77Se NMR spectroscopic study of the molecular composition of sulfur–selenium melts

1992 ◽  
Vol 70 (3) ◽  
pp. 719-725 ◽  
Author(s):  
Tristram Chivers ◽  
Risto S. Laitinen ◽  
Kenneth J. Schmidt
Keyword(s):  
Nmr Spectroscopy ◽  
Spectroscopic Study ◽  
Polymeric Material ◽  
Nmr Spectra ◽  
Random Distribution ◽  
Relative Distribution ◽  
Selenium Content ◽  
Polymeric Chains ◽  
Melt Composition ◽  
Selenium Sulfide

A series of six sulfur–selenium mixtures containing 0.4, 5, 15, 25, 35, and 45 mol% of selenium were heated in evacuated ampoules at 430 °C for 4 h and, keeping the material molten at 135 °C, their natural-abundance 77Se NMR spectra were recorded. The equilibrium melt in each case was found to contain both heterocyclic SenS8−n species and polymeric material. The most abundant eight-membered selenium sulfide rings were SeS7, which was the main cyclic component in all melts studied in this work, and 1,2-Se2S6, the quantity of which increased with increasing selenium content of the melt. In addition the melts contained smaller amounts of 1,3, 1,4, and 1,5 isomers of Se2S6, 1,2,3, 1,2,4, and 1,2,5 isomers of Se3S5, 1,2,3,4, 1,2,3,5, and 1,2,5,6 isomers of Se4S4, 1,2,3,4,5-Se5S3, 1,2,3,4,5,6-Se6S2, and Se8. The relative distribution of the cyclic products as a function of the selenium content in the melt was virtually identical with that obtained earlier in the CS2 solutions of the quenched melts, implying that the extracted quenched melts actually represent the original melt composition as far as the SenS8−n species are concerned. The resonances due to the polymeric material in the melts could best be interpreted by the statistical random distribution of selenium and sulfur in the polymeric chains, the probability of occurrence of the different fragments being governed by the overall composition of the melt. As the selenium content increases, the relative amount of selenium bound in the polymer seems to increase at the expense of heterocyclic selenium sulfides. Keywords: selenium sulfides, sulfur–selenium melt, 77Se NMR spectroscopy.

Some reactions of trimeric silicon phthalocyanine under alkaline conditions

2003 ◽  
Vol 07 (03) ◽  
pp. 176-180 ◽  
Author(s):  
Viktor N. Myakov ◽  
Vyacheslav A. Kuropatov ◽  
Tatyana I. Lopatina ◽  
Valentina N. Sedelnikova
Keyword(s):  
Nmr Spectroscopy ◽  
Spectroscopic Study ◽  
Nmr Spectra ◽  
Ring Current ◽  
Electron System ◽  
Absorption Bands ◽  
H Nmr ◽  
Alkaline Conditions ◽  
Silicon Phthalocyanine

The reaction of bis(trimethylsiloxy)triphthalocyaninatosilicon, Me 3 Si ( OSiPc )3 OSiMe 3 ( Pc 3) with KOH in o-xylene in the presence of 15-crown-5 in vacuum at 200°C has been studied by means of UV-vis, EPR and 1 H NMR spectroscopy. Upon gradual removal of H 2 O , the formation of mono- and dianions of Pc 3 with absorption bands positioned at 575-590 nm was observed. An EPR spectroscopic study revealed that both monoanionic and dianionic of Pc 3 are paramagnetic in solution. 1 H NMR spectra have shown the absence of a ring current in the π-electron system of dianion. The reaction of Pc 3 with KOH or metal Na led to degradation of the Si - O - Si - backbone happened.

NMR spectroscopic investigation of p-substituted 2,4,4,6-tetraphenyl-1,4-dihydropyridines and their oxa and thia analogues

1989 ◽  
Vol 54 (7) ◽  
pp. 1854-1869 ◽  
Author(s):  
Marián Schwarz ◽  
Petr Trška ◽  
Josef Kuthan
Keyword(s):  
Nmr Spectroscopy ◽  
Trifluoroacetic Acid ◽  
Spectroscopic Investigation ◽  
Nmr Spectra ◽  
Dynamic Equilibrium

The 1H, 13C and 19F NMR spectra of photochromic p-substituted 2,4,4,6-tetraphenyl-1,4-dihydropyridines IIa-IIg, 1-methyl-2,4,4,6-tetraphenyl-1,4-dihydropyridines IIIa-IIIg, 2,4,4,6-tetraphenyl-4H-pyrans IVa-IVh, and 2,4,4,6-tetraphenyl-4H-thiopyran V were inspected; it was found that compounds IIa-IIg occur in a dynamic equilibrium with their dihydro tautomer VIa-VIg. Also deuteriodeprotonation of IIa and IIIa and their reaction with trifluoroacetic acid were investigated by NMR spectroscopy.

Unusual Rearrangement of Naphthalene in the Synthesis of a Novel B8-B8-Bridged Derivative in the [(1,2-C2B9H11)2-3-Co]- Series. X-Ray Structure and 11B NMR Spectra of [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- (CH3)4N+

1997 ◽  
Vol 62 (5) ◽  
pp. 746-751 ◽  
Author(s):  
Andreas Franken ◽  
Jaromír Plešek ◽  
Christiane Nachtigal
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Nucleophilic Substitution ◽  
Nmr Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Unusual Rearrangement ◽  
Multinuclear Nmr Spectroscopy ◽  
11B Nmr ◽  
Isolated Compound

On treatment of the [(1,2-C2B9H11)2Co]- ion with naphthalene in presence of AlCl3 a remarkably bridged [8,8'-μ-(CH2-C9H6)-(1,2-C2B9H10)2-3-Co]- ion is obtained as a single isolated compound. The triatomic -CH2-C9H6- bridge is derived from the rearranged naphthalene nucleus. The mechanism of this reaction is obscure but it does resemble the "Electrophile-Induced Nucleophilic Substitution" reported earlier. The structure of the compound was established by multinuclear NMR spectroscopy and by single crystal X-ray diffraction.

IR and 13C, 17O, and 119Sn NMR spectra of some bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids

1991 ◽  
Vol 56 (9) ◽  
pp. 1908-1915 ◽  
Author(s):  
Jaroslav Holeček ◽  
Antonín Lyčka ◽  
Milan Nádvorník ◽  
Karel Handlíř
Keyword(s):  
Infrared Spectroscopy ◽  
Nmr Spectroscopy ◽  
Dicarboxylic Acid ◽  
Nmr Spectra ◽  
Dicarboxylic Acids ◽  
119Sn Nmr ◽  
Carboxylic Groups ◽  
Cyclic Oligomers ◽  
The Media ◽  
Oxygen Atoms

Infrared spectroscopy and multinuclear (13C, 17O, and 119Sn NMR spectroscopy have been used to study the structure of bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids (1-C4H9)2. Sn(X(COO)2), where X = (CH2)n (n = 0-8), CH=CH (cis and trans) and C6H4 (ortho and para).The crystalline compounds are formed by linear or cyclic oligomers or polymers whose basic building units represent a grouping composed of the central tin atom substituted by two 1-butyl groups and coordinated with both oxygen atoms of two anisobidentate carboxylic groups derived from different molecules of a dicarboxylic acid. The environment of the tin atom has a shape of a trapezoidal bipyramid. When dissolvet in non-coordinating solvents, the compounds retain the oligomeric character with unchanged structure of environment of the central tin atom. In the media of coordinating solvents the bis(1-butyl)tin(IV) carboxylates of dicarboxylic acids form complexes whose central hexacoordinated tin atom binds two molecules of the solvent trough their donor atoms. Carboxylic groups form monodenate linkages in these complexes.

scholarly journals Mesoscopic simulations of the in situ NMR spectra of porous carbon based supercapacitors: Electronic structure and adsorbent reorganisation effects

2021 ◽  
Author(s):  
Anagha Sasikumar ◽  
Anouar Belhboub ◽  
Camille Bacon ◽  
Alexander C. Forse ◽  
John Griffin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Nmr Spectroscopy ◽  
Molecular Species ◽  
Porous Carbon ◽  
Nmr Spectra ◽  
Charge Storage ◽  
In Situ Nmr Spectroscopy ◽  
In Situ Nmr ◽  
Carbon Based

In situ NMR spectroscopy is a powerful technique to investigate charge storage mechanisms in carbon-based supercapacitors thanks to its ability to distinguish ionic and molecular species adsorbed in the porous...

The chemistry of pyrrolic compounds. XLII. The synthesis of some diacetyldeuteroporphyrins as intermediates in the preparation of the isomeric protoporphyrins: a comparative spectroscopic study of the diacetyldeuteroporphyrins

1980 ◽  
Vol 33 (3) ◽  
pp. 545 ◽  
Author(s):  
PS Clezy ◽  
CJR Fookes
Keyword(s):  
Chemical Shift ◽  
Spectroscopic Study ◽  
Electronic Spectrum ◽  
Relative Position ◽  
Visible Spectrum ◽  
Oxidative Cyclization ◽  
Relative Distribution ◽  
Absorption Pattern ◽  
The One ◽  
Carbonyl Function

A range of isomeric diacetyldeuteroporphyrins has been synthesized by the oxidative cyclization of appropriately substituted bilenes-b, and the electronic and n.m.r. spectra of these porphyrins have been studied. As a result it has been shown that the relative position of the two acetyl groups influences the absorption pattern of the visible spectrum more precisely than was previously appreciated. In consequence, it is possible to recognize the 1,4, 2,3 and 2,4 relative distribution of the acetyl groups by an examination of the electronic spectrum. In addition, it is clear that the acetyl groups present in this series of porphyrins affect the chemical shift of all the methine protons and not only the one which is directly adjacent to the carbonyl function.

Magnetic resonance imaging (1H) and spectroscopy (1H, 31P) of growing chicken embryos

1993 ◽  
Vol 73 (4) ◽  
pp. 953-965 ◽  
Author(s):  
A. Lirette ◽  
Z. Liu ◽  
D. C. Crober ◽  
R. A. Towner ◽  
U. M. Oehler ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Surface Coil ◽  
Nmr Imaging ◽  
Chicken Embryos ◽  
H Nmr ◽  
Imaging And Spectroscopy ◽  
Two Peaks

Nuclear magnetic resonance (NMR) imaging and spectroscopy techniques were used to observe in vivo anatomical and metabolite changes, respectively, in developing chicken embryos. Proton (1H) NMR images of the eggs revealed major changes in yolk shape from day 2 to day 6. Embryos were visible from day 6 to hatching, and good embryonic anatomical images were obtained. Two peaks were observed from 1H-NMR spectroscopy of fertilized eggs: one for lipid methylene protons, and one for water protons. Water peak to lipid peak ratios did not vary significantly (P > 0.05) from day 2 to day 21 of incubation. Localized 31P-NMR spectra of developing embryos were obtained with either a 31P surface coil or a double-tuned 31P/1H volume coil. The surface-coil method gave a greater signal to noise ratio by a factor of four. The 31P-NMR spectra indicated two peaks at day 2; these were attributed to phosphomonoesters and phosphodiesters. The three peaks characteristic of ATP appeared on day 11 and increased in size until hatching. From day 19, phosphocreatine was detectable. There appeared to be a good correlation between 31P-metabolite changes detected by in vivo 31P-NMR spectroscopy and literature values for biochemical analyses of developing chicken embryos. The advantage in using NMR imaging and spectroscopy techniques is that anatomical and metabolic changes can be obtained in vivo, non-invasively and repeatedly as an embryo develops. Key words: NMR, MRI, embryo, poultry

scholarly journals A Metabolomic Approach to Beer Characterization

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1472
Author(s):  
Nicola Cavallini ◽  
Francesco Savorani ◽  
Rasmus Bro ◽  
Marina Cocchi
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Analytical Methods ◽  
Nmr Spectra ◽  
Full Spectrum ◽  
The Past ◽  
Beer Consumption ◽  
Metabolomic Approach ◽  
Chemometric Tools

The consumers’ interest towards beer consumption has been on the rise during the past decade: new approaches and ingredients get tested, expanding the traditional recipe for brewing beer. As a consequence, the field of “beeromics” has also been constantly growing, as well as the demand for quick and exhaustive analytical methods. In this study, we propose a combination of nuclear magnetic resonance (NMR) spectroscopy and chemometrics to characterize beer. 1H-NMR spectra were collected and then analyzed using chemometric tools. An interval-based approach was applied to extract chemical features from the spectra to build a dataset of resolved relative concentrations. One aim of this work was to compare the results obtained using the full spectrum and the resolved approach: with a reasonable amount of time needed to obtain the resolved dataset, we show that the resolved information is comparable with the full spectrum information, but interpretability is greatly improved.

Structural studies of digitoxin and related cardenolides by two-dimensional NMR

1990 ◽  
Vol 68 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Torbjörn Drakenberg ◽  
Peter Brodelius ◽  
Deane D. McIntyre ◽  
Hans J Vogel
Keyword(s):  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Chair Conformation ◽  
Coupling Constants ◽  
Two Dimensional ◽  
Structural Studies ◽  
Solution Conformation ◽  
Phase Sensitive ◽  
Multiple Relay ◽  
C Nmr

The 1H and 13C NMR spectra of the cardenolides digitoxigenin, digoxigenin, digitoxin, and mono- and bis-digitoxigenin digitoxosides have been completely assigned by two-dimensional NMR spectroscopy. The techniques used include phase-sensitive COSY, multiple relay COSY, and carbon–proton correlation (HETCOR and HMQC) spectra. Various aspects of the solution conformation of the steroid moiety of digitoxin and digoxigenin could be determined from coupling constants and NOE difference experiments and they are indicative of an all-chair conformation. The carbohydrate rings in digitoxin and the mono- and bis-digitoxigenin digitoxosides are also in the chair conformation. Keywords: cardenolides, digitoxigenin, digitoxin, 2-dimensional NMR, conformational analysis.

Nuclear magnetic resonance studies on the anions [M(SnCl3)5Cl]4− (M = Ru, Os) and [Ru(SnCl3)5(MeCN)]3−: the X-ray crystal structure of [N(C2H5)4]4[Ru(SnCl3)5Cl]

1982 ◽  
Vol 60 (11) ◽  
pp. 1304-1316 ◽  
Author(s):  
Louis J. Farrugia ◽  
Brian R. James ◽  
Claude R. Lassigne ◽  
Edward J. Wells
Keyword(s):  
Crystal Structure ◽  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Octahedral Geometry ◽  
Coupling Constants ◽  
Order Effects ◽  
Magnetic Resonance Studies ◽  
X Ray ◽  
Crystallographic Study

The octahedral anions [M(SnCl3)5Cl]4− (M = Ru, Os) have been fully characterized by 119Sn FT nmr spectroscopy. For M = Ru, 117Sn and 115Sn nmr spectra were also recorded, and an X-ray crystallographic study was carried out on the tetraethylammonium salt, isolated as a disolvate from acetonitrile. The Ru—Sn bond lengths indicate some degree of dπ–dπ interactions. The slight distortions from octahedral geometry are discussed in connection with the packing of the chlorine atoms. The Sn nmr spectra reveal the first observed coupling to a 99Ru nucleus (I = 5/2, 12.7% natural abundance), very large 2J(119Sn—117Sn) coupling constants, and the first observed second-order effects on a heteronuclear system. The octahedral anion [Ru(SnCl3)5(MeCN)]3− was also synthesized as the tetraethylammonium salt and characterized spectroscopically.

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