Protonated cyclopropanes. X. Studies on the deamination of n-butylamine-1-14C and the decomposition of 3-(n-butyl-1-14C)-1-phenyltriazene

1978 ◽  
Vol 56 (5) ◽  
pp. 658-662 ◽  
Author(s):  
Choi Chuck Lee ◽  
Randy Reichle ◽  
Ursula Weber
Keyword(s):  
Ion Pair ◽  
Initial Formation ◽  
Aqueous Hclo

The HNO2 deamination of n-butylamine-1-14C (1-NH2-1-14C) in aqueous HClO4 gave a n-butyl-14C alcohol (1-OH-14C) with about 0.7% scrambling of the label from C-1 to C-2, and a sec-butyl-14C alcohol (2-OH-14C) which showed extensive scrambling between C-1 and C-4, as well as small amounts of rearrangement of the label into C-2 and C-3. Analysis of the data suggested that about 2.5% of the 2-OH-14C product could be derived from equilibrating protonated methylcyclopropane intermediates. The HClO4 catalyzed decomposition of 3-(n-butyl-1-14C)-1-phenyltriazene (1-NNNHPh-1-14C) gave the unrearranged 1-OH-1-14C and a 2-OH-14C which showed only about 17–18% scrambling from C-1 toC-4. It is suggested that the different results observed in the deamination and the triazene decomposition may be due to a more ready initial formation of an ion pair in the triazene decomposition.

Flash photolysis of alkali metal anions in tetrahydrofuran and dimethoxyethane

1979 ◽  
Vol 57 (14) ◽  
pp. 1792-1800 ◽  
Author(s):  
W. A. Seddon ◽  
J. W. Fletcher ◽  
F. C. Sopchyshyn ◽  
E. B. Selkirk
Keyword(s):  
Pulse Radiolysis ◽  
Shape Function ◽  
Flash Photolysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Parent Metal ◽  
Initial Formation ◽  
Extinction Coefficients ◽  
Best Fit ◽  
Good Agreement

Flash photolysis of K−, Rb−, and Cs− in tetrahydrofuran (THF) produces the corresponding ion-pairs (K+, es−), (Rb+, es−), and (Cs+, es−), followed by the regeneration of the parent metal anion, M−. In mixed-metal solutions containing Na and M where M is K, Rb, or Cs, photolysis of Na− also forms the (M+, es−) ion-pair and M−, but with the latter then reforming Na− on an extended time scale. Similar results were obtained in dimethoxyethane (DME) at 213 K, but in this case with the initial formation of a loose ion-pair, (M+, es−)loose.Based on a Gaussian–Lorenztian shape function, the 'best-fit' optical bands for the (M+, es−) and M− species were used to simulate the experimental spectra and deduce the corresponding extinction coefficients in both solvents.The overall mechanism is complex but is in good agreement with previous interpretations deduced by pulse radiolysis.

National primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2019

2020 ◽  
pp. 8-12
Author(s):  
Alexandr V. Oborin ◽  
Anna Y. Villevalde ◽  
Sergey G. Trofimchuk
Keyword(s):  
Gamma Radiation ◽  
Energy Flux ◽  
Primary Standard ◽  
Average Energy ◽  
Ion Pair ◽  
X Rays ◽  
Exposure Rate ◽  
Ionization Chambers ◽  
Air Kerma ◽  
Air Kerma Rate

The results of development of the national primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2011 in 2019 are presented according to the recommendations of the ICRU Report No. 90 “Key Data for Ionizing-Radiation Dosimetry: Measurement Standards and Applications”. The following changes are made to the equations for the units determination with the standard: in the field of X-rays, new correction coefficients of the free-air ionization chambers are introduced and the relative standard uncertainty of the average energy to create an ion pair in air is changed; in the field of gamma radiation, the product of the average energy to create an ion pair in air and the electron stopping-power graphite to air ratio for the cavity ionization chambers is changed. More accurate values of the units reproduced by GET 8-2019 are obtained and new metrological characteristics of the standard are stated.

DIE INITIALE VERTEILUNG VON RADIO-C IN DEN ZELLFRAKTIONEN EINIGER RATTENORGANE NACH INJEKTION VON TESTOSTERON-4-14C

1964 ◽  
Vol 47 (1) ◽  
pp. 51-57 ◽  
Author(s):  
K.-O. Mosebach ◽  
W. Dirscherl
Keyword(s):  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Initial Distribution ◽  
Male Rats ◽  
Initial Formation ◽  
Thigh Muscles ◽  
The Absolute ◽  
Cell Fractions

ABSTRACT The initial distribution of radioactive C was studied in the cell fractions of the liver, kidney, testes and thigh muscles after intraperitoneal injection of testosterone-4-14C into 40 day old male rats. To make this possible, the absolute and specific activity values (μc/mg C) were determined. After both ten and twenty minutes the cytoplasm fractions possessed the highest activity values, the only exception being the specific activity of the liver cytoplasm ten minutes after injection when the microsomes of the liver showed a higher activity. After 20 min the mitochondria possessed the highest specific activity values among the corpuscular fractions. The specific activity values in the microsomes of all four organs studied were lower 20 min after the time of injection than after 10 min, a fact, which is suspected to be the result of the initial formation of conjugates in the microsomes.

Extractive Spectrophotometric Method for the Determination of Glibenclamide by Ion-Pair Complex in Pure Form and Pharmaceutical Formulation

2019 ◽  
Vol 9 (o3) ◽  
Author(s):  
RUAA MUAYAD MAHMOOD ◽  
HAMSA MUNAM YASSEN ◽  
SAMAR , NAJWA ISSAC ABDULLA AHMED DARWEESH ◽  
NAJWA ISSAC ABDULLA
Keyword(s):  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Pharmaceutical Formulation ◽  
Ratio Method ◽  
Colored Complex ◽  
Colored Product ◽  
Method Of Continuous Variation ◽  
Job's Method

Simple, rapid and sensitive extractive spectrophotometric method is presented for the determination of glibenclamide (Glb) based on the formation of ion-pair complex between the Glb and anionic dye, methyl orange (MO) at pH 4. The yellow colored complex formed was quantitatively extracted into dichloromethane and measured at 426 nm. The colored product obeyed Beer’s law in the concentration range of (0.5-40) μg.ml-1. The value of molar absorptivity obtained from Beer’s data was found to be 31122 L.mol-1.cm-1, Sandell’s sensitivity value was calculated to be 0.0159 μg.cm-2, while the limits of detection (LOD) and quantification (LOQ) were found to be 0.1086 and 0.3292 μg.ml-1, respectively. The stoichiometry of the complex created between the Glb and MO was 1:1 as determined via Job’s method of continuous variation and mole ratio method. The method was successfully applied for the analysis of pharmaceutical formulation.

LA PARTICIPACIÓN CIUDADANA Y EL DESARROLLO DE LA CULTURA CIENTÍFICA, EN LA FORMACIÓN INICIAL DEL PROFESOR PARA LA EDUCACIÓN TÉCNICA Y PROFESIONAL. UN RETO HECHO REALIDAD.

2015 ◽  
Vol 3 (3) ◽  
Author(s):  
María Isabel Orozco Rivero
Keyword(s):  
Citizen Participation ◽  
Professional Education ◽  
Theory And Practice ◽  
Scientific Development ◽  
Scientific Culture ◽  
Initial Formation ◽  
Theoretical Contribution ◽  
Palabras Clave ◽  
Stated Problem ◽  
Theoretical Foundations

La formación inicial del profesor de la Educación Técnica y Profesional (ETP), debe estar en correspondenciacon la integración del conocimiento científico, el acelerado desarrollo de la ciencia y la tecnologíay las exigencias en la formación de las nuevas generaciones. Esta investigación aborda la problemáticaplanteada en la formación de profesores para la Carrera de Informática y asume como problemacientífico: “¿Cómo contribuir al desarrollo de una cultura científica como base para una participaciónciudadana responsable, en la formación inicial del profesor para la ETP en la Carrera Informática?”. La metodología utilizada constituye una integración de métodos teóricos y empíricos, lo que permitióla elaboración de la propuesta. Se trabajan y sustentan los antecedentes teóricos y metodológicos delproceso de formación inicial del profesor para la Educación Técnica y Profesional. Finalmente, se brindan los resultados de la aplicación de la consulta a expertos como comprobación teórica del mismo ysu aplicación parcial en la práctica. El fundamento teórico y las relaciones sistemáticas que se establecenentre los componentes, constituyen el principal aporte teórico y novedad de la investigación.   Palabras Clave: participación ciudadana, cultura científica, formación inicial, educación técnica y profesional.   ABSTRACT   The basic formation of teachers in Technical and Professional Education (TPE) must be in correspondencewith the integration of scientific development, the accelerated development of science and technology, and the educational demands of the new generations.  This research addresses the stated problem in the formation of teachers for the Informatics Career and assumes the scientific problem: How to contribute to thedevelopment of a scientific culture as the basis of a responsible citizen participation, in the initial formation of the ETP teacher in the Informatics Career? The methodology used integrates both theoretical and empiricalmethods which helped to build up this proposal.  Historical and methodological background of the formation process are worked out and supported.  Finally, results of the application of expert consulting as averification in theory and practice. The theoretical foundations and the systematic relationships established among the components constitute the main theoretical contribution and novelty of this research.   Keywords: citizen participation, scientific culture, initial formation, technical and professional education   Recibido: julio de 2015Aprobado: septiembre de 2015

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

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