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Among the various Schiff bases, those containing 2,4-diaminotoluene as a primary amine and 2-hydroxy-4-methoxybenzaldehyde as a carbonyl compound are new and deserve special attention because their logical spectral properties find application in analytical chemistry as a smart probe. The new Schiff base has been synthesized to its pure crystalline form. It is characterized by single-crystal XRD, FT-IR, NMR, TGA, and mass spectrometry. We have studied the spectral properties of the Schiff base and its aluminium adduct by UV-vis and fluorescence spectroscopy and rationalized them by computational analysis. The Job's plot and mass spectrometry indicate the 1:1 binding ratio between the ligand and the Al3+ ion. The suitable binding constant value (8.329×103 M–1) leads to the development of Al3+ sensation by the Schiff base. The sensor has an appreciably low limit of detection value of 7.638×10–9(M), i.e., 0.00163 ppm for Al3+. The logical behaviour of the probe (NAND-type molecular logic gate with two inputs, Al3+ and EDTA) leads to the development of a renewable aluminium testing kit. [ABSTRACT FROM AUTHOR]

Herein, a newly synthesized intermediate, piperazine-based Schiff base (PBSB) gas sensor was fabricated by the Schiff base condensation of amino functionalized methylpiperazine with aromatic aldehyde containing nitro substituent. This organic sensor material was structurally identified with spectroscopic techniques such as FTIR, HRMS, 1H- and 13C-NMR. The designed sensor candidate was explored for its optical response to chlorinated volatile organic compounds, namely trichloroethylene, dichloromethane and chloroform in the light of structure–property relationship investigation by using surface plasmon resonance (SPR) technique. The results showed that Schiff bases could be candidates for chlorinated vapour sensing materials with their good response and reversibility. Concordantly, compound PBSB exhibited good response against chlorinated solvent vapours aided by the electron-withdrawing group on benzene ring that promoted better intermolecular interactions and opened up a new strategy to create a novel set of responsive materials for gas sensing applications. In addition, the adsorption kinetics of SPR data obtained from PBSB spun film on exposure to these chlorinated vapours at different concentrations was also evaluated using the Elovich Model. The values of the initial adsorption rate, a and Elovich constant, b were analysed depending on the concentration values and the highest values were obtained for dichloromethane between 372.92 and 4377.53 ppm/mm2. [ABSTRACT FROM AUTHOR]

In the present work, 2‐hydroxy‐1‐naphthaldhyde and 2‐hydrazino‐N‐phenyl‐2‐thioxo‐acetamide are combined to create a new Schiff base. The novel ligand and its six new binuclear complexes with Ni(II), Cu(II), Ag(I), Zn(II), Cd(II), and La(III) are characterized via spectroscopic and analytical techniques, such as ultraviolet‐visible (UV–vis), infrared (IR), 1H NMR, 13C NMR, mass spectra, powder X‐ray diffraction (XRD), and thermogravimetric (TG) analysis. The spectral analysis indicated that the novel Schiff base may coordinate with the two metal ions. Additionally, the results indicated a square planar geometry for NiL, CuL, and AgL complexes and an octahedral geometry for ZnL, CdL, and LaL complexes. In contrast to the Schiff base ligand, different complex crystallinities were displayed in the powder XRD patterns. Significant thermodynamic parameter values were computed using the Coats–Redfern method which revealed high thermal stabilities of the complexes in the TG analysis. In vitro antibacterial, DNA‐binding, and anti‐inflammatory techniques were used for the biological evaluation. Moreover, to visualize the anti‐inflammatory action of complexes employing the cyclooxygenase enzyme receptor (PDB ID: 6COX), in silico docking was used. The serial dilution method evaluated the new compounds' in vitro antibacterial efficacy against three bacterial and one fungal strain. The results showed that the novel complexes showed remarkable efficiency against the bacterial growth of gram (+ve) Staphylococcus aureus compared to the parent ligand and the control. On the other hand, the ZnL, CdL, and AgL complexes showed excellent bactericidal activity. The inhibition of protein denaturation followed the following sequence: Ibuprofen > ZnL ˃ NiL ˃ AgL ˃ CuL > CdL > LaL > H2L. UV–visible and gel electrophoresis methods were used to examine the metal complexes and their ligand's affinity for binding DNA. An intercalative binding mechanism was suggested by the findings. [ABSTRACT FROM AUTHOR]

A novel and cost-effective 2,4-dinitrophenyl hydrazine derived from Schiff base 1-benzylidine-2-(2,4-dinitrophenyl) hydrazine (L) was designed and characterized using various spectroscopic techniques. The interaction between L and bovine serum albumin (BSA) has been carried out using UV–Vis and fluorescence spectroscopy, DSC, SEM, and molecular docking methods. The phosphate buffer (pH = 7. 4) solution of BSA showed fluorescence emission maxima at 342 nm. Upon addition of L to the BSA solution, it quenched the fluorescence emission at 342 nm. The quenching of the fluorescence emission is due to the formation of a complex between L and BSA. The binding constant was calculated from the fluorescence titrations and found to be 6. 7 4 5 × 1 0 6 M − 1 . Further, molecular docking analysis was carried out to establish the binding between L and BSA. [ABSTRACT FROM AUTHOR]

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BACKGROUND: To investigate the recovery of molybdate from water and hydrodesulfurization catalysts, a novel synthesized phosphonate Schiff base, 4,4′‐(((2,2‐dimethylpropane‐1,3‐diyl) bis(azaneylylidene)) bis(methaneylylidene)) bis(2‐methoxyphenol) (HMI) and 4‐(((3‐((4‐(((S)‐hydroxyhydrophosphoryl)oxy)‐3‐methoxybenzylidene) amino)‐2,2‐dimethylpropyl)imino)methyl)‐2‐methoxyphenyl hydrogen phosphonate (HIMP), was utilized. This study aimed to assess the structural and property aspects of this synthesized compound using diverse characterizations, including FTIR, Thermogravimetric Analysis (TGA), mass spectrometry (GC–MS), fluorescence transfer spectra, scanning electron microscopy (SEM), and 1H‐NMR, 13C‐NMR, and 31P‐NMR. RESULTS: The study systematically examined several factors controlling molybdate recovery, including temperature, adsorbent dosage, pH, interaction time, and molybdate concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 2, with an interaction time of 40 min, a 0.06 g adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (Qe) of 372.54 mg of Mo per gram, with empirical data fitting the Langmuir and D‐R adsorption models. The kinetics of molybdate uptake followed second‐order kinetics. Thermodynamic aspects, including ΔG°, ΔS°, and ΔH°, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Additionally, molybdate adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified phosphonate Schiff base for molybdate removal. CONCLUSION: The study underscores the potential of the modified phosphonate Schiff base as a crucial adsorbent for molybdate elimination from both solutions and spent hydrodesulfurization catalysts. The findings offer important insights into the adsorption kinetics, thermodynamics, and selectivity of the adsorbent, enhancing our understanding of molybdate recovery processes and their broader applications. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

ABSTRACT Novel selenated azomethine ligand (MSeOH) and its Zn(II), Fe(II), and Cu(II) chelates were synthesized. Their chemical structures were confirmed by molar conductivity, thermal analysis, X‐ray diffraction, IR, NMR, and MS spectroscopic techniques. The antitumor and antimicrobial properties were evaluated against various mammalian cells and pathogenic strains. Furthermore, the antioxidant activities were also assessed using DPPH and SOD bioassays. To gain a deeper understanding of the molecular structure and electronic properties of these complexes, a density functional theory (DFT) study was conducted. The parameters examined in this study provide valuable insight into the bonding, electronic properties, reactivity, and polarity of the compounds under investigation. The biological and theoretical results point to promising activities of the selenated ligand and its complexes. [ABSTRACT FROM AUTHOR]

Twenty-two eco-friendly, novel Schiff bases were synthesized from 2,4,5-trichloro aniline and characterized by using FT-IR, 1H NMR, and 13C NMR techniques. Fungicidal activity against pathogenic fungi Sclerotium rolfsii and Rhizoctonia bataticola and insecticidal activity against the stored grain insect pest Callosobruchus maculatus of the test compounds were evaluated under control condition. All of the investigated compounds, according to the study, exhibited moderate to good antifungal and insecticidal activities. The best antifungal activity against both pathogenic fungi was demonstrated by C15 and C16 whose ED50 values were recorded 11.4 and 10.4 μg/mL against R. bataticola and 10.6 and 11.9 μg/mL against S. rolfsii, respectively. They were further screened in for disease suppression against both pathogenic fungi under pot condition through different methods of applications in green gram (Vigna radiata L.) crop. The compounds C10 and C18 had the highest insecticidal activity, with LD50 values of 0.024 and 0.042 percentages, respectively. Stepwise regression analysis using root mean square error (RMSE) and correlation coefficient (R) method used to validate the quantitative structure activity relationship (QSAR) of synthesized compounds in addition to their fungicidal and insecticidal actions. To the best of our knowledge, this investigation on the 22 new Schiff bases as possible agrochemicals is the first one that has been fully reported. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) nanosheets were functionalized with Schiff base and reduced Schiff base. Covalent and non-covalent functionalized GO nanostructures have been tested for the removal of pesticides with different chemical structures and properties (e.g., Epoxiconazole, Dimethomorph, Cyprodinil, Chlorothalonil, Acetochlor, Trifluralin) from aqueous solutions. The structure and morphology characteristics of the prepared structures were analyzed using techniques such as solid-state nuclear magnetic resonance (SSNMR), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Results of the experiments showed that, although the non-covalent functionalization did not affect the adsorption properties of GO much, the covalent functionalization increased the adsorption capacity of GO against the mentioned pesticides. [ABSTRACT FROM AUTHOR]

Chemotherapy plays a role in many cancer therapies, including breast cancer, but due to its significant side effects, alternate treatment approaches have been investigated. One such alternative is photodynamic therapy (PDT), which employs a combination of oxygen, a photosensitizer (PS), and light of a specific wavelength. Transition metal complexes and SBL have gained interest in PDT. In this study aimed to assess the potential antitumor activity and underlying mechanism of a newly synthesized Schiff base ligand (SBL)-mediated PDT on MCF-7 cells, comparing its efficacy to cisplatin. We synthesized and characterized two novel Pd-conjugated SBL compounds (complex-1 and 2). Following the treatment of MCF-7 cells with these compounds, a light-emitting diode (LED) was utilized to deliver a light dose of 14.8 J/cm2. In MCF-7 cells, we also looked at cytotoxicity, cell death rates, and ROS levels. Results indicated a significant increase in cytotoxicity (IC50:12.5 µM) (p < 0.05) and ROS levels (258.33%) (p < 0.05) in the group treated with complex-1-mediated PDT compared to control. The late apoptotic (29.78%) (p < 0.05) and necrotic (24.23%) (p < 0.05) cell death also increased significantly compared to the control group (1.86 ± 0.92, 1.89 ± 0.32, respectively). In conclusion, our study suggests that the complex-1 compound may serve as a promising candidate for anticancer agents in PDT for MCF-7 cells. In contrast, complex-2-mediated PDT did not demonstrate any observable anticancer activity. [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]

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]

Schiff bases are compounds that are widely distributed in nature and have practical value for industry and biomedicine. Another important use of Schiff bases is identifying metal ions and different molecules, including proteins. Their proneness to hydrolysis limits the utilization of Schiff bases to mainly non-aqueous solutions. However, by introducing –OH and –SH substituents to aromatic amine-bearing rings, it is possible to increase the resilience of the Schiff base to destruction in water. The present paper discusses how the hydroxyl or thiol group influences the spectral properties and kinetics of the hydrolysis and formation of Schiff bases derived from pyridoxal 5′-phosphate and aniline, 2-hydroxyaniline, and 2-mercaptoaniline using quantum chemical data. The spectral variation between different imines can be explained by taking into account the geometry and frontier molecular orbital alteration induced by the substituents. The changes in the hydrolysis rate are analyzed using the computed values of local reactivity indices. [ABSTRACT FROM AUTHOR]

Triphenylamine (TPA)‐based Schiff base chemosensors ((E)‐2‐((4‐(diphenylamino)benzylidene)amino)phenol [TPA‐AP], (E)‐5‐(diphenylamino)‐2‐(((2‐hydroxyphenyl)imino)methyl)phenol [HTPA‐AP], and (E)‐5‐(diphenylamino)‐2‐((phenylimino)methyl)phenol [HTPA‐A]) were synthesized and explored the role of metal chelating hydroxyl functionality position for heavy metal ion sensing. TPA‐AP and HTPA‐AP showed Cu2+ ion‐induced chemical transformation and produced oxazole derivatives with turn‐on fluorescence. In contrast, HTPA‐A exhibited metal chelation‐induced turn‐on fluorescence for Zn2+ ion. The reactive chemical sensing of TPA‐AP and HTPA‐AP led to high selectivity of Cu2+, and other ions did not show any interference. The concentration‐dependent studies of Cu2+ and Zn2+ indicated the limit of detection (LOD) up to 6.07 × 10−7 and 4.6 × 10−7 M, respectively. Further, Cr3+, Fe3+, and Fe2+ coordination with TPA‐AP and HTPA‐AP exhibited visible color change from colorless to yellow. However, the yellow color was disappeared and becomes colorless due to imine hydrolysis. Interestingly, all three metal ions showed different rate of hydrolysis and color disappearance. TPA‐AP with Fe3+ exhibited fast hydrolysis and immediate color change whereas Fe2+ and Cr3+ required longer time. But HTPA‐AP and HTPA‐A produced stable complexes with Cr3+, Fe2+, and Sn2+ and Fe3+ alone showed hydrolysis. Thus, the present studies provide structural insight for designing reactive fluorescence and colorimetric Schiff base chemosensor for heavy metal ions. [ABSTRACT FROM AUTHOR]

Due to their notable antimicrobial activity and optical properties, Schiff base ligands, along with their lanthanide and transition metal complexes, have seen extensive use in various applications. However, despite their potential, a comprehensive investigation into lanthanide and transition metal complexes using the same Schiff base ligand has not been reported to date. In this study, coordination compounds of lanthanide and transition metal ions were synthesized from the Schiff base ligand salicylaldehyde‐dipropylenetriamine. These complexes were characterized by elemental analysis, 1H and 13C NMR, mass spectroscopy, Fourier‐transform infrared spectroscopy ultraviolet–visible spectroscopy (UV–Vis), fluorescence spectroscopy, molar conductivity measurements, and thermogravimetric studies. Furthermore, the molecular structure of the Co (II) complex was determined by means of X‐ray crystallography. Thermogravimetric studies illustrated endothermic and non‐spontaneous degradation pathways of the complexes. UV–Vis spectra showed a new absorption band attributed to the ligand‐to‐metal charge transfer peak supporting the complexation between the ligand and metals. The lanthanide complexes exhibited distinctive luminescence emissions in the Sm (III), Tb (III), and Eu (III) complexes. This observation suggests that the ligand possesses the capability to absorb and efficiently transfer energy to the metal center of these lanthanide ions, thereby resulting in their characteristic luminescent properties. Additionally, antimicrobial investigations revealed that transition metal complexes generally exhibited antimicrobial activity against both gram‐positive and gram‐negative bacterial strains compared to lanthanide metal complexes, in most cases. However, it is noteworthy that the Dy (III) complex displayed the lowest minimum inhibitory concentration and minimum biocidal concentration values of 16 μg/ml against Staphylococcus epidermidis, indicating its potential as a candidate for the treatment of this pathogenic bacterium. The main purpose of this article is to investigate the variations in the synthesis and characterization of lanthanide and transition metal complexes utilizing the same Schiff base ligand suitable for applications in the pharmaceutical industry and optical material sciences. [ABSTRACT FROM AUTHOR]

The new Schiff base ligand was designed from a condensation reaction of isatin with 5‐amino‐2‐hydroxy benzoic acid. Then, the metal complexes were prepared. The structures of the prepared compounds were framed from thermogravimetric analyses (TG–DTG), mass spectrometry, elemental analyses, 1H‐NMR, IR, electronic spectra, UV–vis, and conductivity measurements. Surface and size morphology have been studied by X‐ray powder diffraction and scanning electron microscope (SEM) analysis. The IR spectra suggested that the ligand acted as bidentate coordinated with metal ions through deprotonated carboxylate oxygen atom and oxygen of phenolic group. With the exception of the complexes of Cr (III), Fe (III), and Cd (II), which were non‐electrolytes, the molar conductivities demonstrated the electrolytic behavior of all the rest complexes. The X‐ray diffraction (XRD) analysis patterns for the Schiff base complexes indicated their crystalline nature except the Co (II) complex which had amorphous structure. The ligand and its metal complexes were screened for their antimicrobial activities against two G‐positive, two G‐negative bacteria and against Aspergillus fumigatus and Candida albicans fungi. Additionally, the compounds were evaluated against the MFC‐7 breast cancer cell line for their anticancer activity. The outcomes demonstrated their strong antitumor activity. [Fe(HL)Cl2(H2O)2]0.5H2O complex has the lowest IC50 value = 9 μg mL−1. Molecular modeling studies for the ligand and its Co (II) and Fe (III) complexes were accomplished from density functional theory (DFT) analysis. From molecular docking study, the electrophilic moieties in both complexes displayed good binding interactions with the CDK6, aminoglycoside phosphotransferase, and CYP51 targeted proteins. [ABSTRACT FROM AUTHOR]

Katiragum dialdehyde‐tryptophan Schiff base (KGDT) is developed for selective and efficient detection of Cd2+ ion and hydroquinone (HQ) in the aqueous medium by electrochemical method. KGDT is synthesized by selectively oxidizing the C2‐C3 bond of katiragum with sodium meta periodate (NaIO4) to obtain katiragum dialdehyde (KGD), followed by condensation between KGD and an α‐amino acid (L)‐tryptophan. KGD and KGDT are characterized by 1HNMR, HRMS, and FESEM with EDAX analysis. The electrochemical experiment is carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The electrochemical sensing toward the Cd2+ ion in the DPV method is found to be better compared to the CV method. In the CV method, the limit of detection (LOD) values of Cd2+ ion and HQ are calculated as 8.84 nm and 15.91 nm, respectively. In the DPV method, the LOD values of Cd2+ ion and HQ are found to be 7.24 nm and 15.29 nm, respectively. The proposed sensor, KGDT/GCE, shows satisfactory results in the stability and reproducibility test and also shows excellent practical applicability in real sample analysis. [ABSTRACT FROM AUTHOR]

For synthesizing metal–organic molecules with pro‐drug properties to prevent the accumulation of amyloid beta (Aβ1–42), which is a feature of neurodegenerative Alzheimer's disease, two new Schiff bases with imine/amine donors 2‐([3,3‐diphenylalidene]amino)‐N,N‐dimethylethane‐1‐amine and N,N‐dimethyl‐2‐([quinolin‐4‐ylmethylene]amino)ethane‐1‐amine, as well as their novel Pt (II) complexes (I and II), were synthesized and characterized via Fourier transform infrared spectroscopy, 1H‐ and 13C‐nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and elemental analyses. The spectroscopic data has shown that the ligands are coordinated to the central atom in a chelating manner. Furthermore, the interaction between these complexes and Aβ1–42 was investigated using the electrochemical methods, square wave voltammetry and pencil graphite electrode, while monitoring the changes in the oxidation signal of the Try residue in Aβ1–42. The ability of the compounds to inhibit Aβ1–42 aggregation was investigated using the human neuroblastoma cell line (SH‐SY5Y). Complex II could actively inhibit the aggregation of Aβ1–42 at a molar ratio of 1.0/1.0, and its Aβ1–42 aggregation kinetics were fluorometrically determined using thioflavin T. These results were supported by scanning electron microscopy and transmission electron microscopy analyses. Moreover, the interaction of complex II with Aβ1–16 was investigated via 1H‐NMR spectroscopy. As a result, it was observed that complex II was effective in inhibiting the aggregation of Aβ1–42 at a molar ratio of 1.0/1.0. This result shows that studies can be conducted on the effects of Schiff base‐Pt complexes as potential pro‐drugs on Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Objective: This research aims to synthesize and characterize a new series of bioactive quinazoline derivatives, including Schiff bases, biquinazolinone, and benzothiazine, and to evaluate their bioactivity as antioxidants through both in silico and in vitro investigations. Methods: The new derivatives were synthesized with high yields by reacting Schiff base derivatives of quinazoline with 2-aminobenzoic acid and 2-mercaptobenzoic acid. The characterization of the prepared derivatives was carried out using FTIR, 1H NMR, and 13C NMR techniques. In silico investigations included assessing pharmacokinetic and pharmacodynamic properties through the SwissADME online server and conducting molecular docking studies with the tyrosinase enzyme. In vitro assessments involved evaluating antioxidant activity using the total antioxidant capacity method and the DPPH scavenging activity method. Results and Discussion: In silico analysis revealed favorable pharmacokinetic and pharmacodynamic properties for all compounds. Compounds (III) and (IV) exhibited acceptable pharmacological characteristics. Molecular docking studies showed good docking scores for all compounds with the tyrosinase enzyme. In vitro assessments demonstrated noteworthy to excellent antioxidant activity for all compounds, with compounds (III) and (IV) exhibiting very strong activity compared to the standard reference, ascorbic acid. Conclusions: The synthesized quinazoline derivatives exhibit promising bioactivity as antioxidants, supported by both computational and experimental assessments. These findings suggest their potential for further exploration in the development of antioxidant agents, with particular emphasis on the notable performance of compounds (III) and (IV). [ABSTRACT FROM AUTHOR]

A new bidentate Schiff base ligand (C16H16Cl2N4), condensation product of ethylene diamine and 4-chloro N-phenyl formamide, and its metal complexes [M(C16H16Cl2N4)2(OAc)2] (where M = Mn(II) and Zn(II)) were synthesized and characterized using various analytical and spectral techniques, including high-resolution mass spectrometry (HRMS), elemental analysis, ultraviolet-visible (UV-vis), Fourier-transform infrared (FTIR) spectroscopy, AAS, molar conductance, 1H NMR, and powder XRD. All the compounds were non-electrolytes and nanocrystalline. The synthesized compounds were assessed for antioxidant potential by DPPH radical scavenging and FRAP assay, with BHT serving as the positive control. Inhibitory concentration at 50% inhibition (IC50) values were calculated and used for comparative analysis. Furthermore, the prepared compounds were screened for antibacterial activity against two Gram-negative bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-positive bacteria (Escherichia coli and Salmonella typhi) using disk-diffusion methods, with amikacin employed as the standard reference. The comparison of inhibition zones revealed that the complexes showed better antibacterial activity than the ligand. To gain insights into the molecular interactions underlying the antibacterial activity, the ligand and complexes were analyzed for their binding affinity with S. aureus tyrosyl-tRNA synthetase (PDB ID: 1JIL) and S. typhi cell membrane protein OmpF complex (PDB ID: 4KR4). These analyses revealed robust interactions, validating the observed antibacterial effects against the tested bacterial strains. [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]

A new one‐dimensional thiocyanate‐bridged cobalt(III) Schiff base complex, namely, catena‐poly[[[4‐bromo‐2‐((Z)‐{[2‐(thiophen‐2‐yl)ethyl]imino}methyl)phenolato‐κ2N,O]cobalt(III)]‐μ‐thiocyanato‐κ2N:S], [Co(SCN)(C13H11BrNOS)2]n or [Co(μ1,3‐SCN)L2]n (1), where HL is 4‐bromo‐2‐((Z)‐{[2‐(thiophene‐2‐yl)ethyl]imino}methyl)phenol, a bidentate Schiff base prepared from the condensation reaction of 5‐bromosalicylaldehyde and 2‐(thiophen‐2‐yl)ethylamine, has been synthesized by stirring Co(ClO4)2·6H2O, the Schiff base HL and ammonium thiocyanate (in a 1:2:1 molar ratio) in ethanol medium. The complex was characterized by FT–IR, electronic spectra and single‐crystal X‐ray diffraction (SC‐XRD) studies. The SC‐XRD data suggest that the compound crystallizes in the orthorhombic space group Pca21. The CoIII ion in 1 adopts a distorted octahedral geometry, the metal sites being six‐coordinated by one thiocyanate N atom and one thiocyanate S atom in apical positions, and by two imine N atoms and two phenolate O atoms from two anionic L− ligands which form the basal plane. The thiocyanate ligand acts as a μ‐1,3 bridge, joining neighbouring CoIII atoms and forming a uniform zigzag one‐dimensional polymeric chain. The crystallographic data were also used in the Hirshfeld surface (HS) analysis, which aimed to investigate the nature and quantitative significance of any noncovalent intermolecular interactions inside the crystal lattice. The crystal void parameters have also been computed and show the molecules to be tightly packed. [ABSTRACT FROM AUTHOR]

Transition metal complexes of nickel(II) with 5–bromo–N–(8–quinolyl)salicylaldimine (HqsalBr, HL1); [Ni(qsalBr)2] (1) and 3,5–dibromo–N–(8–quinolyl)salicylaldimine (HqsalBr2, HL2); [Ni(qsalBr2)2] (3) including zinc(II) complex with HL1, [Zn(qsalBr)2] (2), have been synthesized and successfully characterized using various techniques, namely IR, NMR, mass spectrometry, thermogravimetric analysis (TGA), and single crystal X–ray crystallography. DFT calculations were employed to examine the structural and electronic parameters of the complexes at their optimized geometries. The complexes showed strong DNA-binding activities, assessed by UV-Vis and fluorescence spectroscopy, primarily through intercalation. Molecular docking investigations were carried out to provide profound insights into the interaction mechanisms of these complexes with DNA and lung cancer cells. These computational studies revealed that [Ni(qsalBr2)2] (3) exhibits the most favorable negative binding energies, −9.1 kcal/mol with DNA and −9.3 kcal/mol with cancer cells, facilitated by hydrogen bonding and hydrophobic interactions. Furthermore, the in vitro anticancer activity was evaluated against the A549 human lung adenocarcinoma cell line, with [Zn(qsalBr)2] (2) exhibiting the highest potency against this cancer cell line. [ABSTRACT FROM AUTHOR]

This study reports the synthesis and computational investigation of two Schiff bases: (E)-N-(4-bromophenyl)-1-(2,6-dichlorophenyl)methanimine (S1) and (E)-4-(((4-bromophenyl)imino)methyl)phenol (S2), with a focus on their potential antibacterial activity. Schiff bases, known for their versatility and application in medicinal chemistry, are synthesized through the condensation reactions of the appropriate aniline with aldehydes. The molecular structures of S1 and S2 were elucidated using basic spectroscopic methods such as Fourier-transform-infrared, ultraviolet-visible as well as ¹H and 13C-NMR, while the purity of the compounds was ascertained using elemental analysis. The stability, chemical reactivities, and electronic properties of S1 and S2 were evaluated using Density Functional Theory (DFT). The energy band gap (ΔE) of S1 and S2 is 2.81 eV and 3.02 eV, respectively, and this infers that S1 is more reactive as well as less stable than S2. The molecular electrostatic potential (MEP) mapping evaluation showed that both S1 and S2 have more of the yellow, green, and red regions than the blue region, signifying that these structures are prone to electrophilic attack. The compounds were screened against two Gram-negative (Klebsiella pneumoniae and Pseudomonas aeruginosa) and one Gram-positive bacteria (Staphylococcus aureus) to evaluate their antibacterial potential. S1 as well as S2 showed antibacterial potential against Staphylococcus aureus and exhibited less or no activity against Klebsiella pneumoniae and Pseudomonas aeruginosa. In silico studies of S1 and S2 against Staphylococcus aureus were carried out, and the outcomes corroborated the experimental findings. Pharmacological evaluation of S1 and S2 showed that both compounds exhibited less violation of Lipinski’s rule of five (Ro5), which makes them less toxic and orally available. [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]

Copper (Cu2+) is a transition metal ion extensively distributed in numerous foodstuffs of both animals and vegetables. An excess intake of Cu2+ ions cause injury, pneumonitis, a disorder in the nervous system, and gastrointestinal problems. Hence, we have developed a simple and novel Schiff base‐based fluorescence sensor for the detection of Cu2+ ions. The sensor, ‐3‐(1H‐indol‐3‐yl)‐2‐((4‐nitrobenzylidene) amino)propanoic acid (INAP), was synthesized from tryptophan and nitrobenzaldehyde by the reflux method and characterized by various analytical methods. The prepared INAP acted as a chemical sensor and displayed outstanding sensitivity and choosiness characteristics for Cu2+ ions an aqueous solvent. In the presence of Cu2+, it demonstrated a fluorescence change in an aqueous medium with a "turn‐off" phenomenon via complex‐mediated energy transfer characteristics, and the method of continuous variation suggested a 1 : 2 complex formation of the metal ion with INAP. The LOD of the sensor system was calculated to be 1.3 μM for the Cu2+ ion. In addition, the INAP fluorescent probe was applied to tap water samples and found acceptable recoveries. These results suggest that the newly fabricated sensor system would be explored as a chemosensor for the recognition of Cu2+ ions in environmental samples. [ABSTRACT FROM AUTHOR]

Adding carbonyl groups into the hydrogel matrix improves the stability and biocompatibility of the hydrogels, making them suitable for different biomedical applications. In this review article, we will discuss the use of hydrogels based on polysaccharides modified by oxidation, with particular attention paid to the introduction of carbonyl groups. These hydrogels have been developed for several applications in tissue engineering, drug delivery, and wound healing. The review article discusses the mechanism by which oxidized polysaccharides can introduce carbonyl groups, leading to the development of hydrogels through cross-linking with proteins. These hydrogels have tunable mechanical properties and improved biocompatibility. Hydrogels have dynamic properties that make them promising biomaterials for various biomedical applications. This paper comprehensively analyzes hydrogels based on cross-linked proteins with carbonyl groups derived from oxidized polysaccharides, including microparticles, nanoparticles, and films. The applications of these hydrogels in tissue engineering, drug delivery, and wound healing are also discussed. [ABSTRACT FROM AUTHOR]

A new polyimine polymer (PL) containing sulphone functional groups was prepared from polycondensation of Schiff base (L) with terephthaloyl chloride at a very moderate condition. The polymer metal complexes were then synthesized from the reaction of polymer with metal salts. Scanning electron microscope (SEM), Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction analysis (XRD), thermal gravimetric analysis (TGA), derivative thermogravimetry (DTG), proton nuclear magnetic resonance (1H NMR), and CHNS elemental analysis have been used to characterize all the synthesized materials. The excellent thermal stability of PL was specified by TGA. The optical features were assessed with the UV‐visible technique. The polymer complexes represent absorbance at the same wavelength as L and PL. The synthesized polymer metal complexes have a band gap varying from 3.19 (CuPL) to 2.77 (CdPL) eV. The inherent viscosities for the synthesized polymer is 0.4490 dL/g in DMF at 25 °C, indicating their moderate molecular weight. [ABSTRACT FROM AUTHOR]

Aluminum is a widely distributed element and plays an indispensable role in our lives, but excessive intake of Al3+ can cause potential harm to human health. Highly selective methods for the rapid detection of Al3+ are urgently needed. Here, a novel "turn on" fluorescent probe L based on Schiff-base of 2-hydroxy-1-naphthaldehyde and 8-aminoquinoline was obtained in an excellent yield. Probe L presents significant properties such as rapid response, good stability, wide pH range, simple synthetic operation, and provides an efficient strategy for the highly selective detection of Al3+ in an aqueous solution of DMSO/H2O (7:3, v:v). According to Job's curve and fluorescence titration, probe L with Al3+ forms a 2:1 ratio of complex, and the lowest limit of detection is 3.23 × 10−8 mol/L. The possible combination mode for probe L with Al3+ was proposed by comparison with the changes of 1H NMR and FTIR spectra of L and its complex. In addition, the potent applicants for probe L were also investigated, and indicated that it could conveniently be made into a series of sensor strips and applied to rapidly detect trace Al3+ in traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

One of the challenging issues that hinders the application of single-walled carbon nanotubes (SWCNTs) is the poor solubility and the inevitable formation of bundles. Efforts still need to be made towards solving the problem. Herein, we report a non-covalent strategy to disperse aggregated SWCNTs by aromatic cyclic Schiff bases assisted by ultrasonic techniques. The aromatic cyclic Schiff base (OMM) was synthesized via Schiff base reactions, and the molecular structure was determined by ATR-FT-IR, solid-state 13C-NMR, and HRMS. Although the yielded product showed poor solubility in aqueous solution and organic solvents, it could interact with and disperse the aggregated SWCNTs in dimethyl formamide (DMF) under the condition of ultrasound. UV-vis-NIR, FL, Raman spectra, AFM, and TEM, along with computer simulations, provide evidence for the interactions between OMM molecules and SWCNTs and the dispersion thereof. The semiconductive (7,5), (8,6), (12,1), and (9,7)-SWCNTs expressed a preference for dissolution. The capability of dispersion is contributed by π-π, C-H·π, and lone pair (lp)·π interactions between OMM and SWCNTs based on the simulated results. The present non-covalent strategy could provide inspiration for preparing organic cyclic compounds as dispersants for SWCNTs and then facilitate their further utilization. [ABSTRACT FROM AUTHOR]

The inhibition performance and adsorption behavior of an unsymmetrical tridentate Schiff base, 2-(((2-((2-nitrophenyl) thio) phenyl) imino) methyl)phenol (NOS) on mild steel in 2M hydrochloric acid solution has been studied using electrochemical and quantum chemical techniques. The electrochemical outcomes suggest that NOS works as an anodic-type inhibitor. The adsorption process of the NOS Schiff base obeys the Langmuir model. The theoretical evaluation has been performed using DFT calculations to investigate the correlation of effective corrosion inhibition with some NOS Schiff base structural parameters. The obtained results revealed that there was a good agreement between the theoretical and experimental results. [ABSTRACT FROM AUTHOR]

Two new Schiff‐base bismuth (III) complexes were prepared by an equivalent reaction between Schiff‐base ligand and Bi (NO3)3•5H2O with the assistance of Mannitol. The chemical structures of the two complexes were characterized by spectroscopic studies (FT‐IR, NMR, and MS), elemental analysis, and single‐crystal X‐ray diffraction. The ligand‐to‐metal ion ratio was found to be 1:1 in the complexes. During the formation of the complexes, Schiff bases changed from the amidic forms to the iminol forms, and the resulting tautomers could coordinate with bismuth (III) ions to produce dinuclear BiIII complexes(1a and 2a). Structural analyses showed that each Bi (III) ion held a distorted capped octahedron geometry with a seven‐coordinate mode in two complexes. Screening in vitro biological activities revealed that two bismuth (III) complexes exhibited much higher antimicrobial and cytotoxic activity than their parent ligands. The cytotoxic activity of the complex(1a) was close to that of the known anticancer drug (Doxorubicin) by evaluating against SGC7901 cells, with the IC50 value 0.59 μM. The complex(1a) could effectively induce SGC7901 cell apoptosis and its oral acute toxicity for LD50 value was found to be 576 mg kg−1. The content of bismuth (III) in mitochondria was higher than that in the nucleus. [ABSTRACT FROM AUTHOR]

The present study reports the synthesis and characterization of two new halogenated Schiff base copper (II) derivatives, namely [CuII2(3‐Cl‐Salmphen)2] (Cu‐Cl‐Salmphen) and [CuII2(3‐Br‐Salmphen)2] (Cu‐Br‐Salmphen), which were characterized by UV–Vis, FT‐IR, 1H‐NMR, and 13C‐NMR spectroscopy. Single crystal structural analysis revealed that each complex contains two crystallography independent, distorted copper centers, where each Cu center exhibits the same coordination environment with N2O2 donor atoms from two different ligands. To investigate the substitution effect of halogen atoms on the properties of the complexes, the non‐halogenated isomer [CuII2(H‐Salmphen)2] (Cu‐H‐Salmphen) was introduced for comparison. The differences between the halogenated and the non‐halogenated analogues were compared through spectroscopic, electrochemical, DFT, and TD‐DFT theoretical calculations. The optical experimental results indicated that the introduction of halogen atoms decreased the energy gap between the ground and excited states, leading to enhanced optical absorption capabilities of the compounds. Electrochemical tests showed that the halogenated analogues exhibited better electrochemical performance, and with the increase in an atomic number of the halogen atoms, the compounds displayed a gradual increase in cyclic voltammetry peak areas, diffusion coefficients, and conductivities. Theoretical calculations revealed that the introduction of halogen atoms simultaneously expanded the conjugated area of the molecules, decreased the HOMO‐LUMO energy levels of the complexes, and strengthened the intramolecular interactions. Furthermore, the potential mechanism of the tuning effect of halogen atoms on the charge transfer process was proposed. [ABSTRACT FROM AUTHOR]

From the perspective of possible antiviral and antibacterial activity of vanadium‐based complexes, we report the synthesis of new Schiff base ligand (L4) and a new Schiff‐base‐vanadium complex (C2). Both the ligand and the complex were characterized by Fourier transform infrared spectroscopy and Nuclear magnetic resonance techniques. Single‐crystal X‐ray Diffraction analysis has been used to confirm the structure of ligand L4 and complex C2. In addition, L1–4 and C1–3 were tested for their antibacterial effects against Escherichia coli and Staphylococcus aureus. Among the compounds, L2 demonstrated the most potent inhibition of both bacteria, exhibiting the lowest values for minimum inhibitory concentration (CMI) and minimum bactericidal concentration (CMB) (CMI = 0.16, CMB = 0.31 against E. coli, and CMI = CMB = 0.16 against S. aureus). Additionally, L2 produced the largest inhibition zones with diameters of 15.5 ± 0.15 against E. coli and 14.5 ± 0.04 against S. aureus. Furthermore, the antiviral efficacy of L1, L2, L4, C1, C2, and C3 against RNA viruses was assessed. C2 and C3 exhibited the most potent antiviral activity among the tested compounds. [ABSTRACT FROM AUTHOR]

A family of molybdenum complexes with a general formula of [MoO2L]2 have been synthesized and fully characterized, where L is a tridentate ONO Schiff base ligand featuring a Cl substituent in different positions on the aromatic ring of salicylidene‐2‐aminophenolato backbone. The solvent molecule stabilized the monomeric structure of [MoO2LD] (D = DMF or DMSO) allowing single‐crystal X‐ray diffraction of the three new complexes. The dimeric complexes are utilized to catalyze the reaction of aldehydes/ketones with dimedone, leading to 1,8‐dioxo‐octahydro‐xanthene derivatives in N,N‐dimethylformamide. We found that their catalytic activity is enhanced by the electron‐withdrawing group of the Cl substituent on the ONO ligand. In addition, the position of the Cl substituent can also positively influence the catalysis performance: (ortho (L1) > para (L3) > meta (L2) ≈ meta (L4)). The high efficiency of the catalysts promises high yields and selectivity with a low catalyst loading and allows a wide substrate scope of aldehydes/ketones for the reaction. In addition, the method employs recrystallization for purifying products and can be easily scaled up to gram levels, indicating a strong potential for industrial utilization. [ABSTRACT FROM AUTHOR]

The role of manganese in photo‐induced organometallic‐mediated radical polymerization (photo‐OMRP) under LED (light‐emitting diode) irradiation has not been previously explored. In this study, four manganese (II) complexes, namely [Mn(6‐tert‐butyl‐N,N′‐propanebis [salicylimine])] (Mn‐Bu), [Mn(6,3‐di‐tert‐butyl‐N,N′‐propanebis [salicylimine])] (Mn‐Bu2), [Mn(6‐ethoxy‐N,N′‐propanebis [salicylimine])] (Mn‐Ethoxy), and [Mn(6,3‐di‐ethoxy‐N,N′‐propanebis [salicylimine])] (Mn‐Ethoxy2), were synthesized using both symmetrical and non‐symmetrical tetradentate N2O2 Schiff base ligands. The Schiff base ligands were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis), and nuclear magnetic resonance spectroscopy (NMR). The Mn (II) complexes were characterized by FTIR, UV–Vis, elemental analysis, molar conductivity, cyclic voltammetry, MALDI‐TOF mass spectrometry, electron paramagnetic resonance, and rationalized with density functional theory (DFT) studies. All complexes were evaluated as photo‐OMRP mediators under LED irradiation at 390 nm and in the 400–800 nm range. The photopolymerization utilized methyl acrylate (MA) and diphenyl(2,4,6‐trimethylbenzoyl)phosphine oxide (TPO) in varying molar ratios of [MA]/[MnII]/[TPO] (900/1/1, 600/1/1, and 600/1/0.5). The photo‐OMRP of MA mediated by Mn‐Bu2 showed the best control over molecular weight (Mn matching Mn,th) and dispersity (Ð < 1.30) at a [MA]/[MnII]/[TPO] = 600/1/0.5 M ratio. The polymerization system demonstrated a living character, as evidenced by reversible "on/off" light source switching. Furthermore, a block copolymer of poly (methyl acrylate)‐b‐poly (butyl acrylate) was successfully synthesized employing a sequential visible‐light‐induced process, with the Mn‐Bu2 system showing the best results. [ABSTRACT FROM AUTHOR]

The present study was conducted to scrutinize the pharmacological effect of oxazole-embedded Chitosan as an anticancer agent against gastric cancer cells. This compound was synthesized using the classical Schiff base reaction but utilizing the novel green chemical process where cerric ammonium nitrate (CAN) was used as a catalyst in the PEG-400 as solvent media. The target compound was obtained with an excellent yield at the catalyst loading of 5% CAN concentration in 15 min. The Kinase-Glo Plus luminescence kinase assay kit was used to determine the EGFR inhibitory activity of compound 1 where it showed potent activity with IC50 of 2.14 µM. Its effect was also determined on the cellular viability of the Human gastric cancer cell line (SGC7901), liver cancer cell line (HepG2), and lung cancer cell line (A549), where it exhibits potent activity against SGC7901. The compound further showed the concentration-dependent inhibitory effect on migration and invasion of SGC7901. In RT-qPCR analysis, the compound showed induction of apoptosis of SGC7901 cells possibly by restoring the expression of Bcl-2 and Bax near to normal, and inhibition of the mRNA expression of EGFR in a concentrationdependent manner. [ABSTRACT FROM AUTHOR]

Complexes of mixed-ligand Schiff bases [trimetho-prim (TMP) with isatin] (L1) and nitrogen bases [2,2′-bipyridine (bipy)] (L2), [1,10-phenanthroline (phen) (L3)] with metal chlorides: M = Cr3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+ were prepared and characterized by metal content determination (%), FT-IR, electronic, nuclear magnetic resonance, mass spectroscopy, magnetic susceptibility, conductance measurements and elemental analysis (CHN). The bacterial activity of the ligands and their metal compounds was evaluated via various microorganisms. Infrared spectra of Schiff base showed an azomethine peak shifted in complexes that coincide synthesis and coordination of Schiff base through the nitrogen atom of azomethine C=N) and the oxygen atom of the carbonyl group of L1 with metal ions. L2, L3 (bipy, phen) coordinated through the di imine nitrogen atoms. Conductance dimensions suggested the non-conductance nature of all the compounds except Cr(III) complexes, this outcome fits in with the molar conductance value estimated for 1:1 electrolyte in DMF. Magnetic susceptibility analysis and electronic spectra indicated an octahedral geometry for all complexes. Biological study for prepared compounds have been evaluated towards pathogenic microbes Staphylococcus aureus and Bacillus subtilis. Some compounds have stronger antibacterial action than Schiff base towards tested microbes. [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]

This work synthesized new biologically active Cu(I) complexes 1-5, obtained from the reaction of Cu(I) nitrate with different bidentate pyridinyl Schiff base ligands (E)1-(pyridin-2-yl)-N-(p-tolyl)methanimine L1, (E)-1-(pyridin-2-yl)-N-(otolyl) methanimine L2, (E)-N-isopropyl-1-(pyridine-2-yl)methanimine L3, (E)-Nmesityl-(pyridinyl)methanimine L4 and (E)-N-(2,6-dimethylphenyl)-1-(pyridine-2-yl)methanimine L5, with PPh3 ancillary ligand. The metal complexes with general formula [Cu L(PPh3)2]NO3, were characterised by FT-IR, UV-Vis, NMR and MS, X-ray crystallography and elemental analysis. The antibacterial activities against Staphylococcus aureus (SA), Escherichia coli (EC), Klebsiella pneumonia and Pseudomonas aeruginosa (PA) were investigated using agar well diffusion method with ofloxacin as reference. UV-Visible spectra and FT-IR result showed bathochromic shift in the imino (C=N) frequencies in the complexes confirming coordination to the metal centre. Single crystals obtained in complexes 2, 3, 5 revealed orthorhombic crystal systems having Tau (t4) values in the range 0.73 - 0.87 depicting distorted tetrahedral geometries. Coordination to the metal center was bidentate for all the ligands via the pyridinyl N and imine N in conjunction with two triphenylphosphine P in the N^N^P^P fashion in complexes 2, 3, and N^N^P^O fashion in complex 5. The antibacterial activities revealed that all the complexes exhibited better antibacterial activities relative to their parent ligands and PPh3. The study found out that the newly synthesized complexes have better antibacterial performances hence make the metal complexes potential chemotherapeutic agents in drug design. [ABSTRACT FROM AUTHOR]

Oxidized β-cyclodextrin (O-β-CD) nanoparticle was synthesized using oxidation process and Amoxicillin trihydrate (AMOX) model drug was integrated both via Schiff base reaction (C=N bond) as well as inclusion into cavity of O-β-CD to evaluate pH-responsive drug release behavior. The drug loaded nanocarrier (AM-O-β-CD) was characterized and results showed this formation, encapsulation and morphological change with average particle size (398 ± 8.51 nm), negative zeta potential values (− 25.4 ± 1.54) and high entrapment efficiency (86.1%). The in vitro release behavior of AM-O-β-CD was evaluated in physiological buffer conditions (0.1 M PBS, pH 5.2, at 37 °C). It was found that drug-loaded AM-O-β-CD showed sustain, prolonged much higher drug release profile (94.72%) in low pH than that of the pure drug (24.18%) in the same acidic medium. Release kinetics of drug loaded AM-O-β-CD was determined according to well-known mathematical models, revealing that in vitro release profile could be best expressed by Higuchi kinetic model as release data showed the highest linearity (R2 = 0.967) so that drug release takes place due to both dissolution and diffusion as it is expected. As a result, it has been proven that the nanostructure has the potential to be pH sensitive drug carrier, especially for drugs containing NH2 side groups in acidic environments. [ABSTRACT FROM AUTHOR]

Transition metal complexes of nickel(II) with 5–bromo–N–(8–quinolyl)salicylaldimine (HqsalBr, HL1); [Ni(qsalBr)2] (1) and 3,5–dibromo–N–(8–quinolyl)salicylaldimine (HqsalBr2, HL2); [Ni(qsalBr2)2] (3) including zinc(II) complex with HL1, [Zn(qsalBr)2] (2), have been synthesized and successfully characterized using various techniques, namely IR, NMR, mass spectrometry, thermogravimetric analysis (TGA), and single crystal X–ray crystallography. DFT calculations were employed to examine the structural and electronic parameters of the complexes at their optimized geometries. The complexes showed strong DNA-binding activities, assessed by UV-Vis and fluorescence spectroscopy, primarily through intercalation. Molecular docking investigations were carried out to provide profound insights into the interaction mechanisms of these complexes with DNA and lung cancer cells. These computational studies revealed that [Ni(qsalBr2)2] (3) exhibits the most favorable negative binding energies, −9.1 kcal/mol with DNA and −9.3 kcal/mol with cancer cells, facilitated by hydrogen bonding and hydrophobic interactions. Furthermore, the in vitro anticancer activity was evaluated against the A549 human lung adenocarcinoma cell line, with [Zn(qsalBr)2] (2) exhibiting the highest potency against this cancer cell line.

Optimization of nine bis-Schiff bases derived from 5-substituted-8-aminoquinoline (I) and furan-2, 3-di-carbaldehyde (II) molecules was performed using density functional theory (DFT) in B3LYP/6-311G++ (d, p) level of theory and based on the optimized structures, structural parameters, dipole moments, as well as frontier molecular orbitals of the desired bis-Schiff bases (III) were calculated. The statistical thermodynamic functions, i.e., enthalpy changes (ΔHºr = 10.21 kcalmol−1) and Gibbs energy changes (ΔGºr = 12.62 kcalmol−1) were obtained from the theoretical harmonic frequencies (freq keyword). Each of these imines has four geometrical isomers (ZZ, EZ, ZE, and EE), and their relative stability for III-H was studied. It was found that ZZ (III-H) is the most unstable (9.20 kcalmol−1) in four isomers. To check the nonlinear optical (NLO) properties of these organic compounds the first hyperpolarizability (βtotal) and average polarizability (αave) parameters were calculated. All of these bis-Schiff bases (III) have βtotal values larger than the magnitude of the βtotal value for urea (a standard molecule) and III-NO2 is the best NLO material in studied compounds. So for III-NO2, Mulliken atomic charges analysis, frontier orbitals, and molecular electrostatic potential (MEP) surfaces have been studied. [ABSTRACT FROM AUTHOR]

The title coordination polymer with the 4-methyl-N-(pyridin-2-ylmethylidene)aniline Schiff base ligand (L, C13H12N2), [Cd2Cl4(C13H12N2)]n (1), exhibits a columnar structure extending parallel to [100]. The columns are aligned in parallel and are decorated with chelating L ligands on both sides. They are elongated into a supramolecular sheet extending parallel to (01\overline{1}) through π–π stacking interactions involving L ligands of neighbouring columns. Adjacent sheets are packed into the tri-periodic supramolecular network through weak C—H...Cl hydrogen-bonding interactions that involve the phenyl CH groups and chlorido ligands. The thermal stability and photoluminescent properties of (1) have also been examined.

Three Schiff bases (1a, 1b, and 1c) have been prepared from the reaction of o-vanillin with primary amine (aniline, p-toluidine, and p-anisidine). Schiff base derivates from o-vanillin were synthesized using the grinding method for 20 minutes. Physical properties were observed based on color, melting point, and solubility. Synthesis products were also characterized using FTIR, GCMS, 1H-NMR, and 13C-NMR. The antioxidant activity of the Schiff base was tested using DPPH. While the toxicity test uses the BSLT method. The result of this synthesis and characterization Schiff base (1a, 1b, and 1c) showed that the Schiff base compound was formed into 2-methoxy-6 (phenyliminomethyl) phenol; 2-methoxy-6- (((4-methylphenyl) imino) methyl) phenol; and 2-methoxy-6-(((4-methoxyphenyl) imino) methyl) phenol. The result of NMR analysis, on 1H-NMR spectrum showed the shift chemical at 8,5-8,6 ppm which indicates the typical peak of proton (-HC=N-). Meanwhile, the 13C-NMR spectrum shown the shift chemical at 160-162 ppm which indicates the typical peak of carbon (-C=N-). The result of antioxidant activity showed that all Schiff base was antioxidant quite low ability with value of EC50 is 106.2-196.4 ppm. Meanwhile, the result of toxicity test showed that all Schiff base was anticancer with an LC50 value of 9.99-22.29 ppm.

Background and objective: Sulfonamides are a type of antibiotic that are used to treat several infections caused by microorganisms. Sulfonamides are bacteriostatic, meaning they prevent bacterial growth. This study aimed to produce compounds with better antimicrobial activity. Methods: By condensation reaction, Schiff bases were synthesized from sulfonamides (sulfamethoxazole, sulfapyridine, sulfathiazole, sulfadiazine and sulfisoxazole) and vanillin to enhance antimicrobial activity of synthesized compounds. The agar dilution method was used to measuring the minimum inhibition concentration (MIC) of synthesized compounds. Results: The synthesized compounds were characterized by FT-IR, 1H-NMR, 13C-NMR and tested for the antibacterial activity against gram positive bacteria (Staphylococcus aureus), gram negative bacteria (Escherichia coli) and antifungal activity against (Candida albicans). Ciprofloxacin and Fluconazole used as standard drugs for bacteria and fungi. Conclusion: The Schiff base was synthesized, characterized, and exhibited enhanced antimicrobial and antifungal activities.

Polymer-based transition metal complexes have attracted much attention in many fields of application. In this article, a fluorescent polymer-based transition metal complex was prepared by bonding the transition metal complex with the polymer. First, Schiff base salicylaldehyde ethanolamine (HL) as a ligand was prepared by the reaction of salicylaldehyde with ethanolamine. Then, salicylaldehyde glycolamine Zn(ii) transition metal complexes (ZnL2) were synthesized with HL and Zn2+ as the central ion. Finally, a blue fluorescent waterborne-based polyurethane Zn(ii) complex (ZnL2-WPU) with an antibacterial function was prepared with ZnL2 as a chain extender by modified acetone method. The characteristics of fluorescence, heat stability, and bacteriostasis were characterized. Compared with ZnL2, the UV–vis absorption peak of ZnL2-WPU shows a blue shift of about 20 nm. ZnL2-WPU has a strong blue fluorescence emission at 450 nm, and the intensity increases significantly with ZnL2 content. Surprisingly, the fluorescence lifetime of ZnL2-WPU is obviously increased, reaching more than one time that of ZnL2. Interestingly, the antibacterial efficiency of ZnL2-WPU against E. coli reached an incredible 99%. More importantly, ZnL2-WPU uses water as the dispersing medium, which is more environmentally friendly.

A procedure based on dispersive liquid-liquid microextraction (DLLME) for cobalt (Co) 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 Co levels and to evaluate the effectiveness of N-salicylideneaniline (SAN) as a complexing agent for pre-concentration and extraction of Co. An univariate strategy was utilized to achieve the optimum extraction conditions. The estimated limits of detection (LOD) and quantification (LOQ) under optimum conditions were 1.04 and 3.47 µg L−1, respectively. The results achieved by the proposed system were compared with those using the microwave digestion/graphite furnace atomic absorption spectrometer (MWD/GF-AAS) for digest samples and also for some water samples (Direct GF-AAS). The proposed procedure was applied for analyzing eleven environmental samples. The detectable Co levels for water samples ranged from 0.72 to 4.30 µg L−1 with a relative standard deviation of 3.7–8.8%, while the concentration for solid samples ranged from 0.17–4.51 µg g−1 (2.4–11.8 RSD %). DLLME/FAAS proposed procedure is effective, simple, and has the benefit of minimizing the organic solvent consumption by a few microliters, which results in little waste.