Basicity of aliphatic amines in ethanol

Bel’skii, V. E.; Kudryavtseva, L. A.; Derstuganova, K. A.; Teitel'baum, A. B.; Ivanov, B. E.

doi:10.1007/bf00955273

Cited by 3 publications

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“…However, although its effect is different for primary, secondary, and tertiary ones, within each class the relative basicity is not altered, and appropriate correction coefficients are available to normalize this property between them. [ 44 ] Extreme care should be used in studying “naked” AuNPs in a non‐aqueous solvent such as ethanol because even small amounts of salt are known to induce their aggregation. [ 45 ] This is related to the formation of oppositely charged particles in a less solvating medium than water.…”

Section: Resultsmentioning

confidence: 99%

“… a) Values were obtained from the pKa in water and converted by using the equations reported in ref. [44];…”

Section: Resultsmentioning

confidence: 99%

“…[42] Interpolation of these curves provided the apparent, relative dissociation constants of the different amines for the AuNPs surface (pK d,Au Table 1). By plotting the pK d,Au values versus the pK a of the amines, corrected for ethanol as the solvent (pK a,EtOH ), [44] we obtained the graph reported in Figure 2C. The existing correlation between the pK a,EtOH of the amines and the strength of their interaction with the nanoparticle surface indicates there is a linear free energy relationship (LFER) between the proton affinity constant and that for the gold surface.…”

Section: The Basicity Of the Amines Controls Their Interaction With T...mentioning

confidence: 99%

“…[52] To avoid any speculation on these, we prefer to assign the three components heuristically: the 399.6 eV BE component is the typical one related to 1 grafted on the gold surface, the component at 401.0 could indicate the presence of a slightly positively charged N, different from a protonated nitrogen which would be expected at a little higher BE. [44] On the other hand, the component at 398.5 eV BE could be related to slightly negatively charged nitrogen. [74,75] These results appear to indicate the coexistence of RNH 2…”

Section: A Redox Process Is Likely Involved In the Most Tightly Bound...mentioning

confidence: 99%

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The Interaction of Amines with Gold Nanoparticles

et al. 2023

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Understanding the interactions between amines and the surface of gold nanoparticles is important because of their role in the stabilization of the nanosystems, in the formation of the protein corona, and in the preparation of semisynthetic nanozymes. By using fluorescence spectroscopy, electrochemistry, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, and molecular simulation, a detailed picture of these interactions is obtained. Herein, it is shown that amines interact with surface Au(0) atoms of the nanoparticles with their lone electron pair with a strength linearly correlating with their basicity corrected for steric hindrance. The kinetics of binding depends on the position of the gold atoms (flat surfaces or edges) while the mode of binding involves a single Au(0) with nitrogen sitting on top of it. A small fraction of surface Au(I) atoms, still present, is reduced by the amines yielding a much stronger Au(0)–RN.+ (RN., after the loss of a proton) interaction. In this case, the mode of binding involves two Au(0) atoms with a bridging nitrogen placed between them. Stable Au nanoparticles, as those required for robust semisynthetic nanozymes preparation, are better obtained when the protein is involved (at least in part) in the reduction of the gold ions.

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Section: Resultsmentioning

confidence: 99%

“… a) Values were obtained from the pKa in water and converted by using the equations reported in ref. [44];…”

Section: Resultsmentioning

confidence: 99%

Section: The Basicity Of the Amines Controls Their Interaction With T...mentioning

confidence: 99%

Section: A Redox Process Is Likely Involved In the Most Tightly Bound...mentioning

confidence: 99%

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The Interaction of Amines with Gold Nanoparticles

et al. 2023

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“…It is known that the basicity of methylamine is less in ethanol (pКа of conjugate acid is 9.58) than in water (pКа is 10.66). 40,41 Therefore, the less basic ethanolic methylamine deprotonates only the more acidic NH proton of the benzamido group and this results in formation of pyrrole 4d (Scheme 2). The more basic methylamine and dimethylamine aqueous solutions (pКа 10.73) deprotonate the NH group and remove proton from the methyl group of intermediate F that participates in intramolecular crotonic condensation.…”

Section: Resultsmentioning

confidence: 99%

The rearrangement of 3-nitropyridinium salts to 3-nitropyrroles

Куратова¹,

Glyzdinskaya²,

Воронцова³

et al. 2016

Arkivoc

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Enantioselective Transfer Hydrogenation

Blacker¹

2006

The Handbook of Homogeneous Hydrogenation

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Transfer hydrogenation is the movement of a hydride ion and proton (or two protons and two electrons) from a hydrogen donor to a substrate acceptor, effectively a disproportionation. In the case of hydrogenation, molecular hydrogen is the donor, and this topic is considered elsewhere in this Handbook. The substrate acceptor is unsaturated and can be, for example, a ketone, imine or alkene. The hydrogen donor is a good reductant and is often an alcohol, alkane or formate. The reaction is mediated by a catalyst that helps in the hydride transfer. When applied to ketones using isopropanol as the hydrogen donor and a Lewis acid to catalyze the reaction, the non-asymmetric transformation is known as the Meerwein-Pondorf-Verley reaction. Transfer dehydrogenation is the movement of a hydride ion and proton in the opposite direction. For alcohol substrates yielding ketone products, it is also known as the Oppenauer oxidation.If the catalyst is chiral, it can transfer hydride selectively to one prochiral face of an acceptor to provide an optically active product ( Fig. 35.1).A number of excellent reviews have recently been published [1]; consequently, this chapter will consider mainly the practical aspects of asymmetric transfer hydrogenation by reviewing each of the components of the reaction, namely catalyst, hydrogen donor, substrate, product and other elements such as solvent, reaction conditions and scale-up.In broad terms there are three types of catalyst for transfer hydrogenation: dehydrogenases; heterogeneous; and homogenous metal catalysts. Here, the first two are mentioned for completeness, and the main focus of this chapter will be asymmetric transfer hydrogenation with homogenous metal catalysts.Nature uses enantioselective transfer hydrogenation to reduce metabolites, for example pyruvate to give (S)-lactic acid and 2-ketoglutarate to give (S)-2-hydroxyglutarate. The reaction is reversible and the equilibrium position depends on the concentration of the species. The enzyme catalysts are named dehydrogenases, and they employ a soluble cofactor or hydride acceptor called NAD(P) in its oxi- 1215The Handbook of Homogeneous Hydrogenation. Edited by J. G. de Vries and C. J. Elsevier

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Basicity of aliphatic amines in ethanol

Cited by 3 publications

References 1 publication

The Interaction of Amines with Gold Nanoparticles

The Interaction of Amines with Gold Nanoparticles

The rearrangement of 3-nitropyridinium salts to 3-nitropyrroles

Enantioselective Transfer Hydrogenation

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