<sup>13</sup>C‐NMR‐Spektroskopische Untersuchungen an Grignard‐Verbindungen

Leibfritz, Dieter; Wagner, Burkhard O.; Roberts, John D.

doi:10.1002/jlac.19727630119

Cited by 36 publications

(6 citation statements)

References 21 publications

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“…We think that the negative value frequencies arise from carbons that have metals such as Ni, Fe, and V in the nearby chemical environment. In this regard, we suggest the existence of various porphyrin structures, , inorganic salts, and even organometallic compounds such as MgBr(CH 2 CH 3 ) …”

Section: Results and Discussionmentioning

confidence: 93%

“…Furthermore, the HMBC spectrum for sample 5 has two negative carbon resonances, appearing at −5.49 and −6.40 ppm, correlating with the protons at 3.71 and 2.37 ppm, respectively. The correlations between −5.49 ppm ( 13 C) and 3.71 ppm ( 1 H), and between 14.35 ppm ( 13 C) and 1.35 ppm ( 1 H) arise from the existence of MgBr-based organometallic compound . There is a trace of a correlation between triaromatic proton and carbon whose signals are at 8.26 and 129.53 ppm, respectively.…”

Section: Results and Discussionmentioning

confidence: 97%

“…In this regard, we suggest the existence of various porphyrin structures, 64,65 inorganic salts, and even organometallic compounds such as MgBr(CH 2 CH 3 ). 66 Among the proton resonances, the ones between 8.50 and 8.30 ppm are assigned to hydrogens within the structures of triaromatics bonded to each other. The proton signals around 8.23, 8.14, and 7.75 ppm arise from diaromatic hydrogens.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…The correlations between −5.49 ppm ( 13 C) and 3.71 ppm ( 1 H), and between 14.35 ppm ( 13 C) and 1.35 ppm ( 1 H) arise from the existence of MgBr-based organometallic compound. 66 There is a trace of a correlation between triaromatic proton and carbon whose signals are at 8.26 and 129.53 ppm, respectively. Regarding the fjord-and bay-type structures observed in the HMBC spectrum, the correlation between 7.58 and 128.68 ppm is assigned to fjord-type structure, while the one between 7.42 and 123.93 ppm is attributed to bay-type structure.…”

Section: Energy and Fuelsmentioning

confidence: 98%

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Molecular Structure and Solubility Determination of Asphaltenes

Mahmoodinia

Rajasekaran

et al. 2019

Energy Fuels

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Due to their complex chemical structure, identification and characterization of asphaltenes remain a big challenge for researchers in the oil industry. In the current contribution, solution-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectra of the asphaltenes, obtained from either heavy or light crude oil samples, provide information on the chemical structures of asphaltenes at the molecular level. Two-dimensional 1H–13C heteronuclear NMR measurements are particularly useful for differentiating among several structural environments whose signals overlap in the one-dimensional 13C spectra. Both, 2D 1H–13C heteronuclear and 1H–1H homonuclear NMR spectra indicate short- and long-range interactions between different functional groups of the asphaltene samples, revealing even “bay”- and “fjord”-type structures. Based on the NMR correlations between different protons and carbons with different chemical environments, we propose various chemical structures (polyaromatic cores with aliphatic chains, porphyrin derivatives, organic salts). Furthermore, through molecular dynamics simulations, we have obtained Hildebrand solubility parameters of different asphaltene solvents and of two experimental recovered asphaltene structures. Our calculated solubilities are consistent with previous experimental and simulation works.

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Section: Results and Discussionmentioning

confidence: 93%

Section: Results and Discussionmentioning

confidence: 97%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Energy and Fuelsmentioning

confidence: 98%

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Molecular Structure and Solubility Determination of Asphaltenes

Mahmoodinia

Rajasekaran

et al. 2019

Energy Fuels

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“…If one takes allyl magnesium bromide as a model, the 13C resonances are at 113 and 57 ppm with respect to Me4Si. 35 Any lines in the latter region would clearly have been noticed, and certainly with propene, the coverage of such species should be. sufficiently high to observe.…”

Section: Discussionmentioning

confidence: 95%

Adsorption of olefins on zinc oxide. Observations by carbon-13 nuclear magnetic resonance

Ali¹

1981

J. Phys. Chem.

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Beryllium & Magnesium: Organometallic ChemistryBased in part on the article Beryllium & Magnesium: Organometallic Chemistry by E. Alexander Hill which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Saulys

Hill

2005

Encyclopedia of Inorganic Chemistry

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Victor Grignard found in 1900 that solutions of organomagnesium halides form easily in the reaction of an organic halide with magnesium metal in diethyl ether. These Grignard reagents undergo useful reactions with many kinds of substrates. This discovery ushered in a new era in organometallic chemistry and provided chemists with a powerful and versatile reagent for synthesis of a wide variety of organic and organometallic compounds. This article discusses Grignard reagents in the broader context of organomagnesium chemistry. Preparatory methods surveyed include direct reaction of organic halides with the metal, exchange reactions with other organometallic compounds, as well as carbo‐ and hydrometalations. The current level of understanding of the mechanism of Grignard formation is summarized. The formation and reactivity of unusual species such as cluster Grignard reagents, for example, RMg 4 X (R = organic group, and X = halide) and polymagnesium compounds, for example, Ru[C 5 (MgCl) 5 ] 2 are also discussed. The bonding and structure of organomagnesium compounds (as well as that of beryllium analogues) as described by diffraction methods, thermochemical data, colligative properties, spectroscopic (vibrational, nuclear magnetic, and electronic) measurements, kinetic studies, mass spectrometry, and theoretical methods are outlined. The most prominent chemical property of organomagnesium compounds is their ability to deliver an effectively ‘anionic’ organic group with nucleophilic properties. As alkylating reagents, their important reactions include nucleophilic displacement of less basic leaving groups from saturated carbon atoms or other elements, addition to carbonyl groups and other unsaturated functions, and nucleophilic substitution at the acyl group of carboxylic acid derivatives. This broad array of substrates is surveyed, as are the effects of solvents and catalysts on reactivity. Less conspicuous reactions with wholly or predominantly inorganic substrates are also considered. Electron transfer reactions where organomagnesium compounds act as reductants are discussed. Organoberyllium compounds are more difficult to prepare and are less nucleophilic than their magnesium counterparts. These features, together with their high toxicity, have limited their utility. Methods of preparation, as well as descriptions of bonding, structure, and reactivity patterns are presented. Of special note are recent advances in cyclopentadienyl beryllium chemistry, as well as the advent of beryllium–silicon chemistry.

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¹³C‐NMR‐Spektroskopische Untersuchungen an Grignard‐Verbindungen

Cited by 36 publications

References 21 publications

Molecular Structure and Solubility Determination of Asphaltenes

Molecular Structure and Solubility Determination of Asphaltenes

Adsorption of olefins on zinc oxide. Observations by carbon-13 nuclear magnetic resonance

Beryllium & Magnesium: Organometallic ChemistryBased in part on the article Beryllium & Magnesium: Organometallic Chemistry by E. Alexander Hill which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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13C‐NMR‐Spektroskopische Untersuchungen an Grignard‐Verbindungen

Cited by 36 publications

References 21 publications

Molecular Structure and Solubility Determination of Asphaltenes

Molecular Structure and Solubility Determination of Asphaltenes

Adsorption of olefins on zinc oxide. Observations by carbon-13 nuclear magnetic resonance

Beryllium & Magnesium: Organometallic ChemistryBased in part on the article Beryllium & Magnesium: Organometallic Chemistry by E. Alexander Hill which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

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¹³C‐NMR‐Spektroskopische Untersuchungen an Grignard‐Verbindungen