A<sup>1</sup>H and<sup>13</sup>C NMR and UV Study of the State of Hydroxyacetone in Aqueous Solutions

Glushonok, G.K.; Glushonok, T.G.; Maslovskaya, Lidiya A.; Шадыро, О. И.

doi:10.1023/b:rugc.0000007604.91106.60

Cited by 22 publications

(16 citation statements)

References 11 publications

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“…The corresponding spectra of the reaction mixture solution in DMSO‐ d 6 are shown in Figure S12a,b (Supporting Information). The presence of DHA in the mixture is proven by the characteristic position of the ketone carbon 13 C signal at 212.1 ppm, which agrees with the reported value . Besides, the signals of an aldehyde, the other oxidation product, but also a carboxylic acid, are observed at 205.0 ppm (C(H)O) and 177.8 ppm (C(O)OH), respectively.…”

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confidence: 90%

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

et al. 2017

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Cost-efficient, visible-light-driven hydrogen production from water is an attractive potential source of clean, sustainable fuel. Here, it is shown that thermal solid state reactions of traditional carbon nitride precursors (cyanamide, melamine) with NaCl, KCl, or CsCl are a cheap and straightforward way to prepare poly(heptazine imide) alkali metal salts, whose thermodynamic stability decreases upon the increase of the metal atom size. The chemical structure of the prepared salts is confirmed by the results of X-ray photoelectron and infrared spectroscopies, powder X-ray diffraction and electron microscopy studies, and, in the case of sodium poly(heptazine imide), additionally by atomic pair distribution function analysis and 2D powder X-ray diffraction pattern simulations. In contrast, reactions with LiCl yield thermodynamically stable poly(triazine imides). Owing to the metastability and high structural order, the obtained heptazine imide salts are found to be highly active photocatalysts in Rhodamine B and 4-chlorophenol degradation, and Pt-assisted sacrificial water reduction reactions under visible light irradiation. The measured hydrogen evolution rates are up to four times higher than those provided by a benchmark photocatalyst, mesoporous graphitic carbon nitride. Moreover, the products are able to photocatalytically reduce water with considerable reaction rates, even when glycerol is used as a sacrificial hole scavenger.

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confidence: 90%

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

et al. 2017

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“…1 H, 13 C, and 17 O NMR chemical shifts for the relevant species of HA in the same solvents were also calculated by using different theoretical approaches and compared with available experimental data. 14,15…”

Section: Introductionmentioning

confidence: 99%

Matrix-Isolation Study and Ab Initio Calculations of the Structure and Spectra of Hydroxyacetone

2008

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The structure of hydroxyacetone (HA) isolated in an argon matrix (at 12 K) and in a neat solid phase (at 12-175 K) was characterized by using infrared (IR) spectroscopy. The interpretation of the experimental results was supported by high-level quantum chemical calculations, undertaken by using both ab initio (MP2) and density functional theory methods. A potential-energy surface scan, carried out at the MP2/6-311++G(d,p) level of theory, predicted four nonequivalent minima, Cc, Tt, Tg, and Ct, all of them doubly degenerate by symmetry. The energy barriers for conversion between most of the symmetrically related structures and also between some of the nonequivalent minima (e.g., Tg --> Tt and Ct --> Tt) are very small and stay below the zero-point vibrational level associated with the isomerization coordinate in the higher-energy form in each pair. Therefore, only Cc and Tt conformers have physical significance, with populations of 99 and 1%, respectively, in gas phase at room temperature. For the matrix-isolated compound, only the most stable Cc conformer was observed. On the other hand, the polarizable continuum model calculations indicated that in water solution, the population of Tt and Ct conformers might be high enough (ca. 6 and 11%, respectively) to enable their experimental detection, thus supporting the conclusions of a previous IR spectroscopy study [ Spectrochim. Acta A 2005, 61, 477] in which the presence of more than one HA conformer in aqueous solution was postulated. The signatures of these minor conformers, however, do not appear in the spectra of the neat HA crystal, and the crystal structure was rationalized in terms of centrosymmetric hydrogen-bonded dimers consisting of two Cc-like units. Finally, we calculated (1)H, (13)C, and (17)O NMR chemical shifts at different levels of theory and found them to agree with available experimental data.

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“…While the MG diol to tetrol ratio was 60:40 in bulk, at the air–water interface, it was found to shift to 80:20 . Bulk studies also found that 53% of aqueous MG solutions consisted of dimers or oligomers. ,− We recently reported on HA as a model system due to its relative simplicity of being 96–98% in an unhydrated monomeric state. , …”

Section: Resultsmentioning

confidence: 99%

“…16,35−38 We recently reported on HA as a model system due to its relative simplicity of being 96−98% in an unhydrated monomeric state. 78,115 It is interesting to note that HA, which has the most hydrophobic moieties of these organics, actually has the lowest surface activity. As previously stated, HA is also the only molecule that does not favor oligomer formation.…”

Section: Resultsmentioning

confidence: 99%

On the Rise: Experimental and Computational Vibrational Sum Frequency Spectroscopy Studies of Pyruvic Acid and Its Surface-Active Oligomer Species at the Air–Water Interface

et al. 2019

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It is well known that atmospheric aerosol play important roles in the environment. However, there is still much to learn about the processes that form aerosols, particularly aqueous secondary organic aerosols. While pyruvic acid (PA) is often better known for its biological significance, it is also an abundant atmospheric secondary organic ketoacid. It has been shown that, in bulk aqueous environments, PA exists in equilibrium between unhydrated α-keto carboxylic acid (PYA) and singly hydrated geminal diol carboxylic acid (PYT), favoring the diol. These studies have also identified oligomer products in the bulk, including zymonic acid (ZYA) and parapyruvic acid (PPA). The surface behavior of these oligomers has not been studied, and their contributions (if any) to the interface are unknown. Here, we address this knowledge gap by examining the molecular species present at the interface of aqueous PA systems using vibrational sum frequency spectroscopy (VSFS), a surface-sensitive technique. VSFS provides information about interfacial molecular populations, orientations, and behaviors. Computational studies using classical molecular dynamics and quantum mechanical density functional theory are employed in combination to afford further insights into these systems. Our studies indicate populations of at least two intensely surface-active oligomeric species at the interface. Computational results demonstrate that, along with PYA and PYT, both PPA and ZYA are surfaceactive with strong VSF responses that can account for features in the experimental spectra.

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A¹H and¹³C NMR and UV Study of the State of Hydroxyacetone in Aqueous Solutions

Cited by 22 publications

References 11 publications

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

Matrix-Isolation Study and Ab Initio Calculations of the Structure and Spectra of Hydroxyacetone

On the Rise: Experimental and Computational Vibrational Sum Frequency Spectroscopy Studies of Pyruvic Acid and Its Surface-Active Oligomer Species at the Air–Water Interface

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A1H and13C NMR and UV Study of the State of Hydroxyacetone in Aqueous Solutions

Cited by 22 publications

References 11 publications

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

“The Easier the Better” Preparation of Efficient Photocatalysts—Metastable Poly(heptazine imide) Salts

Matrix-Isolation Study and Ab Initio Calculations of the Structure and Spectra of Hydroxyacetone

On the Rise: Experimental and Computational Vibrational Sum Frequency Spectroscopy Studies of Pyruvic Acid and Its Surface-Active Oligomer Species at the Air–Water Interface

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A¹H and¹³C NMR and UV Study of the State of Hydroxyacetone in Aqueous Solutions