ChemInform Abstract: STUDY OF THE MECHANISM OF INTERACTION OF TRIMETHYLHYDROQUINONE AND ITS DERIVATIVES WITH LEWIS ACIDS BY NMR SPECTROSCOPY UNDER HOMOGENEOUS CONDITIONS

1985 ◽  
Vol 16 (36) ◽  
Author(s):  
M. B. TARABRIN ◽  
V. V. CHUPIN ◽  
E. YU. BULYCHEV ◽  
R. P. EVSTIGNEEVA
Keyword(s):  
Nmr Spectroscopy ◽  
Lewis Acids ◽  
Mechanism Of Interaction

Ionic liquids: green solvents and reactive compounds? Reaction of tri-n-butylmethylphosphonium dimethylphosphate with elemental sulfur

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Natalia Tarasova ◽  
Efrem Krivoborodov ◽  
Alexey Zanin ◽  
Yaroslav Mezhuev
Keyword(s):  
Ionic Liquids ◽  
Nmr Spectroscopy ◽  
Oxygen Atom ◽  
Elemental Sulfur ◽  
Green Solvents ◽  
Reaction Products ◽  
Mechanism Of Interaction

AbstractThe opening of the S8 ring with the formation of linear sulfur oligomers in the presence of tri-n-butylmethylphosphonium dimethylphosphate is shown. The reaction products are separated and characterized with 1H, 13C, 31P, 17O NMR spectroscopy, HD-MS, MALDI spectroscopy and XRD. It is shown that dimethylphosphate-anion is active in the reaction, and the addition of sulfur atoms occurs via the oxygen atom of dimethylphosphate-anion. It is found that a mixture of products is formed, which differ in the number of sulfur atoms in the chain. The assumptions were made about the mechanism of interaction of sulfur with tri-n-butylmethylphosphonium dimethylphosphate.

Etude par resonance magnétique multinucléaire d'intermédiaires réactionnels électrophiles. Partie 8. Action des acides de Lewis chlorés COCl2, POCl3, (CH3)2N=CHCl+Cl− et Cl2 sur l'hexaméthylphosphotriamide (HMPT)

1980 ◽  
Vol 58 (9) ◽  
pp. 946-952 ◽  
Author(s):  
S. Poignant ◽  
J. R. Gauvreau ◽  
G. J. Martin
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Study ◽  
Lewis Acids ◽  
Mechanism Of Formation ◽  
Substitution Product ◽  
Vilsmeier Reagent ◽  
Résonance Magnétique

The structural study of the electrophilic intermediates obtained from carboxamides and chlorinated Lewis acids is extended to the phosphoric amides. The action of COCl2 and POCl3 on hexamethylphosphotriamide (HMPT) can lead to a chlorophosphonium salt (3a) the structure of which is proved by nmr spectroscopy (1H, 13C, 31P, 15N). The mechanism of formation is comparable to that of the chloroiminium chloride (Vilsmeier reagent) from the corresponding amides. The action of chlorine on HMPT does not lead to a stable salt of the same kind but essentially to the substitution product (2). A new biphosphorylated compound (6) has been identified when an excess of chlorine is reacted with HMPT.

Synthesis of heteronuclear bifunctional Lewis acids by transmetalation of 1,8-bis(trimethylstannyl)naphthalene with BCl3

2002 ◽  
Vol 80 (10) ◽  
pp. 1308-1312 ◽  
Author(s):  
Marcus Schulte ◽  
François P Gabbaï
Keyword(s):  
Elevated Temperature ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Acid Derivative ◽  
Lewis Acid ◽  
Lewis Acids ◽  
The Novel ◽  
X Ray ◽  
Boron Center ◽  
Chloride Methyl

Reaction of 1,8-bis(trimethylstannyl)naphthalene (1) with an excess of BCl3 at –78°, followed by warming to 0°C, results in the exclusive formation of the novel bifunctional Lewis acid 1-(chlorodimethylstannyl)-8-(dichloroboryl)naphthalene (2), a compound in which a boryl and a stannyl moiety coexist at the peri-positions of a naphthalene core. At elevated temperature compound 2 undergoes a chloride–methyl exchange, which affords 1-(dichloromethylstannyl)-8-(chloromethylboryl)naphthalene (3). Compounds 2 and 3 have been characterized by multi-nuclear NMR spectroscopy. The single crystal X-ray analysis for compound 3 reveals a sterically crowded structure with an essentially trigonal planar boron center, and a tin center pentacoordinated in a [4+1]-fashion. Upon exposure to traces of water, compound 3 is converted into the borinic acid derivative 1-(dichloromethylstannyl)-8-(hydroxymethylboryl)naphthalene (4), which has been characterized by multi-nuclear NMR spectroscopy and single crystal X-ray analysis.Key words: multidentate Lewis acids, organoboranes, organostannanes.

Prototypical arsine–triel adducts (R3AsEX3 for E = B, Al, and Ga)

2010 ◽  
Vol 88 (8) ◽  
pp. 797-803 ◽  
Author(s):  
Eamonn Conrad ◽  
Janet Pickup ◽  
Neil Burford ◽  
Robert McDonald ◽  
Michael J. Ferguson
Keyword(s):  
Infrared Spectroscopy ◽  
Nmr Spectroscopy ◽  
Lewis Acids ◽  
Group 13 ◽  
X Ray ◽  
X Ray Crystallography

Complexes of arsine ligands (R3As, R = Me, Et, Ph) and Lewis acids of group-13 elements of the form EX3 (E = B, X = Ph, C6F5; E = Al, X = Cl, Br, I; E = Ga, X = Cl) have been isolated and characterized by X-ray crystallography, infrared spectroscopy, 1H, 13C{1H}, 11B{1H}, and 27Al NMR spectroscopy. The compounds are compared with rare arsine–triel adducts.

scholarly journals Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

2019 ◽  
Vol 15 ◽  
pp. 1491-1504
Author(s):  
Stanislav V Lozovskiy ◽  
Alexander Yu Ivanov ◽  
Aleksander V Vasilyev
Keyword(s):  
Nmr Spectroscopy ◽  
Lewis Acid ◽  
Crucial Role ◽  
Lewis Acids ◽  
Phosphonic Acids ◽  
Phosphorus Containing ◽  
Allyl Alcohols ◽  
Hydrolysis Of ◽  
Allene System

3-Methylbuta-1,2-dien-1-ylphosphonic acid derivatives (phosphorylallenes) [X2(O=)P–CR=C=CMe2, X = Cl, OMe, NR2, or SAr] undergo intramolecular cyclization into the corresponding 1,2-oxaphospholium ions in the Brønsted superacid TfOH. These cations have been thoroughly studied by means of NMR spectroscopy. The hydrolysis of superacidic solutions of these species afforded cyclic phosphonic acids and other phosphorus-containing compounds. Contrary to Brønsted acids, 3-methylbuta-1,2-dien-1-ylphosphonic dichloride [Cl2(O=)P–HC=C=CMe2] reacted with the Lewis acid AlCl3 in an intermolecular way forming noncyclic intermediates, which were investigated by NMR spectroscopy and DFT calculations. Hydrolysis of these species resulted in the formation of phosphoryl-substituted allyl alcohols and 1,3-butadienes. A strong coordination of the oxygen of the P=O group with AlCl3 prevented the formation of cyclic 1,2-oxaphospholium ions and played a crucial role in the different reactivity of such phosphorylallenes under the action of Brønsted or Lewis acids. Apart from that, the reaction of dichlorophosphorylallenes with arenes and AlCl3 led to products of hydroarylation of the allene system, phosphoryl-substituted alkenes and/or indanes. This is the first example of a Lewis acid-promoted intermolecular hydroarylation of allenes bearing electron-withdrawing substituents. Plausible reaction mechanisms have been proposed on the basis of the investigated reactions, and NMR analysis and DFT studies of the intermediate cationic species.

The Lewis acid complexes of α,β-unsaturated carbonyl and nitrile compounds. A nuclear magnetic resonance study

1982 ◽  
Vol 60 (6) ◽  
pp. 801-808 ◽  
Author(s):  
Ronald F. Childs ◽  
D. Lindsay Mulholland ◽  
Alan Nixon
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Nmr Spectroscopy ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Group ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
C Nmr

1:1 Complexes of a range of Lewis acids with crotonaldehyde (1) have been systematically investigated by 1H and 13C nmr spectroscopy. Lewis acids employed were: BF3, BCl3, BBr3, SnCl4, TiCl4, SbCl5, AlCl3, EtAlCl2, Et2AlCl, Et3Al2Cl3, and Et3Al. Chemical shift changes in 1H nuclei remote from the Lewis acid group were found to be remarkably regular and consistent. The study has been extended to tiglaldehyde (2), pent-3-en-2-one (3), cyclohexenone (4), methyl crotonate (5), and crotonitrile (6) and the relationships between the chemical shift differences associated with complexation of these have been explored.

Fluoride complexation by bidentate silicon Lewis acids

2017 ◽  
Vol 46 (6) ◽  
pp. 1898-1913 ◽  
Author(s):  
Jan Horstmann ◽  
Mark Niemann ◽  
Katarína Berthold ◽  
Andreas Mix ◽  
Beate Neumann ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Lewis Acids ◽  
Fluoride Ion ◽  
X Ray Diffraction ◽  
Open Chain ◽  
X Ray ◽  
Fluoride Complexation ◽  
Ion Complexation

The fluoride ion complexation behavior of the bidentate open-chain Lewis acids Ph2Si(CHCHSiFnMe3−n)2and Ph2Si(CH2–CH2SiFnMe3−n)2(n= 1, 2, 3) was explored in detail by multinuclear low-temperature NMR spectroscopy in solution and by X-ray diffraction experiments.

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