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1.
Inorg Chem ; 59(2): 968-971, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31891256

RESUMO

A dithiolate/hydride bridged Fe-Ni complex, [(CN)(CO)2FeII(µ-pdt)(µ-H)NiII(CN)(PCy3)]- (2, pdt = propane-1,3-dithiolate) has been synthesized by the reaction of [(CN)2(CO)2FeII(pdt)]2- with [NiII(Cl)(H)(PCy3)2] as a synthetic analogue of the Ni-R state of the active site of the [Ni-Fe] hydrogenase. X-ray crystallography of this model complex suggests that the hydride unsymmetrically binds to Ni and Fe similar to natural [Ni-Fe] hydrogenases.


Assuntos
Monóxido de Carbono/química , Complexos de Coordenação/química , Cianetos/química , Hidrogenase/química , Tolueno/análogos & derivados , Monóxido de Carbono/metabolismo , Domínio Catalítico , Complexos de Coordenação/metabolismo , Cianetos/metabolismo , Hidrogenase/metabolismo , Ferro/química , Ferro/metabolismo , Modelos Moleculares , Conformação Molecular , Níquel/química , Níquel/metabolismo , Tolueno/química , Tolueno/metabolismo
2.
Chem Pharm Bull (Tokyo) ; 68(1): 70-76, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31902902

RESUMO

In this study, nickel-aluminium complex hydroxides at different molar ratios (nickel-aluminium = 1 : 2, 1 : 1, 2 : 1, 3 : 1, and 4 : 1, referred to as NA12, NA11, NA21, NA31, and NA41) were prepared, and their adsorption capability for chromium(VI) ion was investigated. Firstly, physicochemical characteristics (SEM images, X-ray diffraction (XRD) patterns, specific surface area, amount of hydroxyl groups, and surface pH) of nickel-aluminum complex hydroxide were evaluated. The amount of chromium(VI) ion adsorbed onto NA11 (15.3 mg/g) was greater than that adsorbed onto the other adsorbents. This research elucidated that the amount of chromium(VI) ion adsorbed using nickel-aluminium complex hydroxide was related to the adsorbent surface properties (r = 0.818-0.875). Subsequently, the adsorbent (NA11) surface before and after adsorption of chromium(VI) ion was evaluated, and chromium energy (577 and 586 eV) detected after adsorption onto the NA11 surface. These results revealed that the NA11 surface properties were very important for the removal of chromium(VI) ion from aqueous solution. In addition, the effects of pH, contact time, and temperature on the adsorption of chromium(VI) ion were evaluated. We confirmed a high recovery percentage of chromium(VI) ion when using sodium hydroxide solution at 10-1000 mmol/L (approximately greater than 80%) in this experimental condition. Thus, NA11 is a promising adsorbent for the removal of chromium(VI) ion from aqueous solution.


Assuntos
Alumínio/química , Cromo/química , Complexos de Coordenação/química , Hidróxidos/química , Níquel/química , Adsorção , Concentração de Íons de Hidrogênio , Íons/química , Temperatura Ambiente , Termodinâmica , Poluentes Químicos da Água/química
3.
Chemosphere ; 242: 125259, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31896176

RESUMO

Activated carbon (AC), prepared from dried loofah sponge, was supported on nickel foam to fabricate AC/Ni electrodes. The characteristics of ammonium electrosorption on AC/Ni electrodes was studied. Results showed that AC prepared in one-step activation (without pre-pyrolysis), i.e., OAC, had relatively low crystallinity, high mesoporosity, and high specific capacitance compared to those made in two-step carbonation followed by activation. Adsorption and desorption density of NH4+ were measured at constant potential of -1.0 V (vs. Hg/HgO) and +0.1 V (vs. Hg/HgO), respectively. Non-faradaic charging contributed to the electrochemical storage and adsorption of ammonium ions on the AC surface with a maximal charge efficiency of 80%, at an applied potential of -1.0 V (vs. Hg/HgO). Multiple-layer adsorption isotherm better described the electrosorption of ammonium ion on OAC/Ni electrodes yielding a maximum adsorption capacity of 6 mg-N g-1, which was comparable with other similar systems. Overall, results clearly demonstrated the effect of synthesis strategy on the capacitive charging behaviors of AC/Ni electrodes and its relationship to NH4+ electrosorption.


Assuntos
Compostos de Amônio/análise , Carvão Vegetal/química , Luffa/química , Níquel/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Capacitância Elétrica , Eletrodos , Íons , Modelos Teóricos , Propriedades de Superfície
5.
Chemosphere ; 239: 124743, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31514007

RESUMO

Ethylenediaminetetraacetic acid (EDTA) could form stable complexes with toxic metals such as nickel due to its strong chelation. In this study, with the same doping level of Co and N, MoO2 and ZIF-67 were used as precursors to prepare MoO2@Co/N and FeC@Co/N electrocatalysts for the modified graphite felt cathodes in heterogeneous-electro-Fenton-like reaction (HEFL) system. The X-ray diffraction and X-ray photoelectron spectroscopy results indicated that both of the catalysts are dominated with pyridinic N (2.42% and 2.82%) upon co-doping Co/N, and FeC@Co/N exhibited an obviously higher additional sp-hybridized nitrogen (sp-N) peak. The co-doping of Co/N induced the lattice modifications to produce more lattice defects, where pyridinic N and sp-N, related with the active sites (C-N, Co-Nx), were formed at near-ring defects along sheet edges through the nitrogen replacement of CC groups. FeC@Co/N demonstrated superior oxygen reduction reaction catalytic activity in terms of Cyclic Voltammetry and Rotating Ring-disk Electrode, and exhibited the remarkably higher current density (30 mA) and lower onset potential (-0.208 V) in Linear Sweep Voltammetry analysis. In the FeC@Co/N/CF modified HEFL system, despite the generated H2O2 concentrations (62.5 mg L-1) is not very high, the reducing reaction of ≡Fe(III)/Co(III)-OH could get the electron directly from the cathode, which would greatly reduce the consumption of H2O2, high utilization efficiency of H2O2 (η: 87.63%) could greatly improve the EDTA-Ni removal (97.5%) and TOC (92.6%). This work demonstrates the feasibility of utilizing FeC@Co/N/CF as a cathode for breaking metal-complex in HEFL process.


Assuntos
Cobalto/química , Ácido Edético/química , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Níquel/química , Catálise , Descontaminação , Técnicas Eletroquímicas/instrumentação , Eletrodos , Grafite/química , Peróxido de Hidrogênio/química , Ferro/química , Nitrogênio/química , Oxirredução , Piridinas/química , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos
6.
J Colloid Interface Sci ; 558: 211-219, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31586740

RESUMO

Porous interconnected carbon nanosheets (PICNs) with high electrochemical performance were prepared by doping urea and a co-hydrothermal precursor derived from soybean stalk (SS) and nickel nitrate. The specific surface area and average pore diameter of the as-synthesized PICNs are 2226.29 m2 g-1 and 1.89 nm, and their N and O contents are 5.08% and 9.4%, respectively, which is beneficial for increasing pseudocapacitance. Furthermore, the doping of the metal Ni increases the graphitization degree of the PICNs and promotes the conversion of pyridine-N to graphitized-N. Therefore, the PICNs possess a high specific capacitance of 407 F g-1 at a current density of 0.5 A g-1, a high capacitance retention of 78.62% even at 20 A g-1, and an outstanding cycling stability (over 93% retention rate after 10,000 charge/discharge cycles). Moreover, an energy density of 36.11 W h kg-1 is achieved at a power density of 517.8 W kg-1 during a two-electrode system test, and a retention rate of 87.5% is obtained after 10,000 cycles. This co-hydrothermal treatment as well as nitrogen-doping approach for preparing porous interconnected carbon from SS not only represents an alternative strategy for carbon-based supercapacitor materials but also provides a new option for the utilization of waste SS.


Assuntos
Carbono/química , Nanoestruturas/química , Níquel/química , Nitrogênio/química , Oxigênio/química , Soja/química , Capacitância Elétrica , Técnicas Eletroquímicas
7.
J Environ Sci (China) ; 87: 173-183, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791490

RESUMO

Efficient removal of formaldehyde from indoor environments is of significance for human health. In this work, a typical binary transition metal oxide that could provide various oxidation states, ß-NiMoO4, was employed as a support to immobilize the active Pt component (Pt/NiMoO4) for catalytic formaldehyde elimination at low ambient temperature (15°C). The results showed that the hydrothermal preparation temperature and time had a noticeable impact on the morphology and catalytic activity of the samples. The catalyst prepared with hydrothermal temperature of 150°C for 4 hr (Pt-150-4) exhibited superior catalytic activity and stability mainly due to its distinctly porous structure, relative abundance of adsorbed surface hydroxyls/water, and high oxidation ability, which resulted from the interaction of Pt with Ni and Mo of the bimetallic NiMoO4 support. Our results might shed light on the rational design of multifunctional catalysts for removal of indoor air pollutants at low ambient temperature.


Assuntos
Formaldeído/química , Modelos Químicos , Catálise , Temperatura Baixa , Nanopartículas Metálicas , Molibdênio/química , Níquel/química , Platina/química
8.
Acta Crystallogr C Struct Chem ; 75(Pt 12): 1658-1665, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31802756

RESUMO

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4-triazole 2-{[5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetic acid (H2L) was synthesized and characterized. Treatment of H2L with cobalt and nickel acetate afforded the dinuclear complexes {µ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ2N1,N5:N2,O}bis[aqua(methanol-κO)cobalt(II)] methanol disolvate, [Co2(C9H6N4O2S)2(CH3OH)2(H2O)2]·2CH3OH (1), and {µ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κ2N1,N5:N2,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni2(C9H6N4O2S)2(H2O)4]·2CH3OH·2H2O (2), respectively. Complex 1 crystallized in the monoclinic space group P21/c, while 2 crystallized in the tetragonal space group I41/a. Single-crystal X-ray diffraction studies revealed that H2L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2. For both of the obtained complexes, extensive hydrogen-bond interactions contribute to the formation of their three-dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1, 2 and H2L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.


Assuntos
Acetatos/química , Cobalto/farmacologia , Complexos de Coordenação/química , Níquel/farmacologia , Compostos Organometálicos/química , Tioglicolatos/farmacologia , Urease/antagonistas & inibidores , Urease/química , Cobalto/química , Cristalografia por Raios X , Ligações de Hidrogênio , Ligantes , Modelos Moleculares , Níquel/química , Tioglicolatos/química
9.
Inorg Chem ; 58(23): 16075-16086, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31729870

RESUMO

GANT61-D is an important hedgehog pathway inhibitor and an interesting ligand candidate for metal coordination. The first examples of metal complexes of the potent hedgehog pathway inhibitor GANT61-D are described. The reaction of Ni(II), Pd(II), and Pt(II) precursors with the hedgehog pathway inhibitor GANT61-D gave [NiII(GANT61-D)(OH2)3(µ2-SO4)(µ3-SO4)] (1), [PdII(Cl)(GANT61-D)]Cl (2), [PtII(Cl)(GANT61-D)]Cl, and [PtII(CBDCA-2H)(GANT61-D)]. X-ray crystal structure analysis revealed that GANT61-D is a versatile N-donor ligand that can act as a bidentate ligand via the diaminopropane (DAP) N atoms or a tridentate ligand via the DAP N atoms and one dimethylaniline N atom. Protonation constants of the GANT61-D ligand in water and in a 60:40 (w/w) dimethyl sulfoxide-water solvent mixture were determined. Potentiometric and spectroscopic data on the NiII(GANT61-D) system indicate the formation of octahedral 1:1 species with medium stability in solution. 1 and 2 exhibited noteworthy in vitro cytotoxicity against medulloblastoma cancer cells.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Níquel/farmacologia , Paládio/farmacologia , Platina/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Cristalografia por Raios X , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Níquel/química , Paládio/química , Platina/química
10.
Environ Sci Pollut Res Int ; 26(33): 34562-34574, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31650478

RESUMO

Novel adsorbent, diethylenetriamine-grafted Spirodela polyrhiza (DSP), was synthesized via modifying natural S. polyrhiza (SP) with diethylenetriamine by cross-linking with epichlorohydrin and applied to adsorb Ni2+ and Pb2+ from water. The effecting parameters on adsorption of Ni2+ and Pb2+ such as adsorbent dosage, pH, contact time, temperature, and initial concentration were studied through equilibrium experiments. The adsorption of Ni2+ and Pb2+ followed the pseudo-second-order model and the Langmuir isotherm adsorption model. The study discusses thermodynamic parameters, including changes in Gibbs free energy, entropy, and enthalpy, for the adsorption of Ni2+ and Pb2+ on DSP, and revealed that the adsorption process was spontaneous and exothermic under natural conditions. The maximum Ni2+ and Pb2+ adsorption capacities of DSP were 33.02 and 36.50 mg/g, respectively. The newly prepared materials were characterized through scanning electron microscopy (SEM), mapping analysis, and zeta potential analysis. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that functional groups (-OH and N-H) were involved in Ni2+ and Pb2+ adsorption. Notably, DSP can be easily regenerated and reused for multiple cycles. Therefore, DSP is a promising adsorbent for effective Ni2+ and Pb2+ removal.


Assuntos
Alismatales/química , Chumbo/química , Níquel/química , Poliaminas/química , Poluentes Químicos da Água/química , Adsorção , Epicloroidrina/química , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Termodinâmica , Água , Poluentes Químicos da Água/análise , Purificação da Água/métodos
11.
Bull Environ Contam Toxicol ; 103(5): 756-762, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31583424

RESUMO

The current study investigated the efficiency and mechanisms of in situ immobilization of artificially Cd-contaminated soils with ferronickel slag (FNS). The available Cd content of soil was measured and the modified European Community Bureau of Reference (BCR) sequential extraction procedure (SEP) was adopted to quantify the evolutions of Cd chemical speciation after the immobilization by the FNS. The results showed that the addition of FNS (5%‒15%) remarkably reduced the available Cd content and increased the pH and cation exchange capacity of soils. The passivation rate of Cd increased from 58.13% to 73.25% as the spiked Cd content rose from 10 to 120 mg kg‒1. The BCR SEP test revealed that the FNS addition substantially reduced the acid soluble fraction and increased the residual fraction of Cd, indicating the reduction of mobility and bioavailability of Cd in soils. The chemical precipitation, ion exchange and surface complexation might be involved in in situ immobilization of Cd-contaminated soils by the FNS.


Assuntos
Cádmio/análise , Poluição Ambiental/análise , Ferro/química , Níquel/química , Poluentes do Solo/análise , Solo/química , Disponibilidade Biológica , Cádmio/química , Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química
12.
Top Curr Chem (Cham) ; 377(6): 29, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31605243

RESUMO

Sustainable and high performance energy devices such as solar cells, fuel cells, metal-air batteries, as well as alternative energy conversion and storage systems have been considered as promising technologies to meet the ever-growing demands for clean energy. Hydrogen evolution reaction (HER) is a crucial process for cost-effective hydrogen production; however, functional electrocatalysts are potentially desirable to expedite reaction kinetics and supply high energy density. Thus, the development of inexpensive and catalytically active electrocatalysts is one of the most significant and challenging issues in the field of electrochemical energy storage and conversion. Realizing that advanced nanomaterials could engender many advantageous chemical and physical properties over a wide scale, tremendous efforts have been devoted to the preparation of earth-abundant transition metals as electrocatalysts for HER in both acidic and alkaline environments because of their low processing costs, reasonable catalytic activities, and chemical stability. Among all transition metal-based catalysts, nickel compounds are the most widely investigated, and have exhibited pioneering performances in various electrochemical reactions. Heterostructured nickel phosphide (NixPy) based compounds were introduced as promising candidates of a new category, which often display chemical and electronic characteristics that are distinct from those of non-precious metals counterparts, hence providing an opportunity to construct new catalysts with an improved activity and stability. As a result, the library of NixPy catalysts has been enriched very rapidly, with the possibility of fine-tuning their surface adsorption properties through synergistic coupling with nearby elements or dopants as the basis of future practical implementation. The current review distils recent advancements in NixPy compounds/hybrids and their application for HER, with a robust emphasis on breakthroughs in composition refinement. Future perspectives for modulating the HER activity of NixPy compounds/hybrids, and the challenges that need to be overcome before their practical use in sustainable hydrogen production are also discussed.


Assuntos
Hidrogênio/química , Níquel/química , Água/química , Catálise , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Técnicas Eletroquímicas , Nanoestruturas/química , Elementos de Transição/química
13.
Inorg Chem ; 58(19): 12601-12608, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31539235

RESUMO

The radical SAM enzyme HydG generates CO- and CN--containing Fe complexes that are involved in the bioassembly of the [FeFe] hydrogenase active cofactor, the H-cluster. HydG contains a unique 5Fe-4S cluster in which the fifth "dangler" Fe and the coordinating cysteine molecule have both been shown to be essential for its function. Here, we demonstrate that this dangler Fe can be replaced with Ni2+ or Co2+ and that the cysteine can be replaced with selenocysteine. The resulting HydG variants were characterized by electron paramagnetic resonance and X-ray absorption spectroscopy, as well as subjected to a Tyr cleavage assay. Both Ni2+ and Co2+ are shown to be exchange-coupled to the 4Fe-4S cluster, and selenocysteine substitution does not alter the electronic structure significantly. XAS data provide details of the coordination environments near the Ni, Co, and Se atoms and support a close interaction of the dangler metal with the FeS cluster via an asymmetric SeCys bridge. Finally, while we were unable to observe the formation of novel organometallic species for the Ni2+ and Co2+ variants, the selenocysteine variant retains the activity of wild type HydG in forming [Fe(CO)x(CN)y] species. Our results provide more insights into the unique auxiliary cluster in HydG and expand the scope of artificially generated Fe-S clusters with heteroatoms.


Assuntos
Proteínas de Bactérias/química , Cobalto/química , Proteínas com Ferro-Enxofre/química , Níquel/química , Selenocisteína/química , Shewanella/química , Domínio Catalítico , Cisteína/química
14.
Chemosphere ; 234: 917-924, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31519100

RESUMO

Nickel, massively used in plating industry but detrimental to ecosystem, tends to form stable complexes with organic additives in industrial effluents. Currently, most of the available processes aim at water decontamination from free toxic metal ions and thus, could not effectively remove nickel-carboxyl complexes from water. Herein, we employed a proprietary combined process Fe(III)/UV/NaOH, namely Fe(III) displacement and UV irradiation followed by alkaline precipitation, to validate its feasibility on the efficient removal of nickel-carboxyl complexes from synthetic and authentic effluents. Fe(III)/UV/NaOH outperformed other commonly used processes including NaOH precipitation, UV/NaOH, Fe(III) coagulation, and Fenton/NaOH. Each unit of the combined process was optimized, and the underlying mechanism was elucidated. Fe(III) displacement favored the stoichiometric release of free nickel ions and formation of Fe(III)-carboxyl complexes, which could be decarboxylated via ligand-metal charge transfer under UV irradiation. The precipitation unit aims at simultaneously removing the released Ni along with Fe species. Attractively, the presence of other organic species (ethylene glycol, ethyl acetate and humic acid) and anions (chloride and sulfate) exerted very slight effect on the final Ni removal, whereas greatly adverse effect occurred on the Fenton process under similar conditions. The feasibility of the combined process was validated by testing on an authentic electroplating effluent, resulting in the residual Ni below 0.1 mg/L, the most stringent discharge standard for Ni in electroplating effluent in China.


Assuntos
Compostos Férricos/química , Níquel/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , China , Ecossistema , Galvanoplastia , Hidróxido de Sódio , Sulfatos , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise
15.
Inorg Chem ; 58(19): 12775-12785, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31545024

RESUMO

The superoxide dismutase (SOD) activity of mononuclear NiII complexes, whose structures are inspired by the NiSOD, has been investigated. They have been designed with a sulfur-rich pseudopeptide ligand, derived from nitrilotriacetic acid (NTA), where the three acid functions are grafted with cysteines (L3S). Two mononuclear complexes, which exist in pH-dependent proportions, have been fully characterized by a combination of spectroscopic techniques including 1H NMR, UV-vis, circular dichroism, and X-ray absorption spectroscopy, together with theoretical calculations. They display similar square-planar S3O coordination, with the three thiolates of the three cysteine moieties from L3S coordinated to the NiII ion, together with either a water molecule at physiological pH, as [NiL3S(OH2)]-, or a hydroxo ion in more basic conditions, as [NiL3S(OH)]2-. The 1H NMR study has revealed that contrary to the hydroxo ligand, the bound water molecule is labile. The cyclic voltammogram of both complexes displays an irreversible one-electron oxidation process assigned to the NiII/NiIII redox system with Epa = 0.48 and 0.31 V versus SCE for NiL3S(OH2) and NiL3S(OH), respectively. The SOD activity of both complexes has been tested. On the basis of the xanthine oxidase assay, an IC50 of about 1 µM has been measured at pH 7.4, where NiL3S(OH2) is mainly present (93% of the NiII species), while the IC50 is larger than 100 µM at pH 9.6, where NiL3S(OH) is the major species (92% of the NiII species). Interestingly, only NiL3S(OH2) displays SOD activity, suggesting that the presence of a labile ligand is required. The SOD activity has been also evaluated under catalytic conditions at pH 7.75, where the ratio between NiL3S(OH2)/ NiL3S(OH) is about (86:14), and a rate constant, kcat = 1.8 × 105 M-1 s-1, has been measured. NiL3S(OH2) is thus the first low-molecular weight, synthetic, bioinspired Ni complex that displays catalytic SOD activity in water at physiological pH, although it does not contain any N-donor ligand in its first coordination sphere, as in the NiSOD. Overall, the data show that a key structural feature is the presence of a labile ligand in the coordination sphere of the NiII ion.


Assuntos
Complexos de Coordenação/química , Cisteína/química , Níquel/química , Compostos de Enxofre/química , Superóxido Dismutase/química , Materiais Biomiméticos/química , Concentração de Íons de Hidrogênio , Ligantes , Oxirredução
16.
Chemosphere ; 226: 934-944, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31509923

RESUMO

The anaerobic ammonium oxidation (anammox) process has the advantages of a high nitrogen removal rate, low operational cost, and small footprint and has been successfully implemented to treat high-content ammonium wastewater. However, very little is known about the toxicity of the heavy metal element Ni(II) to the anammox process. In this study, the short- and long-term effects of Ni(II) on the anammox process in an upflow anaerobic sludge blanket (UASB) reactor were revealed. The results of the short-term batch test showed that the half maximal inhibitory concentration (IC50) of Ni(II) on anammox biomass was 14.6 mg L-1. A continuous-flow experiment was performed for 150 days of operation, and the results illustrated that after domestication, the achieved nitrogen removal efficiency was up to 93±0.03% at 10 mg L-1 Ni(II). The settling velocity, specific anammox activity and EPS content decreased as the Ni(II) concentration increased. Nevertheless, the content of heme c increased as the Ni(II) increased. These results indicate that short-term exposure to Ni(II) has an adverse impact on anammox process, but the anammox system could tolerate 10 mg L-1 Ni(II) stress after acclimation during continuous-flow operation for 150 days. High-throughput sequencing results indicated that the presence of Ni(II) had an impact on the microbial community composition in the anammox reactor, especially Candidatus Kuenenia. At Ni(II) concentrations of 0-10 mg L-1, the relative abundance of Candidatus Kuenenia decreased from 36.23% to 28.46%.


Assuntos
Compostos de Amônio/química , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Níquel/química , Nitrogênio/química , Esgotos/química , Águas Residuárias/química , Anaerobiose , Bactérias/crescimento & desenvolvimento , Oxirredução
17.
Molecules ; 24(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487944

RESUMO

Monovalent NHC-nickel complexes bearing triarylphosphine, in which fluorine is incorporated onto the aryl groups, have been synthesized. Tris(3,5-di(trifluoromethyl)-phenyl)phosphine efficiently gave a monovalent nickel bromide complex, whose structure was determined by X-ray diffraction analysis for the first time. In the solid state, the Ni(I) complex was less susceptible to oxidation in air than the triphenylphosphine complex, indicating greatly improved solid-state stability. In contrast, the Ni(I) complex in solution can easily liberate the phosphine, high catalytic activity toward the Kumada-Tamao-Corriu coupling of aryl bromides.


Assuntos
Complexos de Coordenação/química , Flúor/química , Níquel/química , Fosfinas/química , Catálise , Cristalografia por Raios X , Teoria da Densidade Funcional , Modelos Moleculares , Modelos Teóricos , Conformação Molecular , Estrutura Molecular , Oxirredução
18.
Chemistry ; 25(67): 15351-15360, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31486181

RESUMO

In Rhodospirillum rubrum, the maturation of carbon monoxide dehydrogenase (CODH) requires three nickel chaperones, namely RrCooC, RrCooT and RrCooJ. Recently, the biophysical characterisation of the RrCooT homodimer and the X-ray structure of its apo form revealed the existence of a solvent-exposed NiII -binding site at the dimer interface, involving the strictly conserved Cys2. Here, a multifaceted approach that used NMR and X-ray absorption spectroscopies, complemented with structural bio-modelling methodologies, was used to characterise the binding mode of NiII in RrCooT. This study suggests that NiII adopts a square-planar geometry through a N2 S2 coordinating environment that comprises the two thiolate and amidate groups of both Cys2 residues at the dimer interface. The existence of a diamagnetic mononuclear NiII centre with bis-amidate/bis-thiolate ligands, coordinated by a single-cysteine motif, is unprecedented in biology and raises the question of its role in the activation of CODH at the molecular level.


Assuntos
Cisteína/química , Metalochaperonas/química , Níquel/química , Rhodospirillum rubrum/química , Sequência de Aminoácidos , Sítios de Ligação , Cátions Bivalentes/química , Complexos de Coordenação/química , Ligantes , Modelos Moleculares , Nitrogênio/química , Ligação Proteica , Conformação Proteica , Multimerização Proteica , Solventes/química , Enxofre/química , Termodinâmica
19.
Anal Chim Acta ; 1082: 165-175, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472705

RESUMO

Functional laser scribing carbon paper (LSCP) decorated with highly uniform Ni nanoparticles were constructed through a facile electroless plating. The nanocomposites were characterized by high resolution scanning electron microscope, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The results showed high electron transferring kinetics of this sensor, which can be ascribed to their excellent properties such as rich pore channels, excellent structural durability, and large surface area. These properties facilitated mass transfer and electron conductions. Notably, a systematical response surface methodology simulating-modeling-predicting-optimizing design was employed to simulate, model and optimize processing parameters to gain the optimal conductivity of 8.52 × 106 S m-1. The obtained sensor owned high electrochemical activity and wide linear responses (0.80 µM-2.50 mM and 4.50 mM-15.20 mM), low detection limit of 20 nM (S/N = 3) to the glucose detection. The glucose determination in human serum and perspiration samples are also successful. Therefore, LSCP/NN provides an excellent sensing platform towards flexible biosensors in monitoring physical conditions.


Assuntos
Glicemia/análise , Carbono/química , Nanopartículas Metálicas/química , Níquel/química , Papel , Técnicas Biossensoriais/métodos , Glicemia/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Lasers , Limite de Detecção , Nanocompostos/química , Nanoporos , Oxirredução , Maleabilidade , Suor/química
20.
Biosens Bioelectron ; 143: 111634, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31473379

RESUMO

In this work, Ni(OH)2 nanocages@MnO2 nanosheets core-shell architecture (Ni(OH)2 NCs@MnO2 NSs CSA) was successfully prepared through coordinated etching and precipitation (CEP) route followed by hydrothermal reaction, and then tested as sensitive electrode material for detection of dopamine (DA). The three dimensional (3D) hollow Ni(OH)2 core effectively prevented the aggregation of MnO2 NSs, leading to high utilization rate of MnO2 NSs. Meanwhile, the two dimensional (2D) MnO2 shell endowed Ni(OH)2 NCs with larger specific area and abundant diffusion channels, facilitating mass transport. Ni(OH)2 NCs@MnO2 NSs CSA modified glassy carbon electrode (GCE) exhibited two satisfying sensitivities of 467.1 and 1249.9 µA mM-1 cm-2 within the two linear ranges of 0.02-16.30 µM and 18.30-118.58 µM, respectively. Furthermore, Ni(OH)2 NCs@MnO2 NSs CSA/GCE presented low detection limit of 1.75 nM and short response time of 1.14 s. Overall, Ni(OH)2 NCs@MnO2 NSs/GCE looks promising for analytical sensing of DA thanks to its prominent electrocatalytic dynamic issued from the 3D hollow structure@2D nanosheets core-shell architecture.


Assuntos
Técnicas Biossensoriais , Dopamina/isolamento & purificação , Técnicas Eletroquímicas , Nanoestruturas/química , Dopamina/química , Hidróxidos/química , Compostos de Manganês/química , Níquel/química
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