Morin (2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one) is an abundant flavonoid with various pharmacological and biological activities. Considering the ubiquitous presence of calcium cations in biological systems, it seems relevant to study the interaction of this ion with morin and the influence of pH on this system. In a first step, among the four hypothetical chelation sites, the preferential fixing site, its protonation state and the Ca environment have been determined by combining electronic spectroscopies and density functional theory (DFT) and time-dependent DFT calculations. Then, using the same methodology, the fate of the formed complex with the variation of pH was studied. Calcium chelation occurs with the 3-hydroxy-4-keto site with deprotonation of the hydroxyl group. The coordination number of Ca does not seem to be a determining parameter insofar whatever the number of solvent molecules present in the coordination sphere of the metal, the calculation of the electronic transitions leads to the same results. With the increase in pH, a first deprotonation of the complex occurs at the level of a solvent molecule in the metal coordination sphere, followed by a deprotonation of the hydroxyl function in position 7.
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http://dx.doi.org/10.1016/j.saa.2019.117492 | DOI Listing |
Org Lett
January 2025
Materials Tech Laboratory for Hydrogen & Energy Storage, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences, Ningbo 315201, P. R. China.
A new sequential deprotonation strategy of dimethyl sulfoxide (DMSO) and propargyl alcohol in the presence of a base was developed for the generation of the α-hydroxyl carbanion, which enables rapid and controllable access to a wide range of valuable highly functionalized furans in one pot from alkynes and aldehydes under transition-metal- and additive-free conditions. Preliminary mechanistic studies revealed the crucial role of the base and DMSO. More importantly, deuterium labeling experiments confirmed the formation of the α-hydroxyl carbanion.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Core Facility Center 'Arktika', Northern (Arctic) Federal University, Arkhangelsk 163002, Russia.
N,N'-Dialkylimidazolium-based ionic liquids are capable of completely dissolving lignocellulosic biomass at elevated temperatures and are considered as promising green solvents for future biorefining technologies. However, the obtained ionic liquid lignin preparations may contain up to several percent nitrogen. This indicates strong interactions between the biopolymer and the IL cation, the nature of which has not yet been clarified.
View Article and Find Full Text PDFSci Rep
December 2024
China Special Equipment Inspection and Research Institute, Beijing, 100000, China.
Catalytic CO desorption has emerged as a crucial strategy for enhancing the efficiency of CO capture and reducing energy requirements, thereby advancing chemical absorption methods. This study examines the catalytic effectiveness of titanium pyrophosphate (TiPO) in improving monoethanolamine (MEA)-based CO absorption and desorption processes, comparing its performance with other titanium-based catalysts, including titanium dioxide (TiO), titanium tetrahydroxide (TiO(OH)), and titanium carbide (TiC). In TiPO, Ti ions function as Lewis acid sites by accepting electron pairs (LASs), PO anions act as proton carriers, facilitating rapid proton transfer as Lewis base sites (LBSs), and active hydroxyl groups on the surface, resulting from water molecule dissociation or the deprotonation reaction, function as Brönsted acid sites (BASs).
View Article and Find Full Text PDFNat Commun
December 2024
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
One challenge remaining in the development of Ir-based electrocatalyst is the activity-stability paradox during acidic oxygen evolution reaction (OER), especially for the surface reconstructed IrO catalyst with high efficiency. To address this, a phase selective Ir-based electrocatalyst is constructed by forming bridged W-O moiety in NiIrO electrocatalyst. Through an electrochemical dealloying process, an nano-porous structure with surface-hydroxylated rutile NiWIrO electrocatalyst is engineered via Ni as a sacrificial element.
View Article and Find Full Text PDFJ Mol Graph Model
November 2024
Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovakia. Electronic address:
In this work, the chemical equilibrium between enol and keto tautomers occurring in phenol, naphthols and selected 29 hydroxy substituted polycyclic aromatic hydrocarbons classified into 4 structural types was investigated. The reaction Gibbs energies were computed using the density functional theory combined with the solvent continuum model. We have demonstrated how the consecutive condensation of benzene rings together with two-dimensional molecular arrangement and the position of the hydroxyl group modifies this equilibrium.
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