Ionic solutions and their pivotal roles in organic and biological systems

Kumar, Anil

doi:10.1351/pac199870030615

Cited by 18 publications

(13 citation statements)

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“…It is well-known that the positions of absorption and emission bands for benzenoid and nonbenzenoid hydrocarbons are often very sensitive to external pressure. Thus, if the internal pressure of LP/DE mimics applied pressure, as suggested by Grieco 10 and Kumar, , one will be able to predict where the absorption and fluorescence spectra will occur for the hydrocarbons in LP/DE if the behavior of the hydrocarbons in solution under external pressure has been established.…”

Section: Resultsmentioning

confidence: 99%

“…Kumar also suggested on theoretical grounds that P i does mimic the effect that P a has on the rates of DA reactions. In fact the rates of the Diels−Alder reaction of N -methylmaleimide with anthracene-9-carbinol in aqueous salt solutions correlate nicely with internal pressure, but the internal pressure has only a minimal effect on rates . Likewise, the dimerization of cyclopentadiene correlates with internal pressure, but the correlation is not very good .…”

Section: Introductionmentioning

confidence: 97%

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Chemical and Spectroscopic Studies Related to the Lewis Acidity of Lithium Perchlorate in Diethyl Ether

et al. 1999

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Polarimetric studies on camphor (2) as well as IR studies on crotonaldehyde (CA; 1) and benzonitrile (BN; 3) confirm the conclusion of a previously published NMR study on crotonaldehyde that lithium perchlorate (LP) weakly binds to probe bases in diethyl ether (DE). The weak binding is a consequence of the fact that the lithium ion (actually the LP ion pair and higher aggregates), a powerful Lewis acid in the gas phase, competitively binds to ether and the added base. Methylene camphor (5), (E)-1,3-pentadiene (4), camphene, and phenylacetylene (6) do not bind to LP in DE. Shifts to lower energy of the CO modes of CA in ether solutions containing increasing amounts of LP are consistent with moderate increases in solvent polarity. Only small or no shifts are seen in the C⋮N modes of BN and its 1:1 complex with added LP. Because the C⋮N and especially CO modes are blue shifted under external applied pressure, the large internal pressures of LP/DE do not mimic external applied pressure. Likewise, the small or no changes observed in λmax for the absorption and emission spectra of anthracene (9) and azulene (8) in ether as a function of LP concentration do not conform to what is observed under external applied pressure. Studies of the Diels−Alder reaction of (E)-1,3-pentadiene with methyl acrylate show that the reaction is entirely catalyzed in LP/DE; polarity and internal pressure do not influence product selectivity in this reaction.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Chemical and Spectroscopic Studies Related to the Lewis Acidity of Lithium Perchlorate in Diethyl Ether

et al. 1999

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“…The thermochemical properties of ions are strongly dependent on the medium in which they are measured. , Thermochemical properties of gaseous ions provide a benchmark against which those for solvated ions can be compared, and these comparisons provide insight into the effects that solvents have on ionic properties. Solvents have been proposed to affect the properties of ions in multiple ways and at different levels of interaction . An ion has a pairwise interaction with neighboring solvent molecules, via ion-dipole or ion-induced dipole effects, or can be stabilized by multiple solvent molecules that create a “solvent shell” .…”

Section: Introductionmentioning

confidence: 99%

Hydration Energies of Aromatic Ions in the Gas Phase

Haupert

Wenthold

2012

J. Phys. Chem. A

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The hydration energies of aromatic ions, measured by using energy-resolved collision-induced dissociation measurements, are reported. The hydration energies of protonated acetophenone, aniline, anisole, benzene, benzonitrile, phenol, and toluene are 0.67 ± 0.04, 0.62 ± 0.04, 0.86 ± 0.04, 0.46 ± 0.06, 0.84 ± 0.04, 0.75 ± 0.07, and 0.42 ± 0.04 eV, respectively. The measured values are in good agreement with those predicted by using coupled cluster theory, provided the proper geometries of the ions and sufficient basis set were used.

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“…The reaction takes place between a diene, usually bearing an electron-donating group, and a dienophile, bearing an electron-withdrawing group (Fig. In 1980 Breslow and Rideout reported that the rate of Diels-Alder cycloaddition is enhanced in aqueous systems [37][38][39]. In 1980 Breslow and Rideout reported that the rate of Diels-Alder cycloaddition is enhanced in aqueous systems [37][38][39].…”

Section: Diels-alder Cycloadditionmentioning

confidence: 99%

“…C=X where X = N, S or O or C≡N. The reaction was performed at 80 °C in aqueous conditions, to yield the requisite cycloadduct (39), in isomeric form, which was then purified by chromatography (Fig. The Huisgen dipolar cycloaddition between azides and alkynes has been a successful method for the formation of 5-membered heterocyclic rings for the past four decades [57].…”

Section: [3+2] Cycloadditionsmentioning

confidence: 99%

Cycloadditions as a Method for Oligonucleotide Conjugation

Graham¹,

Enright²

2006

COS

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There is a large requirement in modern molecular biology for the production of specifically conjugated oligonucleotides. For instance, oligonucleotides may be conjugated to fluorescent labels to allow sequence specific detection following a biological assay. A number of methods exist for the conjugation of oligonucleotides and mainly rely on the use of a nucleophile attached to the oligonucleotide reacting with reactive species to form the desired product. A new approach to achieve oligonucleotide conjugations is to use cycloadditions. This review covers the growing use of cycloadditions for labelling of oligonucleotides at various positions within the sequence and the advantages over existing techniques. A number of different dienes have been reported and each is reviewed. Finally, the use of these conjugated oligonucleotides is reported with a view, to demonstrate the advantages of using cycloaddition for the conjugations.

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Ionic solutions and their pivotal roles in organic and biological systems

Abstract: Abstract

Cited by 18 publications

References 0 publications

Chemical and Spectroscopic Studies Related to the Lewis Acidity of Lithium Perchlorate in Diethyl Ether

Chemical and Spectroscopic Studies Related to the Lewis Acidity of Lithium Perchlorate in Diethyl Ether

Hydration Energies of Aromatic Ions in the Gas Phase

Cycloadditions as a Method for Oligonucleotide Conjugation

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