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

To develop a green nanomaterial for specialty applications, spherical nanocellulose (SNC) was functionalized to a semicarbazone-Schiff base via a polymer analogous reaction. Firstly, SNC was synthesized from cellulose extracted from huge forest biomass, pine needles (PNs). The glucopyranose ring of SNC was oxidatively cleaved at C2-C3 to form SNC-dialdehyde (SNC-DA) by periodate oxidation. Both the aldehydic groups generated were reacted with semicarbazide to form a semicarbazone-Schiff base, referred to as functional spherical nanocellulose (FSNC). All the materials synthesized were characterized by FTIR, FESEM, EDS, TEM, and XRD studies. The FSNC was evaluated as an adsorbent for [Hg.sup.2+] ions. The adsorption adhered to pseudo-second order kinetics and Langmuir adsorption isotherm having a maximum adsorption capacity/Lungmuir adsorption capacity of 172.412 mg/g at 60 min. The selectivity of FSNC for [Hg.sup.2+] ions was confirmed from its appreciable removal (82%) from solution in tap water and 70% with other metal ions. FSNC exhibited bifunctional nature as it possesses antimicrobial activity against bacteria, that is, Gram (+) (Bacillus aereus) and Gram (--) (Escherichia coll and Salmonella typhi), and a fungus Byssochlamys fiilva. FSNC showed good recyclability up to eight sorption-desorption cycles. Thus, we have valorized biomass into an eco-friendly and low-cost bifunctional material as an adsorbent for [Hg.sup.2+] ions cum antimicrobial agent. Highlights * Spherical nanocellulose (SNC) prepared via acidic hydrolysis from pine needles * SNC functionalized to semicarbazone-based bifunctional Schiff base * The Schiff base is a rapid and efficient [Hg.sup.2+] ions adsorbent * The Schiff base has good antimicrobial activities against Gram (-) bacteria * Biowaste-based adsorbent has the potential to sustain the bio-circular economy KEYWORDS antimicrobial, pine needles, Schiff base, semicarbazone, spherical nanocellulose, 1 | INTRODUCTION The sustainability development goals have a deep link with the failing water quality and low availability of drinkable water across the world. (1) Among different pollutants, dyes [...]

Pd-catalyzed sequential intramolecular annulation/intermolecular [3+2] cycloaddition of 5-allenyloxazolidine-2,4-diones with dipoles was achieved. Under palladium catalysis, various 5-allenyloxazolidine-2,4-diones reacted with 1,3-dipoles such as nitrile N-oxides, azomethine imines or nitrilimines to give a series of functionalized spiroheterocycles in high yields. The scale-up reaction and further derivation of products were successful. A plausible mechanism was also proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

Three bis-benzimidazolyl bidentate ligands with phenolyl ether linkers, 1,n-bis[2-(1H-1,3-benzimidazol-1-ylmethyl)phenoxy]alkane (L1: n = 1, L2: n = 3, L3: n = 4), and their six metal complexes were synthesized by the reactions of the respective ligands with metal salts. The six metal complexes included two cobalt(II) complexes ([Co(L1)(NO3)2] (1) and [Co(L3)(LA)]n (6) (LA = maleate)), two copper(II) complexes ([Cu(L1)(SO4)]2 (4) and [Cu(L3)(SO4)]2 (5)), one zinc(II) complex ([Zn(L1)(NO3)2] (2)) and one nickel(II) complex ([Ni(L2)(NO3)2] (3)). Complexes 1 and 2 had one 16-membered macrometallocycle, and complex 3 had one 18-membered macrometallocycle. In complexes 4 and 5, two SO42- joined two macrometallocycles together (16-membered macrometallocycle for 4 and 19-membered macrometallocycle for 5). In complexes 1-5, each macrometallocycle was constructed from one ligand and one metal ion. In complex 6, 19-membered macrometallocycles were connected together by maleate groups (LA) to form a 1D polymeric chain, where each 19-membered macrometallocycle was constructed from one L3 and one Co(II) ion. In crystal packings of complexes 1-6, H-bonds, π--π interactions and C--H•••π contacts participated in the formation of 2D supramolecular layers and 3D supramolecular architectures. The conformations of complexes 1-6 were also analyzed. Additionally, the recognition performance of complex 1 as a chemosensor for HSO4- was studied through fluorescence spectra, UV/vis spectra, 1H NMR titrations, HRMS spectra and IR spectra. The large binding constant (1.81 x 104 M-1) showed that there was a strong acting force between 1 and HSO4-, and the low detection limit (1.40 x 10-7 mol L-1) indicated that the detection of 1 for HSO4- was sensitive. The experimental results showed that complex 1 can effectively differentiate HSO4- from other anions. [ABSTRACT FROM AUTHOR]

The reaction of Schiff base ligand N,N′-bis(salicylidene)ethylenediamine (H2L) with [CoII2(μ-OH2)(O2CCMe3)4(HO2CCMe3)4] (CoII2-Piv) (Piv = pivalate) and Ln(NO3)3·xH2O (for 1, 3, 4x = 5; for 2, x = 6) salts in the presence of triethylamine afforded [CoIIILnIII(L)(μ-Piv)2(η1-Piv)2(η1-OHMe)2] [where Ln = Dy, for 1; Tb, for 2; Ho, for 3; and Er, for 4] complexes. The heterometallic dinuclear ensemble is built via the bridging coordination action of [L]2− and four [Piv]− ligands. Further, the Ln(III) center is coordinated by two η1-OHMe ligands. Shape analysis of all the Ln(III) centers in 1–4 reveals the existence of a distorted triangular dodecahedron geometry. Magnetic studies revealed that compound 1 shows slow magnetic relaxation under zero-field at low temperatures whereas compound 4 displays field-induced slow magnetic relaxation. This phenomenon is in agreement with the results of theoretical studies. [ABSTRACT FROM AUTHOR]

Three bis-benzimidazolyl bidentate ligands with phenolyl ether linkers, 1,n-bis[2-(1H-1,3-benzimidazol-1-ylmethyl)phenoxy]alkane (L1: n = 1, L2: n = 3, L3: n = 4), and their six metal complexes were synthesized by the reactions of the respective ligands with metal salts. The six metal complexes included two cobalt(II) complexes ([Co(L1)(NO3)2] (1) and [Co(L3)(LA)]n (6) (LA = maleate)), two copper(II) complexes ([Cu(L1)(SO4)]2 (4) and [Cu(L3)(SO4)]2 (5)), one zinc(II) complex ([Zn(L1)(NO3)2] (2)) and one nickel(II) complex ([Ni(L2)(NO3)2] (3)). Complexes 1 and 2 had one 16-membered macrometallocycle, and complex 3 had one 18-membered macrometallocycle. In complexes 4 and 5, two SO42- joined two macrometallocycles together (16-membered macrometallocycle for 4 and 19-membered macrometallocycle for 5). In complexes 1-5, each macrometallocycle was constructed from one ligand and one metal ion. In complex 6, 19-membered macrometallocycles were connected together by maleate groups (LA) to form a 1D polymeric chain, where each 19-membered macrometallocycle was constructed from one L3 and one Co(II) ion. In crystal packings of complexes 1-6, H-bonds, π--π interactions and C--H•••π contacts participated in the formation of 2D supramolecular layers and 3D supramolecular architectures. The conformations of complexes 1-6 were also analyzed. Additionally, the recognition performance of complex 1 as a chemosensor for HSO4- was studied through fluorescence spectra, UV/vis spectra, 1H NMR titrations, HRMS spectra and IR spectra. The large binding constant (1.81 x 104 M-1) showed that there was a strong acting force between 1 and HSO4-, and the low detection limit (1.40 x 10-7 mol L-1) indicated that the detection of 1 for HSO4- was sensitive. The experimental results showed that complex 1 can effectively differentiate HSO4- from other anions. [ABSTRACT FROM AUTHOR]

ABSTRACT The escalating fascination with Schiff bases stems from their versatile applications in medicine, pharmacology, biology, fine organic synthesis, and industrial processes. This minireview seeks to provide an in‐depth exploration of the synthesis of Schiff bases, specifically focusing on their derivation from 3‐aminopropylalkoxysilanes or 3‐aminopropylsilatranes. Additionally, the review delves into the utilization of Schiff bases in crafting metal complexes, unraveling their practical significance in various domains. Spanning from 1995 to 2024, this review is aimed at encapsulating the evolution of knowledge and advancements in the chemistry of Schiff bases during this period. [ABSTRACT FROM AUTHOR]

Hydrazone‐type Schiff bases have been widely explored owing to their therapeutic properties. These compounds are known to have antibacterial, antifungal, anticancer, and antioxidant properties, among others. In the present study, six hydrazone‐based Schiff bases (BB1–BB6) were synthesized by the reaction between derivatives of benzaldehyde and benzo hydrazide in methanolic medium in the presence of catalytic amount of formic acid. The synthesized compounds were characterized using various spectroscopic techniques such as NMR (1H, 13C, COSY, DEPT, HSQC, HMBC, and NOESY), FTIR, UV‐Vis, elemental (CHN) analysis, and high‐resolution mass spectroscopy. In addition, single crystal structures of BB2, BB4, and BB6 were obtained. In vitro antidiabetic and antioxidant potential of the compounds was evaluated on glucosidase, amylase, NO, FRAP, and DPPH assays, respectively. In all the assays, compounds BB6, BB4, and BB2 showed higher activity than the others. To further explore the chemical reactivity properties and their mechanism of action against the tested assays, DFT and molecular docking study were performed, and the results obtained reinforce the experimental study data. [ABSTRACT FROM AUTHOR]

ABSTRACT Given the widespread and diverse effects of transition metal ions such as copper and zinc in multiple biological processes, this research endeavor addresses herein the microwave‐aided synthesis of two novel tetradentate ONNO (L1) and tridentate NNO (L2) donor Schiff base ligands derived from 4,5‐dimethyl‐1,2‐phenylenediamine and 4‐bromo‐2‐hydroxybenzaldehyde in a 1:2 ratio and from 4,5‐dimethyl‐1,2‐phenylenediamine and 5‐methoxy‐2‐hydroxybenzaldehyde in a 1:1 ratio, with their respective zinc, ZnL1(1) and ZnL2(3), and copper, CuL1(2) and CuL2(4), Schiff base metal complexes, which are comprehensively characterized utilizing physiochemical and analytical techniques, along with geometry optimization using the DFT approach. Spectrophotometric analyses have been used to assess the biomimetic activity in the conversion of 3,5‐DTBC to 3,5‐DTBQ with turnover numbers 53.4 and 78 h−1 in methanol for 2 and 4, whereas the zinc complexes are found to be ineffective. With CT‐DNA, possible modes of interaction with the synthesized complexes have been explored using absorption spectroscopy, where the associated binding constants ranged between 1.541 × 105 and 2.186 × 105 M−1. EtBr‐bound DNA was used in the fluorescence quenching experiments with Stern–Volmer constant (Ksv) values in the range 4.084 × 104 and 3.402 × 104 M−1, showing a stronger association with CT‐DNA. The compounds' ability to inhibit bacterial strains was also examined in vitro, as well as their ability to reduce inflammation, through the protein denaturation method and the DPPH assay for antioxidant activity have been performed. Furthermore, molecular docking simulations have been carried out to obtain a deeper comprehension of the molecular‐level interactions with CT‐DNA and cyclooxygenase‐2 (COX‐2). [ABSTRACT FROM AUTHOR]

Uranium (U) is a radiologically and chemically toxic element that occurs naturally in water, soil, and rock at generally low levels. However, anthropogenic uranium can also leach into groundwater sources due to mining, ore refining, and improper nuclear waste management. Over the last few decades, various methods for measuring uranium have emerged; however, most of these techniques require skilled scientists to run samples on expensive instrumentation for detection or require the pretreatment of samples in complex procedures. In this work, a Schiff base ligand (P1) is used to develop a simple spectrophotometric method for measuring the concentration of uranium (VI) with an accurate and affordable light-emitting diode (LED) spectrophotometer. A test for a higher-order polynomial relationship was used to objectively determine the calibration data's linearity. This test was done with a Python program on a Raspberry Pi computer that captured the spectrophotometer's calibration and sample measurement data. [ABSTRACT FROM AUTHOR]

ABSTRACT The reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ). [ABSTRACT FROM AUTHOR]

ABSTRACT A novel Schiff base (BSSMO) and its copper complex have been synthesized, and their structure was delineated using single crystal XRD studies. Computational techniques were used to design and evaluate BSSMO‐based luminophores, revealing a significant intramolecular hydrogen bond within the molecule. Understanding ESIPT is crucial for optimizing photophysical and luminophore properties of organic molecules, especially for advancing optoelectronic devices. The study also explored the mechanisms of GSIPT and ESIPT for these BSSMO‐based luminophores using transition state theory, charge distribution, molecular orbital analysis, and quantum theory of atoms in molecules. Results advocated that BSSMO‐L2 exhibits higher absorption compared with BSSMO‐L1 and the same trend is observed in emission spectral studies. However, the intensity of enol emissions in BSSMO‐L2 is lower than that of keto (BSSMO‐L3) emissions and the S1 (Keto form) emission of BSSMO‐L3 shows significantly larger values, making it attractive for optoelectronic devices. The findings offer valuable insights for the development of ESIPT emitters with distinct photophysical properties. The in silico antidiabetic study of BSSMO‐L2 explores the interaction with PPAR‐γ protein, revealing a moderate affinity and stable complex, enhancing its bio‐potential for future applications. The in vitro anticancer study of Cu‐BSSMO‐L2 complex shows a potential anticancer effect through mitochondrial and extrinsic death receptor mediated pathways. These insights contribute to the design of novel benzenesulfonamide‐based bioactive molecules. [ABSTRACT FROM AUTHOR]

The article focuses on recent advancements in chemistry, highlighting the development of new materials and chemical processes. Topics include the synthesis of insensitive energetic materials with enhanced detonation performance, the use of vanadium(V) complexes for syndiospecific ring-opening metathesis polymerization (ROMP) of cyclic olefins, and the exploration of metal-support interactions to enhance catalytic activity for hydrogen production.

The equimolar reaction between 1,9-bis(N,N-dimethylaminomethyl)-5,5′-diphenyldipyrromethane, H2L1 or 1,9-bis(3,5-dimethylpyrazolylmethyl)-5,5′-diethyldipyrromethane, H2L2 and [NiCl2(DME)] in the presence of KH yielded the neutral mononuclear nickel(II) complexes [Ni(L1)-κ4N,N,N,N], 1 and [Ni(L2)-κ4N,N,N,N], 2, respectively. Their X-ray structures revealed the formation of triple chelation by the ligand in both structures with quite different nickel(II)-surrounded square planar geometries owing to the steric difference between –NMe2 and 3,5-dimethylpyrazolyl groups. While the –NMe2 group substituted ligand L1 afforded nickel complex 1 with a plane of symmetry, 3,5-dimethylpyrazole substituted L2 rendered helical chirality in the structure of complex 2. Both the enantiomers (Δ and Λ) of complex 2 were observed in the crystal lattice. Their solution state behaviors were consistent with the solid-state structures as monitored by 1H NMR spectroscopy. Both the enantiomers of complex 2 were present in a dynamic equilibrium in solution and studied by variable temperature 1H NMR spectroscopy. Similar to the chiral complex, the corresponding ligand H2L2 also exhibited chirality as shown by its crystal structure and the two ligand enantiomers participated in a very fast dynamic interconversion, which became slower upon metalation. [ABSTRACT FROM AUTHOR]

Two mononuclear complexes, [Cu(L1)2] (complex 1) and [Cu(HL2)2](NO3)2 (complex 2) where HL1 is 1-((cyclohexylmethylimino)methyl)-naphthalen-2-ol and HL2 is 4-bromo-2-((2-morpholinoethylimino)methyl)phenol, have been synthesized under mild conditions and characterized by different standard analytical methods. Single crystal X-ray diffraction analysis shows that the copper atoms in both copper(II) complexes are in a square planar geometry. These complexes have been used as catalysts in the oxidation of benzyl alcohol and benzyl alcohol with various substituents in the presence of NaOCl as the terminal oxidant. The results show that complex 1 acts as a better catalyst than the other with the highest yield of 91% in the case of 4-methoxy benzyl alcohol oxidation. The copper complex transfers the oxygen of sodium hypochlorite to the alcohol to produce the aldehyde. The use of NaOCl as an oxidant in alcohol oxidation is rare although it is cheap and nonexplosive. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis of four new complexes: the dimeric precursor [Ir(dmppz)2(μ-Cl)]2 (1) (Hdmppz -- 3,5-dimethyl-1-phenyl-1H-pyrazole) and heteroleptic bis-cyclometalated complexes: [Ir(dmppz)2(Py2CO)]PF6•½CH2Cl2 (2), [Ir(dmppz)2(H2biim)]PF6•H2O (3), and [Ir(dmppz)2(PyBIm)]PF6 (4), with auxiliary N,N-donor ligands: 2-di(pyridyl)ketone (Py2CO), 2,2'-biimidazole (H2biim) and 2-(2'-pyridyl)benzimidazole (PyBIm). In the obtained complexes, SC-X-ray analysis revealed that Ir(III) has an octahedral coordination sphere with chromophores of the type {IrN2C2Cl2} (1) or {IrN4C2} (2-4). The complexes obtained, which have been fully characterised by physicochemical methods (CHN, TG, FTIR, UV-Vis, PL and ¹H, 13C, 15N NMR), were used to continue our studies on the factors influencing the cytotoxic properties of potential chemotherapeutic agents (in vitro). To this end, the following studies are presented: (i) comparative analysis of the effects on the biological properties of N,N-donor ligands and C,N-donor ligands in the studied complexes, (ii) studies of the interactions of the compounds with the selected molecular target: DNA and BSA (UV-Vis, CD and PL methods), (iii) and the reactivity towards redox molecules: GSH, NADH (UV-Vis and/or ESI-MS methods), (iv) cytotoxic activity (IC50) of potential chemotherapeutics against MCF-7, K-562 and CCRF-CEM cell lines. [ABSTRACT FROM AUTHOR]

ABSTRACT Nano‐sized bivalent metal complexes, specifically [M(L)2] with L = 2‐((E)‐((4,5‐dimethyl‐2‐(((E)‐4‐methylbenzylidene)amino)phenyl)‐imino)methyl)benzenethiol] (C23H22N2S) and M = Cu (II) (C1), Co (II) (C2), Ni (II) (C3), and Zn (II) (C4), underwent synthesis and subsequent characterization. Elemental analyses, infrared, NMR, mass, electronic, magnetic susceptibility, conductivity assessments, and X‐ray diffraction studies were used to assess our bivalent metal complexes. DFT studies were used to study the tautomeric equilibrium of the tridentate thio‐Schiff base ligand (HL), via the DFT\B3LYP method in connection with a 6–311G* correlation consistent basis set. Two tautomers, which are thione and thiol forms, were studied to estimate the predominant one. The metal formed four coordinated with the tridentate N2S donor thio‐Schiff base to form octahedral geometry complexes. The SEM, TEM, XRD, AFM, and EDX of the studied complexes unveiled distinct and strong diffraction peaks, signifying their crystalline nature and providing evidence of their particle sizes being within the nano‐size. The crystal sizes calculated for all complexes were determined to be ranging from 27.73 to 76.39 nm. The interactions between metal complexes and calf thymus DNA, and their potential for mimicking insulin activity, were investigated in a controlled lab setting by measuring their ability to inhibit alpha‐amylase. The antimicrobial potential of thio‐Schiff base ligand (HL) plus complexes (C1–C4) were tested. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal (II) chelates. Our flow cytometry data indicate significant levels of apoptosis and cell cycle arresting in both liver and breast cancer cell lines. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) constitute an assorted class of multi-dimensional materials that offer the potential to serve as luminescent sensors for the sensitive and selective detection of antibiotics in wastewater. Herein, a new Zn(II)-based MOF with the formula [Zn(PMA)0.5(bbp)·H2O·DMA] (1) (bbp = 3,5-bis(benzoimidazo-1-ly)pyridine; PMA = pyromellitic acid) was synthesized by a solvothermal method and characterized. Crystallographic analysis reveals that MOF 1 possesses a 4,4-connected net with the Schläfli symbol {32·4·52·6}2{32·42·52}. The fabricated MOF exhibited luminescent property and was employed as a luminescent sensor to sensitively and selectively detect tetracycline (TCY) antibiotic amongst thiamphenicol (THI), 2-methyl-4-chlorophenoxyacetic acid (MCPA), tetracycline (TCY), sulfamethoxazole (SMT), thiabendazole (TBZ), tinidazole (TDZ), sulfadiazine (SDZ), chloramphenicol (CAP), metamitron (MMT), and dinotefuran (DTF). Further, restoration of the emissive response of TCY@1 was achieved by adding salicylic acid with a concomitant bathochromic shift in the emissive response. The possible sensing mechanism and restoration of emissive response were assessed with the aid of theoretical calculations. [ABSTRACT FROM AUTHOR]

O-Vanillin derived Schiff base 1-[(E)-(2-hydroxy-3-methoxybenzylidene) amino]-4-methylthiosemicarbazone (VCOH) has been synthesized for colorimetric and fluorescence chemosensors towards PO43− ions. A fluorescence 'turn-on' sensing mechanism of VCOH towards PO43− ions has been explained due to emission from the VCO− ion formed upon transfer of the phenolic proton of VCOH to a PO43− ion. The 1 : 1 stoichiometry between the VCOH probe and PO43− ion is confirmed by Job's plot based on UV-vis titration. The limit of detection (LOD) of VCOH towards PO43− ions is found to be 0.49 nM. The PO43− ion sensing property of probe VCOH has been applied to prepare portable paper strips and for the analysis of real water samples. Fluorescence 'turn-on' and 'turn-off' responses of VCOH towards PO43−and H+ respectively have been used to construct a molecular logic gate. Fluorescence based sensing studies in which the concentration of analytes is adjusted over a broad range can be both laborious and expensive. In order to address these challenges, we have utilized various soft computing methods, including artificial neural networks (ANN), fuzzy logic (FL), and adaptive neuro-fuzzy inference systems (ANFIS), to appropriately model the 'turn-on' and 'turn-off' behaviors of the VCOH probe upon addition of PO43− and H+ respectively as well as to predict the experimental sensing data. [ABSTRACT FROM AUTHOR]

Square planar complexes of Ni(II) and Pd(II) of a new redox-active pentadentate azo-appended 2-aminophenol ligand (H4L = N,N′-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2′-diamino-ortho-azobenzene) in three accessible redox levels [amidophenolate(2−), semiquinonate(1−) π radical, and quinone(0)] were synthesized. The coordinated HL(3−) ligand provides four donor sites [two N(iminophenolates), an N′(azo), and an O(phenolate)], while the phenolic OH group remains free in the three complexes. Cyclic voltammetry on complex [Ni(L)] 1 and its corresponding Pd(II) analogue [Pd(L)] 2 in CH2Cl2 displayed three redox responses (two oxidative at E1/2 = 0.06 V and Epa (anodic peak potential) = 0.80 V and one reductive at −0.77 V for 1 and at E1/2 = 0.08 V and Epa = 0.85 V and at −0.74 V for 2vs. Fc+/Fc). The chemical oxidation of 1 with AgSbF6 afforded [Ni(L)]SbF6·2CH2Cl2 (3·2CH2Cl2). Complex [Pd(L*)] 4, which is coordinated by a phenoxazinyl derivative of L(4−), was obtained via intraligand cyclization in the parent complex 2 under basic oxidizing conditions. The molecular structures of 1, 2, 3·2CH2Cl2 and 4 were elucidated through X-ray crystallography at 100 K. Characterization using 1H NMR, X-band EPR, and UV–VIS–NIR spectroscopy established that the complexes have [NiII{(LISQ)˙2−}] 1, [PdII{(LISQ)˙2−}] 2, [NiII{(LIBQ)−}]SbF6/1+SbF6−(3), and [PdII{(L*AP)˙2−}] 4 electronic states. Complexes 1, 2, and 4 possess paramagnetic St (total spin) = 1/2 ground-state, whereas 3 is diamagnetic (St = 0). Density functional theory (DFT) electronic structural calculations at the B3LYP level rationalized the observed experimental results. Time-dependent (TD)-DFT calculations allowed us to identify the nature of the observed absorption spectra. [ABSTRACT FROM AUTHOR]

We present herein magneto-structural studies of three heterometallic Zn2Dy complexes: [Zn2Dy(L)2Cl2(H2O)](ClO4)·4H2O (1), [Zn2Dy(L)2Br2(H2O)](ClO4)·4H2O (2) and [Zn2Dy(L)2(OAc)I(H2O)]I3·4H2O (3), utilizing a new Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,2-diaminocyclohexane (H2L). Complexes 1 and 2 exhibit remarkable magnetic relaxation behaviour with relatively high energy barriers in zero field (Ueff: 244 K for 1 and 211 K for 2) and notable hysteresis temperatures, despite the low local geometric symmetry around the central DyIII ions. The SMM performance of these complexes is further enhanced under an applied magnetic field, with Ueff increasing to 309 K for 1 and 269 K for 2, positioning them as elite members within the Zn–Dy SMM family. These findings emphasize the substantial influence of remote modulation on ZnII beyond the first coordination sphere of DyIII ions on their dynamic magnetic relaxation properties. Ab initio studies demonstrate that the relative orientation of the phenoxo-oxygen donor atoms around the DyIII ion is critical for determining the magnetic anisotropy and relaxation dynamics in these systems. Additionally, experimental and theoretical investigations reveal that the coordination of the bridging acetate towards the hard plane, combined with significant distortion from the ideal ZnO2Dy diamond core arrangement caused by the acetate ion, results in low magnetic anisotropy in complex 3, thereby leading to field-induced SMM behaviour. Overall, this study unveils the effects of co-ligands on the SMM performance in a series of linear trinuclear Zn–Dy–Zn complexes, which exhibit low local geometric symmetry around the DyIII centres. [ABSTRACT FROM AUTHOR]

The present review deeply delves the major methods for the synthesis of organotellurium compounds along with their biological significance. Elaboration of various precursors (ligands) including Schiff bases, naphthoquinones, amino acids, β-hydroxy alkylated compounds, β-phenyltelluro alcohols, β-aryltelluro amines, β-aryl-chalcogenium azides, chalcogenobiotin, benzenesulfonamide, carbonic anhydrase, and Sulpha compounds has been briefly described. Furthermore, the article investigates their possible biological uses, specifically as antioxidant and anticancer agents while comparing their effectiveness with their respective ligands and with the standard medications in terms IC50 values. All types of details are haunted to make the information a priceless resource for researchers who wish to probe deeper into and examine the diverse roles that organotellurium complexes play in biological settings. [ABSTRACT FROM AUTHOR]

ABSTRACT Amid growing environmental concerns and the need for a sustainable future, green synthetic methodologies are gaining popularity for their simplicity and nontoxicity. In pursuit of the eco‐friendly synthesis of nanomaterials, the study reports an innovative synthesis of Ag‐CuO nanocomposites via the coprecipitation method utilizing Citrus limetta fruit juice extract as the bioreductant and stabilizing agent. The morphological and structural characteristics of the fabricated nanocomposites were evaluated by ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Raman and Brunauer–Emmett–Teller (BET) analyses. The nanocomposites were crystalline with particle sizes ranging from 15 to 24 nm and exhibited spherical and rod‐like shapes. The band gap value and specific surface area of the nanocomposites were found to be 1.5 eV and 25.50 m2/g, respectively. The photoluminescence (PL) analysis and electrochemical studies revealed significant charge separation and effective charge migration behaviour of the nanocomposites, respectively. The nanocomposites effectively catalysed the synthesis of Schiff bases from aryl aldehydes and aromatic amines at room temperature and without solvents. The reactions proceeded in a brief time with excellent product yields, and the nanocatalyst retained its activity for five consecutive cycles. The nanocomposites also efficiently catalysed the photodegradation of Congo red dye under visible light. A significant degradation of 94.33% was attained in 55 min, and the nanocatalyst maintained its efficacy over four consecutive reaction cycles. Moreover, the nanocomposites exhibited notable anticancer properties against the MCF‐7 (human breast) cell line, demonstrating a remarkable cytotoxicity rate of 87.79%. The findings highlight the efficacy of the biosynthesized nanocomposites in catalysis, environmental remediation and biological applications. [ABSTRACT FROM AUTHOR]

New magnetic yolk-shell mesoporous silica nanoparticles (Fe3O4@V-mSiO2-PNVCL) were prepared by grafting temperature-sensitive amino-terminated poly (N-vinylcaprolactam) (PNVCL-NH2) on the surface of aldehyde-functionalized magnetic mesoporous silica nanoparticles (Fe3O4@V-mSiO2-CHO) through a Schiff base reaction. Various characterizations were used to confirm the structures, and the drug loading and release behaviors were studied. The drug loading was achieved as PNVCL stretched at room temperature and the drug loading content was up to 54.7% due to the large cavities. The encapsulation of drug from leakage in the blood environment was realized as PNVCL collapsed at physiological temperature. The fracture of pH-liable imine bonds in a slightly acidic tumor environment triggered the burst release of cargo. The Fe3O4@V-mSiO2-PNVCL showed super paramagnetic behavior (21.01 emu∙g−1) which could achieve magnetic targeting. The MTT assay confirmed that the nanoparticles exhibited low cytotoxicity. Furthermore, the cellular uptake experiments indicated that DOX-loaded nanoparticles were successfully internalized into cancer cells. Therefore, the composite nanoparticles are ideal choices for drug carriers. [ABSTRACT FROM AUTHOR]

In recent years, extensive research has focused on cannabidiol (CBD), a well-studied non-psychoactive component of the plant-derived cannabinoids. CBD has shown significant therapeutic potential for treating various diseases and disorders, including antioxidants and anti-inflammatory effects. Due to the promising therapeutic effect of CBD in a wide variety of diseases, synthetic derivatization of this compound has attracted the attention of drug discovery in both industry and academia. In the current research, we focused on the derivatization of CBD by introducing Schiff base moieties, particularly (thio)-semicarbazide and aminoguanidine motifs, at the 3-position of the olivetolic ring. We have designed, synthesized, and characterized new derivatives based on CBD's framework, specifically aminoguanylhydrazone- and (thio)-semicarbazones-CBD-aldehyde compounds. Their antioxidant potential was assessed using FRAP and DPPH assays, alongside an evaluation of their effect on LDL oxidation induced by Cu2+ and AAPH. Our findings suggest that incorporating the thiosemicarbazide motif into the CBD framework produces a potent antioxidant, warranting further investigation. [ABSTRACT FROM AUTHOR]

Several novel copper (II) complexes of reduced Schiff bases containing fluoride substituents were prepared and structurally characterized by single-crystal X-ray diffraction. The complexes exhibited diverse structures, with the central atom in distorted tetrahedral geometry. The biological effects of the products were evaluated, specifically their cytotoxicity, antimicrobial, and antiurease activities, as well as affinity for albumin (BSA) and DNA (ct-DNA). The complexes showed marked cytotoxic activities in the HepG2 hepatocellular carcinoma cell line, considerably higher than the standard cisplatin. The cytotoxicity depended significantly on the substitution pattern. The best activity was observed in the complex with a trifluoromethyl group in position 4 of the benzene ring—the dichloro[(±)-trans-N,N′-bis-(4-trifluoromethylbenzyl)-cyclohexane-1,2-diamine]copper (II) complex, whose activity (IC50 28.7 μM) was higher than that of the free ligand and markedly better than the activity of the standard cisplatin (IC50 336.8 μM). The same complex also showed the highest antimicrobial effect in vitro. The affinity of the complexes towards bovine serum albumin (BSA) and calf thymus DNA (ct-DNA) was established as well, indicating only marginal differences between the complexes. In addition, all complexes were shown to be excellent inhibitors of the enzyme urease, with the IC50 values in the lower micromolar region. [ABSTRACT FROM AUTHOR]

A curious and noticeable structural feature in Schiff bases from 2-aminoaldoses is the fact that imino tautomers arranged equatorially in the most stable ring conformation exhibit a counterintuitive reverse anomeric effect (RAE) in the mutarotational equilibrium, i.e., the most stable and abundant anomer is the equatorial one (β). As shown by our very recent research, this effect arises from the total or partial inhibition of the exo-anomeric effect due to the presence of an intramolecular hydrogen bond between the anomeric hydroxyl and the iminic nitrogen in the axial anomer (α). When the Schiff base adopts either an enamine structure or the imino group is protonated, the exo-anomeric effect is restored, and the axial α-anomer becomes the most stable species. Although the intramolecular H-bonding should appropriately be interpreted as a genuine stereoelectronic effect, the magnitude of the RAE could be affected by other structural parameters. Herein and through a comprehensive analysis of benzylidene, cinnamylidene, naphthalene, phenanthrene, and anthracene aldehydes, we show the robustness of the RAE effect, which is similar in extent to simple aldehydes screened so far, irrespective of the size and/or hydrophobicity of the substituent at the nitrogen atom. [ABSTRACT FROM AUTHOR]

An electroactive polyazomethine was prepared directly on a transparent electrode by the polycondensation of bis(triphenylamine) dialdehyde and its complementary methoxytriphenylamine diamine. The spray-and-bake method of coating the electrode for preparing electrochromic layers could be upscaled to prepare working devices larger than standard test devices. The film prepared by thermally annealing the complementary monomers was both electroactive and switched its color with an applied potential. The yellow electrochromic polyazomethine could be electrochemically oxidized reversibly to obtain a blue film. The electrochromic test device fabricated from the polyazomethine was operated upwards of 1 h for performance assessment. The electrochromic response times of the electrochromic device were ca. 3.3 and 1.2 s for the coloration and bleaching, respectively. The upscaled device prepared by the straightforward coating approach had consistent metrics with the small-area test device. [ABSTRACT FROM AUTHOR]

The present study focuses on the synthesis and structural characterization of a novel dinuclear CuII complex, [trichloridocopper(II)]-μ-chlorido-{bis[2-hydroxy-N′-(propan-2-ylidene)benzohydrazide]copper(II)} monohydrate, [Cu2Cl4(C10H12N2O2)2]·H2O or [Cu(H2L)2(μ-Cl)CuCl3]·H2O [H2L = 2-hydroxy-N′-(propan-2-ylidene)benzohydrazide]. The complex crystallizes in the monoclinic space group P21/n with one molecule of water, which forms interactions with the ligands. The first copper ion is penta-coordinated to two benzohydrazine-derived ligands via two nitrogen and two oxygen atoms, and one bridging chloride, which is also coordinated by the second copper ion alongside three terminal chlorines in a distorted tetrahedral geometry. The arrangement around the first copper ion exhibits a distorted geometry intermediate between trigonal bipyramidal and square pyramidal. In the crystal, chains are formed via intermolecular interactions along the a-axis direction, with subsequent layers constructed through hydrogen-bonding interactions parallel to the ac plane, and through slipped π–π stacking interactions parallel to the ab plane, resulting in a three-dimensional network. The intermolecular interactions in the crystal structure were quantified and analysed using Hirshfeld surface analysis. Residual electron density from disordered methanol molecules in the void space could not be reasonably modelled, thus a solvent mask was applied. [ABSTRACT FROM AUTHOR]

Organic compounds display several electronic and structural features which enable their application in various fields, ranging from biological to non-biological. These compounds contain heteroatoms like sulfur, nitrogen and oxygen, which provide coordination sites to act as ligands in the field of coordination chemistry and are used as chemosensors to detect various metal ions. This review article covers different organic compounds including thiourea, Schiff base, pyridine, thiophene, coumarin, triazolyl pyrenes, imidazole, fluorescein, thiazole, tricarbocyanine, rhodanine, porphyrin, hydrazone, benzidine and other functional groups based chemosensors, that contain heteroatoms like sulfur, nitrogen and, oxygen for fluorimetric and colorimetric detection of Ag+ in different environmental, agricultural, and biological samples. Further, the sensing mechanism and performances of these chemosensors have been discussed, which could help the readers for the future design of highly efficient, selective, and sensitive chemosensors for the detection and determination of Ag+ ions. [ABSTRACT FROM AUTHOR]

The new methacrylic azomethine-containing monomers with side chain quinoline moiety were synthesized by reaction of their corresponding alcohols with methacryloyl chloride. The polymers based on new monomers were synthesized by free radical polymerization. Polymers were characterized by 1HNMR spectroscopy, and the results of their photochemical and optical activities are presented. [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]

Developing environmentally benevolent and sustainable approaches is a vital objective of research in any field. By upholding these parameters and strategizing the methodology, herein we report the development of a new heterogeneous nanocatalyst based on Schiff base functionalized Pd(II) complex onto titania-coated magnetic nanoparticles [Pd@SB/Fe3O4–TiO2]. The developed catalytic system is well characterized with various techniques such as FE-SEM, TEM, XPS, XRD, TGA, BET, FTIR, VSM, CHN, EDX, and ICP-AES analysis. The catalytic activity of [Pd@SB/Fe3O4–TiO2] for the Suzuki coupling reaction to synthesize biaryls and for the hydrogenation reaction of aromatic nitro compounds to synthesize aromatic amines under sustainable reaction conditions was tested which revealed excellent results. Pd@SB/Fe3O4–TiO2 showed remarkably higher activity than the homogeneous PdCl2 and Pd(OAc)2, which might be due to the presence of electronic synergism between support and Pd. Schiff base functionalization provides excellent support to the palladium as leaching of the metal was not observed. The magnetic core of the catalyst ascertains its easy recoverability, thereby maintaining the sustainability of the reaction. The magnetic catalyst was easily separable with the help of an external magnet and showed very good recyclability for up to six cycles with no appreciable loss in catalytic efficiency. Furthermore, the reported catalyst remains unchanged even after six consecutive runs as established by the FTIR, XPS, and XRD analysis of the recovered catalyst. [ABSTRACT FROM AUTHOR]

Reactions of a chromone‐based hydrazone (SalHFC; HL) with Ni(II), Co(II), and Cd(II) ions yielded new solid chelates with the general formula [M(L)X].nZ, M = Ni(II), Co(II) and Cd(II), X = NO3− or OAc−, n = 0.5–2, Z = H2O or EtOH for complexes 1, 3, 4, 6, 7, 8 and [M2(L)(OAc)3X].0.5EtOH.nH2O, M = Ni(II) and Co(II), X = H2O or EtOH, n = 1 or zero for complexes 2 and 5. The synthesized chelates have been successfully characterized by means of different analytical and spectroscopic tools. SalHFC performs as a monoanionic tridentate in all chelates except chelate 2 and 5 (monoanionic tetradentate). Molar conductivity measurements demonstrated a non‐electrolytic manner of all chelates. Nickel(II) and cobalt(II)‐SalHFC chelates displayed tetrahedral geometries whereas cadmium(II) chelates (7 and 8) were octahedral. TG was employed to inspect the thermal degradation patterns of SalHFC‐complexes, and the Coats‐Redfern equations were employed to estimate the kinetic parameters of the thermal degradation steps. Density functional theory (DFT) level implementation in the Gaussian 09 program at B3LYP/6‐311G(d,p) level was efficaciously used to predict the molecular structural properties of SalHFC and its chelates and the theoretical data and experimental findings were then integrated. SalHFC and its chelates displayed anticancer action against the HepG2 cell line and the results were verified by molecular docking studies. [ABSTRACT FROM AUTHOR]

Levofloxacin and 4‐aminoantipyrine undergo a condensation process to synthesize a novel Schiff base ligand (L). Metal complexes containing Co(II), Cu(II), Cd(II), Mn(II), Zn(II), Cr(III), Ni(II), and Fe(III) metal ions are prepared using this Schiff base ligand. The new ligand and its complexes are characterized by elemental analyses, Fourier transform infrared, mass spectrometry, ultraviolet–visible, magnetic moment, 1H‐NMR, molar conductivity, and powder X‐ray diffraction, and further thermogravimetric analysis (TG, DTA) verifies their thermal stability. The metal to ligand ratio is 1:1, according to the analytical results. Spectroscopic methods reveal that metal complexes are expected to have an octahedral geometry and demonstrate a neutral tridentate ligand behavior. It also becomes apparent from the molar conductivity values that all metal complexes are electrolytic in nature except zinc(II) and cadmium(II) complexes which are non‐electrolytes. Moreover, the bioactivity of the compounds are investigated. The antibacterial activity is investigated in relation to various Gram‐positive and Gram‐negative bacteria. The results give good indication for higher activity of the prepared compounds than the standard antibiotic drug. Also, the antioxidant activity of the newly prepared ligand and its complexes has been investigated via 2,2‐diphenyl‐1‐picrylhydrazyle (DPPH) free radical scavenging assay. The findings show that Schiff base complexes exhibit good antioxidant activity. Finally, theoretical density functional theory using density functional theory/B3LYP method and molecular docking studies with two receptors of 3T88 and 3Q8U are calculated for the investigated compounds. [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]

Four novel lanthanide La (III), Ce (III), Nd (III), and Dy (III) complexes with (Z)‐4‐(benzo[d]thiazol‐2‐ylamino)‐3‐((benzo[d]thiazol‐2‐ylimino)methyl)‐2H‐chromen‐2‐one (L) were prepared and characterized. The novel compounds' structural compositions were elucidated by the application of analytical and spectroscopic methodologies. From physical and chemical measurements, the general formula for the [LnLCl3]2H2O complexes (C1‐C4) was proposed, which was proven by theoretical measurements. Using cisplatin, gentamicin, ampicillin, and ascorbic acid as standards, the compound's anticancer, antibacterial, and antioxidant qualities were assessed, and activities followed the order: Ce (III)L(C2) > Nd (III)L(C3) > Dy (III)L(C4) > La (III)L(C1) > L where the Ce (III) complexes exhibited the highest activity followed by Nd (III) complexes. Molecular docking studies were performed using the MOA2022 software to identify putative binding mechanisms for the methionine adenosyl‐transferases in liver cancer (PDB ID: 5A19) and the most active site of the Bacillus subtilis receptor (PDB ID: 5e6k), where the strength of the interaction increases with the negative binding energy L ˂ [LaLCl3] ˂ [DyLCl3] ˂ [NdLCl3] ˂ [CeLCl3]. [ABSTRACT FROM AUTHOR]

Equimolar reactions of Zn2+ and Cd2+acetates with the carbothiohydrazide, [2‐HO‐C6H4‐C(H) = N‐N(H)‐C(=S)‐N(C2H4)2O] chelating agent (H2L) have produced the binuclear [M(L)]2 metal chelates. The isolated compounds have been evaluated by elemental analyses, XRD, molar conductivities, 1H and 13C‐NMR, FTIR, FAB‐MS, UV–Vis, and thermal analyses. The crystal structure of the chelating agent has been resolved and indicates the presence of the chelating agent exclusively in its E conformer regarding the C(H) = N bond. Elemental analyses and molar conductance data indicated that the investigated metal chelates are nonelectrolytes and were formed with 2 M:2 L stoichiometry. FT‐IR along 1H‐NMR spectral data gave evidence for a di‐anionic chelating agent that bonded with central metal ions via azomethine N, deprotonated phenolic O, and thiolate S atoms. The anti‐corrosion performance of the chelating agent and its metal chelates have been evaluated for protecting carbon steel (CS) in 15% HCl aqueous solution using electrochemical examination (EIS and PDP), surface examination (SEM and XPS) and theoretical approach (DFT calculations and MC simulation). The results revealed that [Zn(L)]2 complexes remarkably performed with an inhibition efficiency of about 94.7%, which was better than those for [Cd(L)]2 complex (93.0%) and H2L (88.2%), respectively. The EIS results revealed the gradual rise of charge transfer resistance (Rct) with concentration, while the PDP proved the mixed‐type inhibition performance with cathodic advantage consistent with the Langmuir adsorption model. It was verified that the Zn (II) complex could adsorb on the metallic surface, forming a protective layer responsible for mitigating the corrosion reaction and ions diffusion. This study provided novel inhibitors with structures designed and developed for inhibiting the corrosion process with marked performance. The results derived from various methodologies contribute to a substantiated interpretation of the mechanism of inhibition. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel porous metal–organic framework named Co2(bbda)2(DMF)2·5H2O, or MOF‐UoR‐1, synthesized via hydrothermal techniques employing a unique Schiff base ligand. The framework underwent comprehensive characterization, confirming its microporous nature through gas‐sorption measurements. MOF‐UoR‐1 demonstrated remarkable efficacy as a catalyst for the one‐step synthesis of pyrimidine analogs. Structural validation of the synthesized pyrimidines was accomplished via 1H‐nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) analyses. Through systematic experimentation, the optimal catalyst dosage (40 mg) was determined, showcasing its effectiveness across various aldehydes, 1,3‐carbonyl compounds, and urea substrates. Noteworthy is the broad applicability of this environmentally friendly protocol, which offers advantages such as high yields (96%), rapid reaction times (90 min), straightforward product isolation, and product purity without necessitating column chromatography. Furthermore, the catalytic integrity of the framework remained intact, enabling its reuse without compromising performance. This research presents a promising approach for the synthesis of pyrimidine derivatives, with significant implications for sustainable and efficient chemical synthesis methodologies. [ABSTRACT FROM AUTHOR]

Purpose: The paper aims to the preparation of novel disperse dye based on azo salicylaldehyde derivatives TF-A [2-hydroxy-5-((3-(trifluoromethyl)phenyl)diazenyl)benzaldehyde] and full evaluation of their use as disperse dye TF-ASC [bis 2-hydroxy-5-((3-(trifluoromethyl)phenyl)diazenyl)benzaldehyde Schiff base with 4,4'-methylenedianiline] for dyeing polyester fabric at various conditions. Design/methodology/approach: The dispersed dye was synthesized via Schiff base condensation in the presence of ceric ammonium nitrate cerium ammonium nitrate 10 mmole% as an eco-friendly catalyst at room temperature. The chemical structure of the prepared dye was characterized via elemental analysis, Fourier-transform infrared spectroscopy, 1H- and 13 C-NMR spectroscopic analysis tools. This study thoroughly examined the dyeing of disperse dye TF-ASC on polyester at various conditions. The characteristics of dyed polyester fabric were measured by colour measurements, as well as light, washing, crock fastness and finally, colour strength. The discrete fourier transform (DFT) theoretical studies, including EHOMO, ELUMO and optimized geometrical structure, were assumed and discussed in detail. Findings: The results showed that the synthesized organic dye TF-ASC was highly functional and appropriate for this kind of dyeing method. The dyeing fabrics obtained from disperse dye TF-ASC, properties possess high colour strength as well as good overall fastness properties. These dyes had a high affinity for polyester fabric, with just a tiny change in dye affinity when the pH was changed, even under alkaline circumstances. The dye levelness and shade depth of the colour results were good, and there were a variety of hues from light brownish yellow to deep brownish yellow. The results obtained from DFT computational studies such as EHOMO, ELUMO, optimized structure, diploe moment µ and electrophilicity index deduced that prepared organic dye TF-ASC is more applicable as a dispersed dye. Originality/value: This research is significant because it provides a new dye for dyeing polyethylene terephthalate fibres with exceptional brightness and levelness; the method of preparation is a useful pathway due to its being known as a green chemistry method. [ABSTRACT FROM AUTHOR]

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

In situ mesenchymal stem cells (MSCs) regenerative therapy holds promising potential for treating osteoarthritis. However, MSCs engraftment and intra-articular inflammation limit the therapeutic efficacy of this approach. This study introduces porous microspheres (PMs) composed of aldehyde-modified poly(lactic-co-glycolic acid), that encapsulate platelet derived growth factor-AB and kartogenin. Metformin (Met) is also incorporated onto the microsphere through a Schiff base reaction to create PMs@Met. In vitro, in vivo and ex experiments revealed that PMs@Met can be injected into the joint cavity, effectively recruiting endogenous MSCs in situ. This approach creates a favorable environment for MSCs proliferation. It also controls the intra-articular inflammatory environment by modulating the polarization of synovial macrophages, ultimately promoting cartilage repair. In summary, our study presents an innovative tissue engineering strategy for the treatment of osteoarthritis-induced articular cartilage injuries. Cell therapy using autologous mesenchymal stem cells (MSCs) has potential to slow the progression of osteoarthritis (OA). Nonetheless, there are some disadvantages to adopting in situ MSCs therapy, including difficulties with MSC engraftment into cartilage-deficient regions, the effect of intra-articular inflammation on MSC therapeutic efficacy, and attaining selective chondrogenic MSC differentiation. We created injectable PLGA microspheres (PMs) that were loaded with PDGF-AB and KGN. Metformin was bonded to the surface of microspheres using a Schiff base reaction. The microspheres can recruit intra-articular MSCs and encourage their development into chondrocytes. The microspheres actively modulate the inflammatory joint environment by altering synovial macrophage polarization, thereby supporting MSCs in effective cartilage treatment. To summarize, microspheres hold great potential in the treatment of OA. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a previously unknown aldazine, N’-[4-((E)-{(2Z)-[(12-{[(1E)- (dimethylamino)methylene]amino]amino}-2,3-dihydro-1H-benzo[b]xanthene4-yl)methylene]hydrazone}methyl]-2,3-dihydro-1H-benzo[b]xanthene-12-yl]-N,Ndimethylimidoforma-mide was synthesized by reacting the corresponding aldehyde with hydrazine hydrate. The spectral characteristics of the two azomethine dyes were studied: N,N-dimethyl-N’-{4-[(E)-(phenylimino)methyl]-2,3-dihydro-1H-xanthen-9- yl}imidoformamide and N’-[4-((E)-{(2Z)-[(12-{[(1E)-(dimethylamino)methylene]amino]- 2,3-dihydro-1H-benzo[b]xanthen-4-yl)methy-lene]hydrazono}methyl]-2,3-dihydro-1Hbenzo[b]xanthen-12-yl]-N,N-dimethylimidoformamide. Both dyes exhibit a bathochromic shift in their absorption maxima at lower pH levels. The observed deepening of the color can be attributed to the protonation of the azomethine nitrogen atom and the change in the hybridization of the orbital that carries the unpaired electron pair of the azomethine nitrogen atom, switching from the sp² orbital to the unhybridized p-orbital, which is capable of conjugation with the xanthene fragment. The color of N,N-dimethyl-N’-{4- [(E)-(phenylimino)methyl]-2,3-dihydro-1H-xanthen-9-yl}imidoformamide changes from yellow to red as the pH decreases, while the color of N’-[4-((E)-{(2Z)-[(12-{[(1E)- (dimethylamino)methylene]amino]-2,3-dihydro-1H-benzo[b]xanthen4-yl)methylene]hydrazono}methyl]-2,3-dihydro-1H-benzo[b]xanthen-12-yl]-N,Ndimethylimidoformamide shifts from red to blue. The synthesized dyes have potential as pH indicators in acidic environments. These dyes demonstrate a color change not only in response to pH reduction but also in the presence of transition metal salts. [ABSTRACT FROM AUTHOR]

In our antioxidant screening of some Vietnamese plant extracts, the CHCl3-soluble fraction from Calotropis gigantea (L.) W.T.Aiton flowers showed moderate DPPH free radical scavenging activity with an IC50 value of 55.8 μg/mL. Thus, a further phytochemical study was carried out to obtain five alkaloids, including a new β-carboline-type alkaloid, caloside H (1). These known compounds were identified as 5-hydroxy-(2-methoxymethyl)pyridine (2), nicotinic acid (3), p-(acetylamino)phenol (4), and thymine (5). These structures were determined based on the NMR spectroscopic analysis. In antioxidant assay, caloside H at concentration of 100 μM showed DPPH radical scavenging capacity with a percentage of inhibition of 40.2%. In addition, a plausible biosynthetic pathway for the formation of caloside H was proposed based on the Schiff base formation and Mannich-like reaction. [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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In this study, new chitosan Schiff base functionalized malic acid (CS-SB/MA) and its Fe2O3 (CS-SB/MA/Fe) composite were prepared through a simple route and characterized by different techniques including FT-IR, XRD, TGA, DSC, FESEM, and BET. The characterization results indicated that the desired compounds, CS-SB/MA and CS-SB/MA/Fe, were successfully prepared. In addition, the adsorption of Eosin Y (EY) from aqueous solution using the as-prepared compound, CS-SB/MA/Fe, was studied. The influence of important parameters such as pH solution and contact time were also studied and reported. EY adsorption by the as-prepared CS-SB/MA/Fe2O3 composite was found to be optimal at a pH solution of 5, a contact time of 90 min, and an adsorbent dosage of 0.02 g. The maximum removal percentage and adsorption capacity were calculated to be 93.56% and 65.52 mg/g, respectively. The EY adsorption followed by the pseudo-second-order (PSO) kinetic model as a chemisorption process including different interactions between anionic groups of EY and the functional groups of CS-SB/MA/Fe. Therefore, the prepared chitosan-base adsorbent, CS-SB/MA/Fe, has great potential application for the removal of organic dyes from wastewater. [ABSTRACT FROM AUTHOR]

Integrating multi‐step reactions through tandem catalysis offers potential for efficient chemical engineering processes, but designing an efficient tandem catalyst is challenging. Herein, we report tailoring the d‐band centers of Ni through alloying with a second metal (M = Fe/Co/Cu/Ga), which enables it to be multifunctional site for tandem reductive amination. A linear correlation of d‐band center with yield of primary amine product was observed. Density functional theory and experiments revealed the upshifted d‐band center strengthened the adsorption of Schiff base intermediate in advantageous di(C&N) mode, also narrowed the adsorption energy gap between NH3 and H2. Furthermore, the multifunctional nanoparticles provide a confined space with short diffusion pathway for NH3* and H* to timely react with Schiff base. As a result, the NiFe/AlOx with a d‐band center nearest to the Fermi level exhibited the highest primary amine yield of 96.2% with five consecutive reusability under extremely low H2 pressure, which is superior to other reported precious‐metal‐based catalysts. [ABSTRACT FROM AUTHOR]

Conventional thermosetting polymers, mostly derived from nonrenewable petroleum resources, are not reprocessable and recyclable due to their highly cross-linked three-dimensional networks and face the disadvantage of high flammability. To solve these issues, in this study, we synthesized a novel Schiff base covalent adaptable thermoset from a furan-derived tri-aldehyde monomer (TMFP) and a furan-derived di-amine monomer (DFDA). The as-prepared TMFP-DFDA-Vitrimer exhibited superior anti-flammability with a high limiting oxygen index (LOI) of 35.0% and a UL-94 V-0 rating, which was attributed to the excellent charring ability. Additionally, TMFPDFDA-Vitrimer could also be conveniently recycled by chemical decomposition under a mixed hydrochloric acid/tetrahydrofuran (HCl/THF) solution. After recycling for 5 times, the thermal, mechanical, and flame retardant properties of the recycled TMFP-DFDA-Vitrimer retained almost unchanged compared to the original one. This work provides a prime instance to develop advanced thermosetting polymers from abundant furan-based compounds. [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.)