As-prepared Complex Research Articles

A novel electrochemical sensor based on Fe3+-curcumin/multi-walled carbon nanotubes complex enabling electrochemical sensing of hydroxylamine

This work reported a novel electrocatalyst, Fe3+-curcumin/multi-walled carbon nanotubes (MWCNTs) complex, for efficient detection of hydroxylamine by modifying the glassy carbon electrode (Fe3+-curcumin/MWCNTs-modified electrode). The Fe3+-curcumin/MWCNTs complex was prepared via a green and facile one-pot synthesis method and the as-prepared complex was characterized using TEM, EDS, XRD, XPS, and EIS. Subsequently, the Fe3+-curcumin/MWCNTs complex modified electrode was adopted as an electrochemical sensor for hydroxylamine detection. The catalytic peak current for sensing the hydroxylamine using the Fe3+-curcumin/MWCNTs-modified electrode was 9.5 times higher the catalytic peak current using the curcumin/MWCNTs-modified electrodes. The overpotential was reduced by 550 mV compared to MWCNTs-modified electrodes. The interfacial electron transfer rate was 0.37 s−1 for the Fe3+-curcumin/MWCNTs-modified electrode. Furthermore, the Fe3+-curcumin/MWCNTs-modified electrode exhibited outstanding sensing performance within analyte concentration range from 0.05 to 1100 μM (a low detection limit of 0.02 μM, S/N = 3). Finally, the constructed sensor was successfully adopted for the hydroxylamine detection from the hydrolysis of the pralidoxime iodide injections, demonstrating the practical applications.

A zinc(II) complex based on 5-(ethylamino)isophthalic acid and trans-1,2-di(4-pyridyl)ethene with a threefold interpenetrated crystal structure: synthesis, crystal structure and room temperature phosphorescence

Abstract A coordination complex {[Zn(EtAIPA)(dpe)]·H2O} n (1), has been synthesized under hydrothermal conditions based on 5-(ethylamino)isophthalic acid (H2EtAIPA) and trans-1,2-di(4-pyridyl)ethene (dpe). The title complex was characterized by elemental analysis, UV/Vis absorption, single-crystal X-ray diffraction and emission properties. The as-prepared complex appears as a puckered 2D (4,4) network, The individual 2D nets are interlocked with each other to form a 3-fold parallel interpenetrated 2D architecture. Time-resolved measurements reveal cyan phosphorescence emission at room temperature.

Hydrolytic reactivity of novel copper(II) complexes with reduced N-salicylate threonine Schiff bases: distinguishable effects of various micelles

Three new bi- or tetranuclear copper (II) complexes (complexes 1, 2 and 3) with reduced N-salicylate threonine were synthesized and characterized by single crystal X-ray diffraction, X-ray powder diffraction, UV–vis, and thermogravimetric analysis. Single-crystal diffraction analysis reveals that these complexes have similar coordination modes and conformations which were linked into multidimensional networks through some weak interactions. These three complexes were employed to promote the hydrolytic cleavage of p-nitrophenyl picolinate (PNPP) and p-nitrophenyl acetate (PNPA). Catalytic reactivities of the as-prepared complexes show that in the hydrolysis of p-nitrophenyl acetate (PNPA) these three complexes provide 51, 45, 39-fold rate acceleration as compared to spontaneous hydrolysis of PNPA at pH 7.0, respectively. Under selected conditions, excess three orders of magnitude rate enhancement were observed for the catalytic hydrolysis of another carboxylic ester, p-nitrophenyl picolinate (PNPP). Furthermore, these complexes efficiently promote the PNPA hydrolysis in micellar solution of cetyltrimethylammonium bromide (CTAB) or bis(hexadecylhexmethyl ammonium)ethane bromide (16−6−16) giving rise to excess two orders of magnitude rate enhancement which is approximate 2.0 − 4.0 times higher than that in the buffer. However, the introduction of micelles of n-lauroylsarcosine sodium (LSS) or double-chained C22/8 surfactant did not increase the rate or even inhibited the hydrolysis reaction in contrast with buffered aqueous medium.

Self-healing, injectable hydrogel based on dual dynamic covalent cross-linking against postoperative abdominal cavity adhesion

Clinically, increasing the peritoneal barrier is an effective adjunct to reducing postoperative peritoneal adhesion. This study presents a facile template for preparing a supramolecular hybrid hydrogel through dynamic covalent cross-linking between carboxymethyl chitosan (CMCS), 2-formylphenylboronic acid (2-FPBA), and quercetin (Que). The as-prepared complex CMCS/2-FPBA/Que (CFQ) hydrogel exhibited favorable antibacterial, anti-inflammatory, and antioxidant effects. A L929 cytotoxicity evaluation confirmed the favorable cytocompatibility of the CFQ hydrogel. The postoperative anti-adhesion ability of the CFQ hydrogel was further evaluated in rats with lateral wall defects and cecal abrasions. Compared with control groups, the tissue adhesion rate was significantly reduced by increasing the Que concentration in all the hydrogel-treated groups. Additionally, the sustained-release time of the C3F0.8Q0.08 hydrogel can exceed 14 days, which is highly desirable for clinical wound treatment. Statement of significancePostoperative adhesions are a very common postoperative complication that seriously affects the quality of life of patients. The currently commonly used methods for preventing adhesion mainly use degradable barrier materials for physical separation. In this study, we prepared a dual dynamic covalently cross-linked CFQ hydrogel, which is not only degradable and injectable, but also has multiple properties such as antibacterial, antioxidant and anti-inflammatory, which can effectively prevent postoperative adhesion and promote wound healing.

Bulky oxadithiolate-bridged [FeFe]‑hydrogenase mimics [Fe2(μ-R2odt)(CO)4(κ2-diphosphine)] (R = Ph and H) with chelating diphosphines

In order to develop an attractive generation of bulky oxadithiolate-bridged [FeFe]‑hydrogenase mimics with chelating diphosphines, two new series of asymmetrically diphosphine-substituted diiron model complexes [Fe2(μ-R2odt)(CO)4(κ2-diphosphine)] (3–5) with bulky Ph2odt bridge and their reference counterparts (6–8) with common odt bridge were obtained from the Me3NO-assisted substitutions of diiron hexacarbonyl precursors [Fe2(μ-R2odt)(CO)6] (R2odt = (SCHR)2O, R = Ph (1) and H (2)) with different diphosphines such as (Ph2P)2NBn (labelled PNBnP, Bn = benzyl), (Ph2PCH2)2NBn (PCNBnCP), and (Ph2PCH2)2CH2 (DPPP)), respectively. All the as-prepared complexes have been characterized by elemental analysis, IR plus NMR spectroscopies, and particularly by X-ray crystallography for 3–8. It is interesting to note that complexes 3 and 6 chelating by small bite-angle PNBnP diphosphine have the favorable dibasal isomer whereas analogues 4, 5 and 7, 8 chelating by flexible backbone PCNBnCP or DPPP ligands possess the main apical-basal isomer in solution or in the solid state. Further, the electrochemical properties of two pairs of representative complexes 3, 6 and 5, 8 are explored and compared by cyclic voltammetry (CV) in the absence and presence of trifluoroacetic acid (CF3CO2H) as proton source, indicating that the complete protonations of 3, 6 and 5, 8 with higher concentration of CF3CO2H lead to two new catalytic waves for the electrocatalytic proton reduction to hydrogen (H2).

A highly effective and reusable platinum nanoblock based on graphene/ polyamino acid nanofilms for 4-nitrophenol degradation

To develop Pt nanomaterials with facile approach is of great significance for the improvement of their catalytic properties for organic pollutants degradation. In this study, we report a simple in-situ reduction strategy to prepare Pt nanoblocks based on graphene/ polyamino acid self-assembly nanofilms. Polyamino acid modified graphene nanofilms severed as the nanoreactor and reducing agent for further fabrication of Pt nanoblocks. The as-prepared complex efficiently transformed 4-nitrophenol into 4-aminophenol completely within 4.5 min (kapp is 0.962 min−1) and kept good long-term stability. We expect this work to offer a new valuable insight for facile preparation of Pt materials as efficient and recyclable catalysts for water pollution remediation.

Synthesis, characterization and relaxivity validations of Gd(III) complex of DOTA tetrahydrazide as MRI contrast agent

We report a novel Gadolinium(III) complex of (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetra(acetohydrazide) (Gd(III)L1) as a potential contrast agent for high resolution images in MRI and its molecular structure prediction by DFT calculations. The DOTA tetrahydrazide ligand framework (L1) was synthesized by the reaction of 1,4,7,10-tetraazacyclododecane (cyclen) with bromo derivative of conjugated t-butyl carbazate and followed by the subsequent cleavage of Boc moieties. The corresponding Gd(III) complex was prepared in an aqueous medium with the adjustment of pH to 7.0. The Gd(III)L1 complex shows the longitudinal relaxivity of 4.9 mM−1s−1 and transverse relaxivity of 6.2 mM−1s−1 at 37 ⁰C. The as-prepared complex Gd(III)L1 displays the enhanced intensity of T1 weighted phantom MR images with various concentrations at 7.0 T MRI scanner, which pave the way to achieve higher resolution images in MRI.

Structural and electrochemical investigations of new mononuclear nickel(II) dithiolate complexes bearing a pendant amine

To further develop the biomimetic chemistry of [FeFe]- and [NiFe]-hydrogenases for the catalytic reduction of protons to hydrogen (H2), two new mononuclear Ni(II) ethanedithiolate complexes [{(Ph2PCH2)2NR}Ni(SCH2CH2S)] (R = tert-butyl (Bu t ), 1 and n-butyl (Bu n ), 2) with pendant amine-containing diphosphines were synthesized in moderate yields from the treatments of mononickel dichlorides [{(Ph2PCH2)2NR}NiCl2] with ethanedithiol (HSCH2CH2SH) with triethylamine (Et3N) as an acid-binding agent at room temperature. The as-prepared complexes 1 and 2 have been fully characterized by means of elemental analysis, nuclear magnetic resonance (NMR) spectrum, and X-ray crystallography. Further, the electrochemical properties of 1 and 2 are investigated in the absence or presence of acetic acid (HOAc) by using cyclic voltammetry (CV), suggesting that they can be considered as the active electrocatalysts for proton reduction to H2.

Application of Samarium- and Terbium-Sensitized Luminescence via a Multivariate-Based Approach for the Determination of Orbifloxacin

A lanthanide-based optical sensor has been developed for the sensitive and reliable spectrofluorometric determination of the fluoroquinolone antibiotic orbifloxacin (ORLX). Reaction of ORLX and two lanthanide metal ions, Sm(III) and Tb(III), in aqueous buffered solution produced highly fluorescent complexes. Plackett–Burman design (PBD) was used to explore the impact of four factors, pH, temperature (Temp), contact time (CT), and metal volume (MV), on the fluorescence intensity (FI) of the produced complexes. The obtained data showed that pH was the most significant variable. A blend of pH = 5.0, MV = 2.0 mL, T = 25°C, and CT = 10 min was used to achieve the maximum FI. FT-IR and Raman analyses were performed for the crystals of the as-prepared complexes. Obtained data showed shifting in most of the absorption bands, confirming the complexation of ORLX with both metal ions. Job’s method showed that the stoichiometry for the reaction of ORLX with Sm(III) and Tb(III) was 1 : 1. The proposed method was validated following the ICH guidelines. Injection formulation was analyzed successfully with the developed method with high recovery (99.42–100.91%). The detection and quantification limits were 0.987 and 3.289 ng/mL for the ORLX-Sm(III) complex and 1.020 and 3.399 ng/mL for the ORLX-Tb(III) complex, respectively.

Copper (II) Heterocyclic Thiosemicarbazone Complexes as Single-Source Precursors for the Preparation of Cu9S5 Nanoparticles: Application in Photocatalytic Degradation of Methylene Blue

In this study, two copper(II) complexes, [Cu(C6H8N3S2)2]Cl2 (1) and [Cu(C7H10N3S2)2]Cl2·H2O (2), were synthesized from 2-(thiophen-2-ylmethylene)hydrazine-1-carbothioamide (L1H) and 2-(1-(thiophen-2-yl)ethylidene)hydrazine-1-carbothioamide (L2H) respectively and characterized using various spectroscopic techniques and elemental analyses. The as-prepared complexes were used as single-source precursors for the synthesis of oleylamine-capped (OLA@CuxSy), hexadecylamine-capped (HDA@CuxSy), and dodecylamine-capped (DDA@CuxSy) copper sulphide nanoparticles (NPs) via the thermolysis method at 190 °C and 230 °C and then characterized using powder X-ray diffraction (p-XRD), UV-visible spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The p-XRD diffraction patterns confirmed the formation of crystalline rhombohedral digenite Cu9S5 with the space group R-3m. The TEM images showed the formation of nanoparticles of various shapes including hexagonal, rectangular, cubic, truncated-triangular, and irregularly shaped Cu9S5 nanomaterials. The SEM results showed aggregates and clusters as well as the presence of pores on the surfaces of nanoparticles synthesized at 190 °C. The UV-visible spectroscopy revealed a general blue shift observed in the absorption band edge of the copper sulphide NPs, as compared to bulk CuxSy, with energy band gaps ranging from 2.52 to 3.00 eV. Energy-dispersive X-ray spectroscopy (EDX) confirmed the elemental composition of the Cu9S5 nanoparticles. The nanoparticles obtained at 190 °C and 230 °C were used as catalysts for the photocatalytic degradation of methylene blue (MB) under UV irradiation. Degradation rates varying from 47.1% to 80.0% were obtained after 90 min of exposure time using only 10 mg of the catalyst, indicating that Cu9S5 nanoparticles have potential in the degradation of organic pollutants (dyes).

Two bis-ligand-coordinated Zn(ii)-MOFs for luminescent sensing of ions, antibiotics and pesticides in aqueous solutions.

Two organometallic complexes with two and three-dimensional architectures were constructed by using multiple ligands and Zn(ii) ions: [Zn3(BTC)2(DTP)4(H2O)2]·(H2O)4 (Zn-1) (BTC = benzene-1,3,5-tricarboxylic acid and DTP = 3,5-di(1,2,4-triazol-1-yl)pyridine) and [Zn2(NTD)2(DTP)] (Zn-2) (NTD = 1,4-naphthalenedicarboxylic acid). The as-prepared complexes were characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and fluorescence analysis. Fluorescence sensing tests revealed that the two complexes are effective, sensitive and selective toward cationic Fe3+ and anionic MnO4− and Cr2O72−. During the antibiotic sensing process, cefixime (CFX) for Zn-1 and nitrofurantoin (NFT) for Zn-2 exhibited the highest quenching efficiencies. For sensing pesticides, the highest quenching efficiencies were exhibited by imidacloprid (IMI) toward Zn-1 and Zn-2. The fluorescence quenching of the complexes that was induced by antibiotics, pesticides and MnO4− was attributed to both the inner filter effect (IFE) and the fluorescence resonance energy transfer (FRET) effect.

Temperature-induced structural diversity of two coordination polymers: magnetic properties and treatment activity on depression via activating the nigrostriatal dopamine D2 receptor

By applying the mixed-ligand approach, two new Co(II)-including coordination polymers (CPs) {[Co2(Glu)2(1,4-mbix)2(H2O)2]·H2O}n, (1) and {[Co(Glu)(1,4-mbix)]·4H2O}n (2), were formed by taking glutarate (Glu2−) blended with 1,4-bis [(2-methyl-1H-imidazol-1-yl)methyl]benzene (1,4-mbix) by using different reaction temperatures. The as-prepared complexes were evaluated through IR spectroscopy, elemental analysis, powder X-ray diffraction analysis (PXRD), TG analysis and single-crystal X-ray diffraction. The structural characterization results show that complex 1 features a 3D framework structure with a four-connected neb-type topology, while complex 2 demonstrates a 2D layered structure with a four-connected sql-type topology. The magnetic studies show that compounds 1 and 2 have antiferromagnetic coupling between the adjacent metallic ions. Their biological activity on depression animal model was determined and the mechanism was detected. Firstly, the depression animal model was built and the compounds were given for indicated treatment. The nigrostriatal dopamine D2 receptor content was measured by real time reverse transcription-polymerase chain reaction (RT-PCR). The content of the 5-hydroxy trptamine (5-HT) and Norepinephrine (NE) was measured by enzyme linked immunosorbent assay (ELISA) detection kit after compounds treatment.

Mononuclear nickel(II) dithiolate complexes with chelating diphosphines: Insight into protonation and electrochemical proton reduction

Inspired by the metal active sites of [FeFe]- and [NiFe]‑hydrogenases, a series of mononuclear Ni(II) ethanedithiolate complexes [{(Ph2PCH2)2×}Ni(SCH2CH2S)] (X = NCH2C5H4N-p (2a), NCH2C6H5 (2b), NCH2CHMe2 (2c), and CH2 (2d)) with chelating diphosphines were readily synthesized through the room-temperature treatments of mononuclear Ni(II) dichlorides [{(Ph2PCH2)2×}NiCl2] (1a-1d) with ethanedithiol (HSCH2CH2SH) in the presence of triethylamine (Et3N) as acid-binding agent. All the as-prepared complexes 1a-1d and 2a-2d are fully characterized through elemental analysis, nuclear magnetic resonance (NMR) spectrum, and by X-ray crystallography for 1b, 2a-2d. To further explore proton-trapping behaviors of this type of mononuclear Ni(II) complexes for catalytic hydrogen (H2) evolution, the protonation and electrochemical proton reduction of 2a-2c with aminodiphosphines (labeled PCNCP = (Ph2PCH2)2NR) and reference analogue 2d with nitrogen-free diphosphine (dppp = (Ph2PCH2)2CH2) are studied and compared under trifluoroacetic acid (TFA) as a proton source. Interestingly, the treatments of 2a-2d with excess TFA resulted in the unexpected formation of dinuclear Ni(II)-Ni(II) dication complexes [{(Ph2PCH2)2×}2Ni2(μ-SCH2CH2S)](CF3CO2)2 (3a-3d) and mononuclear Ni(II) N-protonated complexes [{(Ph2PCH2)2N(H)R}Ni(SCH2CH2S)](CF3CO2) (4a-4c), which has been well supported by high-resolution electrospray ionization mass spectroscopy (HRESI-MS), NMR (31P, 1H) as well as fourier transform infrared spectroscopy (FT-IR) techniques, and especially by X-ray crystallography for 3d. Additionally, the electrochemical properties of 2a-2d are investigated in the absence and presence of strong acid (TFA) by using cyclic voltammetry (CV), showing that the complete protonation of 2a-2d gave rise to dinuclear Ni2S2 species 3a-3d for electrocatalytic proton reduction to H2.

Influence of Ni (II) oxime complex coupled with the combination of diverse sized ZnO nanoparticles on Photovoltaic Performance

The one side selective synthesis of quinoline carboxylic acid oxime complex was carried out successfully. The as-prepared quinoline carboxylic acid oxime complex was complexed with nickel (II) salts to form nickel (II) oxime complex. These complexes were further adsorbed onto ZnO films containing ZnO nanoparticles of various sizes. ZnO films containing a diverse proportion of ZnO nanoparticles were investigated to enhance the photovoltaic efficiency of the dye-sensitized solar cell. The as-synthesized complex was characterized by scanning electron microscopy (SEM), Ultra violet visible spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FT-IR) spectroscopy, 1Hydrogen Nuclear magnetic resonance spectroscopy (1HNMR), Liquid chromatography coupled with mass spectrometry (LC-MR), Brunauer–Emmett–Teller (BET), and Attenuated total reflection Infra-red spectroscopy (ATR-IR). The combination of large and small ZnO nanoparticles has significantly improves the photovoltaic efficiency. The optimum mixing ratio for the best performance (0.127%) of a dye-sensitized solar cell is achieved by mixing the small: large ZnO particles in a ratio 60:40. The increased efficiency is due to the harvesting of light caused by scattering effect from larger sized ZnO particles. The ZnO layer consisting of smaller particles which are very next to the ZnO bigger particles makes a good electronic contact between film electrode and the Indium-doped tin oxide glass substrate resulting in the increases in the dye molecules adsorption. The over-layered, large-sized ZnO particles enhance the light-harvesting by light scattering effect. Compared to the other mixtures of ZnO films, there is a decrease in the photovoltaic performance of the solar cell when ZnO particles (small and large in a ratio 1:1) were adsorbed onto the Ni (II) oxime complex, which are caused due to the decrease in the surface area and dye aggregation.

Synthesis, spectral and thermo-kinetics explorations of Schiff-base derived metal complexes

AbstractSchiff-base ligand, 2,6-bis(benzimino)-4-phenyl-1,3,5-triazine (L), and its transition metal complexes of Co(ii), Ni(ii), and Cu(ii) were synthesized by refluxing the reaction mixture and its analytical, spectral, and thermogravimetric characteristics were explored by various techniques: AAS, FT-IR, UV-vis, TG-DTG, CHNS/O, and VSM. It was observed that all the metal containing complexes are non-electrolytic, mononuclear, and paramagnetic in nature, confirmed by the molar conductance and magnetic susceptibility measurements. Optical spectral data were used to investigate the geometrical and spectral parameters of [Co(L)(ac)2], [Ni(L)(ac)2], [Cu(L)(ac)2], [Cu(L)(acac)2], and [Cu(L)(fmc)2] complexes. Simultaneous thermal analyses (TG-DTG) in nitrogen atmosphere reveal that the ligand decomposes in one step, [Co(L)(ac)2], [Ni(L)(ac)2], and [Cu(L) (ac)2] complexes are decomposed in three steps, whereas [Cu(L)(acac)2] and [Cu(L) (fmc)2] are decomposed in five and two steps, respectively. In addition, activation energy (Ea) and pre-exponential factor (ln A) were evaluated by TG-DTG decomposition steps of compounds using the Coats–Redfern formula. Enthalpy (∆H), entropy (∆S), and Gibbs free energy (∆G) of the as-prepared metal complexes were also speculated by various thermodynamic equations.

RETRACTED ARTICLE: Nonanuclear coordination complex based on {Co9L12}6+ cores: protective effect on coronary heart disease by reducing the inflammatory cytokines releasing

A new coordination complex with the chemical formula of [Co9(bta)12(NO3)6(DMA)6]·3DMA (1), (DMA = N,N-dimethylacetamide) was formed by solvothermal reaction of Co(NO3)2·6H2O with Hbta (Hbta = benzotriazole). The as-prepared complex 1 was characterized via thermogravimetric (TG) analysis, analysis of element, X-ray single-crystal diffraction, and powder X-ray diffraction (PXRD). Furthermore, the treatment activity of the compound on the Coronary atherosclerotic heart disease (CHD) was assessed and mechanism was investigated at the same time. First, the release of inflammatory cytokines in plasma was detected by enzyme linked immunosorbent assay (ELISA) test kit. Then, the real time reverse transcription-polymerase chain reaction (RT-PCR) was finished to determine the tumor necrosis factor-a induced protein-8 type2 (TIPE2) expression levels in endothelial cells. The molecular docking results reveal the possible interacting poses for the potential capability of immune homeostasis.

Synthesis of novel organotin(IV) complex for multiple applications: as biologically potent and single molecular precursor

This work reports a facile solution-based synthesis of novel single molecular precursor (SMP), triphenylstannyl 4-((4-bromophenyl) amino)-4-oxobut-2-enoate complex (2). The as-prepared SMP was characterized by single crystal X-rays diffraction, elemental analysis, 1H NMR, 13C NMR and Mass spectrometry. The thermal properties of as-prepared SMP were assessed by thermogravimetric analysis and differential calorimetry. The as-prepared complex showed excellent DNA binding property in vivo experiments. The as-prepared complex (2) also revealed good antileishmanial and anticancer properties. Lastly, high-quality transparent SnO2 thin films were obtained by aerosol-assisted chemical vapors deposition on common window glass. The morphological and structural studies of as-deposited thin films were performed by XRD and FE-SEM.

Novel copper(II) and zinc(II) complexes of halogenated bidentate N,O-donor Schiff base ligands: Synthesis, characterization, crystal structures, DNA binding, molecular docking, DFT and TD-DFT computational studies

Eight novel complexes, including: [Cu(L1)2]: C1, [Cu(L2)2]: C2, [Cu(L3)2]: C3, [Cu(L4)2]: C4, [Zn(L1)2]: Z1, [Zn (L2)2]: Z2, [Zn (L3)2]: Z3, and [Zn (L4)2]: Z4, with four bidentate N,O-donor halogenated bis-Schiff base ligands (HL1: 4-Bromo-2-[(4-fluorophenylimino) methyl]phenol; HL2: 4-Bromo-2-[(4-chlorophenylimino)methyl]phenol; HL3: 4-Bromo-2-[(4-bromophenylimino) methyl]phenol; HL4: 4-Bromo-2-[(4- iodophenylimino)methyl]phenol) were synthesized and their structures were proved by SC-XRD, FT-IR, UV-Vis, and 1H NMR spectroscopic techniques. The single crystal X-ray diffraction analysis reveals that a distorted tetrahedral geometry is formed in zinc complex whereas a slightly distorted square planar geometry is formed in both copper(II) complexes of C3 and C4. Theoretical calculations of the complexes were carried out via DFT as well as TD-DFT using B3LYP method employing the Def2-TZVP basis set, where the calculation results are in accordance with the experimental results. NBO analysis has been used to elucidate charge transfer information of the Z1, C3 and C4 complexes. Moreover, interaction of ligands and complexes with FS-DNA was assessed using UV-Vis spectroscopy as well as molecular docking. The experimental and theoretical results reveal that the DNA-binding affinity of as-prepared complexes increases with decreasing in electronegativity of substituted halogen atom.

RETRACTED ARTICLE: TWO Cu(II)-BASED COORDINATION POLYMERS: STRUCTURAL DIVERSITY AND TREATMENT ACTIVITY AGAINST NEONATAL SEPSIS BY ENHANCING THE ANTIBACTERIAL RESPONSE OF THE IMMUNE SYSTEM

In this work, two Cu(II)-based coordination polymers with the chemical formulae of [Cu(333cptpy)2]n·2nH2O (1, H333cptpy = 4′-(3-carboxyphenyl)-3,2′:6′,3″-terpyridine) and [Cu(233cptpy)2(H2O)2]n (2, H233cptpy = 4′-(2-carboxyphenyl)-3,2′:6′,3″-terpyridine) are hydrothermally synthesized using two positionally isomeric pyridyl-carboxylate ligands. The two as-prepared complexes are studied via X-ray single crystal diffraction along with the elemental analysis. Furthermore, the protective effect of compounds 1 and 2 against neonatal sepsis is evaluated. Firstly, ELISA is performed to detect the content of the C-reactive protein (CRP) in the serum of newborns after treatment with compounds 1 and 2. Next, the inflammatory level in the body is detected by the RT-PCR measurement of nf-κb and tnf-α.

Synthesis of Au/Co9S8 composite aerogels by one-step sol–gel method as hydrogen evolution reaction electrocatalysts

The development of effective electrocatalysts for hydrogen evolution reaction (HER) with a high performance and low-cost is greatly desirable to meet the increasing demands for sustainable energy. In this work, we herein demonstrate Au nanoparticles (NPs)-coupled Co9S8 (Au/Co9S8) aerogels with a porous feature and high surface area via a simple sol–gel approach. Besides, the as-prepared complexes are supposed to generate synergistic effect to greatly promote the HER electrocatalysis in an alkaline electrolyte. The improved electric conductivity of the resulting composite can accelerate the HER kinetics. Notably, the as-prepared Au/Co9S8-10 aerogel displays a good electrocatalytic property for HER with an overpotential of 35 mV at 10 mA cm−2 and a small Tafel slope of 64 mV dec−1. The porous architecture not only improves the contact area at interfaces but also allows faster mass transportation during electrochemical process. Furthermore, the catalyst declares a promising electrochemical stability over 40 h of continuous HER catalysis with only 6% loss of its initial activity. Hence, this work offers a guiding strategy for synthesizing nanostructured earth abundant electrocatalyst with an enhanced HER performance.