Anionic fructose-related conformational and positional isomers assigned through PES experiments and DFT calculations

2017 ◽  
Vol 19 (34) ◽  
pp. 23325-23344 ◽  
Author(s):  
Zhen Zeng ◽  
Elliot R. Bernstein
Keyword(s):  
Dft Calculations ◽  
Chain Structure ◽  
Positional Isomers ◽  
Open Chain ◽  
Conformational Isomers

Fructose− exists as an open chain structure with substrate dependent specific conformational isomers. (Fructose-H2O)− evidences two types of positional isomers.

CONFORMATIONAL EQUILIBRIA IN OPEN-CHAIN α,β-UNSATURATED KETONES

1961 ◽  
Vol 39 (11) ◽  
pp. 2225-2235 ◽  
Author(s):  
K. Noack ◽  
R. Norman Jones
Keyword(s):  
Raman Spectra ◽  
Equilibrium Mixture ◽  
Infrared And Raman Spectra ◽  
Temperature Dependent ◽  
Trans Form ◽  
Open Chain ◽  
Unsaturated Ketones ◽  
Conformational Isomers ◽  
Alkyl Substitution ◽  
Conformational Equilibria

The infrared and Raman spectra of trans-Δ3-penten-2-one have been measured over the temperature range +30° to −75° and +85° to +5° respectively. The temperature-dependent changes observed in the spectra indicate that this ketone exists as an equilibrium mixture of s-cis and s-trans conformational isomers in the liquid state. The s-trans form is the more stable and is present exclusively in the crystalline solid.Similar measurements have been carried out on Δ3-buten-2-one. The infrared and Raman spectra of this ketone also exhibit temperature effects that can be explained by a similar equilibrium, though the evidence is not as conclusive as for trans-Δ3-penten-2-one.The influence of alkyl substitution at the α- and β-carbon atoms on the relative stability of the s-cis and s-trans forms of α,β-unsaturated ketones is discussed.

Anionic ribose related species explored through PES experiments, DFT calculations, and through comparison with anionic fructose species

2017 ◽  
Vol 19 (42) ◽  
pp. 28950-28962 ◽  
Author(s):  
Zhen Zeng ◽  
Elliot R. Bernstein
Keyword(s):  
Dft Calculations ◽  
Related Species ◽  
Open Chain

Generation of (ribose-H)− is dependent on deposition substrates, while generation of two types of (ribose-H2O)− isomers (open chain) is not.

scholarly journals Crystal structure of sodium (1S)-D-lyxit-1-ylsulfonate

2016 ◽  
Vol 72 (5) ◽  
pp. 628-631
Author(s):  
Alan H. Haines ◽  
David L. Hughes
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Chain Structure ◽  
Zigzag Chain ◽  
Sugar Chain ◽  
Open Chain ◽  
Torsion Angles ◽  
Hydroxymethyl Group ◽  
Sodium Hydrogen ◽  
Group Form

The title compound, Na+·C5H11O8S−[systematic name: sodium (1S,2S,3S,4R)-1,2,3,4,5-pentahydroxypentane-1-sulfonate], is formed by reaction of D-lyxose with sodium bisulfite (sodium hydrogen sulfite) in water. The anion has an open-chain structure in which one of the oxygen atoms of the sulfonate residue, the S atom, the C atoms of the sugar chain and the O atom of the hydroxymethyl group form an essentially planar zigzag chain with the corresponding torsion angles lying between 179.80 (11) and 167.74 (14)°. A three-dimensional bonding network exists in the crystal structure involving hexacoordination of sodium ions by O atoms, three of which are provided by a single D-lyxose–sulfonate unit and the other three by two sulfonate groups and one hydroxymethyl group, each from separate units of the adduct. Extensive intermolecular O—H...O hydrogen bonding supplements this bonding network.

scholarly journals Taking the next step toward inert Mn2+ complexes of open-chain ligands: the case of the rigid PhDTA ligand

2018 ◽  
Vol 42 (10) ◽  
pp. 8001-8011 ◽  
Author(s):  
Kristof Pota ◽  
Zoltán Garda ◽  
Ferenc Krisztián Kálmán ◽  
José Luis Barriada ◽  
David Esteban-Gómez ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Electrochemical Properties ◽  
Dissociation Kinetics ◽  
Open Chain ◽  
Equilibrium Dissociation

Equilibrium, dissociation kinetics, relaxometric and electrochemical properties of the [Mn(PhDTA)]2− complex were investigated and the structure of the [Mn(PhDTA)]2− complex was studied by using DFT calculations.

The Lability of Sulfur Atoms in Vulcanization

1960 ◽  
Vol 33 (4) ◽  
pp. 1010-1014
Author(s):  
G. A. Blokh
Keyword(s):  
High Energy ◽  
Chain Structure ◽  
Elementary Sulfur ◽  
Open Chain ◽  
Isotope Method ◽  
Sulfur Containing ◽  
Unstable Intermediate ◽  
Sulfur Containing Compounds

Abstract The application of the isotope method to the investigation of the mechanism of the action of accelerator and vulcanizing agents has made it possible to look at this question in quite a new light. With the help of the isotope S it has been demonstrated that in the process of curing there takes place a continuous exchange of atoms of sulfur in the structure of the accelerators, and of elementary sulfur as a vulcanizing agent, with the formation of unstable intermediate compounds. The sulfur thus liberated undoubtedly has high energy, as a result of which it combines rapidly with the rubber. It must be remembered in this connection that the reacting elementary sulfur is an eight-membered S8 ring, while the sulfur liberated from the sulfur containing compounds has the open chain structure:

scholarly journals Isoxazolium N-ylides and 1-oxa-5-azahexa-1,3,5-trienes on the way from isoxazoles to 2H-1,3-oxazines

2014 ◽  
Vol 10 ◽  
pp. 1896-1905 ◽  
Author(s):  
Alexander F Khlebnikov ◽  
Mikhail S Novikov ◽  
Yelizaveta G Gorbunova ◽  
Ekaterina E Galenko ◽  
Kirill I Mikhailov ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Experimental Studies ◽  
Diazo Compounds ◽  
Stationary Points ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Open Chain ◽  
Isoxazole Ring ◽  
Diazo Esters ◽  
Probable Reaction

Theoretical and experimental studies of the reaction of isoxazoles with diazo compounds show that the formation of 2H-1,3-oxazines proceeds via the formation of (3Z)-1-oxa-5-azahexa-1,3,5-trienes which undergo a 6π-cyclization. The stationary points corresponding to the probable reaction intermediates, isoxazolium N-ylides, were located by DFT calculations at the B3LYP/6-31G(d) level only for derivatives without a substituent in position 3 of the isoxazole ring. These isoxazolium N-ylides are thermodynamically and kinetically very unstable. According to the calculations and experimental results 2H-1,3-oxazines are usually more thermodynamically stable than the corresponding open-chain isomers, (3Z)-1-oxa-5-azahexa-1,3,5-trienes. The exception are oxaazahexatrienes derived from 5-alkoxyisoxazoles, which are thermodynamically more stable than the corresponding 2H-1,3-oxazines. Therefore, the reaction of diazo esters with 5-alkoxyisoxazoles is a good approach to 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes. The reaction conditions for the preparation of aryl- and halogen-substituted 2H-1,3-oxazines and 1,4-di(alkoxycarbonyl)-2-azabuta-1,3-dienes from isoxazoles were investigated.

scholarly journals Sodium (1R)-D-glucit-1-ylsulfonate monohydrate

2012 ◽  
Vol 68 (4) ◽  
pp. m377-m378 ◽  
Author(s):  
Alan H. Haines ◽  
David L. Hughes
Keyword(s):  
Complex Cation ◽  
Three Dimensional ◽  
Addition Product ◽  
Chain Structure ◽  
Water Molecules ◽  
Open Chain ◽  
Carbon Chains ◽  
Molecular Anions ◽  
Dimensional Network ◽  
Cation Coordination

The title salt, Na+·C6H13O9S−·H2O, crystallizes with three independent cations, molecular anions and solvent water molecules in the asymmetric unit. This crystalline monohydrate addition product, formed by reaction of D-glucose and sodium hydrogen sulfite in water, forms a three-dimensional network through complex cation coordination and extensive intermolecular hydrogen bonding. Each of the independent molecules has an open-chain structure with the carbon chains adopting a sickle-like conformation, similar to that found in the potassium salt [Coleet al.(2001).Carbohydr. Res.335, 1–10], but there are significant differences in the patterns of complexation.

ChemInform Abstract: Stabilization of the Open-Chain Structure of D-Galacturonic Acid in a Dimeric Complex with Oxovanadium(IV).

ChemInform ◽  
1990 ◽  
Vol 21 (40) ◽  
Author(s):  
M. BRANCA ◽  
G. MICERA ◽  
D. SANNA ◽  
A. DESSI ◽  
H. KOZLOWSKI
Keyword(s):  
Galacturonic Acid ◽  
Chain Structure ◽  
Dimeric Complex ◽  
Open Chain

Infrared study of the self-association of water dissolved in 1,2-dichloroethane

1968 ◽  
Vol 46 (4) ◽  
pp. 567-570 ◽  
Author(s):  
C. Jolicoeur ◽  
A. Cabana
Keyword(s):  
Low Frequency ◽  
Solute Concentration ◽  
Chain Structure ◽  
Linear Increase ◽  
Small Frequency ◽  
Open Chain ◽  
Infrared Study ◽  
Frequency Shifts ◽  
Polymeric Species ◽  
Self Association

The infrared spectra, in the 3 micron region, of H2O or HDO dissolved in 1,2-dichloroethane are presented. Self-association of the solute molecules is revealed by the appearance of a shoulder on the low frequency side of the OH stretching bands of monomeric H2O or HDO. From the linear increase of the intensity of the shoulder with the third power of the solute concentration, it is inferred that trimers constitute the main polymeric species present in these solutions. The small frequency shifts of the OH stretching mode of trimeric water favors a cyclic rather than an open-chain structure. The observation of a single band for the trimer correlates with this last assertion.

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

1986 ◽  
Vol 64 (8) ◽  
pp. 1567-1572 ◽  
Author(s):  
Robert D. Singer ◽  
Keith Vaughan ◽  
Donald L. Hooper
Keyword(s):  
Condensation Product ◽  
Chair Conformation ◽  
Chain Structure ◽  
Open Chain ◽  
Bicyclic System ◽  
Mannich Condensation ◽  
Diazonium Ions ◽  
Buffer Mixture ◽  
Aqueous Mixture ◽  
Slow Decomposition

Reaction of a series of diazonium salts with either hexamine or an aqueous mixture of ammonia–formaldehyde affords 3,7-bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes; several new examples of this novel class of bicycloheterocycle have been prepared and characterized. Analysis of the low-temperature nmr spectra of one compound in this series shows that the bicyclic system prefers the chair–chair conformation. The bis(arylazo)tetraazabicyclononanes, which are surprisingly stable in aqueous buffer compared to analogous triazenes of open-chain structure, do undergo slow decomposition at slightly acidic pH in an acetone–buffer mixture. The apparent product of this decomposition is the arylamine, which is observed as the Mannich condensation product, ArNH•CH2CH2COCH3.

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