Bidentate Chelating Research Articles

Enhanced Electrochemical Performance of Copper(II) Metal Organic Framework‐Ternary Quantum Dots Composite towards the Detection of Bisphenol A

AbstractTernary quantum dot metal organic framework (MOFs) composite sensor formulated as (ZnInSe2@[Cu(2‐HNA)2(H2O)]) with an enhanced electrochemical performance was synthesized from a copper(II) metal‐organic framework complex ([Cu(2‐HNA)2(H2O)]) and ZnInSe2 ternary quantum dot (TQDs). The compounds were characterized by Fourier transform infrared spectroscopy, Ultraviolet‐Visible spectroscopy, transmission electron microscopy, scanning electron microscopy, single crystal X‐ray crystallography, and photoluminescence. Molecular structure of the copper(II) complex revealed a distorted square pyramidal geometry with two molecules of 2‐hydroxy‐1‐naphthaldedyde at the basal planes as bidentate chelating ligands with a coordinated water molecule at the apical position. TEM micrographs revealed monodispersed composite with an average particle size of 3.2 nm. The composite and its precursors were used as ectrochemical sensor for the detection of bisphenol A, using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. The composite modified on a gold electrode exhibited enhanced electrochemical performance in comparison to those of the MOFs and TQDs. The reaction process at the surface of the modified electrode with the composite is diffusion controlled with a limit of detection, and limit of quantitation of 4.70 nM and 14.26 nM over a concentration range of 10–50 nM (S/N=3). The gold modified composite electrode is stable and could serve as a model for the development of electrochemical sensor to determine BPA.

Synthesis, crystal structure and exploration of N,N'-(ethane-1,2-diyl)bis(4-acetylbenzenesulfonamide) (EDBABS) fabricated glassy carbon electrode as highly sensitive barium (Ba2+) sensor: An electrochemical approach

Environmental pollution spurred by dint of noxious chemicals and heavy metals has popped up as a pressing threat for present day community. In this study, we synthesized the N,N'-(ethane 1,2-diyl)bis(4-acetylbenzene-1-sulfonamide) (EDBABS) and N,N'-(cyclohexane-1,2-diyl)bis(4-acetylbenzenesulfonamide) (CDBABS) as bidentate chelating agents with the intention to detect the heavy metal cations in water systems. Conventional spectroscopic techniques such as UV-Vis spectroscopy, Fourier transform-infra red (FT-IR) spectroscopy, 1H-NMR and 13C-NMR in addition to single crystal X-ray diffraction studies were performed to expound structural characterization data of these newly synthesized non-reported bidentate chelating agents. After Characterization, a novel electrochemical current – potential (I-V) approach based on their modified GCEs was applied to detect the toxic cations in water systems. For this purpose, Keithley electrometer was employed as a constant voltage source. On the trail of fabricating an efficient as well as selective electrochemical sensor, for the detection of heavy metal cations in phosphate buffer system of pH = 7.0, EDBABS and CDBABS coupled with nafion as adhesive conducting binder were coated separately onto the Glassy Carbon Electrodes (GCEs). it was delineated that newly designed EDBABS/Nafion/GCE induced a high current response for Ba2+ cations in the presence of other interfering heavy metal cations (Y3+, Sn2+, Sb3+, Mn2+, Hg2+, Cr3+, As3+ and Ag+) than CDBABS/Nafion/GCE and found to be selective and sensitive towards Ba2+ cations, predominantly contributing towards environmental pollution. In order to optimize this newly designed EDBABS/Nafion/GCE as selective electrochemical Ba2+ cationic sensor, different analytical parameters such as sensitivity, limit of detection (LOD) at S/N of 3, limit of quantification (LOQ), and linear dynamic range (LDR) turned out to be satisfactory towards Ba2+ cations. The calibration curve emerged to be linear with a broad concentration range of Ba2+ cations from 0.1 nM to 0.01M and sensitivity was estimated as 3.481 × 10−3µAµM−1cm−2 in addition to (r2) as 0.9834, limit of detection (LOD) as 0.027nM (at S/N=3) and limit of quantification (LOQ) as 0.091nM. Within the realm of extensive environmental protection and public health care field, this work inducts a reliable and effective way for the fabrication of sensitive as well as selective cationic electrochemical sensors based on chelating agents which can be launched as an advanced approach for quick probing of heavy metal cations in water systems, reliably and effectively.

Leveraging Phenazine‐Based Ligands for Optimized Perovskite Optoelectronic Performance Through Chelation and Redox Engineering

AbstractPerovskite nanocrystals (PNCs) hold immense potential for optoelectronic and photovoltaic applications. However, their performance is hindered by surface defects that promote non‐radiative recombination and reduce stability. Surface engineering, particularly through defect passivation, is crucial for achieving high‐performing perovskite solar cells. Chelation has been shown to significantly improve the efficiency and stability of perovskite solar cells. In this study, a novel chelation strategy using 1,10‐Phenanthroline (Phen) is presented as a bidentate chelating ligand to effectively target and passivate these detrimental surface defects. By strategically designing a Phenanthroline derivative, dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine (Phen‐derivative) with optimized redox potentials, dual functionality: efficient defect passivation and hole transport is achieved. X‐ray photoelectron spectroscopy (XPS) confirms the superior binding capability of the Phen‐derivative due to chelation. This strong interaction facilitates efficient and ultrafast charge transfer from PNCs and the formation of a long‐lived charge‐separated state, as evidenced by sustained bleaching in transient absorption spectra. A metal‐dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine complex (Ir‐complex) derived from dipyrido[3,2‐a:2′,3′‐c]phenazin‐11‐amine, but lacking a chelation site, hinders desired hole transfer despite similar charge transfer energetics. This work emphasizes the critical role of chelation‐mediated interfacial interactions and energy alignment in designing effective charge shuttle molecules and unlocking the potential of lead‐chelating hole transporters for next‐generation light‐harvesting technologies.

Structural and Biological Studies of Bioactive Silver(I) Complexes with Coumarin Acid Derivatives.

Two new Ag(I) complexes with coumaric carboxylic acid derivatives have been synthesized. Structural studies of these noncrystalline complexes have been performed using a methodology that combines laboratory and synchrotron techniques, supported by density functional theory calculations. The arrangement of ligands around the Ag(I) cation has been refined using infrared, extended X-ray absorption fine structure, and X-ray absorption near edge structure spectroscopies. Different coordination modes of carboxylate ligands are observed for the studied compounds. Carboxylate bridges are characteristic for the Ag(I) complex with 4-oxo-4H-1-benzopyran-2-carboxylic acid (1), while a bidentate chelating motif was found for the complex with 2-oxo-2H-1-benzopyran-3-carboxylic acid (2). Additionally, the carbonyl oxygen atom of the coumarin ring coordinates to the silver cation in complex 2, while it is inactive in complex 1. Antimicrobial evaluation has been performed for both compounds. The complexes show activity against selected bacteria as well as Candida yeast. This activity is slightly lower for bacteria and the same or higher for Candida in relation to the reference substances: ciprofloxacin or fluconazole.

Enantioselective formal (3 + 3) cycloaddition of bicyclobutanes with nitrones enabled by asymmetric Lewis acid catalysis

The absence of catalytic asymmetric methods for synthesizing chiral (hetero)bicyclo[n.1.1]alkanes has hindered their application in new drug discovery. Here we demonstrate the achievability of an asymmetric polar cycloaddition of bicyclo[1.1.0]butane using a chiral Lewis acid catalyst and a bidentate chelating bicyclo[1.1.0]butane substrate, as exemplified by the current enantioselective formal (3 + 3) cycloaddition of bicyclo[1.1.0]butanes with nitrones. In addition to the diverse bicyclo[1.1.0]butanes incorporating an acyl imidazole group or an acyl pyrazole moiety, a wide array of nitrones are compatible with this Lewis acid catalysis, successfully assembling two congested quaternary carbon centers and a chiral aza-trisubstituted carbon center in the pharmaceutically important hetero-bicyclo[3.1.1]heptane product with up to 99% yield and >99% ee.

Passivating perovskite surface defects via bidentate chelation for high-performing solar cells

Surface defects seriously damage carrier transport by forming non-radiative recombination centers on the perovskite film, which negatively affect the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Here we present a strong chelate coordination bond to anchor the surface of the perovskite film. Employing Bathophenanthroline (BPhen) as a π-conjugated bidentate chelator, the uncoordinated Pb2+ can be firmly anchored accompanying with the reduced surface recombination sites, giving rise to suppressed non-radiative recombination and enhanced charge carrier extraction. With the BPhen, the perovskite film shows an approximately threefold longer carrier lifetime than the control device, leading to a champion PCE of 24.09 % and a high stable performance with retained over 80 % of its initial efficiency after 1000 h exposed to relative humidity (RH) of 65 ± 5 %.

Bis(amino acidato)copper(II) compounds in blood plasma: a review of computed structural properties and amino acid affinities for Cu2+ informing further pharmacological research.

Neutral bis(amino acidato)copper(II) [Cu(aa)2] coordination compounds are the physiological species of copper(II) amino acid compounds in blood plasma taking the form of bis(l-histidinato)copper(II) and mixed ternary copper(II)-l-histidine complexes, preferably with l-glutamine, l-threonine, l-asparagine, and l-cysteine. These amino acids have three functional groups that can bind metal ions: the common α-amino and carboxylate groups and a side-chain polar group. In Cu(aa)2, two coordinating groups per amino acid bind to copper(II) in-plane, while the third group can bind apically, which yields many possibilities for axial and planar bonds, that is, for bidentate and tridentate binding. So far, the experimental studies of physiological Cu(aa)2 compounds in solutions have not specified their complete geometries. This paper provides a brief review of my group's research on structural properties of physiological Cu(aa)2 calculated using the density functional theory (DFT) to locate low-energy conformers that can coexist in aqueous solutions. These DFT investigations have revealed high conformational flexibility of ternary Cu(aa)2 compounds for tridentate or bidentate chelation, which may explain copper(II) exchange reactions in the plasma and inform the development of small multifunctional copper(II)-binding drugs with several possible copper(II)-binding groups. Furthermore, our prediction of metal ion affinities for Cu2+ binding with amino-acid ligands in low-energy conformers with different coordination modes of five physiological Cu(aa)2 in aqueous solution supports the findings of their abundance in human plasma obtained with chemical speciation modelling.

Organic-Inorganic Coupling Strategy: Clamp Effect to Capture Mg2+ for Aqueous Magnesium Ion Capacitor.

The rapid transport kinetics of divalent magnesium ions are crucial for achieving distinguished performance in aqueous magnesium-ion battery-based energy storage capacitors. However, the strong electrostatic interaction between Mg2+ with double charges and the host material significantly restricts Mg2+ diffusivity. In this study, a new composite material, EDA-Mn2O3, with double-energy storage mechanisms comprising an organic phase (ethylenediamine, EDA) and an inorganic phase (manganese sesquioxide) was successfully synthesized via an organic-inorganic coupling strategy. Inorganic-phase Mn2O3 serves as a scaffold structure, enabling the stable and reversible intercalation/deintercalation of magnesium ions. The organic phase EDA adsorbed onto the surface of Mn2O3 as an elastic matrix, works synergistically with Mn2O3, and utilizes bidentate chelating ligands to capture Mg2+. The robust coordination effect of terminal biprotonic amine in EDA enhances the structural diversity and specific capacity characteristics of the composite material, as further corroborated by density functional theory (DFT) calculations, ex-situ XRD, XPS, and Raman spectroscopy. As expected, an aqueous magnesium ion capacitor with EDA-Mn2O3 serving as the cathode can reach 110.17 Wh/kg. This study aimed to explore the practical application value of organic‒inorganic composite electrodes with double-energy storage mechanisms.

Effect of carboxyl group on photoelectrochemical performance of TiO2nanowire arrays for water splitting.

TiO2is one of the most studied semiconductor materials for the photoelectrochemical water splitting to hydrogen production, but it only responds to ultraviolet light. The introduction of organic compound is one of the common means to expand the visible light response of TiO2. In this work, rutile TiO2nanowire arrays (NWs) were grown on conductive glass by a modified solvothermal method using oleic acid as the key additive. The obtained TiO2NWs are characterized using x-ray diffraction, x-ray photoelectron spectroscopy, infrared spectroscopy and electrochemical characterization. The results show that the carboxyl groups arising from oleic acid are chemically bonded with the TiO2NWs in the form of chelating bidentate, which increases the visible light absorption range and active sites of TiO2, and reduces the transfer resistance between the photoelectrode and the electrolyte. The photocurrent density is doubled to 0.17 mA cm-2at 1.23 V vs. RHE. This work provides a novel idea for the design of metal oxide semiconductor photoanodes by adsorbing organic compounds.

Cinquefoil Knot Possessing Dynamic and Tunable Metal Coordination.

While the majority of knots are made from the metal-template approach, the use of entangled, constrained knotted loops to modulate the coordination of the metal ions remains inadequately elucidated. Here, we report on the coordination chemistry of a 140-atom-long cinquefoil knotted strand comprising five tridentate and five bidentate chelating vacancies. The knotted loop is prepared through the self-assembly of asymmetric "3 + 2" dentate ligands with copper(II) ions that favor five-coordination geometry. The formation of the copper(II) pentameric helicate is confirmed by X-ray crystallography, while the corresponding copper(II) knot is characterized by XPS and LR-/HR ESI-MS. Upon removal of the original template, the knotted ligand facilitates zinc(II) ions, which typically form four- or six-coordination geometries, resulting in the formation of an otherwise inaccessible zinc(II) metallic knot with coordinatively unsaturated metal centers. The coordination numbers and geometries of the zinc(II) cations are undoubtedly determined by X-ray crystallography. Despite the kinetically labile nature and high reversibility of the zinc(II) complex preventing the detection of 5-to-6 coordination equilibrium in solution, the effects on metal-ion coordination induced by knotting hold promise for fine-tuning the coordination of metal complexes.

Zn2+ chelating peptide GFLGSP: Characterization of structure/Zn2+ chelating mode and the potential mechanisms for promoting Zn2+ transport in Caco-2 cells

This study focused on exploring the Zn2+ chelating peptide GFLGSP: the characterization of structure/Zn2+ chelating mode and the potential mechanisms for promoting Zn2+ transport in Caco-2 cells. The findings revealed the bidentate chelating between Zn2+ and carboxyl oxygen atom in Pro6 residue. Thereafter, the secondary structure of GFLGSP remained unchanged, but there was an increase in zeta potential and particle size. Notably, the GFLGSP-Zn2+ complex enhanced the Zn2+ transport rate and modulated ZIP4 and ZNT1 expression in a Caco-2 cells monolayer model. As revealed by molecular docking analysis, GFLGSP interacted with ZIP4 through intermolecular hydrogen bonds as well as Van der Waals forces. The Zn2+ transport mechanisms of the GFLGSP-Zn2+ complex encompassed ZIP4 (vital channel), endocytosis (primary pathway) and paracellular transport (supplementary pathway). Based on these results, the tilapia skin collagen-derived GFLGSP hold promise as the potential dietary Zn2+ supplement.

A new monomeric octahedral cadmium(II) complex based on 1,1-bis(3-methyl-4-imidazoline-2-thione)methane ligand with dye adsorption ability

A new cadmium complex with a flexible imidazolinethione ligand has been successfully synthesized. The ligand acts as a bidentate chelating molecule, resulting in the structure being a monomer. In this monomer, cadmium has an octahedral geometry coordinated by four sulfur atoms from two mbit ligands where mbit = 3,3'-methylenebis(1-methyl-1,3-dihydro-2H-imidazole-2-thione) and two oxygen atoms from the DMF molecules. The ClO 4 − anions are uncoordinated and neutralize the positive charge of the cationic complex. The title complex has a good capacity for adsorbing several organic dyes from pollutant solutions.

Silver Complex Bearing N-Heterocyclic Carbene Bidentate Chelating Ligand as an Efficient Catalyst in Solvent-Free KA2 Coupling.

We report a synthesis of silver complexes bearing chelating bidentate N-heterocyclic carbene, with various substitutions at the terminal positions of the imidazole moiety of the NHC units. The long aliphatic substituents proved to be beneficial in terms of the synthetic efficiency of the complexes, compared to previously reported methyl substitution. The complexes demonstrated excellent suitability for the KA2 coupling reaction, providing quaternary carbon-containing propargylic amines in yields up to 95 %, under solvent-free conditions. The method showed high tolerance for a wide range of substrates, including naturally occurring ketones, underscoring its practicality. To our knowledge, this represents the first use of a well-defined silver species in KA2 coupling, marking an advancement in the field.

Insights into microwave‐promoted synthesis of 3‐methyl‐4‐phenyl‐4,9‐dihydro‐1H‐pyrazolo[3,4‐d][1,2,4]triazolo[1,5‐a]pyrimidine derivatives catalyzed using new Pd (II),Cu (II),VO (II), and Ag(I) complexes as a heterogeneous catalyst and computational studies

Four novel Pd (II), Cu (II), VO (II), and Ag(I) complexes were prepared from benzimidazole ligand through bidentate chelating mode. Alternative spectral and analytical tools were applied to elucidate their structural and molecular formulae. This study was extended to investigate stability and stoichiometry of complexes in solution, using standard methods. In addition, the best atomic distribution within structural forms was obtained via the density functional theory (DFT) method. This computational study fed us with significant physical characteristics for differentiation. Also, DFT/time‐dependent DFT computations were performed applying (B3LYP/6‐311++G[d,p]/aug‐cc‐pVTZ/aug‐cc‐pVTZ‐PP) level in order to investigate the electronic behavior of the compounds. These results demonstrated good agreement with the experimental data. Computational data discriminate Pd (II) complex by some physical features, which may be promising in the catalytic field. This complex was selected to play a catalytic function to synthesize 3‐methyl‐4‐phenyl‐4,9‐dihydro‐1H‐pyrazolo[3,4‐d][1,2,4]triazolo[1,5‐a]pyrimidine derivatives using microwave irradiation in a one‐pot reaction. The catalyst was selected for this application based on the history of Pd (II) complexes and the properties expected theoretically. A condensation reaction for 3‐methyl‐5‐pyrazolone, aromatic aldehyde, and 5‐aminotetrazole was carried out under mild reaction conditions by microwave irradiation. All reaction conditions were optimized among those variable Lewis acid catalysts in comparison with our new complexes. DOBPAPd catalyst displayed superiority in overall trials with high yield, short time, and green conditions (solvent H2O/EtOH). Also, the recovery of hetero catalyst was succeeded and reused by the same efficiency up to five times after that the efficiency was reduced. The mechanism of action was proposed based on the ability of Pd (II) for adding extra‐bonds over z‐axis and supported by theoretical aspects.

Morphological studies, photocatalytic degradation of organic dyes and anticancer potential of copper sulfide nanoparticles prepared from bis(diallyl dithiocarbamato)copper(II) complex

Bis(diallyl dithiocarbamato)copper(II) complex was synthesized and characterized by single crystal X-ray crystallography. The molecular structure revealed dimeric copper(II) complex consisting of two copper(II) ions that coordinate two molecules of diallydithiocarbamato anions in bidentate chelating modes and the centrosymmetrically related diallydithiocarbamato anions bridges the S-atom of the adjacent chelating ligand to formed square pyramidal geometry around the copper(II) ions. Copper sulfide nanoparticles were prepared at 160 °C by thermolysis of the copper(II) complex in dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to study the effect of capping agents on the structural morphologies, photocatalytic properties, and anticancer potential of the as-prepared copper sulfides nanoparticles. Powder X-ray diffraction patterns confirmed Cu9S5 digenite crystalline phases for CuS-DDA and CuS-HDA while CuS-ODA is covellite crystalline phase. HRTEM images showed spherical particles with particle sizes in the range 2–25 nm. The copper sulfide nanophotocatalysts are efficient for the degradation of bromophenol blue with the highest photocatalytic efficiency of 95.14 % for CuS-DDA followed by CuS-HDA with 94.52 % and 93.95 % for CuS-ODA. The anticancer potentials of the compounds showed that CuS-HDA is the most potent with IC50 values of 1.22 µg/mL against HEK293 and 28.78 µg/mL against HeLa.

Assessing the antimicrobial and cytotoxic activities of VO(IV), Cr(III), Cu(II)-metformin-schiff-base's complexes enhanced by gold nanoparticles

A new series of VO(IV), Cr(III), and Cu(II) complexes have been synthesized by condensation of metformin with β-diketones (acetylacetone, benzoylacetone, dibenzoylmethane) in the presence of metal salts. The elemental analysis, magnetic susceptibility, conductivity assessments, Infra-Red, UV–visible spectroscopy measurements, SEM, XRD, ESR, GCMS–, DTA, and DTG were used to characterize the novel compounds. The results show that every complex has a metal: ligand ratio of 1:1. The complexes exhibit distorted tetrahedral structural geometry for Cu(II), square pyramidal and octahedral geometry for VO(IV), and octahedral geometry for Cr(III), according to their electronic absorption spectra and magnetic susceptibility studies. Using the computer program Expo2014, crystallographic parameters were estimated for the complexes. The outcomes show that every complex has triclinic crystal structures with the space group P-1, apart from complex [VOL1OSO3], which has a monoclinic structure with the P 1 2 1 space group. In contrast to the complex [VOL1OSO3], which includes monodentate sulfate, conductivity data, XRD, EDX, and GC–MS verified the purity and composition of the compounds being studied. IR data showed that the complexes Na.[VOL2O2SO2] and Na.[VOL3O2SO2] has bidentate chelating sulfate ion. TG, DTG, and DTA have all been used to investigate the complexes' thermal stabilities. Some Schiff-base metformin complexes under investigation had their biological activity evaluated both with and without the addition of AuNPs. Various bacteria and harmful fungi strains have been used to screen the antimicrobial activity. The findings indicate that only copper-loaded Schiff base complexes on AuNPs gave promising results versus Staphylococcus aureus, Escherichia coli, Salmonella, and Candida albicans. On human cell lines of breast cancer (MCF7) and cancer of the human liver (HEPG2), in vitro cytotoxic activity was tested. Results showed that vanadium benzoylacetone doped with gold nanoparticles, with an IC50 value of 7 µg/ml against the HEPG2 cell line and 9.8 against MCF7 has the most effective cytotoxic effect.

Characterization of the H2/NOx reaction process over the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst

An excellent textual properties and performance La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst was synthesized. The reaction mechanism of H2/NOx over the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst was investigated by temperature programmed reduction/ desorption/ surface reaction (TPR/D/SR) technologies and in-situ diffuse reflectance Fourier transform (DRIFT) technology. The results show that cerium or palladium species are inserted into the cells of LaCoO3, as well as they synergetic promote the redox properties of the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst. Surface activated nitrates exist over the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst, with thermal stable increasing in the order: absorbed N2O4 < monodentate nitrates < chelating bidentate nitrates < nitrates unidentate < free ionic nitrates < bulk free ionic nitrates. H2 preferentially reacted with absorbed N2O4 and monodentate nitrates at low temperatures, due to their high activity. The concentration of generated NH3 from the redox reaction of H2/NOx achieves the maximum value between 350 and 450 °C over the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst. Compared with the NOx adsorption process at 50 °C, monodentate nitrates and absorbed N2O4 disappeared due to their low thermal stability, chelating bidentate nitrates become stronger, as well as free ionic nitrates converted to bulk free ionic nitrates with higher thermal stability at 350 °C. When H2 is exposed to NOx species adsorbed on La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3, chelating bidentate nitrates and bulk free ionic nitrates are consumed gradually, indicating that although the bulk free ionic nitrates own high stability, it also could be consumed by involving in the H2/NOx reaction at 350 °C. The quantitative H2/NO reaction experiments confirmed the results of H2-TPSR and NSR. It is beneficial to the formation of NH3 when the H2/NO ratio is more than 2.5. Comparing traditional Pt-BaO/Al2O3 catalyst, the La0.9Ce0.1Co0.9Pd0.1O3-BaO/Al2O3 catalyst exhibit an excellent performance, including considerable NH3 production property, lower N2O selectivity, and the precious metal saving.

Structure, Antioxidant Activity and Antimicrobial Study of Light Lanthanide Complexes with p-Coumaric Acid.

This paper presents the results of a study of the effects of the lanthanide ions Ce3+, Pr3+, Nd3+ and Sm3+ on the electronic structure and antioxidant and biological (antimicrobial and cytotoxic) properties of p-coumaric acid (p-CAH2). Structural studies were conducted via spectroscopic methods (FTIR, ATR, UV). Thermal degradation studies of the complexes were performed. The results are presented in the form of TG, DTG and DSC curves. Antioxidant properties were determined via activity tests against DPPH, ABTS and OH radicals. The reducing ability was tested via CUPRAC assays. Minimum inhibitory concentrations (MICs) of the ligand and lanthanide complexes were determined on E. coli, B. subtilis and C. albicans microorganisms. The antimicrobial activity was also determined using the MTT assay. The results were presented as the relative cell viability of C. albicans, P. aeruginosa, E. coli and S. aureus compared to controls and expressed as percentages. In the obtained complexes in the solid phase, lanthanide ions coordinate three ligands in a bidentate chelating coordination mode through the carboxyl group of the acid. Spectroscopic analysis showed that lanthanide ions increase the aromaticity of the pi electron system of the ligand. Thermal analysis showed that the complexes are hydrated and have a higher thermal stability than the ligand. The products of thermal decomposition of the complexes are lanthanide oxides. In the aqueous phase, the metal combines with the ligand in a 1:1 molar ratio. Antioxidant activity tests showed that the complexes have a similar ability to remove free radicals. ABTS and DPPH tests showed that the complexes have twice the ability to neutralise radicals than the ligand, and a much higher ability to remove the hydroxyl radical. The abilities of the complexes and the free ligand to reduce Cu2+ ions in the CUPRAC test are at a similar level. Lanthanide complexes of p-coumaric acid are characterised by a higher antimicrobial capacity than the free ligand against Escherichia coli bacteria, Bacillus subtilis and Candida albicans fungi.

Preparation, spectroscopic and anticancer investigations of metal-drug complexes associated between flumequine antibiotic drug with lanthanum(III), samarium(III) and terbium(III) chloride

Flumequine ligand (FLQ) metal complexes of the [M(FLQ)2(Cl)(H2O)].nH2O type, where M are (La(III), Sm(III), and Tb(III)) and FLQ is flumequine have been synthesized. The FLQ metal complexes could be prepared using MCl3 : flumequine in stoichiometry of 1:2 in situ bidentate chelation. The characterization of FLQ complexes obtained have been done using elemental analyses (%C, %H and %N), molar conductivity (Ʌm), infrared spectroscopy (FTIR), electronic spectra (UV-Vis), thermal analysis (TGA), and physicochemical techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) measurements at room temperature. Accordingly, these complexes are indicative of an octahedral coordination structure. Flumequine ligand has a bidentate fashion through the oxygen atoms of carbonyl (quinolone) and carboxylic groups. The findings demonstrated the anti-cancer efficacy of these compounds against HepG-2 and MCF-7 cancer cell lines at extremely low doses of up to 58.2 mg/mL. The La(III) complex was shown to have the highest selectivity against cancer cells in comparable with both samarium and terbium(III) complexes.&#x0D; KEY WORDS: Flumequine, Lanthanide metal ions, FTIR, EDX, Complexation, Anticancer activity&#x0D; Bull. Chem. Soc. Ethiop. 2024, 38(3), 671-684. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v38i3.10

Amphoteric Chelating Ultrasmall Colloids for FAPbI3 Nanodomains Enable Efficient Near-Infrared Light-Emitting Diodes.

Perovskite light-emitting diodes (PeLEDs) are the next promising display technologies because of their high color purity and wide color gamut, while two classical emitter forms, i.e., polycrystalline domains and quantum dots, are encountering bottlenecks. Weak carrier confinement of large polycrystalline domains leads to inadequate radiative recombination, and surface ligands on quantum dots are the main annihilation sites for injected carriers. Here, pinpointing these issues, we screened out an amphoteric agent, namely, 2-(2-aminobenzoyl)benzoic acid (2-BA), to precisely control the in situ growth of FAPbI3 (FA: formamidine) nanodomains with enhanced space confinement, preferred crystal orientation, and passivated trap states on the transport-layer substrate. The amphoteric 2-BA performs bidentate chelating functions on the formation of ultrasmall perovskite colloids (<1 nm) in the precursor, resulting in a smoother FAPbI3 emitting layer. Based on monodispersed and homogeneous nanodomain films, a near-infrared PeLED device with a champion efficiency of >22% plus enhanced T80 operational stability was achieved. The proposed perovskite nanodomain film tends to be a mainstream emitter toward the performance breakthrough of PeLED devices covering visible wavelengths beyond infrared.