Intermolecular hydrogen bond interactions in the thiourea/water complexes (Thio-(H2O)n) (n = 1, …, 5): X-ray, DFT, NBO, AIM, and RDG analyses

Akman, Feride; Issaoui, Noureddine; Kazachenko, Аleksandr S.

doi:10.1007/s00894-020-04423-3

Cited by 112 publications

(25 citation statements)

References 35 publications

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“…It is established that the values of that ratio greater than 1 account for purely non covalent interactions, while values lower than one indicate a covalent character. [ 42,60 ] Concerning the HBs studied herein, the values of −g( r )/v( r ) are slightly lower than 1 (0.9215 and 0.9927) indicating a small covalent character in the studied bonds. Furthermore, the analysis of ∇ 2 ρ ( r ) values, [ 42,60,61 ] indicates the weak character of the HBs of CAP.…”

Section: Resultsmentioning

confidence: 72%

“…[ 42,60 ] Concerning the HBs studied herein, the values of −g( r )/v( r ) are slightly lower than 1 (0.9215 and 0.9927) indicating a small covalent character in the studied bonds. Furthermore, the analysis of ∇ 2 ρ ( r ) values, [ 42,60,61 ] indicates the weak character of the HBs of CAP. The values of E (half of the potential energy at the BCP) clearly show a difference of 4.9727 kcal/mol, the O 37 ‐H 38 , …, O 35 HB having the highest value (−13.0451 kcal mol −1 ).…”

Section: Resultsmentioning

confidence: 87%

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DFT insights into the structure, reactivity and radical scavenging activity of cycloartocarpesin

Fouégué

Tedongmo

Ntieche

et al. 2021

J of Physical Organic Chem

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Daily increase in the number of patients suffering from illnesses due to reactive species has induced the permanent discovery and study of antioxidant compounds. The structure, reactivity, and antioxidant activity (AOA) of a phenolic compound named cycloartocarpesin (CAP), evaluated at DFT/B3LYP/6‐31 + G(d,p) level, is reported herein in the gas, pentyl ethanoate, and water phases. Bader topological analysis revealed that two of the three O‐H groups of CAP are involved in hydrogen bonds while the average local ionization energy (ALIE) and appropriate Fukui functions showed that electrons in the near vicinity of C7, C10, and C12 are the least tightly held and can easily be attacked by radicals. Analysis of the transition state of the reaction between CAP and HOO• radical shows that the proton coupled electron transfer process is not favored. Moreover, analyses of electronic spectra calculated at TD‐DFT/B3LYP/6‐31 + G(d,p) has interestingly demonstrate the ability of CAP to filtrate UVA, UVB, and UVC, thus exhibiting a photo‐protective activity.

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Section: Resultsmentioning

confidence: 72%

Section: Resultsmentioning

confidence: 87%

DFT insights into the structure, reactivity and radical scavenging activity of cycloartocarpesin

Fouégué

Tedongmo

Ntieche

et al. 2021

J of Physical Organic Chem

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“…That is, with an increase in the chain of a substituent in urea derivatives, their reactivity in sulfation reactions with sulfamic acid decreases. The reactivity of urea and its derivatives can also be associated with a change in the content of hydrogen bonds [45][46][47].…”

Section: The Role Of the Activator In The Process Of Sulfation Of Xanthan With Sulfamic Acidmentioning

confidence: 99%

Food Xanthan Polysaccharide Sulfation Process with Sulfamic Acid

Kazachenko

Vasilieva

Borovkova

et al. 2021

Foods

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Xanthan is an important polysaccharide with many beneficial properties. Sulfated xanthan derivatives have anticoagulant and antithrombotic activity. This work proposes a new method for the synthesis of xanthan sulfates using sulfamic acid. Various N-substituted ureas have been investigated as process activators. It was found that urea has the greatest activating ability. BBD of xanthan sulfation process with sulfamic acid in 1,4-dioxane has been carried out. It was shown that the optimal conditions for the sulfation of xanthan (13.1 wt% sulfur content) are: the amount of sulfating complex per 1 g of xanthan is 3.5 mmol, temperature 90 °C, duration 2.3 h. Sulfated xanthan with the maximum sulfur content was analyzed by physicochemical methods. Thus, in the FTIR spectrum of xanthan sulfate, in comparison with the initial xanthanum, absorption bands appear at 1247 cm−1, which corresponds to the vibrations of the sulfate group. It was shown by GPC chromatography that the starting xanthan gum has a bimodal molecular weight distribution of particles, including a high molecular weight fraction with Mw > 1000 kDa and an LMW fraction with Mw < 600 kDa. It was found that the Mw of sulfated xanthan gum has a lower value (~612 kDa) in comparison with the original xanthan gum, and a narrower molecular weight distribution and is characterized by lower PD values. It was shown by thermal analysis that the main decomposition of xanthan sulfate, in contrast to the initial xanthan, occurs in two stages. The DTG curve has two pronounced peaks, with maxima at 226 and 286 °C.

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“…The PCM by Tomasi and coworkers has particularly been useful in computational chemistry to model solvation effects. [ 21–23 ] As an advantage, the PCM can display a statistically averaged (continuum) solvent so that meaningful data can be obtained. [ 16 ] The PCM mainly defines structureless polarizable medium of bulk of solvent on the basis of its dielectric constant.…”

Section: Computational Detailsmentioning

confidence: 99%

“…[ 30 ] The AIM theory has widely been used to identify H‐bonds in many chemical and biological systems and to analyze this interaction as electron density (ρ), its Laplacian (∇ 2 ρ), and the total electron energy density (H) at the bond critical points (BCPs). [ 22,31–33 ]…”

Section: Computational Detailsmentioning

confidence: 99%

Theoretical insights of solvent effect on tautomerism, stability, and electronic properties of 6‐ketomethylphenanthridine

Asadi

Masoodi

Mehrabi

2021

J of Physical Organic Chem

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In this manuscript, the influence of solvent on stability and electronic properties of enolimine, enaminone, and iminone forms of 6‐ketomethylphenanthridine is theoretically investigated using polarizable continuum model (PCM). Here, PCM is used during optimization of structures of tautomeric forms in solution. Water, ethanol, acetone, acetonitrile, chloroform, diethyl ether, dichloromethane, and dimethyl sulfoxide are chosen as solvent. The calculations are performed at M06‐2X/6‐311++G(d,p) level. In gas phase and in the solvents, the stability of tautomers increases as enaminone > enolimine > iminone. The topological properties of electron charge density are also studied for better understanding of stability of tautomers. It is observed that the stability of tautomers is diminished by increasing dielectric constant of solvent. Also, the increase in dielectric constant of solvent kinetically and thermodynamically facilitates the enolimine ⇌ enaminone tautomerization. To obtain more valuable information on stabilities of tautomers in water phase, the PCM calculations have also been performed with one water molecule. At M06‐2X/6‐311++G(d,p) level of theory, the stability of complexes is amplified as enaminone–water > iminone–water (V) > iminone–water (IV) > enolimine–water. The relationships between dielectric constant of solvent and some electronic properties of tautomers such as band gap, electron affinity, electrophilicity index, first ionization energy, electronic chemical potential, chemical softness, and hardness are also investigated.

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Intermolecular hydrogen bond interactions in the thiourea/water complexes (Thio-(H2O)n) (n = 1, …, 5): X-ray, DFT, NBO, AIM, and RDG analyses

Cited by 112 publications

References 35 publications

DFT insights into the structure, reactivity and radical scavenging activity of cycloartocarpesin

DFT insights into the structure, reactivity and radical scavenging activity of cycloartocarpesin

Food Xanthan Polysaccharide Sulfation Process with Sulfamic Acid

Theoretical insights of solvent effect on tautomerism, stability, and electronic properties of 6‐ketomethylphenanthridine

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