Search

Schiff bases are organic compounds recognized for their biological activities, including antiviral, antibacterial, antifungal, and anticancer properties, making them promising candidates in medicinal chemistry. In this studio, a series of Schiff bases 3a–h derived from 4-aminoantipyrine and substituted cinnamaldehydes were evaluated in vitro against liver (HepG2) and thyroid (THJ29T) cancer cells, Gram-positive and Gram-negative multidrug-resistant bacteria, and biofilm-forming pathogens. Six compounds demonstrated anticancer activity, though some exhibited toxicity to non-tumor cells. Compounds 3b, 3f, and 3h showed notable anticancer potential, while 3f and 3h also exhibited strong antibacterial effects, with 3f being the most effective against multidrug-resistant bacteria strains. These Schiff bases also inhibit biofilm formation, suggesting their potential for treating biofilm-related infections. In-silico analyses of their ADME properties, global reactivity descriptors, and binding affinities corroborated these findings. The Schiff base 3f has a strong binding affinity for DNA gyrase and vitamin D receptor, suggesting potential mechanisms for its antibacterial and anticancer activities.Article Highlights: Six Schiff bases showed antiproliferative activity against tumor cell lines, with compound 3f being the most potent. Compounds 3h and 3b had higher therapeutic index values, with 3h demonstrating selectivity for tumor cells. Compounds 3f and 3h exhibit antibacterial activity against multidrug-resistant bacteria strains, with 3f being the most potent. [ABSTRACT FROM AUTHOR]

The structural and electronic behavior of thiosemicarbazone (TSC)-based metal complexes of Mn (II), Fe (II), and Ni (II) have been investigated. The synthesized metal complexes were characterized using elemental analysis, magnetic susceptibility, molar conductivity, FTIR, and UV–Vis spectroscopy, the computational path helped with further structural investigation. The solubility test on the TSC and its complexes revealed their solubility in most organic solvents. DFT computational analysis was performed, and quantum reactivity parameters of the octahedral optimized complexes were calculated to describe the reactivity via the stability states of the synthesized complexes. FMOs map was generated to confirm similar findings and MEP analysis was applied to elaborate the important electrophilic and nucleophilic sites on the studied surfaces. Also, other important topological analyses such as electron localization function and reduced density gradient, to establish the favorable noncovalent interactions, were studied. In silico molecular docking approach was studied against the gram-positive bacteria Bacillus cereus to predict the potent inhibition behavior of the studied complexes. The findings summarized the inhibition prediction of the most interactive [NiL2Cl2], then [FeL2Cl2] complexes as confirmed by the binding energy values (− 7.1 kacl/mol and − 6.4 kacl/mol, respectively). Another In silico results, with gram-positive bacteria (S. aureus), estimated similar results of the experimental finding, where [MnL2Cl2] (− 9.2 kcal/mol) is the more effective predicted antibacterial inhibitor. Fluorescence microscopy was used to examine the inhibition of bacterial biofilm, and the DPPH assay was used to measure antioxidant activity, followed by an understanding of the behavior of the current complexes toward free radicals' removal. The findings observed less aggregated bacterial strains covered with the studied complexes leading to less dense biofilm covering. [ABSTRACT FROM AUTHOR]

Nickel complexes are a potential candidate for antibacterial and antifungal activity. A new Ni (II) complex, bis(2-methoxy-6-{[(2-methylpropyl)imino]methyl}phenolato)nickel (II) (2), was synthesised by reacting, bis(3-methoxy-salicylaldehyde)nickel (II) (1) with isobutylamine. It was characterised by single crystal X-ray diffraction (ScXRD), UV-Vis, NMR, IR, mass spectrometry, and thermogravimetry (TG) to study its structure and physico-chemical properties. The ScXRD showed a square planar geometry, and monoclinic crystal system with a space group P21/n. The TG analysis revealed its thermal durability pre and post-melting up to 225 oC with a weight loss of only 2%. The optimized molecular structure, energy gap between HOMO and LUMO, and intermolecular interactions were studied by computational methods. The microbial activity evaluation showed significant anti-bacterial activity against E. coli and S. aureus when the concentration exceeded 40 µg/mL, and a prominent anti-fungal activity over C. albicans and C. tropicalis above 30 µg/mL. The values of minimum inhibitory concentration (MIC) for bacteria (MIB) and fungi (MIF) implied its potential to inhibit the growth of microbes. Docking studies revealed that the molecule binds well with proteins such as PDB: 2W9H for Dihydrofolate Reductase of S.aureus as shown by its binding energy of -8.62 kcal.mol− 1. [ABSTRACT FROM AUTHOR]

Context: Isatin-Schiff bases have wide applications in chemistry. The π conjugated electronic system and heterocylic structure of these materials make them valuable for use as photosensitized materials. The delocalization of π-electrons throughout the structure causes the UV–vis absorption spectra to shift to longer wavelengths. In this study, the isatin manganese carbonyl complex shifted the UV–vis absorption wavelength to a longer wavelength (vis. 400–700 nm) compared with our previous studies. The isatin derivatives (ISE (3[4-ethyl(phenyl)imino][indoline-2-one]), ISB (3[4-butly(phenyl)imino][indoline-2-one])) and their Mn carbonyl complexes MnISE ((ISE)Mn(CO)3), and, MnISB ((ISB)Mn(CO)3) were investigated via density functional theory (DFT) in different solvent media. The most stable complexes were found in medium polarity THF. The calculated HOMO–LUMO energy gap shows that the charge transfer occurs within the molecule. The HOMO–LUMO energy gap was increased with increasing solvent polarity for all investigated compounds. The smaller energy gap indicates that charge transfer occurs within the Mn(II) complex, in contrast to ISE and ISB, which exhibit larger energy gaps. As a result, the maximum absorption of Mn complexes shifts to the visible region. MnISB has the smallest HOMO–LUMO energy gap in THF. Additionally, the global reactivity parameters indicated that the MnISE complex has the highest electrophilicity index. DFT calculations have also been performed to investigate polarizability and first-order hyperpolarizability of these compounds. In water, the ISE had higher NLO values than the other structures did. These results indicate that all the studied molecules in different solvents could be good candidates for use in photosensitized and nonlinear optical materials. Methods: Geometries were determined at the DFT level via the LANL2DZ basis set for Mn and cc-PVTZ for other atoms in the molecules with the B3LYP functional. The UV–vis absorption spectra and HOMO–LUMO energies of ISE, ISB, and their Mn complexes were calculated by Time-dependent DFT (TDDFT) with CAM-B3LYP using the same basis sets. The UV–vis absorption spectra of ISE were also measured in acetonitrile and compared with the calculated spectra, which were consistent with the experimental results. All calculations were repeated in different solvents with the polarizable continuum model (PCM). [ABSTRACT FROM AUTHOR]

This study focuses on enhancing the thermal stability of Poly(vinyl chloride) (PVC) by introducing Schiff bases, aiming to mitigate thermal degradation. The investigation employs a comprehensive array of analysis techniques, including Fourier Transform Infrared Spectroscopy (FTIR), weight loss estimation, and microscopy (optical, scanning electron, and atomic force) to assess the impact of the modifications. Oven-aging tests reveal notable improvements in color stability for modified PVC films. Results consistently indicate a prolonged color change process in modified PVC, signifying enhanced thermal stability. The modifications demonstrate a remarkable ability to neutralize HCl and passivate labile chlorine atoms; this contributes to elevated thermal resistance and effective prevention of thermal degradation in PVC. This study marks a positive stride towards the development of more stable and reliable PVC materials, with implications for diverse applications demanding superior thermal performance. [ABSTRACT FROM AUTHOR]

The oxidation of 5-HMF to HMFCA is an important yet complex process, as it generates high-value chemical intermediates. Achieving this transformation efficiently requires the development of non-precious, highly active catalysts derived from renewable biomass sources. In this work, we introduce UoM-1 (UoM, University of Mazandaran), a novel cobalt-based metal-organic framework (Co-MOF) synthesized using a simple one-step ultrasonic irradiation method. The synthesis employed the ligand 4,4'-((1E,1'E)-((5-carboxy-1,3-phenylene)bis(azaneylylidene))bis (methaneylylidene))dibenzoic acid (H3bdda). A comprehensive suite of analytical techniques, including FT-IR, EDX, ICP, XRD, TEM, DLS, FESEM, and BET-BJH, was used to confirm the structural integrity of the synthesized material. The catalytic performance of UoM-1 was investigated for the selective conversion of HMF to HMFCA, demonstrating its effectiveness as a low-cost, accessible catalyst. To promote a more sustainable and environmentally friendly approach, the oxidation reactions were performed in deep eutectic solvents, which offer a green, low-energy alternative to traditional solvents. This study shows that the UoM-1 catalyst not only provides an economical solution but also aligns with modern green chemistry principles, making it a highly promising candidate for future catalytic applications. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

New cyclotriphosphazene derivatives featuring amide–Schiff base linkages with a hydrazine bridge and different terminal ends, such as decyl alkyl chains and hydroxy groups, were successfully synthesized and characterized. Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and CHN elemental analysis were used to characterize the structures of these compounds. The formation of hydrazine-bridged cyclotriphosphazene derivatives with amide–Schiff base linkages was confirmed by the FTIR spectra, showing a primary amine band for the amide linkage around ~3300 cm−1 and a band for the Schiff base linkage near ~1595 cm−1. This was further supported by NMR analysis, which displayed an amide proton (H-N-C=O) at ~δ 10.00 ppm and an azomethine proton (H-C=N) within the δ 8.40–8.70 ppm range. The 31P NMR spectra of cyclotriphosphazene compounds display a singlet at ~δ 8.20 ppm, indicating an upfield shift that suggests the complete substitution of all phosphorus atoms with identical side chains. Furthermore, CHN analysis verified the purity of the synthesized compounds, with a percentage error below 2%. The introduction of hydrazine bridges and amide–Schiff base linkages into the cyclotriphosphazene core significantly enriches the molecular structure with diverse functional groups. These modifications not only improve the compound's stability and reactivity, but also expand its potential for a wide range of applications. [ABSTRACT FROM AUTHOR]

Due to the promising characteristics of aminoguanidine Schiff bases, ongoing research focuses on synthesizing and characterizing different compounds of this class to establish structure–property relationships. However, the pronounced alkalinity of the aminoguanidine residue makes isolating its Schiff bases in neutral form challenging. In the reaction of salicylidene-aminoguanidine ([HL]NO3) with a strong base (NaOH), the partially neutralized product of the formula [HL]NO3∙L·H2O was obtained in the form of single crystals. This compound could be considered a cocrystal in which protonated and neutral forms of the Schiff base coexist. Furthermore, the coordinating properties of [HL]NO3 towards zinc and organotin were investigated, and instead of the expected crystals of complex compounds, a novel polymorph of the ligand was obtained. Additionally, the reaction of [HL]NO3, NH4VO3 and salicylaldehyde was carried out to achieve the condensation of the free NH2-group in the aminoguanidinium fragment, targeting a vanadium(V) complex with tetradentate ligand. However, a purely organic compound containing three salicylaldehyde residues and two imine groups, i.e., C21H18N2O3, was isolated. All the obtained compounds were characterized by elemental and spectroscopic analysis, conductometry and SC-XRD analysis. The data were compared to those of similar structures, and the results provide further insight into the properties of these compounds and their future investigation for potential usage. [ABSTRACT FROM AUTHOR]

A Schiff base, 2-((E)-((furan-2-yl)methylimino)methyl)benzofuran-3-ol has been synthesized and assessed using elemental analysis, infrared spectroscopy, nuclear magnetic resonance, mass spectroscopy and thermal analysis (TGA). The complexes' analytical results confirm the synthesis of a 1:2 [M:L] ratio of the formula [ML2], where M corresponds to the ions Cu(II), Ni(II), Zn(II), Mn(II) and L for the deprotonated Schiff base. Metal ions are bidentately coupled to Schiff base via azomethine-N and phenolic-oxygen groups, as inferred from infrared spectra. The disc diffusion technique has been used to test the ligands and their metal chelates for their antibacterial properties against specified microorganisms. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The basic nucleus S-(4-(((E)-benzylidene)amino)-5-phenyl-4H-1,2,4-triazol-3-yl) 2-((4-(((E)-benzylidene)amino)-5-phenyl-4H-1,2,4-triazol-3-yl)thio) ethanethioate T.4 produced with many steps, from the cyclization of T.2 with carbon disulfide/ potassium hydroxide using ethanol as a solvent followed by the addition of hydrazine hydrate for 12 hours while experiencing reflux. To create the Schiff base T.3, the successfully synthesized by reflux of T.2 with 1,4-dicarbaldehyde then react T.3 with chemical was exposed to condensation with chloroacetyl chloride. Physical characteristics, such as the melting point, and spectroscopic analysis were used to confirm the compounds (FT-IR) and (1H- NMR).The basic nucleus S-(4-(((E)-benzylidene)amino)-5-phenyl-4H-1,2,4-triazol-3-yl) 2-((4-(((E)-benzylidene)amino)-5-phenyl-4H-1,2,4-triazol-3-yl)thio) ethanethioate T.4 produced with many steps, from the cyclization of T.2 with carbon disulfide/ potassium hydroxide using ethanol as a solvent followed by the addition of hydrazine hydrate for 12 hours while experiencing reflux. To create the Schiff base T.3, the successfully synthesized by reflux of T.2 with 1,4-dicarbaldehyde then react T.3 with chemical was exposed to condensation with chloroacetyl chloride. Physical characteristics, such as the melting point, and spectroscopic analysis were used to confirm the compounds (FT-IR) and (1H- NMR).

Water contamination by hazardous heavy metal ions and organic compounds causes environmental damage towards aquatic species and human health. Thus the evolution of highly selective, affordable, rapid and effective analytical tools for the removal and detection of toxic heavy metal ions and organic compounds in aqueous environments is a challenging objective. Electrochemical detection of metal ions and organic compounds is a very useful and effective method, where modified electrodes with metal nanocomposite particles are used. Materials with high porosity, low-charge transfer resistance and large electroactive area are desirable for electrode modification in order to act as an efficient electrochemical sensor. It has been established that natural polysaccharide-based graft copolymers with acrylic monomers can be efficiently used as 'bio-template' for preparing mono and bimetallic/metal oxide composite nanoparticles for sensing and catalytic applications. This is because of the fact that polysaccharide-based graft copolymers are eco-friendly in nature and have the potential to act as reducing and stabilizing agents. The bio-template-based metal/metal oxide nanocomposites are successfully used for the electrochemical sensing of some heavy metal ions, like Hg2+, Cd2+, Th4+, Zn2+, Pb2+, etc., and toxic phenolic compounds, and also show efficient catalytic application in azo dye degradation and p-nitrophenol reduction. The developed electrochemical sensors are selective, sensitive and effective for the detection of toxic heavy metal ions in real water samples. Here we summarize the various investigations carried out using metal/metal oxide nanocomposite particles (mono and bimetallic) in electrochemical sensing of toxic heavy metal ions and catalytic applications. [ABSTRACT FROM AUTHOR]

Abstract Elevated Arsenic and Chromium levels in surface and ground waters are a significant health concern in several parts of the world. Chitosan quinoxaline Schiff base (CsQ) and cross-linked chitosan quinoxaline Schiff base (CsQG) were prepared to adsorb both Arsenate [As(V)] and Chromium [Cr(VI)] ions. The thermo-gravimetric analysis (TGA), X-ray diffraction analysis (XRD), and Fourier-transform infrared spectroscopy (FTIR) were used to investigate the prepared Schiff bases (CsQ) and (CsQG). The UV–VIS spectra showed a shift in the wavelength area of the modified polymer, indicating the reaction occurrence, besides the variation of the shape and intensity of the peaks. The XRD patterns showed the incensement of the amorphous characteristic. On the other hand, the thermal stability of the modified polymers is better according to TGA studies; also, the morphology of the modified chitosan was investigated before and after crosslinking (CsQ and CsQG) using a scanning electron microscope (SEM) where the surface was fall of wrinkles and pores, which then were decreased after cross-linking. Contact time, temperature, pH, and initial metal ion concentration were all studied as factors influencing metal ion uptake behavior. The Langmuir, Temkin, Dubinin–Radushkevich, and Freundlich isotherm models were used to describe the equilibrium data using metal concentrations of 10–1000 mg/L at pH = 7 and 1 g of adsorbent. The pseudo-first-order and pseudo-second-order kinetic parameters were evaluated. The experimental data revealed that the adsorption kinetics follow the mechanism of the pseudo-second-order equation with R2 values (0.9969, 0.9061) in case of using CsQ and R2 values (0.9989, 0.9999) in case of using CsQG, demonstrating chemical sorption is the rate-limiting step of the adsorption mechanism. Comparing the adsorption efficiency of the synthesized Schiff base and the cross-linked one, it was found that CsQ is a better adsorbent than CsQG in both cases of As(V) and Cr(VI) removal. This means that cross-linking doesn’t enhance the efficiency as expected, but on the contrary, in some cases, it decreases the removal. In addition, the newly modified chitosan polymers work better in As(V) removal than Cr(VI); the removal is 22.33% for Cr(VI) and 98.36% for As(V) using CsQ polymer, whereas using CsQG, the values are 6.20% and 91.75% respectively. On the other hand, the maximum adsorption capacity (Qm) for As(V) and Cr(VI) are 8.811 and 3.003 mg/g, respectively, using CsQ, while in the case of using CsQG, the Qm value reaches 31.95 mg/g for As(V), and 103.09 mg/g for Cr(VI).

Abstract As a springboard to explore novel potent inhibitors of cholinesterase enzymes (AChE and BChE) responsible for causing Alzheimer disorder, the current study was conducted to synthesize pyrrole derived triazole based Schiff base scaffolds by facile synthetic route. These compounds were validated by 1HNMR, 13CNMR and HREI-MS. All these scaffolds (1–16) were examined for their inhibitory activity against AChE and BChE in contrast to Donepezil (10.20 ± 0.10 and 10.80 ± 0.20 µM) and Allanzanthone (12.40 ± 0.10 and 13.10 ± 0.10 µM). All pyrrole derived triazole based Schiff base scaffolds (1–16) showed varied range of inhibitory potentials against acetylcholinesterase and butyrylcholinesterase enzymes with lowest inhibition concentration values ranging from 5.10 ± 0.40–27.10 ± 0.10 µM (for AChE) and 5.60 ± 0.30–28.40 ± 0.30 µM (for BChE). SAR analysis of these derivatives revealed analog 7 as lead molecule against targeted enzyme, while analog 6 and 11 were ranked as second and third most potent scaffolds. Binding affinity and selectivity of potent molecules against targeted enzymes were examined by molecular docking and obtained results showed that potent molecule have versatile significant binding interactions with stated enzymes. Furthermore, safety profiles of potent analogues were predicted via ADMET protocols. Graphical Abstract

The current research was conducted to assess the in silico and in vitro potential of the heterocyclic Schiff base compound (E)-1-(5-nitrothiophen-2-yl)-N-(2-(trifluoromethyl)phenyl)methanimine(N2TPM). This Schiff base was synthesized according to the reported method using ethanol as solvent, and the reaction was monitored on TLC till completion of the reaction. The compound structure was elucidated using spectroscopic techniques such as UV/Vis, FT-IR, 1H-NMR, and 13C-NMR. Molecular structure was determined using a single XRD, which revealed that the compound was triclinic. Analysis of intermolecular interactions in crystalline compounds was performed using Hirshfeld surface analysis and 2D fingerprint plots. The structure of the compound was optimized using the B3LYP hybrid functional with the basis set 6-31G(d,p). The compound’s theoretical and experimental parameters (bond length, bond angle, molecular orbital energies, electronic transitions, and vibration frequencies) were compared with each other which are in close agreement. R² values were found to be 0.9914 for bond lengths and 0.9859 for bond angles. In vitro, esterase potential of the synthesized compound was checked using a spectrophotometric model, while in silico molecular docking studies were performed with Auto-dock against two enzymes of the esterase family. The docking studies and in vitro assessment predicted that such molecules could be used as enzyme inhibitors against tested enzymes; acetylcholine esterase (AChE) and butyrylcholine esterase (BChE). the compound showed a binding score of -10.4159, a binding energy of -10.2743 with AChE, a binding score of -10.3378 and a binding energy of -9.8889 with BChE.

Five new lanthanide complexes based on azomethine (Schiff bases) ligands have been synthesized, including La, Nd, Er, Gd, and Dy. Complexes were synthesized using the azomethine Schiff bases resulting from condensation reactions between 4-aminoantipyrine and acetonylacetone. The structural characteristics of azomethine obtained are characterized quantitatively and qualitatively through various techniques, including elemental analyses, magnetic susceptibility measurement, molar conductivity, infrared, ultraviolet absorption, GC-mass, and 1H- and 13C-NMR spectroscopy studies. The structural characteristics of Ln+3 complexes indicate that the complexes possess a composition of a specific type. Based on the elemental analyses, magnetic susceptibility measurement, molar conductivity, and ultraviolet absorption spectroscopy data, it can be inferred that the central metal ion is surrounded by a coordination number of 10, the general formula of [Ln(L)2(NO3)]·nNO3nH2O. The physical measurements confirmed that the synthesized complexes exhibit non-electrolyte behavior and paramagnetic properties. The antibacterial activity of the compounds was assessed in vitro against 4 pathogenic strains: E. coli, S. aureus, K. pneumoniae, and S. mutans. The evaluation was conducted using the agar disc spreading method. The results demonstrated that certain complexes exhibited significant antibacterial efficacy in comparison to the biological activity of the ligand.

Abstract New azo Schiff base disperse dyes based on a chromene moiety were synthesized by reacting (2-amino-7-hydroxy-4-(4-methoxyphenyl)-4 H-chromene-3 carbonitrile) and(2-amino-4-(3,4-dimethoxyphenyl)-7-hydroxy-4 H-chromene-3-carbonitrile), with vanillin and ninhydrin, producing new chromene Schiff base derivatives, which in turn were coupled with 2-chloro-4-nitroaniline diazonium salt to give new 4 azo disperse dyes (1–4). The structures of the prepared dyes were confirmed using elemental analysis, 1HNMR spectroscopy, mass spectrometry, and IR. The synthesized dyes were applied to polyester and nylon fabrics using different dyeing techniques: high temperature- high pressure, and ultrasonic dyeing methods. The highest K/S values for all investigated dyes were achieved usinga high temperature-high pressure dyeing technique. Also, the color reflectance of all synthesized dyes with different dyeing shades (1%, 2%, and 3%) was obtained. The fastness properties of the dyed samples using the investigated dyes showed good color fastness toward light, washing, rubbing, and perspiration fastness. The presence of a chromene moiety and Schiff base in the investigated dyes promotes a higher antimicrobial activity on nylon and polyester fabrics against all tested bacteria (E. coli gram-negative and Staphylococcus aureus gram-positive) and two fungi, Aspergillus Niger and Candida albicans.

Abstract Solid supported catalysts have several synthetic applications. Herein, finely ground eggshells were used as a solid support for the preparation of transition metal (Ni, Zn, Cu, Sn and Co) based catalysts to synthesize 2,4-dinitrophenylhydrazone (3) and dihydropyrimidinones (7 and 8). The effect of catalyst load, time and temperature on product yield was studied. Box Behnken Model was employed, and three predictors named catalyst amount (A), reaction time (B), and reaction temperature (C) were used to find the correlation of the predictors with the yield. Second order polynomial equation was used to estimate the effects of these factors. According to the statistical model, about 12% increase in yield was observed as a result of one-unit increase in reaction time while all other terms were kept constant. The values of S (18.1616) and R2 (71.2%) indicate that the statistical model gave an adequate fit to data. Quadratic model for the response surface was used for the analysis of variance (ANOVA) results, the larger F-values, and smaller p-values indicated that the predictors are in good agreement. The linear model terms of predictors were found to be significantly effective for yield (P

As a springboard to explore novel potent inhibitors of cholinesterase enzymes (AChE and BChE) responsible for causing Alzheimer disorder, the current study was conducted to synthesize pyrrole derived triazole based Schiff base scaffolds by facile synthetic route. These compounds were validated by 1HNMR, 13CNMR and HREI-MS. All these scaffolds (1–16) were examined for their inhibitory activity against AChE and BChE in contrast to Donepezil (10.20 ± 0.10 and 10.80 ± 0.20 µM) and Allanzanthone (12.40 ± 0.10 and 13.10 ± 0.10 µM). All pyrrole derived triazole based Schiff base scaffolds (1–16) showed varied range of inhibitory potentials against acetylcholinesterase and butyrylcholinesterase enzymes with lowest inhibition concentration values ranging from 5.10 ± 0.40–27.10 ± 0.10 µM (for AChE) and 5.60 ± 0.30–28.40 ± 0.30 µM (for BChE). SAR analysis of these derivatives revealed analog 7 as lead molecule against targeted enzyme, while analog 6 and 11 were ranked as second and third most potent scaffolds. Binding affinity and selectivity of potent molecules against targeted enzymes were examined by molecular docking and obtained results showed that potent molecule have versatile significant binding interactions with stated enzymes. Furthermore, safety profiles of potent analogues were predicted via ADMET protocols. [ABSTRACT FROM AUTHOR]

Two new zinc(II) complexes, triethylammonium dichlorido[2-(4-nitrophenyl)-4- phenylquinolin-8-olato]zinc(II), (C6H16N) {Zn(C21H13N2O3) Cl2] (ZnOQ), and bis(triethylammonium) (2,2'-[1,4-phenylenebis(nitrilomethylidyne)]dipheno- lato}bis[dichloridozinc(II)], (C6H16N)2[Zn2(C20H14N2O2)Cl4] (ZnBS), were synthesized and their structures were determined using ESI-MS spectrometry, H NMR spectroscopy, and single-crystal X-ray diffraction. The results showed that the ligands 2-(4-nitrophenyl)-4-phenylquinolin-8-ol (HOQ) and N,N'-bis(2- hydroxybenzylidene) benzene-1,4-diamine (H2BS) were deprotonated by tri- ethyl-amine, forming the counter-ion Et3NH+, which interacts via an N-H...O hydrogen bond with the ligand. The ZnII atoms have a distorted trigonal- pyramidal (ZnOQ) and distorted tetrahedral (ZnBS) geometries with a coordination number of four, coordinating with the ligands via N and O atoms. The N atoms coordinating with ZnII correspond to the heterocyclic nitrogen for the HOQ ligand, while for the H2BS ligand, it is the nitrogen of the imine (CH=N). The crystal packing of ZnOQ is characterized by C-H...π inter- actions, while that of ZnBS by C-H...Cl interactions. The emission spectra showed that ZnBS complex exhibits green fluorescence in the solid state with a small band-gap energy, and the ZnOQ complex does exhibit non-fluorescence. [ABSTRACT FROM AUTHOR]

Schiff bases are organic compounds that are often used as ligands in metal complexes. In addition to the C=N double bond, which is characteristic of Schiff bases, intermolecular hydrogen bonds are frequently observed in both the twisting of planar substituents in organic compounds and the geometric structure of the coordination environment in metal complexes. The results of the crystal structure analyses are stored in databases, which can be used to assess three-dimensional structures. To examine the important structural aspects for novel molecular and material designs, this review examines the important discussion of crystal structure "features" from various viewpoints based on papers on Schiff bases and Schiff base metal complexes from recent years. [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]

Schiff base reactions are widely used in pharmacy, catalysis, and volatile aldehyde detection. However, common biomarker sensing methods struggle to monitor this reaction process precisely due to their sensitivity, their time-consuming nature, and complex substrates. Here, we introduce the Nanoparticle-on-Mirror structure for in situ monitoring this reaction process through the application of a Au nanoparticle-p-Aminothiophenol-Au thin-film platform by surface-enhanced Raman scattering (SERS). Owing to the exposure of -NH2 groups and the local ultra-strong electromagnetic field in the nanocavity, the Schiff base reactions process can be rapidly monitored within two minutes. Meanwhile, the monitoring platform can detect benzaldehyde molecules as low as 10−6 M, showing excellent SERS performance. Notably, the Au-nanoparticle-p-Aminothiophenol-Au thin-film platform exhibited anti-interference and specificity, being able to identify BA in the presence of interference. The use of the Au-nanoparticle-p-Aminothiophenol-Au thin-film platform provides a sensing method for Schiff base reactions with accuracy and simplicity of operation, achieving a balanced approach for low-cost and high-performance real-time monitoring, which is expected to be applied in various catalytic reaction process monitoring and catalyst design processes. [ABSTRACT FROM AUTHOR]

Purpose: The in vivo and in vitro antitumor activities of hydroxyurea derivative Schiff bases (SBs) metal complexes were investigated in immortalized human colon cancer cell lines (HT-29 cells) and rat models. Methods: For the in vitro studies, three concentrations (5, 10, and 20 μM) of the 1-hydroxy-3-(E)-pyridine-3-ylmethylidene urea derivative SB (L)-metal complexes (L-Cd, L-Cu, L-Zn) were used to determine the viability of HT-29 cell line with dimethylsulphoxide (DMSO) as control. On the other hand, colorectal cancer was induced with subcutaneous administration of azoxymethane (AOM; 15 mg/kg) in 35 Wistar albino rats, which were assigned to five treatment groups consisting of DMSO (negative control), cisplatin (15 mg/kg, positive control), AOM + L-Cd (25 mg/kg), AOM + L-Cu (25 mg/kg) and AOM + L-Zn (25 mg/kg) groups, respectively. Tumor formation was observed by macroscopic and microscopic examinations. Results: Tumour formation was not observed in the positive control group. The rats treated with AOM (excluding L-Cu and cisplatin group) displayed severe dysplasia and adenocarcinoma formations in the oil+DMSO, L-Cd and L-Zn groups. When compared with the cisplatin group in the in vivo studies, the Cu complex had a more favorable effect against colon cancer. Conclusion: Consequently, hydroxyurea derivative SB-metal complexes exhibit antiproliferative activity in both in vitro (p < 0.0001) and in vivo studies. [ABSTRACT FROM AUTHOR]

A procedure based on dispersive liquid-liquid microextraction (DLLME) for cadmium (Cd) quantification in an Iraqi environmental matrix by flame atomic absorption spectroscopy (FAAS) was applied in this work. A case study approach was chosen to obtain further in-depth information on the Cd levels and to evaluate the effectiveness of N-salicylideneaniline (SAN) as a complexing agent for preconcentration and extraction of Cd. Univariate strategy was utilized for achieving the optimum extraction conditions: 75.0 μL of carbon tetrachloride as the extraction solvent, 10 mL of a sample solution adjusted the pH at 8.50 containing 0.8% (w/v) SAN, and 1400 μL of methanol as the dispersive solvent, within 30 s complexation time. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 0.26 and 0.87 μg/L, respectively. Enrichment factors were obtained in two manners, found to be 24.4 and 44.3. To evaluate the accuracy of the method, known amounts of analytes were spiked and compared with the results achieved using microwave digestion/graphite furnace atomic absorption spectrometer (MWD/GF-AAS) for solid samples, and direct graphite furnace atomic absorption spectrometer (GF-AAS) for water samples. Procedure was applied for analyzing eight environmental samples, the Cd levels for water samples ranged from 3.01 to 7.33 μg/L with a relative standard deviation (4.1–10.4 RSD%), while the concentration for the solid sample (Mentha piperita) was 2.71 μg/g (RSD% = 7.4). DLLME/FAAS proposed procedure is eff ective, simple, and has the benefi t of minimizing the organic solvent consumption, by a few microliters, which results in little waste. [ABSTRACT FROM AUTHOR]

The objective of this paper was to synthesize and characterize cobalt (II) complexes of 2-{[(2 hydroxy-5-nitrophenyl)methylidene]amino} nicotinic acid derived from o-phenylenediamine and 5- nitrosalicaldehyde using FTIR, 1HNMR, 13CNMR, GCMS and screened to establish their potential as antimicrobial agents, compared with standards Ampiclox for bacteria and ketoconazole for fungal infections. Antimicrobial activity screening of the Schiff base exhibited biological activity virtually against all forms of bacteria andfungi isolates with the B. subtilis and E coli having same minimum inhibition concentrations of 1.8mm each and with the exception of Candidas albicans which exhibited zero diameter zone of inhibition. In this study, it was found that the synthesized Schiff bases exhibited two digits purity range, implying that they were relatively stable. Furthermore, the in silico molecular docking analysis of the Scihff bases is incorporated to predict their binding affinity to established molecular targets in C. albicans, S. aureus, and E. coli. The findings posited that the binding affinity of the Schiff base (9.3 kJ mol-1) is better than that of both the complex (9.0 kJ mol-1) and even the standard drugs (7.6 and 7.9 kJ mol-1) respectively. This lends credence to the Schiff Base as a better pharmaceutical than the present drug in usage, hence the need to harness them for daily use by pharmacies. [ABSTRACT FROM AUTHOR]