Comparative Study of the Efficacy of Metal Removal from Contaminated Aqueous Solutions by Solid Bidentate Ligands&Liquid Plant Materials

Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.

A fast and in-depth self-reconstruction of anion ligands optimized CoFe-based pre-catalysts for water oxidation

The design of efficient and robust non-precious metal electrocatalysts towards oxygen evolution reaction(OER)is of great value for developing green energy technologies.The in-situ formed high-valence(oxy)hydroxides species during the reconstruction process of pre-catalysts are recognized as the real contributing sites for OER.However,pre-catalysts generally undergo a slow and inadequate self-reconstruction.Herein,we reported a PO^(3-)_(4)optimized CoFe-based OER catalysts with amorphous structure,which enables a fast and deep reconstruction during the OER process.The amorphous structure induced by ligands PO^(3-)_(4)is prone to evolution and further form active species for OER.The electron interaction between metal sites can be modulated by electron-rich PO^(3-)_(4),which promotes generation of high active CoOOH.Simultaneously,the etching of PO^(3-)_(4)from the pre-catalysts during the catalytic process is in favor of accelerating the self-reconstruction.As a result,as-prepared precatalyst can generate high active CoOOH at a low potential of 1.4 V and achieve an in-depth reconstructed nanosheet structure with abundant OER active sites.Our work provides a promising design of pre-catalysts for realizing efficient catalysis of water oxidation.

Metal-organic frameworks with mixed-ligands strategy as heterogeneous nucleation center to assist crystallization for efficient and stable perovskite solar cells

Deep-level defects and random oriented configuration in perovskite crystallization process would cause the nonradiative recombination and further affect the performance of perovskite solar cells(PSCs).Herein,two metal-organic frameworks(MOFs)with tunable Lewis-base passivation sites have been constructed(Cd-Httb and Cd-Httb-BDC,Httb=5-(4-(1H-1,2,4-triazole-1-yl)benzyl)-1h-tetrazole,BDC=1,4-dicarboxybenzene)to eliminate deep-level defects and simultaneously as nanostructured heterogeneous nucleation seed to assist the growth of large-grained perovskite films.Compared with the control and Cd-Httb,Cd-Httb-BDC designed with mix-ligands strategy exhibited the enhanced inducted effect on the crystallization and nucleation of high-quality perovskite films during annealing process.Consequently,the resultant Cd-Httb-BDC-modified device achieved higher power conversion efficiency(PCE)(22.18%)than the control(20.89%)and Cd-Httb(21.56%).Meanwhile,the unencapsulated Cd-Httb-BDC-modified device still maintained 90%of initial PCE after 1500 h in ambient conditions and exhibited enhanced thermal stability(85℃ in N_(2) atmosphere).This work presented a successful example of mixligands strategy on construction of high-quality MOF-assisted perovskite films for high-efficient and stable PSCs.

Unraveling structure and performance of protein a ligands at liquid–solid interfaces: A multi-techniques analysis

Oriented ligand immobilization is one of the most effective strategies used in the design and construction of a high-capacity protein A chromatography. In this work, cysteine was introduced as anchoring sites by substituting a specific residue on Helix Ⅰ, Ⅱ, and at C-terminus of antibody binding domain Z from protein A, respectively, to investigate structural evolution and binding behavior of protein A ligands at liquid-solid interfaces. Among the three affinity dextran-coated Fe_(3)O_(4) magnetic nanoparticles(Fe_(3)O_(4)@Dx MNPs), affinity MNPs with the immobilized ligand via N11C on Helix Ⅰ(Fe_(3)O_(4)@Dx-Z_(1) MNPs) had the highest helical content, and MNPs with the immobilized ligand via G29C on Helix Ⅱ(Fe_(3)O_(4)@Dx-Z_(2) MNPs) had the lowest helical content at the same pHs. It was attributed to less electrostatic attraction of ligand to negatively charged surface on Fe_(3)O_(4)@Dx-Z_(1) MNPs because of less positive charged residues on Helix Ⅰ(K6) than Helix Ⅱ(R27/K35). Among the three affinity MNPs, moreover, the highest affinity to immunoglobulin G(IgG) binding was observed on Fe_(3)O_(4)@Dx-Z_(1) MNPs in isothermal titration calorimetry measurement, further validating greater structural integrity of the ligand on Fe_(3)O_(4)@Dx-Z_(1) MNPs. Finally,the study of IgG binding on MNPs and 96-well plates showed that anchoring sites for ligand immobilization had distinct influences on IgG binding and IgG-mediated antigen binding. This work illustrated that anchoring sites of the ligands had a striking significance for the molecular structure of the ligand at liquid-solid interfaces and raised an important implication for the design and optimization of protein A chromatography and protein A-based immunoassay analysis.

Controllably partial removal of thiolate ligands from unsupported Au_(25) nanoclusters by rapid thermal treatments for electrochemical CO_(2)reduction

Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.

In Silico Evaluation of Potential Ligands of Cancer Cells for Surfactin from Bacillus spp.

Cancer is one of the most prevalent diseases worldwide,which causes significant morbidity and mortality.Designing and developing a potential anti-cancer drug is an active field of research worldwide.Microorganisms have been considered a potential source of anti-cancer drugs.One such microbe-derived compound is surfactin,which shows potential anti-cancer activities.In this study,we evaluated the binding potential of surfactin with several cancer cell ligands via an in-silico approach.Hence,molecular docking studies were performed to test the binding potential of surfactin against four targets.The analyses revealed that surfactin from Bacillus sp.can bind with the targeted ligands(coenzyme A,D-leucine,glycerol,and(R)-3-hydroxytetradecanal)with significant affinity.Surfactin showed the highest binding affinity(-7.7 kcal mol-1)to coenzyme A among the targeted ligands.These results may be useful for developing anti-cancer drugs.Nevertheless,further experimental studies are needed to investigate the ligand binding capacity and anti-cancer potential of such surfactin-like molecules.

A Series of Lanthanide-organic Frameworks Constructed by Ln_4(OH)_4 Clusters and Mixed Ligands

Three new lanthanide-organic compounds, namely, [Ln_2(OH)_2(oba)(2-pc)_2]n(Ln =Er(1), Ho(2), and Dy(3))(oba = 4,4?-oxybis(benzoate), 2-pc = 2-pyrazinecarboxylic acid) have been obtained under hydrothermal conditions. These compounds are isostructural and exhibit 2 D layered structures by incorporating [Ln_4(μ_3-OH)_4]^(8+) clusters and the mixed linkers of oba and 2-pc. It is interesting that decarboxylation occurred in the ortho position and 2,3-pyrazinedicarboxylic acid was partially transformed into 2-pc under hydrothermal conditions. Compound 3 emits a typical Dy^(3+) emission spectrum. Furthermore, the PXRD, TGA and IR spectra were also studied.

Anticancer actions of PPARγ ligands:Current state and future perspectives in human lung cancer

Peroxisome proliferator-activated receptors(PPARs) are ligand-dependent nuclear transcription factors and members of the nuclear receptor superfamily.Of the three PPARs identified to date(PPARγ,PPARβ/δ,and PPARα),PPARγ has been studied the most,in part because of the availability of PPARγagonists(also known as PPARγ ligands)and its significant effects on the management of several human diseases including type 2 diabetes,metabolic syndrome,cardiovascular disease and cancers.PPARγ is expressed in many tumors including lung cancer,and its function has been linked to the process of lung cancer development, progression and metastasis.Studies performed in gynogenic and xenograft models of lung cancer showed decreased tumor growth and metastasis in animals treated with PPARγ ligands.Furthermore,data are emerging from retrospective clinical studies that suggest a protective role for PPARγ ligands on the incidence of lung cancer.This review summarizes the research being conducted in this area and focuses on the mechanisms and potential therapeutic effects of PPARγ ligands as a novel anti-lung cancer treatment strategy.

Two Novel 2D Lanthanide-organic Frameworks Based on Different Carboxylate-containing Mixed Ligands

Two novel lanthanide-organic polymers [Er2（pdc）2（o-bdc）（H2O）2]·H2O（1,H2pdc = 2,6-pyridinedicarboxylic acid,o-H2bdc = 1,2-benzenedicarboxylic acid） and Er（Himdc）（mbdc）0.5（H2O）（2,H3imdc = 4,5-imidazoledicarboxylic acid,m-H2bdc = 1,3-benzenedicarboxylic acid） have been synthesized and characterized by elemental analysis,IR,thermogravimetric analysis and X-ray single-crystal diffraction studies.1 crystallizes in monoclinic,space group P21/c,while 2 in the orthorhombic space group Pbcn.Both compounds 1 and 2 display two-dimensional network structures. For 1, the tetranuclear parallelogram {Era} cluster as a building block is further assembled into a wonderful 2D grid, and the layers are interconnected via hydrogen bonds and π-π stacking interactions to yield a 3D supramolecular architecture; for 2, its configuration is a rare double-decker structure. These two complexes represent good examples for using mixcarboxylate-containing ligands to construct diverse 2D lanthanide coordination polymers.

Controlled Self-assembly of Two Coordination Polymers via subtly Varying Bis(2-methyl imidazole) Ligands:from 3-Connected(6,3) Net to 4-Connected sql Net

Two coordination polymers constructed from 3,4-thiophenedicarboxylic acid and bis（2-methyl imidazole） ligands, namely, {[Cd2（tdc）2（bip）2]·7H20}n （1） and [Cd（tdc）（bib）]n （2） （Hgtdc = 3,4-thiophenedicarboxylic acid, bip = 1,3-bis-（imidazol-2-methyl）propane and bib = 1,4-bis（imidazol-2-methyl）butane）, have been synthesized and structurally characterized by single-crystal X-ray diffraction. Structural analyses reveal that 1 exhibits a two-dimensional （2D） layered network with 3-connected （6,3） topology, which is further connected into a three- dimensional （3D） supramolecular structure by intermolecular hydrogen bonds. However, 2 features a 2D network which can be rationalized as a 4-connected sql net. The results indicate the subtle difference of auxiliary bis（imidazol-2-methyl） ligands may lead to diverse architectures. Moreover, they exhibit luminescence emission in the solid state at room temperature.

Alkoxy substituted MeO-BIPHEP-type diphosphines ligands for asymmetric hydrogenation of aryl ketones

In this paper,a series of optically active MeO-BIPHEP-type ligands,（S）-6,6′-dimethoxy-2,2’-bis（di-p-alkoxyphenylphosphine）- 1,1′-biphenyl were synthesized and used to prepare the ruthenium complex.The effects of para-substituted were observed,the results showed that the ruthenium catalysts[diphosphine RuCl;diamine]containing both t-Bu and i-Pr substitutions have better activities and enantioselectivities than the non-substituted ruthenium catalysts in the asymmetric hydrogenation of acetophenone.

Synthesis,Structure and Fluorescent Property of a New Isolated Zn6Co9 Heteronuclear Cluster Constructed by Four Kinds of Ligands

A novel zero-dimensional heteronuclear cluster based on N-（phosphonomethyl）imi- no-diacetic acid （H4PMIDA） and Phen （1,10-phenanthroline）, [Zn6Co9（PMIDA）6（Phen）6（NO3）4（H2O）6]·2NO3·16H2O, has been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectrum, thermal analysis, and single-crystal X-ray diffraction. The isolated 15- nuclearity cluster [Zn6Co9（PMIDA）6（Phen）6（NO3）4（H2O）6]^2＋ was constructed by four kinds of ligands, and its charges are balanced by NO3^–. Each isolated cluster is further extended into a 3D supramolecular network through π？？？π interaction and C–H…O hydrogen bonds. Moreover, the solid-state fluorescent property of this complex has also been investigated at room temperature.

Peroxisome Proliferator-Activated Receptor-γActivated by Ligands Can Inhibit Human Lung Cancer Cell Growth through Induction of Apoptosis

To study the expression of peroxisome proliferator-activated receptor-7(PPAR-γ) in lung cancer cells, and to testify if the PPAR-γ agonists can inhibit human lung cancer cell growth through induction of apoptosis, PPAR-γ was detected in two lung cancer cell lines by RT-PCR and immuno-histochemistry, the inhibition of human lung cancer cell growth was investigated by MTT and cell counts, and the apoptosis was assessed by TUNEL. The results showed that: (1) PPAR-γ expressed on two lung cancer cell lines; (2) PPAR-γ activated by ligands could inhibit human lung cancer cell growth remarkably; (3) PPAR-γ agonists could induce apoptosis to inhibit lung cancer cell growth. It was concluded that PPAR-γ expressed in lung cancer cell can be activated by ligands and can inhibit lung cancer cell growth through induction of apoptosis.

Two Zinc Complexes Supported by in situ Formed Etheric Ligands

Two zinc complexes, [Zn(MPIP)Cl2](1) and [Zn(EPIP)Cl2](2), where MPIP = 1-(methoxymethyl)-3-(pyridin-2-yl)imidazo[1,5-a]pyridine and EPIP = 1-(ethoxymethyl)-3-(pyridin-2-yl)imidazo[1,5-a]pyridine, were synthesized under solvothermal conditions. The etheric ligand MPIP was formed in situ via metal ligand reaction between(3-(pyridin-2-yl)imidazo[1,5-a]pyridin-1-yl)methanol(HPIPM) and methanol solvent. Similarly, the ligand EPIP was generated in situ from the reaction of HPIPM with ethanol solvent. The structures of 1 and 2 were characterized by X-ray single-crystal diffraction analysis. They are four-coordinated mononuclear complexes, and the ZnII ion of 1 and 2 displays distorted tetrahedral geometry. The photoluminescent properties of 1 and 2 were investigated. Strong emissions were observed for both 1 and 2, which were ascribed as the intraligand(π-π*) fluorescent transitions. This paper provides a simple and efficient method for the synthesis of etheric compounds.

Flexible Bis(benzimidazole)-based Ligands Directed the Structure Characteristics of Coordination Polymers Based on Diphenic Acid Co-ligands:Syntheses, Structures and Properties

Two new coordination polymers [Cu_2(bbim)(dpa)_2(C_2H_5OH)_2](1), [Co(dpa)_2(bbbm)](2)(H_2dpa = diphenic acid, bbim = 1,1?-(1,6-hexanediyl)bis-1H-benzimidazole, bbbm = 1,1?-(1,4-butanediyl)bis-1 H-benzimidazole) constructed from bis(benzimidazole)-based ligands with different lengths and diphenic acid co-ligand have been synthesized under solvothermal conditions.Complex 1 possesses Cu-dpa helical chains. The adjacent chains are connected by the bbim ligands into two-dimensional(2D) 3-connected(63) topology. Differently, the layer structure of 2 was consisted by one-dimensional chains containing alternated 8-and 18-membered rings. Furthermore,the thermal stability and fluorescence property for all crystalline materials have been investigated.

Potential PET Ligands for Imaging of Cerebral VPAC and PAC Receptors: Are Non-Peptide Small Molecules Superior to Peptide Compounds?

Pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) have been known for decades to mediate neuroendocrine and vasodilative actions via G-protein-coupled receptors of Class B. These are targets of imaging probes for positron emission tomography (PET) or single photon emission tomography (SPECT) in tumor diagnostics and tumor grading. However, they play only a subordinate role in the development of tracers for brain imaging. Difficulties in development of non-peptide ligands typical for cerebral receptors of PACAP and VIP are shared by all members of Class B receptor family. Essential landmarks have been confirmed for understanding of structural details of Class B receptor molecular signalling during the last five years. High relevance in the explanation of problems in ligand development for these receptors is admitted to the large N-terminal?ectodomain markedly different from Class A receptor binding sites and poorly suitable as orthosteric binding sites for the most small-molecule compounds. The present study is focused on the recently available receptor ligands for PAC1, VPAC1 and VPAC2 receptors as well as potential small-molecule lead structures suitable for use in PET or SPECT. Recently, biaryl, cyanothiophene and pentanamide structures with affinities in nM-range have been proposed as non-peptide ligands at VPAC1 and VPAC2 receptors. However, most of these ligands have been classified as non-competitive related to the orthosteric binding site of endogenous peptide ligands of VPAC receptors. For PAC1 receptors have been identified hydrazide compounds for which an inhibitory and potentially competitive mechanism of receptor binding has been postulated based on molecular docking studies.

Comparative effects of α2δ-1 ligands in mouse models of colonic hypersensitivity

AIM: To investigate anti-hypersensitive effects of α2δ-1 ligands in non-inflammatory and inflammationassociated colonic hypersensitivity(CHS) mouse models.METHODS: To induce an inflammation-associated CHS, 1% dextran sulfate sodium(DSS) was administered to C57Bl/6J male mice, in drinking water, for 14 d. Regarding the non-inflammatory neonatal maternal separation(NMS)-induced CHS model, wild-type C57BI/6J pups were isolated from their mother from day 2 to day 14(P2 to P14), three hours per day(from 9:00 a.m. to 12:00 p.m.). Colorectal distension was performed by inflating distension probe from 20 μL to 100 μL by 20 μL increment step every 10 s. After a first colorectal distension(CRD), drugs were administered subcutaneously, in a cumulative manner,(Gabapentin at 30 mg/kg and 100 mg/kg; Pregabalin at 10 mg/kg and 30 mg/kg; Carbamazepine at 10 mg/kg and 30 mg/kg) and a second CRD was performed one hour after each injection.RESULTS: The visceromotor response(VMR) to CRD was increased by our NMS paradigm protocol in comparison to non-handled(NH) mice, considering the highest distension volumes(80 μL: 0.783 ± 0.056 mV /s vs 0.531 ± 0.034 m V/s, P < 0.05 and 100 μL: 1.087 ± 0.056 m V/s vs 0.634 ± 0.038 m V/s, P < 0.05 for NMS and NH mice, respectively). In the inflammationassociated CHS, DSS-treated mice showed a dramatic and significant increase in VMR at 60 and 80 μL distension volumes when compared to control mice(60 μL: 0.920 ± 0.079 m V/s vs 0.426 ± 0.100 m V/s P < 0.05 and 80 μL: 1.193 ± 0.097 mV /s vs 0.681 ± 0.094 mV /s P < 0.05 for DSS- and Water-treated mice, respectively). Carbamazepine failed to significantly reduce CHS in both models. Gabapentin significantly reduced CHS in the DSS-induced model for both subcutaneous injections at 30 or 100 mg/kg. Pregabalin s i g n i f i c a n t l y r e d u c e d V M R t o C R D i n t h e n o n-inflammatory NMS-induced CHS model for the acute subcutaneous administration of the highest cumulative dose(30 mg/kg) and significantly reduced CHS in lowdose DSS-treated mice in a dose-dependent manner. Finally, the percent decrease of AUC induced by acute GBP or Pregabalin treatment were higher in the inflammatory DSS-induced CHS model in comparison to the non-inflammatory NMS-induced CHS model.CONCLUSION: This preclinical study demonstrates α2δ-1 ligands efficacy on inflammation-associated CHS, highlighting their potential clinical interest in patients with chronic abdominal pain and moderate intestinal inflammation.

Synthesis of Novel Polypyridine Ligands

Some novel polypyridine ligands containing adsorbing groups were synthesized with the purpose of developing new ruthenium(II) polypyridine complexes to be used in solar cell based on dye-sensitized nanocrystilline TiO2 film electrode.

Synthesis and Photoluminescence of Three Europium (Ⅲ) Ternary Complexes with New Secondary Ligands of Different Structure

Three new 1,10-phenanthroline derivatives, dipyrido (3,2-f: 2,3-h) quinoxaline (DPQN), imidazo (5,6-f)-(1,10)-phenanthroline (IP) and 3-phenyl-imidazo (5,6-f)-(1,10)-phenanthroline (PIP) were designed and synthesized as a secondary ligand to coordinate with europium (Ⅲ) ion while dibenzoylmethane (DBM) was used as the first ligand. The compositions of the ligands and the europium (Ⅲ) ternary complexes were confirmed by elementary analysis, IR and (()~1H-NMR) spectroscopy. The UV-visible absorption spectra, thermal stability, photoluminescence spectra, quantum yield and fluorescence life time of the Eu(Ⅲ) complexes were investigated. The effect of the structure of the secondary ligand on the photoluminescence of the complexes was discussed. The results show that the synthesized Eu(Ⅲ) complexes are good red-emitiing materials for potential application in fabrication of organic electroluminescence devices.