Synthesis and Mechanism of Spherical Ag-doped Polypyrrole Assisted by Complexing Agents

Over 700 compounds were screened at 10−4 M concentration as inhibitors of the conversion of L-tryptophan-14C to serotonin-14C in crude rat brain homogenates. Most of the compounds had little or no inhibitory effect. Those with strong inhibitory properties were tested as inhibitors of 5-hydroxytryptophan decarboxylase and, if active on the decarboxylase, were assayed as tryptophan hydroxylase inhibitors. Except for a few oxidizing and complexing agents and for some substituted p-phenylenediamines, the compounds found to inhibit tryptophan hydroxylase by >50% belonged to the three types of inhibitors already known, i.e. catechols, phenylalanine and ring-substituted phenylalanines, and 6-substituted tryptophans. The numerous data in this screen make possible some comments as to the structural requirements for activity within each class. A comparison of the results on tryptophan hydroxylase with data on tyrosine hydroxylase inhibition in similar homogenates makes it clear that two separate, if somewhat similar, enzymes are involved.

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Anion Coordination Improves High-Temperature Performance and Stability of NaPF6-Based Electrolytes for Supercapacitors

Energies ◽

10.3390/en14154409 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4409

Author(s):

J. Landon Tyler ◽

Robert L. Sacci ◽

Jagjit Nanda

Keyword(s):

Thermal Stability ◽

Electrolyte Solution ◽

Elevated Temperatures ◽

Electrochemical Impedance ◽

Cycle Life ◽

Stable Complex ◽

Complexing Agents ◽

Anion Coordination ◽

Decomposition Processes ◽

Hexamethyl Phosphoramide

Electrolyte stability can be improved by incorporating complexing agents that bind key decomposition intermediates and slow down decomposition. We show that hexamethyl-phosphoramide (HMPA) extends both the thermal stability threshold of sodium hexafluorophosphate (NaPF6) in dimethoxyethane (DME) electrolyte and the cycle life of double-layer capacitors. HMPA forms a stable complex with PF5, an intermediate in PF6 anion thermal degradation. Unbound, this intermediate leads to autocatalytic degradation of the electrolyte solution. The results of electrochemical impedance spectroscopy (EIS) and galvanostatic cycling measurements show large changes in the cell without the presence of HMPA at higher temperatures (≥60 °C). Fourier transform infrared spectroscopy (FTIR) on the liquid and gas phase of the electrolyte shows without HMPA the formation of measurable amounts of PF5 and HF. The complimentary results of these measurements proved the usefulness of using Lewis bases such as HMPA to inhibit the degradation of the electrolyte solution at elevated temperatures and potentially lead to improve cycle life of a nonaqueous capacitor. The results showed a large increase in capacitance retention during cycling (72% retention after 750,000 cycles). The results also provide evidence of major decomposition processes (0% capacitance retention after 100,000 cycles) that take place at higher temperatures without the additive of a thermal stability additive such as HMPA.

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Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽

10.3390/ma14102518 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2518

Author(s):

Dorota Kołodyńska ◽

Yongming Ju ◽

Małgorzata Franus ◽

Wojciech Franus

Keyword(s):

Experimental Data ◽

Aspartic Acid ◽

Ph Value ◽

Complexing Agents ◽

X Ray Diffraction ◽

Experimental Conditions ◽

Modified Zeolite ◽

X Ray ◽

Slow Release Fertilizers ◽

Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

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Pyridine derivatives as complexing agents. XIII. The stability of the palladium(II) complexes with pyridine, 2,2′-bipyridyl, and 1,10-phenanthroline

Inorganica Chimica Acta ◽

10.1016/s0020-1693(00)82229-x ◽

1986 ◽

Vol 113 (2) ◽

pp. 101-108 ◽

Cited By ~ 43

Author(s):

Giorgio Anderegg ◽

Hans Wanner

Keyword(s):

Complexing Agents ◽

Pyridine Derivatives ◽

The Stability

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Irregular Electrodeposition of Cu-Sn Alloy Coatings in [EMIM]Cl Outside the Glove Box with Large Layer Thickness

Coatings ◽

10.3390/coatings11030310 ◽

2021 ◽

Vol 11 (3) ◽

pp. 310

Author(s):

Lars Lehmann ◽

Dominik Höhlich ◽

Thomas Mehner ◽

Thomas Lampke

Keyword(s):

Layer Thickness ◽

Alloy System ◽

Liquid Solution ◽

Complexing Agents ◽

X Ray Diffraction ◽

X Ray ◽

Argon Stream ◽

Ionic Liquid Solution ◽

The Relationship ◽

Layer Composition

Thick Cu−Sn alloy layers were produced in an [EMIM]Cl ionic-liquid solution from CuCl2 and SnCl2 in different ratios. All work, including the electrodeposition, took place outside the glovebox with a continuous argon stream over the electrolyte at 95 °C. The layer composition and layer thickness can be adjusted by the variation of the metal-salts content in the electrolyte. A layer with a thickness of up to 15 µm and a copper content of up to ωCu = 0.86 was obtained. The phase composition was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Furthermore, it was found that the relationship between the alloy composition and the concentration of the ions in the electrolyte is described as an irregular alloy system as according to Brenner. Brenner described such systems only for aqueous electrolytes containing complexing agents such as cyanide. In this work, it was confirmed that irregular alloy depositions also occur in [EMIM]Cl.

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The effect of complexing agents in chemical solution deposition of metal chalcogenide thin films

Materials Chemistry Frontiers ◽

10.1039/d0qm00931h ◽

2021 ◽

Author(s):

Sucheta Sengupta ◽

Rinki Aggarwal ◽

Yuval Golan

Keyword(s):

Thin Films ◽

Chemical Solution Deposition ◽

Metal Ion ◽

Chemical Deposition ◽

Review Article ◽

Complexing Agents ◽

Chemical Solution ◽

Solution Deposition ◽

Metal Chalcogenide ◽

Chalcogenide Thin Films

This review article gives an overview of different complexing agents used during chemical deposition of metal chalcogenide thin films and their role in controlling the resultant morphology by effective complexation of the metal ion.

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EFFECTS OF COMPLEXING ON THE HOMOGENEOUS REDUCTION OF MERCURIC SALTS IN AQUEOUS SOLUTION BY MOLECULAR HYDROGEN

Canadian Journal of Chemistry ◽

10.1139/v56-176 ◽

1956 ◽

Vol 34 (10) ◽

pp. 1372-1381 ◽

Cited By ~ 7

Author(s):

G. J. Korinek ◽

J. Halpern

Keyword(s):

Aqueous Solution ◽

Molecular Hydrogen ◽

Hydrogen Molecule ◽

Bimolecular Reaction ◽

Mercury Atom ◽

Complexing Agents ◽

Mercuric Ion ◽

Rate Determining Step ◽

Homogeneous Reduction

The effects of various complexing agents on the homogeneous reduction of mercuric salts by molecular hydrogen in aqueous solution were determined. In all cases the kinetics suggest that the rate-determining step is a bimolecular reaction between a mercuric ion or complex and a hydrogen molecule, probably leading to the formation of an intermediate mercury atom. The reactivity of various mercuric complexes was found to decrease in the following order: HgSO4 > Hg++ > HgAc2, HgPr2 > HgCl2 > HgBr2 > Hg(EDA)2++. Addition of anions such as OH−, CO3=, Ac−, Pr−, and Cl−, in excess of the amounts required to form stable mercuric complexes, was found to increase the rate. An interpretation of these effects is given.

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