scholarly journals Reduction and Oxidation of Cu Species in Cu-Faujasites Studied by IR Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4765
Author(s):  
Łukasz Kuterasiński ◽  
Jerzy Podobiński ◽  
Ewa Madej ◽  
Małgorzata Smoliło-Utrata ◽  
Dorota Rutkowska-Zbik ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Room Temperature ◽  
Probe Molecules ◽  
First Order ◽  
Reduction And Oxidation

The process of reduction (by hydrogen and ethanol) and oxidation (by oxygen and NO) of Cu sites in dealuminated faujasite-type zeolites (of Si/Al = 31) was studied by infrared (IR) spectroscopy with CO (for Cu+) and NO (for Cu2+) as probe molecules. Two zeolites were studied: one of them contained mostly Cu+exch., whereas another one contained mostly Cu2+ and Cu+ox. The susceptibility of various forms of Cu for reduction were investigated. IR experiments of CO sorption evidenced that Cu+ox. was more prone for the reduction than Cu+exch. According to NO sorption studies, Cu2+exch. was reduced in the first order before Cu2+ox. Ethanol reduced mostly Cu2+ and, also, some amounts of Cu+. The treatment with oxygen caused the oxidation of Cu+ (both Cu+exch. and Cu+ox.) to Cu2+. The adsorption of NO at 190K produced Cu+(NO)2 dinitrosyls, but heating to room temperature transformed dinitrosyls to mononitrosyls and increased the Cu2+ content.

scholarly journals The Properties of Cu Ions in Zeolites CuY Studied by IR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4686
Author(s):  
Jerzy Podobiński ◽  
Mariusz Gackowski ◽  
Grzegorz Mordarski ◽  
Katarzyna Samson ◽  
Michał Śliwa ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Positive Charge ◽  
Co Adsorption ◽  
The Other ◽  
Probe Molecules ◽  
Adsorption And Desorption ◽  
Other Hand ◽  
Close Proximity ◽  
No And Co Adsorption ◽  
Cu Ions

The properties of both Cu2+ and Cu+ ions in zeolite CuY were followed with NO and CO as probe molecules. Cu2+ was found to be located in SII, SII*, and SIII sites, whereas Cu+ was found in SII and SII* sites. The fine analysis of the spectra of Cu2+-NO and Cu+-CO adducts suggests that both in SII and in SII* sites two kinds of Cu cations exist. They differ in the positive charge, which may be related to the varying numbers of AlO4− in close proximity. The experiments of NO and CO adsorption and desorption evidenced that both Cu2+ and Cu+ sites of highest positive charge bind probe molecules most strongly but activate them to a lesser extent than the Cu sites of lowest positive charge. The experiments of reduction with hydrogen evidenced that the Cu ions of higher positive charge are first reduced by hydrogen. On the other hand, Cu sites of the lowest positive charge are first oxidized by oxygen. The experiments with CuNaY zeolites of various Cu contents suggest that the first introduced Cu (at low Cu contents) created Cu+, which was the most neutralized by framework oxygens. Such Cu cations are the most stabilized by framework oxygens.

scholarly journals Dichloro(η6-p-cymene)(P,P-diphenyl-N-propyl-phosphinous amide-κP)ruthenium(II)

Molbank ◽  
10.3390/m1217 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1217
Author(s):  
Rebeca González-Fernández ◽  
Pascale Crochet ◽  
Victorio Cadierno
Keyword(s):  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Title Compound ◽  
Room Temperature ◽  
Toluene Solution ◽  
Catalytic Behavior ◽  
Multinuclear Nmr

The title compound, i.e., [RuCl2(η6-p-cymene)(PPh2NHnPr)] (2), was obtained in a 71% yield by reacting a toluene solution of the chlorophosphine complex [RuCl2(η6-p-cymene)(PPh2Cl)] (1) with two equivalents of n-propylamine at room temperature. The aminophosphine complex 2 was characterized by elemental analysis, multinuclear NMR (31P{1H}, 1H and 13C{1H}) and IR spectroscopy. In addition, its catalytic behavior in the hydration of benzonitrile was briefly explored.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

A Study of the Interactions Between Oligoamidephosphate (OAPh) and Curatives in a Sulphenamide-Accelerated Sulphur Vulcanizing System

1999 ◽  
Vol 19 (2) ◽  
pp. 95-108 ◽  
Author(s):  
Todorka G. Vladkova ◽  
Alexander Chr. Alaminov ◽  
Milka G. Pankova
Keyword(s):  
Differential Scanning Calorimetry ◽  
Zinc Oxide ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sulphur Vulcanization

Abstract The possible interactions between oligoamidephosphate (OAPli) and the curatives of a sulphenamide-accelerated sulphur vulcanizing system were studied by differential scanning calorimetry, IR-spectroscopy, and X-ray analysis. The interactions in double mixtures were between OAPh and zinc oxide (ZnO) and OAPh and sulphur. The OAPh/ZnO interaction that starts at room temperature seems to be the key for understanding the peculiarities of sulphenamide-accelerated sulphur vulcanization in the presence of OAPh.

scholarly journals Engineering Increased Stability in the Antimicrobial Peptide Pediocin PA-1

2000 ◽  
Vol 66 (11) ◽  
pp. 4798-4802 ◽  
Author(s):  
Line Johnsen ◽  
Gunnar Fimland ◽  
Vincent Eijsink ◽  
Jon Nissen-Meyer
Keyword(s):  
Antimicrobial Peptide ◽  
Molecular Mass ◽  
Room Temperature ◽  
Bacteriocin Activity ◽  
Food Preservative ◽  
Food Grade ◽  
First Order ◽  
Methionine Residue ◽  
First Order Kinetics

ABSTRACT Pediocin PA-1 is a food grade antimicrobial peptide that has been used as a food preservative. Upon storage at 4°C or room temperature, pediocin PA-1 looses activity, and there is a concomitant 16-Da increase in the molecular mass. It is shown that the loss of activity follows first-order kinetics and that the instability can be prevented by replacing the single methionine residue (Met31) in pediocin PA-1. Replacing Met by Ala, Ile, or Leu protected the peptide from oxidation and had only minor effects on bacteriocin activity (for most indicator strains 100% activity was maintained). Replacement of Met by Asp was highly deleterious for bacteriocin activity.

Influence of the Ge distribution on the first order magnetic transition of the MnFe(P,Ge) magnetocaloric material

2018 ◽  
Vol 20 (26) ◽  
pp. 18117-18126 ◽  
Author(s):  
Zhen-Lu Zhang ◽  
Dan-Min Liu ◽  
Wei-Qiang Xiao ◽  
Hui Li ◽  
Shao-Bo Wang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Transition ◽  
First Order

MnFe(P,Ge) is a promising magnetocaloric material for potential refrigeration applications near room temperature.

Ferroelectricity of trimethylammonium bromide below room temperature

2020 ◽  
Vol 8 (17) ◽  
pp. 5868-5872 ◽  
Author(s):  
Zhangran Gao ◽  
Yuying Wu ◽  
Zheng Tang ◽  
Xiaofan Sun ◽  
Zixin Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Curie Temperature ◽  
Ferroelectric Phase Transition ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
First Order

Ferroelectricity of trimethylammonium bromide was discovered near room temperature, which undergoes a first-order paraelectric–ferroelectric phase transition at the Curie temperature around 286 K.

{K-[2 2 2]-Crypt}2Se7·H20; Synthese, IR-Spektrum und Kristallstruktur

1991 ◽  
Vol 46 (1) ◽  
pp. 63-67 ◽  
Author(s):  
Volker Müller ◽  
Kurt Dehnicke ◽  
Dieter Fenske ◽  
Gerhard Baum
Keyword(s):  
Ir Spectroscopy ◽  
Structure Determination ◽  
Room Temperature ◽  
Helical Chain ◽  
Space Group ◽  
X Ray

{K-[2 2 2]-Crypt}2Se7·H20 has been prepared by the reaction of a solution of potassium polyselenide in dimethylformamide at room temperature as black crystals, which were characterized by IR spectroscopy as well as by an X-ray structure determination. Space group P21/n, Z = 4, 5055 observed unique reflexions, R = 0.103. Lattice dimensions at 20 °C: a = 1435(1), b = 1320(1), c = 2966(2) pm, β = 102.50(6)° The heptaselenide ion represents approximately part of a helical chain of polymeric selenium.

scholarly journals Enhancement of zero-field skyrmion density in [Pt/Co/Fe/Ir]2 multilayers at room temperature by the first-order reversal curve

2020 ◽  
Vol 127 (22) ◽  
pp. 223901 ◽  
Author(s):  
Mangyuan Ma ◽  
Calvin Ching Ian Ang ◽  
Yong Li ◽  
Zizhao Pan ◽  
Weiliang Gan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Zero Field ◽  
First Order

scholarly journals Kinetic Profiling of the Hydrolytic Reaction of Benazepril: Metabolic Pathway Simulation

2018 ◽  
Vol 101 (4) ◽  
pp. 1009-1013
Author(s):  
A Hemdan ◽  
Adel M Michael
Keyword(s):  
Room Temperature ◽  
Enzyme Inhibitor ◽  
Internal Standard ◽  
Official Method ◽  
First Order ◽  
First Order Kinetics ◽  
Accuracy And Precision ◽  
Inhibitor Analysis ◽  
Hydrolytic Reaction ◽  
Significant Difference

Abstract A simple, specific, and rapid kinetic study of benazepril (BNZ) hydrolysis was developed and validated using HPLC. BNZ was degraded using 0.1 N sodium hydroxide at room temperature to produce benazeprilat, which is an active metabolite of BNZ and acts as an angiotensin-converting enzyme inhibitor. Analysis was carried out using an Athena C18 column (4.6 × 250 mm, 5 µm particle size). The mobile phase consists of a mixture of phosphate buffer (pH 4.5) and acetonitrile (53 + 47, v/v) at a flow rate of 1 mL/min. UV detection was accomplished at 242 nm using moexipril as the internal standard. The method was validated according to International Conference on Harmonization guidelines, and the calibration curve was linear over the range 10–100 µg/mL, with acceptable accuracy and precision. Kinetic profiling of the hydrolysis was shown to follow pseudo-first-order kinetics. The method was applied to the assay of BNZ in combined dosage form with no interference from other ingredients. The obtained results were statistically compared with those of the official method, showing no significant difference.

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