Voltammetric Determination of Nitrophenols at a Nickel Dimethylglyoxime Complex – Gold Nanoparticle Modified Glassy Carbon Electrode

Olorundare, Foluke O. G.

doi:10.20964/2016.09.47

Cited by 13 publications

(5 citation statements)

References 49 publications

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“…Pressure experiments have shown that the M ... M interactions account also for the compressibility of these structures and the pressure-dependent changes of colour and electronic properties [3,4,8,12,[26][27][28][29][30][31]. These virtually insoluble metal ... metal stacked solids are the basis for applications of the three compounds [M(Hdmg) 2 ] (M = Pt, Pd, Ni) for the extraction or removal of these elements [32][33][34][35], as components of solid catalysts [36][37][38][39][40], as solid but easily evaporable precursors [37][38][39][40][41][42][43][44][45][46][47], and in optical devices (e.g., pressure calibrants/indicators) [3,4,12,[26][27][28][29][30][31][48][49][50][51].…”

Section: Introductionmentioning

confidence: 99%

DFT Investigation of the Molecular Properties of the Dimethylglyoximato Complexes [M(Hdmg)2] (M = Ni, Pd, Pt)

Niazi

Klein

2021

Inorganics

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Important applications of the NiII, PdII and PtII complexes [M(Hdmg)2] (H2dmg = dimethylglyoxime) stem from their metal...metal stacked virtually insoluble aggregates. Given the virtual insolubility of the materials, we postulated that the rare reports on dissolved species in solution do not represent monomolecular species but oligomers. We thus studied the structural and spectral properties of the monomolecular entities of these compounds using density functional theory (DFT) and time-dependent DFT computations in dimethyl sulfoxide (DMSO) as a solvent. The molecular geometries, IR and UV-vis spectra, and frontier orbitals properties were computed using LANL2DZ ecp and def2TZVP as basis sets and M06-2X as the functional. The results are compared with the available experimental and other calculated data. The optimised molecular geometries proved the asymmetric character of the two formed O–H…O bonds which connect the two Hdmg‒ ligands in the completely planar molecules. Calculated UV-vis spectra revealed the presence of three absorptions in the range 180 to 350 nm that are red-shifted along the series Ni–Pd–Pt. They were assigned to essentially ligand-centred π−π* transitions in part with metal(d) to ligand(π*) charge transfer (MLCT) contributions. The notorious d‒p transitions dominating the colour and electronics of the compounds in the solid-state and oligomeric stacks are negligible in our monomolecular models strongly supporting the idea that the previously reported spectroscopic observations or biological effects in solutions are not due to monomolecular complexes but rather to oligomeric dissolved species.

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Section: Introductionmentioning

confidence: 99%

DFT Investigation of the Molecular Properties of the Dimethylglyoximato Complexes [M(Hdmg)2] (M = Ni, Pd, Pt)

Niazi

Klein

2021

Inorganics

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“…Above this value, 4‐NP is mainly present as the 4‐nitrophenolate (4‐NPL) form. This result indicates that the non‐dissociated form of 4‐NP can be better adsorbed than its dissociated form on the electrode surface, providing a higher reduction current .…”

Section: Resultsmentioning

confidence: 99%

Silver Nanoparticles‐Silsesquioxane Nanomaterial Applied to the Determination of 4‐Nitrophenol as a Biomarker

et al. 2019

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A novel silsesquioxane material was synthetized and used as a stabilizing agent for silver nanoparticles. This hybrid material was characterized by FTIR, 29Si CP‐MAS NMR, 13C DEPT 135° NMR and TGA techniques and the silver nanoparticles were characterized from DLS, UV‐Vis spectroscopy, zeta‐potential, TEM and SAXS results. The silver nanoparticles obtained were spherical in shape with a diameter of 3.74 nm. The nanomaterial was successfully applied in the modification of a glassy carbon electrode and a pronounced current response was obtained in the determination of the biomarker 4‐nitrophenol. Quantum chemical calculations, using density functional theory, were also performed in order to evaluate the redox properties of the analyte. Two different linear ranges were obtained applying optimal square wave voltammetry conditions. The reduction peak currents obtained were linear for 4‐NP concentrations in the ranges of 0.29 to 1.50 μmol L−1 (Ed=−0.6 V and td=20 s) and 2.75 to 31.5 μmol L−1, with a theoretical (signal to noise=3) limit of detection of 0.05 μmol L−1 (td=20 s). The proposed method was successfully applied to the determination of 4‐NP in synthetic serum samples at different levels of 4‐NP with a recovery range of 94–101 %. Validation was performed using a comparative method through the capillary electrophoresis (CE) technique.

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“…On the other hand, the presence of 4-NP displayed welldefined redox peaks (Figure S10b) that are similar to the typical cyclic voltammetry of 4-NP reported. 47,48 The cyclic voltammograms of Au-magnetic NPs were standardized by Au NP content, resulting in Au-feroxyhyte NPs as the most electroactive in the reduction of 4-NP to 4-AP, since larger cathodic and anodic peak currents were achieved (Figure 8a). This result is in agreement with the kinetics studied by UV−vis spectrophotometry and might be attributed to the high surface area of the ferroxyhyte NPs, as well as the reactive amine groups of lysine.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Gas-Directed Production of Noble Metal-Magnetic Heteronanostructures in Continuous Fashion: Application in Catalysis

Larrea

Eguizábal

Sebastián

2019

ACS Appl. Mater. Interfaces

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Complex nanomaterials produced by scale-up batch processes lack suitable control of shape, size distribution, chemical composition, and quality, because heat and mass transfer are seriously affected as the reactor volume increases. Here we use a novel continuous synthesis procedure, the active gas–liquid segmented flow, to produce noble metal-magnetic heteronanostructures with enormous interest in the fields of catalysis, biomedicine, environmental sensors, food monitoring, and chemical analysis. The microreactor technology proposed scales down the reaction volume to gain advantage of the large surface area to volume ratio with respect to conventional batch-type reactors, improving heat and mass transport and, consequently, promoting a uniform heating and mixing. The gas phase was introduced in the chemical reactor as gas slugs of nanoliter scale with a dual role: (1) passive mixing and (2) chemical directing agent to tune the crystallization of nanostructures in a continuous fashion. The shape, size, and magnetic properties of the resulting heteronanostructures, as well as the density, size, and composition of noble metal nanoparticles were tuned to show the versatility of the proposed approach in a timeline of 4 min. We demonstrated that the produced nanostructures provide excellent catalytic properties in the catalyzed hydrogenation of nitrophenols to aminophenols. Electron microscopy, UV–vis spectroscopy, and cyclic voltammetry studies showed the remarkable catalytic performance of the produced heteronanostructures.

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Voltammetric Determination of Nitrophenols at a Nickel Dimethylglyoxime Complex – Gold Nanoparticle Modified Glassy Carbon Electrode

Cited by 13 publications

References 49 publications

DFT Investigation of the Molecular Properties of the Dimethylglyoximato Complexes [M(Hdmg)2] (M = Ni, Pd, Pt)

DFT Investigation of the Molecular Properties of the Dimethylglyoximato Complexes [M(Hdmg)2] (M = Ni, Pd, Pt)

Silver Nanoparticles‐Silsesquioxane Nanomaterial Applied to the Determination of 4‐Nitrophenol as a Biomarker

Gas-Directed Production of Noble Metal-Magnetic Heteronanostructures in Continuous Fashion: Application in Catalysis

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