt acetate and nickel acetate obtained two cobalt/nickel complexes: (η3-O,N,O-L2)2M (M = Co, 5; Ni, 6). Reactions of HL1 and one equivalent of Ru(PPh3)3Cl2 in tetrahydrofuran in the presence of triethylamine afforded a ruthenium(II) complex, (η3-O,N,S-L1)Ru(PPh3)2Cl (7). The molecular structures of HL1 and 1-7 have been confirmed by single-crystal X-ray diffraction. In addition, the UV–Vis, infrared, and fluorescence spectroscopies of 1–7 along with their electrochemical properties were also investigated. [ABSTRACT FROM AUTHOR]

Thiazole based Schiff base scaffolds in recent years have become the integral part of the drug development. These scaffolds are gaining much importance due to their widespread uses as versatile building blocks for the construction of lead drug molecules. Their excellent biological activities have encouraged us to prepare newer compounds with aryl group in the fourth position of thiazoles incorporating azomethine linkages. The strategies so far reported to obtain 4-aryl thiazoles are time consuming, tedious, and costly. In this context, we report a facile one pot synthetic method to obtain novel 4-aryl thiazoles with excellent yield (83–98%), lesser reaction time (40 min) and under milder conditions with no catalyst and no purification techniques. [ABSTRACT FROM AUTHOR]

A new Schiff base ligand of 6,6′-(1Z,1′Z)-(butane-1,4-diylbis(azanylyidene))bis (phenylmethanylylidene))bis(3-octyloxy) phenol) was synthesized and characterized using XRD and different spectroscopic analyses (FTIR, 1H NMR, 13C NMR, and UV–Vis.) DFT/B3LYP/6-31G(d,p) level of theory was applied successfully to the present compound. Theoretically calculated parameters of the synthesized compound were compared with the experimentally obtained results. The optimized structure has been investigated using the same level of theory for various studies, including frontier molecular orbital analysis, molecular electrostatic potential, chemical reactivity indexes, natural bond orbital analysis, electrostatic potential, and the electrophilicity-based charge transfer with DNA bases. [ABSTRACT FROM AUTHOR]

L-lysine monohydrate was treated with formaldehyde to produce 6-amino-2-(methyleneamino)hexanoic acid (LH) whose potassium salt (LK) was further refluxed with R2SnCl2 (R = Me, 1; n-Bu, 2; Ph, 3) or R3SnCl (R = Me, 4; n-Bu, 5; Ph, 6) in methanol to yield the organotin(IV) products (1–6). FTIR spectroscopy displayed chelating coordination of the carboxylate group and a trigonal bipyramidal geometry of tin in the solid-state which was also verified by computational studies.1H NMR spectra displayed signals of ligand skeleton and organotin(IV) moieties. Microanalysis (CHN) data agreed well with the molecular composition of products. Thermogravimetric analysis (TGA) showed highest thermal stability of 5. HOMO and LUMO energy levels are −5.44 to −6.04 and −0.10 to +0.1 eV, respectively. The smallest and highest energy (between HOMO and LUMO) were observed in 1 and 6, respectively. The order of dipole moment is 1 > 4>5 > 3>6 > 2. The significant shielding and de-shielding phenomena observed in 13C NMR spectra of 3 and 6 can be attributed to the existence of delocalized electrons. Antibacterial potential (disc diffusion method) decreased in the order Ciprofloxacin > 1 > 3>6 > 4>2 > 5>LH against Escherichia coli and 1 > 3 = Ciprofloxacin > 4 ≥ 6 > 2>5>LH against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Schiff base (EDBSAD) was prepared by the hydrothermal method to be as adsorbent materials. The obtained EDBSAD can be characterised by FT-IR, UV-vis, XRD, and SEM. The adsorption desulphurisation performance of the adsorbent for dibenzothiophene in model oil was investigated. The results showed that the EDBSAD had a specific adsorption desulphurisation effect. The optimal adsorptive condition was as follows: adsorbent amount 0.5 g and adsorption time 8 min. Under the optimal situation, the maximal adsorption capacity of this adsorbent for DBT was 25.45 mg/g. In addition, the adsorption isotherms and kinetics were studied, and the associated parameters were derived. Langmuir models and pseudo-second-order kinetic presented best fitting results for DBT adsorbing on the adsorbent EDBSAD. [ABSTRACT FROM AUTHOR]

AbstractA novel adsorbent, 6,6′,6″-((benzene-1,3,5-triyltris(azaneylylidene))tris(methaneylylidene))tris(2-ethoxyphenol) (BAMP), was synthesized through a condensation method and evaluated for its potential to adsorb Zirconium ions from aqueous solutions. The synthesized adsorbent underwent characterization using FTIR, BET, 1HNMR, 13 C-NMR, and GC-Mass analysis. Various operational parameters, including pH, ionic strength, equilibrium time, initial concentration, and temperature, were systematically investigated in batch mode. The highest sorption efficiency was achieved at pH 2, with a 90-minute contact time and a dose of 0.08, at room temperature. The adsorption of Zr(IV) ions onto the synthesized BAMP was best described by the Freundlich and Temkin isotherm models. The adsorption process for Zr(IV) ions was found to be spontaneous, as evidenced by the negative value of ΔG° calculated across all temperatures. The positive value of ΔH° indicated that the adsorption of Zr(IV) ions onto BAMP is an endothermic process, while the positive value of ΔS° suggested that the adsorption occurs randomly. The novel adsorbent exhibited remarkable adsorption capability, with a maximum adsorption capacity of 344.83 mg/g for Zr(IV) at ambient temperature. Adsorption kinetics data were well described by the pseudo-second-order equation, intra-particle diffusion rate, and Elovich models. Furthermore, successful recovery of Zr(IV) from zircon mineral concentrate samples from Jabal Tuwalah Intrusion, Medina Region, Saudi Arabia, served as a foundation for the production of nano-porous zirconium oxide using 1-propanol as a surfactant. The resulting white precipitate of nano-porous zirconium oxide underwent characterization using XRD, EDX, TGA, and TEM. [ABSTRACT FROM AUTHOR]

AbstractNatural polymers, such as polysaccharides and proteins, have been used to prepare several delivery systems owing to their abundance, bioactivity, and biodegradability. They are usually modified or combined with small molecules to form the delivery systems needed to meet different needs in food systems. This paper reviews the interactions of proteins, polysaccharides, and polyphenols in the bulk phase and discusses the design strategies, coupling techniques, and their applications as conjugates in emulsion delivery systems, including traditional, Pickering, multilayer, and high internal-phase emulsions. Furthermore, it explores the prospects of the application of conjugates in food preservation, food development, and nanocarrier development. Currently, there are seven methods for composite delivery systems including the Maillard reaction, carbodiimide cross-linking, alkali treatment, enzymatic cross-linking, free radical induction, genipin cross-linking, and Schiff base chemical cross-linking to prepare binary and ternary conjugates of proteins, polysaccharides, and polyphenols. To design an effective target complex and its delivery system, it is helpful to understand the physicochemical properties of these biomolecules and their interactions in the bulk phase. This review summarizes the knowledge on the interaction of biological complexes in the bulk phase, preparation methods, and the preparation of stable emulsion delivery system. [ABSTRACT FROM AUTHOR]

A new polymeric copper(II) complex [Cu3L3(μ3-NO3)]n·2nNO3, derived from the Schiff base ligand N'-(pyridin-2-ylmethylene)isonicotinohydrazide (HL) with copper nitrate in methanol, was prepared and characterized by elemental analysis, IR and UV-Vis spectra. The structure of the complex was further confirmed by single crystal X-ray diffraction technique. The Schiff base ligand coordinates to the Cu atoms through the phenolate O, imino O, and two pyridine N atoms. The Cu atom is in a square pyramidal coordination, with the three chelate donor atoms of the Schiff base ligand and the terminal nitrogen donor atom of a symmetry related Schiff base ligand defining the basal plane, and with one oxygen atom of the coordinated nitrate ligand at the apical position. The nitrate ligand bridges three [CuL] units with a crystallographic three fold rotation axis symmetry. The effect of the complex on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied. [ABSTRACT FROM AUTHOR]

In the current study, two new unsymmetrical liquid crystalline homologous series of dimers with a rigid biphenyl core were synthesised using an ether-linking group. Several spectroscopic methods, including FT-IR, 1H-NMR, 13C-NMR, elemental analysis and mass spectrometry, were used to describe the synthesized dimers. Differential scanning calorimetry (DSC) and polarised optical microscopy (POM) were used to assess their mesomorphic properties. The results showed that the number of methylene spacers significantly affected the thermal properties of the synthesized dimers. To ascertain photophysical behaviour, UV–Visible spectroscopy was employed. Nematic-type mesophase patterns with good mesophase range and thermal stability were seen in both series. Dimers with flexible spacers (n = 2, 4, 6) had the best liquid crystalline nature out of all the dimers. The relationships between structure and its mesogenic property, the effects of various flexible spacers, the mesophase ranges, and the photo-isomerization of liquid crystalline dimers were all investigated. DFT Studies were carried out to gain a better understanding of structural features. [ABSTRACT FROM AUTHOR]

A variety of di- and poly-nuclear zinc(II) complexes with salicylaldehyde-based azine ligands have been synthesized and their structures and properties have been reported. This review represents an overview on properties of these complexes. The synthesis and structures of the complexes are also discussed briefly. Only complexes are considered in this review whose X-ray structures are available. Different methods of synthesizing di- and poly-nuclear complexes are discussed. The structures of the complexes and magnetic properties are compared. The less explored areas of potential applications of these complexes are also highlighted. [ABSTRACT FROM AUTHOR]

Two aliphatic diamine-bridged ferrocene ligands (C2-Fe-Ligand and C6-Fe-Ligand) were synthesized with aliphatic diamine and formylferrocene, and the corresponding bimetallic active site complexes (Ni-C2-Fe, Co-C2-Fe, and Ni-C6-Fe) were prepared to catalyze ethylene oligomerization. The ligands and the corresponding complexes were characterized by FTIR, 1H NMR, TG, ESI-MS, XRD, and SEM. The SEM results of the ligands confirmed that the length of the bridged group had an influence on the morphology, and an increase in the carbon length led to irregular short rods to the irregular flakes with a large size. The bimetallic complexes catalyzed efficiently ethylene oligomerization with MAO as co-catalyst, and these complexes produced C4 and C6 olefins. Ni-C2-Fe showed higher activity of 6.31 × 104 g·(mol Ni·h)−1 in cyclohexane at Al/Ni molar ratio of 700, temperature of 25 °C, and pressure of 0.5 MPa. Compared with single active site catalysts, the bimetallic active site catalysts had a higher selectivity for C4 olefin because of the competitive insertion of ethylene between different active centers. The modification of the metal center tuned the catalytic performance of the complexes in ethylene oligomerization. [ABSTRACT FROM AUTHOR]

The intricate molecular architecture of ESIPT salicylaldehyde Schiff bases facilitates dynamic processes, inducing tunable photoluminescent properties. Notably, their halochromic nature, exhibiting colour changes in response to external stimuli, adds a vibrant dimension to their molecular repertoire. This sensitivity extends to environmental factors, making them valuable indicators for alterations in surroundings. The compound (E)-N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methylbenzohydrazide (PTBH) demonstrates exceptional sensitivity to ammonia, enabling real-time detection (LOD = 0.14 nM) in both solution (ratiometric) and the solid state. Moreover, their metal chelation capability allows simultaneous sensing of Mg2+ and Fe2+ ions, addressing environmental hazards. Exploiting molecular recognition, the fluorescent probe serves as sensors for amino acids, opening new avenues in biomedical diagnostics. The study introduces a novel solid-state emissive Schiff base, highlighting its stimuli-responsive photoluminescent properties and diverse applications, emphasising its potential in intelligent fluorescent materials for analytical and sensing technologies. [ABSTRACT FROM AUTHOR]

In this study, we report a newly synthesized Schiff base molecule named (E)-N-(2-chloropyridin-3-yl)-1-(5-nitro-2-(piperidin-1-yl)phenyl)methanimine. We also report its structural, chemical, surface, and electronic properties, potential targets, drug-likeness, ADME and toxicity profile, and docking studies for the main protease (Mpro) of SARS-CoV-2. The scope of this study includes the topological and electronic properties, intermolecular interactions, physicochemical and pharmacokinetic properties, metabolic pathways, toxicity endpoints, blood–brain barrier (BBB) permeability, and intestinal absorption activities. We performed the above analyses using bioinformatics/chemoinformatics tools and computational techniques. The topic crystal/compound (TC) contains two crystallographically independent molecules in the asymmetric unit (Z′ = 2). TC is open to attack by electrophilic and nucleophilic species and is a soft, chemically reactive, kinetically unstable material. There are no deviations from the known drug-likeness rules. BBB penetration and GI absorption of TC are possible. The docking values of the complex Mpro/TC and Mpro/native ligand N3 were calculated to be −8.10 and −7.11 kcal/mol, respectively. Therefore, we can say that TC is a potential Mpro inhibitor and can be investigated for further laboratory studies. [ABSTRACT FROM AUTHOR]

Abstract Two palladium Schiff base complexes supported on magnetic nanoparticles, namely, P,N-Pd-Fe3O4 and CPS-MNPs-NNN-Pd, were successfully used as efficient heterogeneous catalysts for the Suzuki coupling reaction under mild and green conditions. We compared the catalytic activity of these two catalysts and the results indicated that the CPS-MNPs-NNN-Pd catalyst promoted the reaction more efficiently due to its structure. Only 0.1 mol% of CPS-MNPs-NNN-Pd catalyst was required to promote the Suzuki reactions and these reactions were performed efficiently for aryl iodides, bromides, and also chlorides. Notably, this catalyst had higher TON and TOF numbers than most of the previously reported catalysts. Moreover, the catalyst could be easily separated from the reaction mixture under the outer or external magnetic field and reused at least for 4 times without appreciable loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

The present work reports the synthesis of two simple tailor-made anils (o-hydroxybezylidene-orthochloroaniline & o-hydroxynaphthalidene-orthochloroaniline) and their characterization by 1H & 13C Nuclear magnetic resonance(NMR), single X-ray diffraction spectroscopy(SC-XRD) and DFT studies. DFT-B3LYP optimized the molecular structures with a 6-311G (d, p) basis set to accomplish the global minimum energy state. 1H NMR confirmed the occurrence of H-bonding between the phenolic hydrogen and azomethine nitrogen in both molecules, further supported by SC-XRD analysis and DFT studies. The structural parameters such as bond angle, bond length, and dihedral angle derived from the optimized structure of molecules with C1 symmetry were compared with the corresponding parameters extracted from the ORTEP diagrams for both anils. Appreciable harmony of the structural parameters was achieved between these two analyses, confirming the anils' purity. Slight discrepancy observed between DFT and SC-XRD analyses was attributed to the difference in the state of the molecules. Geometric optimization indicated the molecules to be coplanar. The MEP surface and atomic charges on the atoms envisaged the electron population and charged sites of the anils. Conclusively, both the anils have a suitable structural hierarchy for superior electron transport from the phenyl rings over the entire molecular framework suitable for optoelectronics applications. [ABSTRACT FROM AUTHOR]

Nano-[Fe3O4@SiO2/N-propyl-1-(thiophen-2-yl)ethanimine][ZnCl2] as a nano magnetite Schiff base complex and reusable catalyst was successfully applied for the preparation of some pyrido[2,3-d]pyrimidines by the reaction of aryl aldehyde, malononitrile, and 6-amino-1,3-dimethyluracil with high yields and short reaction times. [ABSTRACT FROM AUTHOR]