Application de la spectrométrie infrarouge, Raman et résonance magnétique nucléaire à l'étude des complexes en solution aqueuse. Al3+–H2C2O4

1977 ◽  
Vol 55 (21) ◽  
pp. 3689-3699 ◽  
Author(s):  
M. Jaber ◽  
F. Bertin ◽  
G. Thomas-David
Keyword(s):  
Aqueous Solution ◽  
Nmr Spectra ◽  
Raman Spectrometry ◽  
Characteristic Frequencies ◽  
Résonance Magnétique ◽  
Successive Formation ◽  
Characteristic Signal ◽  
Metal Ligand ◽  
C Nmr ◽  
Solution Aqueuse

A study by Raman spectrometry of the system Al3+–H2C2O4 in aqueous solution as a function of the acidity of the solution and of the ratio t = [metal]/[ligand] shows very clearly the successive formation of the complexes Al(C2O4)+, Al(C2O4)2−, and Al(C2O4)33−. The formation of the species Al(C2O4)+, which had been rejected by some authors, is confirmed and it was easily possible to identify its characteristic frequencies as well as those of the species Al(C2O4)2−. The 27Al and 13C nmr spectra confirm these results and allow the identification of each complex by means of a clearly characteristic signal. Moreover, the results of this study permit the rejection of the hypothesis of the formation of hydroxylated complexes, at least in important quantities.It also was possible to use the intensities of the Raman scattering bands at eight selected characteristic frequencies of the species Al(C2O4)+, Al(C2O4)2−, and Al(C2O4)33− to determine their distribution as a function of the acidity of the solution. [Journal translation]

Application de la spectrométrie infrarouge et Raman à l'étude des complexes en solution aqueuse: Fe3+–H2C2O4

1980 ◽  
Vol 58 (12) ◽  
pp. 1220-1228 ◽  
Author(s):  
Mohsen Jaber ◽  
François Bertin ◽  
Germaine Thomas-David
Keyword(s):  
Aqueous Solution ◽  
Raman Spectra ◽  
Raman Effect ◽  
Raman Band ◽  
Ir And Raman Spectra ◽  
Raman Spectrometry ◽  
Exciting Line ◽  
Successive Formation ◽  
Ir And Raman ◽  
Solution Aqueuse

A study by Raman spectrometry of the System Fe3+–H2C2O4 in aqueous solution shows very clearly the successive formation of the three complexes: Fe(C2O4)+, Fe(C2O4)2−, Fe(C2O4)33−. Each species is characterised by a specific Raman spectrum.The evolution of Raman band intensities with the range of exciting line, and the comparison between ir and Raman spectra of Fe(III) and Al(III) complexes, show for Fe(III) species a pre-resonance Raman effect.

Tautomerization tendencies of 2-acetylcycloalkanones, 2-acetyl-1,3-cycloalkanediones, and cyclic β-keto esters of five- and six-membered rings

2001 ◽  
Vol 79 (4) ◽  
pp. 448-454 ◽  
Author(s):  
Antonio Rojas ◽  
Alfonso Perez-Encabo ◽  
Ignacio Herraiz-Sierra ◽  
Carlos A Blanco
Keyword(s):  
Aqueous Solution ◽  
Rate Constants ◽  
Nmr Spectra ◽  
Tautomeric Equilibrium ◽  
Concentration Effects ◽  
Keto Esters ◽  
H Nmr ◽  
Kinetics Studies ◽  
Dilute Aqueous Solution ◽  
C Nmr

NMR and kinetics studies of the tautomeric equilibrium of 2-acetylcycloalkanones, 2-acetyl-1,3-cycloalkanediones, and methyl 2-oxocycloalkanecarboxylates of five- and six-membered rings have been carried out. By comparing 1H NMR and 13C NMR spectra recorded in D2O–DOCD3 and CDCl3, with those results derived using a bromination kinetic procedure in dilute aqueous solution, information concerning tautomeric interconversion is provided. Some discussions considering ionisation equilibria and rate constants involved have also been considered. Solvent and concentration effects on keto-enol equilibria have also been discussed.Key words: 2-acetylcycloalkanones, 2-acetyl-1,3-cycloalkanediones, methyl 2-oxocycloalkanecarboxylates, equilibrium, tautomerization, ionization.

Étude de la réactivité des thiényldiazines: nitration et résonance magnétique nucléaire de 13C dans H2SO4 concentré

1982 ◽  
Vol 60 (21) ◽  
pp. 2668-2674 ◽  
Author(s):  
Jean Bourguignon ◽  
Stella Chapelle ◽  
Pierre Granger ◽  
Guy Queguiner
Keyword(s):  
Electronic Structure ◽  
Electrophilic Substitution ◽  
Nmr Spectra ◽  
Competitive Reactions ◽  
Résonance Magnétique ◽  
C Nmr

The reactivity of the thienyl diazines 1 to 7 has been studied by means of the nitration reaction. In order to examine any relationship between the reactivity and the electronic structure of these compounds, we have recorded their 13C nmr spectra in CDCl3 and in concentrated sulfuric acid.The 13C results are correlated to relative reactivities observed during competitive reactions between the thienyl diazines 1 and 2, 2 and 7, 2 and 4, 2 and 6.This method is a rarely-used approach for the study of electrophilic substitution of a molecule in the reaction mixture.

Study of the properties of pyridine-2-azo-p-phenyltetramethylguanidine as a metal ion complexing agent

1991 ◽  
Vol 69 (8) ◽  
pp. 1238-1244 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Arnold Jarczewski
Keyword(s):  
Complex Formation ◽  
Stability Constants ◽  
Metal Ion ◽  
Nmr Spectra ◽  
Dissociation Constants ◽  
Activation Parameters ◽  
Complexing Agent ◽  
The Stability ◽  
Metal Ligand ◽  
C Nmr

Pyridine-2-azo-p-phenyltetramethylguanidine (PAPT) was synthesized and the properties of this compound examined. The dissociation constants of the conjugate acids in H2O are [Formula: see text] and [Formula: see text] at 25 °C at I = 0.1, and in acetonitrile are [Formula: see text] and [Formula: see text]. The properties of metal–ligand chelates in acetonitrile have been examined and the stability constants for Ni2+, Co2+, and Zn2+ complexes measured. The rates of reaction of PAPT with Ni2+, Co2+, and Zn2+ in acetonitrile have been determined and the activation parameters measured for the complex formation of LNi2+. The stability constants for both complexing centres of PAPT have been calculated. The 13C NMR spectra for PAPT and LNi2+ are quoted. The expected enhancement of the metal ion complexing ability of PAPT due to the strongly electron-releasing nature of the tetramethylguanidinyl group was not found. Key words: metal ion complexes, pyridine-2-azo-p-phenyltetramethylguanidine, stability constants, pKa.

Effets de substituants en résonance magnétique nucléaire du 13C. Etude des dérivés du phényl-2 furanne et du phényl-2 pyrrole

1976 ◽  
Vol 54 (11) ◽  
pp. 1827-1836 ◽  
Author(s):  
Gilbert Dana ◽  
Odile Convert ◽  
Jean-Pierre Girault ◽  
Etienne Mulliez
Keyword(s):  
Electron Density ◽  
Benzene Ring ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Para Position ◽  
Simple Relationship ◽  
Résonance Magnétique ◽  
Derivatives Of ◽  
C Nmr

The 13C nmr spectra of derivatives of phenylfuran and phenylpyrrole were studied. The α and β carbons of the heterocycle, conjugated to the substituent X in the para position of the benzene ring, show variations in chemical shifts which bear a simple relationship to the donor properties of X. This is interpreted by the change in electron density caused by this conjugation. This conjugation seems more important in the series of 2-phenylpyrroles than in the series of 2-phenyl-furans especially if the behaviour of then α position is considered.[Journal translation]

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

13C NMR spectra of 1-aryl-ferrocenylethylenes

1986 ◽  
Vol 51 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Eva Solčániová ◽  
Štefan Toma ◽  
Tibor Liptaj
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
13C Nmr Spectra ◽  
Bridge Group ◽  
C Nmr ◽  
Electron Effects

13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.

The synthesis and stereochemistry of the ternary cobalt(III) complex with a stereospecific ligand derived from (S)-leucine

1986 ◽  
Vol 51 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Milan Strašák ◽  
Pavol Novomeský
Keyword(s):  
Ir Spectroscopy ◽  
Aqueous Medium ◽  
Absorption Spectroscopy ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Methyl Groups ◽  
Electron Absorption Spectroscopy ◽  
Electron Absorption ◽  
C Nmr

A new stereospecific ligand, ethylenediamine-N,N'-di(S)-α-isocapronic acid, was synthesized by condensation of (S)-leucine with 1,2-dibromoethane in alkaline aqueous medium. It follows from the 1H and 13C NMR spectra that the terminal methyl groups are chemically and magnetically nonequivalent. Of the four theoretically possible isomers of the ternary cobalt (III) complex with ethylenediamine, separation on catex yielded only one, whose absolute configuration was determined by a combination of 1H and 13C NMR, electron absorption spectroscopy and CD and IR spectroscopy.

17O and 13C NMR spectra of some geminal diacetates

1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
13C Nmr Spectra ◽  
Other Hand ◽  
Carboxylic Esters ◽  
C Nmr ◽  
Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

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