scholarly journals 109Ag Nuclear Magnetic Resonance Studies of Organic and Inorganic Silver Complexes

1976 ◽  
Vol 31 (12) ◽  
pp. 1532-1538 ◽  
Author(s):  
K. Jucker ◽  
W. Sahm ◽  
A. Schwenk
Keyword(s):  
Aqueous Solutions ◽  
Chemical Exchange ◽  
Chemical Shifts ◽  
Linear Functions ◽  
Silver Salts ◽  
Two Samples ◽  
Chemical Shift Data ◽  
Limits Of Error ◽  
Ethyl Amine ◽  
Good Agreement

AbstractThe NMR lines of 109Ag have been investigated in solutions of several silver salts in acetonitrile, propionitrile, pyridine, and ethylenediamine, and also in aqueous solutions of Na2S2O3 and ethyl-amine. In these solvents the Ag+ -ions form one or several complexes. In any case a single NMR line was to be detected, i. e. a rapid chemical exchange between different complexes in a sample may be assumed. The concentration dependence of the chemical shifts was determined with high accuracy for these solutions. From these results the chemical shift data of some defined complexes were derived. The chemical shifts of mixtures of AgCl and AgBr and also of AgCl and Agl dissolved in 70% aqueous solution of ethylamine are linear functions of the anions mole fraction. In two samples of AgNO3 dissolved in organic solvents, the ratio υ(109Ag)/υ(107Ag) = 1.149 640 (1) was measured in good agreement with the value from silver salts in aqueous solutions; i. e. no primary isotopic effect was to be detected within these limits of error (0.9 ppm).

Chemical‐Shift Data for Water and Aqueous Solutions

1966 ◽  
Vol 45 (9) ◽  
pp. 3296-3298 ◽  
Author(s):  
Heinrich H. Rüterjans ◽  
Harold A. Scheraga
Keyword(s):  
Chemical Shift ◽  
Aqueous Solutions ◽  
Chemical Shift Data ◽  
Shift Data

scholarly journals NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas

2011 ◽  
Vol 7 ◽  
pp. 1205-1214 ◽  
Author(s):  
Damjan Makuc ◽  
Jennifer R Hiscock ◽  
Mark E Light ◽  
Philip A Gale ◽  
Janez Plavec
Keyword(s):  
Conformational Changes ◽  
Chemical Shifts ◽  
Dihydrogen Phosphate ◽  
Nmr Studies ◽  
Receptor Complexes ◽  
Hydrogen Bond Interactions ◽  
Weak Binding ◽  
Oxo Anions ◽  
Induced Changes ◽  
Good Agreement

The conformational properties of 1,3-diindolylureas and thioureas were studied by a combination of heteronuclear NMR spectroscopy and quantum mechanics calculations. NOE experiments showed that the anti–anti conformer along the C7–N7α bonds was predominant in DMSO-d 6 solution in the absence of anions. Anion-induced changes in the 1H and 15N chemical shifts confirm the weak binding of chloride anions with negligible conformational changes. Strong deshielding of ureido protons and moderate deshielding of indole NH was observed upon the addition of acetate, benzoate, bicarbonate and dihydrogen phosphate, which indicated that the predominant hydrogen bond interactions occurred at the urea donor groups. Binding of oxo-anions caused conformational changes along the C7–N7α bonds and the syn–syn conformer was preferred for anion–receptor complexes. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations.

scholarly journals Proper motions in the Galactic bulge: Plaut's window

2007 ◽  
Vol 3 (S245) ◽  
pp. 351-354
Author(s):  
Katherine Vieira ◽  
Dana Cassetti-Dinescu ◽  
René A. Méndez ◽  
R. Michael Rich ◽  
Terrence M. Girard ◽  
...  
Keyword(s):  
Proper Motion ◽  
Galactic Rotation ◽  
Red Giants ◽  
Proper Motions ◽  
Motion Study ◽  
Solar Motion ◽  
Two Samples ◽  
Red Clump ◽  
Good Agreement ◽  
Peak Value

AbstractA proper motion study of a field of 20′ × 20′ inside Plaut's low extinction window (l,b)=(0o, −8o), has been completed. Relative proper motions and photographicBVphotometry have been derived for ~ 21,000 stars reaching toV~ 20.5 mag, based on the astrometric reduction of 43 photographic plates, spanning over 21 years of epoch difference. Proper motion errors are typically 1 mas yr−1. Cross-referencing with the 2MASS catalog yielded a sample of ~ 8700 stars, from which predominantly disk and bulge subsamples were selected photometrically from theJHcolor-magnitude diagram. The two samples exhibited different proper-motion distributions, with the disk displaying the expected reflex solar motion. Galactic rotation was also detected for stars between ~2 and ~3 kpc from us. The bulge sample, represented by red giants, has an intrinsic proper motion dispersion of (σl, σb) = (3.39, 2.91)±(0.11, 0.09) mas yr−1, which is in good agreement with previous results. A mean distance of$6.37^{+0.87}_{-0.77}$kpc has been estimated for the bulge sample, based on the observedKmagnitude of the horizontal branch red clump. The metallicity [M/H] distribution was also obtained for a subsample of 60 bulge giants stars, based on calibrated photometric indices. The observed [M/H] shows a peak value at [M/H] ~ −0.1 with an extended metal poor tail and around 30% of the stars with supersolar metallicity. No change in proper motion dispersion was observed as a function of [M/H]. We are currently in the process of obtaining CCDUBV RIphotometry for the entire proper-motion sample of ~ 21,000 stars.

scholarly journals Measurement and Prediction of Densities of Ternary Aqueous Mixtures Involving Sodium Polyacrylate

2004 ◽  
Vol 4 (1) ◽  
pp. 64
Author(s):  
Z. A. Noor Fadzlina ◽  
T. T. Teng ◽  
M. Abdul Rahman
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Percentage Error ◽  
Sodium Polyacrylate ◽  
Aqueous Systems ◽  
Aqueous Mixtures ◽  
Density Prediction ◽  
Density Values ◽  
Good Agreement

The densities of the binary aqueous solutions of sodium polyacrylate (NaPM) at 20°C, 25°C, and 300C up to 0.17 m and LiCI at 25°C and 300C up to 3.13 m were measured using a vibrating tube digital densitimeter. The measured experimental data were then fitted to the polynomial d = do + IA;m'. The densities of the ternary aqueous systems NaPM-NaCI, NaPM-LiCI, and NaPM-sucrose were also =1 measured from 20°C to 30°C. The isopycnotic equation, Imi / moi was used to predict the densities of the ternary aqueous systems mentioned. The results show that predicted and observed density values are in good agreement. The overall percentage error of density prediction for the system NaPM-NaCI-H20 is 0.067. For the system NaPM-LiCI-HP,the overall percentage error is 0.074; and, for the system NaPM-sucrose-H20, the overall percentage error is 0.065.

scholarly journals 45Scandium NMR Investigations in Aqueous Solutions

1983 ◽  
Vol 38 (3) ◽  
pp. 317-321 ◽  
Author(s):  
E. Haid ◽  
D. Köhnlein ◽  
G. Kössler ◽  
O. Lutz ◽  
W. Messner ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Chemical Shifts ◽  
Isotope Effects ◽  
Larmor Frequency ◽  
Relaxation Rates ◽  
Nmr Chemical Shifts ◽  
Typical Behaviour ◽  
Solvent Isotope ◽  
Scandium Chloride ◽  
Solvent Isotope Effects

Abstract45Sc NMR chemical shifts, linewidths, and longitudinal relaxation rates have been measured in aqueous solutions of scandium chloride and sulphate as a function of the appropriate acid. A common typical behaviour of these parameters without sudden changes has been observed. Also signals in the basic range have been obtained. H2O -D2O solvent isotope effects on Larmor frequency and relaxation rates are presented.

scholarly journals Nonlinear Determination Method for Self-Heating Initiative Temperature of Sulfide Ores

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Huimin Jin ◽  
Wei Pan ◽  
Xue Shen ◽  
Shuangyi Cheng
Keyword(s):  
Approximate Entropy ◽  
The Self ◽  
Graph Analysis ◽  
Hurst Index ◽  
Sulfide Ores ◽  
Self Heating ◽  
Two Samples ◽  
Change Characteristics ◽  
Safety Production ◽  
Good Agreement

The purpose of this article is to explore a new method to determine the self-heating initiative temperature of sulfide ores for preventing spontaneous combustion of sulfide ores. Two typical ore samples with self-heating characteristics are studied by wavelet transform, recursive graph analysis, Hurst index extraction, and approximate entropy detection. On this basis, self-heating initiative temperature of sulfide ores was measured. The results indicate that the Hurst index of both ore samples in the experiment is greater than 0.5; moreover, the Hurst index in the later period of the experiment is greater than that of the earlier period. The self-heating of sulfide ores is an unsteady process with positive persistence and obvious mutation, so the possibility of self-heating of sulfide ores can be determined according to the change characteristics of Hurst index. The mutation times of the two samples are 864 min and 819 min, respectively, reference values of self-heating initiative temperature are 219.4°C and 232.3°C, and the average relative error is only 1.49%, which are in good agreement with the measured values, and therefore, it provides basis for safety production of high-sulfur ore mine.

Preparation of Biologically Active Compositions from Aqueous Solutions of L-Cysteine, Silver Salts and Polyvinyl Alcohol

2018 ◽  
Vol 50 (3) ◽  
pp. 161-165
Author(s):  
D. V. Vishnevetskii ◽  
V. S. Laguseva ◽  
A. I. Ivanova ◽  
S. D. Khizhnyak ◽  
P. M. Pakhomov
Keyword(s):  
Polyvinyl Alcohol ◽  
Aqueous Solutions ◽  
Biologically Active ◽  
Silver Salts

Determination of Uncombined Intermediates in FD&C Yellow No. 6 by High-Pressure Liquid Chromatography

1974 ◽  
Vol 57 (2) ◽  
pp. 358-359
Author(s):  
Manjeet Singh
Keyword(s):  
High Pressure ◽  
Chromatographic Method ◽  
Sulfanilic Acid ◽  
Sunset Yellow ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Method ◽  
Two Samples ◽  
Liquid Chromatographic ◽  
Good Agreement

Abstract A high-pressure liquid chromatographic method is presented for the isolation and determination of uncombined intermediates in FD&C Yellow No. 6 (sunset yellow FCF, CI. No. 15895). Samples of FD&C Yellow No. 6 containing 0.1-0.4% sulfanilic acid, 0.1-0.4% 6-hydroxy-2-naphthalenesulfonic acid, and 0.3— 1.0% 6,6'-oxybis(2-naphthalenesulfonic acid) were prepared and analyzed using this method. Recoveries ranged between 94 and 101%. Twenty-two samples of FD&C Yellow No. 6 were analyzed by the conventional column elution chromatographic method as well as by the high-pressure liquid chromatographic method. Good agreement was obtained between the 2 methods.

Berechnung der 19F- und 195 Pt-NMR-Verschiebungen von FIuoro-Chloro-Bromo-Platinaten(IV) / Calculation of 19F and 195Pt NMR Shifts of Fluoro-Chloro-Brom o-Platinates(IV )

1997 ◽  
Vol 52 (4) ◽  
pp. 435-442 ◽  
Author(s):  
H.-H. Drews ◽  
W. Preetz
Keyword(s):  
Experimental Data ◽  
Chemical Shifts ◽  
Coupling Constant ◽  
Lower Field ◽  
Trans Influence ◽  
Nmr Signals ◽  
Increments Of Chemical Shifts ◽  
Good Agreement

By reaction of [PtBr4]2- with XeF2 in dichloromethane product mixtures containing nine fluoro-chloro-, four fluoro-bromo- and 15 fluoro-chloro-bromo-platinates(IV) are formed. All complexes are detectable by in situ l9F NMR measurements. Due to the increasing trans influence F < Cl < Br, the signals <5(19F) of symmetric F-Pt-F axes observed at highest field are shifted downfield on the average by 93 ppm as compared with δ(19F•) of F••Pt-Cl′ axes, and further to lower field by 40 ppm for <5(F••) of F••-Pt-Br″ axes. For the same reason the coupling constant 1J(F••Pt) ≈ 1099 Hz is by 13.3 % smaller than 1J(F•Pt) ≈ 1268 Hz, which is by 32.3 % smaller than δ(FPt) ≈ 1873 Hz. Based on the axis method, and taking into account characteristic increments of chemical shifts depending on cis influences, the calculation of the 195Pt NMR signals of 27 observed species of the system [PtFnCl6-n-mBrm]2- n, m = 0 - 6, has been successful. The 195Pt NMR shifts of further 29 so far not detected complexes are predicted. Using parameters depending on the geometry of the complex, the 19F NMR shifts of 28 F-containing platinates(IV) have been calculated in good agreement with the experimental data. 19F resonances are predicted for 19 so far missing complexes.

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