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Artículos de revistas sobre el tema "Solvation Consequences"

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Publicado: 18 de mayo de 2024

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1

Louis, C. y J. Bessière. "Propriétés de solvation des solutions concentrées en acide phosphorique". Canadian Journal of Chemistry 64, n.º 3 (1 de marzo de 1986): 608–14. http://dx.doi.org/10.1139/v86-098.

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Solvation properties of ions inH2O–H3PO4 media (1–14 M) are characterized with their solvation transfer activity coefficients f. These are calculated from normal potential or solubility values, and indicate an increasing solvation for anions and decreasing solvation for cations in concentrated acid solutions. For each species, the range depends on its number of charges, on the existence of oxygen atoms in its structure, and on its basic properties. The consequences of variation of solvation on oxidation–reduction reactions and solubility properties are studied.
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2

Raczynska, Ewa D. y Krzysztof Wozniak. "ChemInform Abstract: Consequences of Internal Solvation in the Gas Phase". ChemInform 31, n.º 32 (3 de junio de 2010): no. http://dx.doi.org/10.1002/chin.200032272.

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3

WANG, ZHEN-GANG. "VARIATIONAL ELECTROSTATICS FOR CHARGE SOLVATION". Journal of Theoretical and Computational Chemistry 07, n.º 03 (junio de 2008): 397–419. http://dx.doi.org/10.1142/s0219633608003824.

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We show that the equations of continuum electrostatics can be obtained entirely and simply from a variational free energy comprising the Coulomb interactions among all charged species and a spring-like term for the polarization of the dielectric medium. In this formulation, the Poisson equation, the constitutive relationship between polarization and the electric field, as well as the boundary conditions across discontinuous dielectric boundaries, are all natural consequences of the extremization of the free energy functional. This formulation thus treats the electrostatic equations and the energetics within a single unified framework, avoiding some of the pitfalls in the study of electrostatic problems. Application of this formalism to the nonequilbrium solvation free energy in electron transfer is illustrated. Our calculation reaffirms the well-known result of Marcus. We address the recent criticisms by Li and coworkers who claim that the Marcus result is incorrect, and expose some key mistakes in their approach.
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4

Fraenkel, Gideon, Joseph H. Duncan y Jinhai Wang. "Restricted Stereochemistry of Solvation of Allylic Lithium Compounds: Structural and Dynamic Consequences". Journal of the American Chemical Society 121, n.º 2 (enero de 1999): 432–43. http://dx.doi.org/10.1021/ja983047h.

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5

Radhika, Veerati y . "Conductance Study of Benzyl Bromide Reaction with Cyclicamines in Aqueous-Ethanol Medium". International Journal of Engineering & Technology 7, n.º 3.3 (21 de junio de 2018): 143. http://dx.doi.org/10.14419/ijet.v7i3.3.14508.

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Nucleophilic substitution reaction of benzyl bromide and cyclicamines in ethanol aqueous intermediate reactivity can suggest that the nucleophile increases through their pKa values. A linear correlation exists between computed values of the dipole moment, rate and electronegativity of the nucelophiles. The two reactants suggest that frontier molecular orbital interactions ion-solvation and correlation of time with the HOMO-LUMO breach of that the reaction. But it is not orbital controlled as well as forbidden by the electrostatic interactions along with mixed solvent composition between the reactants. The influence on the solvation of ions before reaction has been discuss with facilitate by R-factor. Thermodynamic properties are evaluate and report. The consequences of the learning to be interpreted in terms of ion-solvent exchanges and solvent properties comparing with electrostatic interaction between the reactants.
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6

Steel, William H., James B. Foresman, Daniel K. Burden, Yuen Y. Lau y Robert A. Walker. "Solvation of Nitrophenol Isomers: Consequences for Solute Electronic Structure and Alkane/Water Partitioning". Journal of Physical Chemistry B 113, n.º 3 (22 de enero de 2009): 759–66. http://dx.doi.org/10.1021/jp805184w.

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7

Ghiviriga, Ion y Daniela C. Oniciu. "Steric hindrance to the solvation of melamines and consequences for non-covalent synthesis". Chem. Commun., n.º 22 (2002): 2718–19. http://dx.doi.org/10.1039/b206811g.

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8

Debadrita Roy, Sukdev Majumder, Biplab Rajbanshi, Subhadeep Saha y Biswajit Sinha. "Physicochemical investigation of L-Asparagine in green solvent arrangements with the manifestation of solvation consequences". World Journal of Advanced Research and Reviews 13, n.º 2 (28 de febrero de 2022): 401–28. http://dx.doi.org/10.30574/wjarr.2022.13.2.0164.

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Solution behaviour prevailing in L-Asparagine in two aqueous ionic liquid solutions, namely (Benzyl tri–methyl ammonium chloride; Benzyl tri-ethyl ammonium chloride) have been studied by investigation of physico-chemical parameters; density, viscosity, refractive index, conductance and surface tension measurement respectively. The nature of interactions occurring in the solution have been calculated on the basis of apparent molar volume, viscosity A and B-coefficient, molar refraction at 298.15K,303.15K,308.15K and at 0.001m, 0.003m, 0.005m concentrations. The limiting apparent molar volumes (φV0) obtained from Masson equation, viscosity parameters, A and B coefficients obtained from Jones-Doles equation, Molar refraction (RM) from the Lorentz-Lorenz equation that describe the nature of solute-solute and solute-solvent interactions in the solution. Specific Conductance of the experimental solution, which applied to ascertain the ionic nature of the system. The different thermodynamic data, Δμ10≠, Δμ20≠, ΔH0≠, and TΔS0≠ also suggest the presence of strong interactions in the studied systems. The various types of interactions existing among amino acids in presence of ionic liquids which are the protein backbone would advance a many-dimensional challenge in the arena of solution chemistry. Studies of such systems could be forward-thinking further using the correlated results of the investigation.
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9

Gupta, Bhupender S., Bo-Ren Chen y Ming-Jer Lee. "Solvation consequences of polymer PVP with biological buffers MES, MOPS, and MOPSO in aqueous solutions". Journal of Chemical Thermodynamics 91 (diciembre de 2015): 62–72. http://dx.doi.org/10.1016/j.jct.2015.07.022.

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10

Kumar, Suresh y Hardeep Anand. "Ionic Association of Potassium and Tetrabutylammonium Thiocyanate Salts in Binary Mixtures of γ-Butyrolactone and N,N-Dimethylacetamide at 298.15 K and 308.15 K". Asian Journal of Chemistry 34, n.º 10 (2022): 2749–56. http://dx.doi.org/10.14233/ajchem.2022.23856.

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Solvation consequences of potassium thiocyanate (KSCN) and tetrabutylammonium thiocyanate (Bu4NSCN) in γ-butyrolactone (GBL), N,N-dimethylacetamide (DMA) and their binary mixtures in concentration range (0.01-0.001) mol Kg–1 of 0, 25, 50, 60, 80 and 100 mol% DMA at T = 298.15 K and 308.15 K have been studied using conductometric study and some samples of KSCN in GBL + DMA binary mixtures of different electrolytic concentrations at ambient conditions studied by FTIR spectroscopic methods. The Shedlovsky equation has been used to elucidate the data in terms of the limiting molar conductances (Λo), ion-pair association constants (KA). The Walden products (Λoηo), solvated radii (ri) and standard free energies of association (ΔGºA) were further evaluated in terms of solvation of ions. The reference electrolyte tetrabutylammonium tetraphenylborate (Bu4NBPh4) was used to determine the limiting molar ionic conductances. In pure solvents and their binary mixtures, electrolytes showed a strong association. The K+ ions have greater solvation in GBL than in DMA observed on basis of solvated radii in GBL + DMA binary solvent mixtures at both experimental temperatures. The study demonstrates that the ion-solvent interactions decrease on enhancing the temperature. The FTIR analysis was applied to obtain information about molecular as well as ionic association of KSCN in GBL + DMA binary mixtures at the ambient conditions, which has provided the information on structuring infrared modes of vibrational stretching frequencies according to the nature of the solvents or the cations. Shifting of vibrational frequencies of several functional groups of DMA and GBL in binary mixed solvents has been observed in terms of ion-ion, ion-solvent and solvent-solvent interactions.
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11

., Habibur Rahaman, Kalipada Sarkar ., Debasmita Das . y Mahendra Nath Roy . "Diverse Interactions of N-Methyl Glycine in Aqueous Paracetamol Solution with the Manifestation of Solvation Consequences". Journal of Advanced Chemical Sciences 4, n.º 4 (5 de enero de 2019): 601–5. http://dx.doi.org/10.30799/jacs.199.18040403.

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12

Roy, Mahendra Nath, Partha Sarathi Sikdar y Pritam De. "Physico-chemical study of lithium perchlorate in alkanols (C3–C5) with the manifestation of solvation consequences". Journal of Molecular Liquids 187 (noviembre de 2013): 368–73. http://dx.doi.org/10.1016/j.molliq.2013.09.009.

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13

Rodriguez-Larrea, David, Beatriz Ibarra-Molero y Jose M. Sanchez-Ruiz. "Energetic and Structural Consequences of Desolvation/Solvation Barriers to Protein Folding/Unfolding Assessed from Experimental Unfolding Rates". Biophysical Journal 91, n.º 5 (septiembre de 2006): L48—L50. http://dx.doi.org/10.1529/biophysj.106.087932.

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14

Ishida, Tateki y Peter J. Rossky. "Consequences of Strong Coupling between Solvation and Electronic Structure in the Excited State of a Betaine Dye". Journal of Physical Chemistry B 112, n.º 36 (11 de septiembre de 2008): 11353–60. http://dx.doi.org/10.1021/jp801660b.

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15

Roy, Mahendra Nath, Pritam De y Partha Sarathi Sikdar. "Study of solvation consequences of α-amino acids in aqueous ionic liquid solution probed by physicochemical approach". Fluid Phase Equilibria 352 (agosto de 2013): 7–13. http://dx.doi.org/10.1016/j.fluid.2013.03.030.

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16

Sato, Bruno M., Clarissa T. Martins y Omar A. El Seoud. "Solvation in aqueous binary mixtures: consequences of the hydrophobic character of the ionic liquids and the solvatochromic probes". New Journal of Chemistry 36, n.º 11 (2012): 2353. http://dx.doi.org/10.1039/c2nj40506g.

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17

Rutherford, Jennifer L., Daniele Hoffmann y David B. Collum. "Consequences of Correlated Solvation on the Structures and Reactivities of RLi-Diamine Complexes: 1,2-Addition and α-Lithiation Reactions of Imines by TMEDA-Solvatedn-Butyllithium and Phenyllithium". Journal of the American Chemical Society 124, n.º 2 (enero de 2002): 264–71. http://dx.doi.org/10.1021/ja002979u.

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18

Paolucci, Christopher, John R. Di Iorio, William F. Schneider y Rajamani Gounder. "Solvation and Mobilization of Copper Active Sites in Zeolites by Ammonia: Consequences for the Catalytic Reduction of Nitrogen Oxides". Accounts of Chemical Research 53, n.º 9 (11 de agosto de 2020): 1881–92. http://dx.doi.org/10.1021/acs.accounts.0c00328.

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19

van Noort, Paul C. M., Joris J. H. Haftka y John R. Parsons. "A simple McGowan specific volume correction for branching in hydrocarbons and its consequences for some other solvation parameter values". Chemosphere 84, n.º 8 (agosto de 2011): 1102–7. http://dx.doi.org/10.1016/j.chemosphere.2011.04.042.

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20

Mondal, Jaygopal, Ashutosh Dutta, Koyeli Das, Debasmita Das, Paramita Karmakar, Swarnab Sengupta, Arindam Bhattacharya, Rajesh Kumar Das y Mahendra Nath Roy. "Probing Subsistence of Host Guest Inclusion Complexes of Oligosaccharides with Allopurinol for Regulatory Release with the Manifestation of Solvation Consequences". Volume 5,Issue 1,2019 5, n.º 1 (6 de mayo de 2019): 621–28. http://dx.doi.org/10.30799/jacs.205.19050105.

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21

Mitrasinovic, Petar M. "Small-Molecule Interaction with G-Quadruplex DNA". Croatica chemica acta 92, n.º 1 (2019): 43–57. http://dx.doi.org/10.5562/cca3456.

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Targeting G-quadruplex (G4) DNA structures by small molecules is a potential strategy for directing gene therapy of cancer disease. Herein, novel insights into non-covalent interactions between a structurally diversified spectrum of ligands and a G-quadruplex DNA (formed in the c-Myc oncogene promoter region) are reported. Solvation-induced effects on and entropic contributions to the binding free energy are explored. In addition, the correlation of G4 domain motions and active site rearrangements with the binding of highest affinity ligands, being associated with the fundamentally distinguishable modes of interaction (external stacking: BRACO-19, TMPyP4, and CX-3543; groove binding: Sanguinarine, Tetrahydropalmatine, and Hoechst 33258), is quantitatively evaluated and elaborated by observing thermodynamic consequences of the receptor conformational flexibility changes in the asymptotic regime (t → ∞) of molecular dynamics (MD) simulation. BRACO-19 and Tetrahydropalmatine are identified as unique (thermodynamically favorable and highly selective) G4-DNA binders. Implications of the present study for experimental research are elucidated.
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22

Thompson, Niklas B., Karen L. Mulfort y David M. Tiede. "Toward a quantitative description of solvation structure: a framework for differential solution scattering measurements". IUCrJ 11, n.º 3 (1 de mayo de 2024): 423–33. http://dx.doi.org/10.1107/s2052252524003282.

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Appreciating that the role of the solute–solvent and other outer-sphere interactions is essential for understanding chemistry and chemical dynamics in solution, experimental approaches are needed to address the structural consequences of these interactions, complementing condensed-matter simulations and coarse-grained theories. High-energy X-ray scattering (HEXS) combined with pair distribution function analysis presents the opportunity to probe these structures directly and to develop quantitative, atomistic models of molecular systems in situ in the solution phase. However, at concentrations relevant to solution-phase chemistry, the total scattering signal is dominated by the bulk solvent, prompting researchers to adopt a differential approach to eliminate this unwanted background. Though similar approaches are well established in quantitative structural studies of macromolecules in solution by small- and wide-angle X-ray scattering (SAXS/WAXS), analogous studies in the HEXS regime—where sub-ångström spatial resolution is achieved—remain underdeveloped, in part due to the lack of a rigorous theoretical description of the experiment. To address this, herein we develop a framework for differential solution scattering experiments conducted at high energies, which includes concepts of the solvent-excluded volume introduced to describe SAXS/WAXS data, as well as concepts from the time-resolved X-ray scattering community. Our theory is supported by numerical simulations and experiment and paves the way for establishing quantitative methods to determine the atomic structures of small molecules in solution with resolution approaching that of crystallography.
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23

Galiano-Roth, Angela S. y David B. Collum. "Structure and reactivity of lithium diisopropylamide (LDA). The consequences of aggregation and solvation during the metalation of an N,N-dimethylhydrazone". Journal of the American Chemical Society 111, n.º 17 (agosto de 1989): 6772–78. http://dx.doi.org/10.1021/ja00199a042.

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24

Abboud, J. L. M. y R. Notari. "Critical compilation of scales of solvent parameters. Part I. Pure, non-hydrogen bond donor solvents". Pure and Applied Chemistry 71, n.º 4 (1 de enero de 1999): 645–718. http://dx.doi.org/10.1351/pac199971040645.

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Introduction and Fundamental ConceptsIt has long been known that solvents often affect chemical reactivity, this involving, e.g., the shift of the position of chemical equilibria (thermodynamic aspect) as well as significant changes in reaction rate constants (kinetic aspect). Physical properties, particularly the frequencies and intensities of transitions in IR, UV-visible, fluorescence, NMR and ESR spectroscopies are also known to be affected by solvents.These phenomena are consequences of differences in the solvation of reagents and products (thermodynamic effects) or reagents and activated complexes (kinetic effects). Differential solvation of species in the ground and excited states accounts for the spectral phenomenology indicated above. Differences in solvation of a given solute in two different solvents determine the size of the corresponding partition coefficient.It is customary to state that these effects reflect the influence of "solvent polarity". According to Reichardt, "solvent polarity" is "the overall solvation capability (or solvation power) of solvents, which in turn depends on the action of all possible, nonspecific and specific intermolecular interactions between solute ions or molecules and solvent molecules, excluding, however, those interactions leading to definite chemical alterations of the ions or molecules of the solute (such as protonation, oxidation, reduction, chemical complex formation, etc.)".This definition underscores the extreme complexity of "solvation effects" at the molecular level. This notwithstanding, solvent effects (SE) often display some remarkable regularities that allow in many cases an "empirical treatment" that sheds light on their origin and main contributors.Consider a solute S and two different properties P1 and P2, taking the values {P10, P11, ..., P1i, ...} and {P20, P21, ..., P2i, ...} respectively in solvents S0, S1, ..., Si,...A scale of SEs is simply constructed by taking for each solvent, Si, the difference P1i - P10, S0 being chosen as a reference solvent. If the property P1 is a "good descriptor" of SEs on P2, equation (1) holds for solvent Si : P2i - P20 = k (P1i - P10) (1)or P2i - P20 = kpi (2)wherein k is a constant independent of the solvents and determined solely by P2. pi is the "solvent parameter" characteristic of solvent Si.More generally, the properties being compared might belong to two different solutes.For any property Pm of any solute, and if P1 is a "good descriptor", equation (3) holds: Pmi - Pm0 = kmpi (3)We draw attention to the (frequently overlooked) fact that if equations such as (3) were truly general, then, all SEs would be linearly related to an extremely high degree of precision and a single, universal scale of SEs would exist. This is against all the available experimental evidence. Excellent correlations of narrower scope do exist however, that successfully link a very large amount of experimental data for a substantial variety of solvents and solutes and a relatively small number of empirical scales.In this compilation, scales are selected on the basis of criteria to be discussed below. For each of them, the most reliable values of solvent parameters are given. The physical foundations and the scope of the scales are discussed. Some suggestions regarding their use are made. For the purpose of facilitating future work in the field, some indications are given regarding the experimental determination of the various parameters.Solvent-solute interactions always involve dispersion or London's forces and, very often, dipolar and/or multipolar interactions. Current theoretical models including London's, Hildebrand's and/or reaction field (RF) theories allow to express these "non specific" parts of SEs as functions of physical properties such as the refractive index, relative permittivity and thermodynamic properties of the solvent.Quantitative rankings of solvents ("solvent scales") can thus be constructed on the basis of such properties as the refractive index, n; electric permittivity (formerly known as dielectric constant), er; Hildebrand's solubility parameter, dH; the modulus of the molecular dipole moment, μ, and various functions thereof. These scales shall be termed "model-independent". Quite generally, it is assumed that dispersive and electrostatic interactions are independent and additive. Following Palm and Koppel, it is further assumed that other contributions to solvent-solute interactions, notably hydrogen bonding are also independent from and additive to, the "non specific" contributions.Use is often made of "model-dependent" scales. They are based on the similarity principle: the ranking of the efficiency of solvents on a given property is quantitatively compared to their influence on a reference physical or chemical property of a referencesolute ("molecular probe"). The associated formalism is quite simple and has been outlined above. These scales can be divided into two different categories, depending on whether they quantify the overall "polarity effect" of the solvent, in Reichardt's sense or else, they are intended to measure one or various components of the overall solvation power of the solvent.Some scales have been built on the basis of a statistical treatment of SEs on large sets of experimental data of various origins. They are absolutely "empirical" in that they try to quantify "average" SEs without specifically seeking a formal link with current theoretical concepts on solvent-solute interactions.Last we mention that the case of self-associated solvents and mixtures thereof involves a number of conceptual and experimental difficulties that, in our opinion, justify a separate treatment.Here we deal with non-hydrogen bond donor solvents, although a number of weak hydrogen bond donor solvents are also included.Part I of this compilation is organized as follows:Description of the Tables.Physical properties and model-independent scales.Table I. Model-dependent scales: a) "Overall solvation" scales.b) Scales of dipolarity/polarizability.c) Scales of hydrogen bonding accepting power (hydrogen bonding basicity).d) Scales of "hard" and "soft" Lewis acidity and basicity.Statistical scales.Table II.General comments on the scales.
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25

Roy, Mahendra Nath, Binoy Chandra Saha y Kalipada Sarkar. "Physico-chemical studies of a biologically active molecule (L-valine) predominant in aqueous alkali halide solutions with the manifestation of solvation consequences". Physics and Chemistry of Liquids 53, n.º 6 (7 de julio de 2015): 785–801. http://dx.doi.org/10.1080/00319104.2015.1048446.

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26

Roy, Mahendra Nath, Pritam De y Partha Sarathi Sikdar. "Physicochemical study of solution behaviour of alkali metal perchlorates prevailing in N,N-Dimethyl Formamide with the manifestation of ion solvation consequences". Journal of Molecular Liquids 204 (abril de 2015): 243–47. http://dx.doi.org/10.1016/j.molliq.2015.01.010.

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27

Bełdowski, Piotr, Maciej Przybyłek, Przemysław Raczyński, Andra Dedinaite, Krzysztof Górny, Florian Wieland, Zbigniew Dendzik, Alina Sionkowska y Per M. Claesson. "Albumin–Hyaluronan Interactions: Influence of Ionic Composition Probed by Molecular Dynamics". International Journal of Molecular Sciences 22, n.º 22 (16 de noviembre de 2021): 12360. http://dx.doi.org/10.3390/ijms222212360.

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The lubrication mechanism in synovial fluid and joints is not yet fully understood. Nevertheless, intermolecular interactions between various neutral and ionic species including large macromolecular systems and simple inorganic ions are the key to understanding the excellent lubrication performance. An important tool for characterizing the intermolecular forces and their structural consequences is molecular dynamics. Albumin is one of the major components in synovial fluid. Its electrostatic properties, including the ability to form molecular complexes, are closely related to pH, solvation, and the presence of ions. In the context of synovial fluid, it is relevant to describe the possible interactions between albumin and hyaluronate, taking into account solution composition effects. In this study, the influence of Na+, Mg2+, and Ca2+ ions on human serum albumin–hyaluronan interactions were examined using molecular dynamics tools. It was established that the presence of divalent cations, and especially Ca2+, contributes mostly to the increase of the affinity between hyaluronan and albumin, which is associated with charge compensation in negatively charged hyaluronan and albumin. Furthermore, the most probable binding sites were structurally and energetically characterized. The indicated moieties exhibit a locally positive charge which enables hyaluronate binding (direct and water mediated).
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28

Karmakar, Paramita, Debasmita Das, Biplab Rajbanshi, Debadrita Roy, Samapika Ray, Narendra Nath Ghosh, Ashim Roy et al. "Physicochemical and computational investigations of some food chemicals prevalent in aqueous 1-butyl-1-methyl-pyrrolidinium chloride solutions with the manifestation of solvation consequences". Journal of Molecular Liquids 353 (mayo de 2022): 118800. http://dx.doi.org/10.1016/j.molliq.2022.118800.

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29

Gupta, Jyoti, Dinesh Chand y Anil Kumar Nain. "Study to reconnoiter solvation consequences of l-arginine/l-histidine and sodium salicylate in aqueous environment probed by physicochemical approach in the temperature range (293.15–318.15) K". Journal of Molecular Liquids 305 (mayo de 2020): 112848. http://dx.doi.org/10.1016/j.molliq.2020.112848.

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30

Anbalagan, K. y L. Devaraj Stephen. "Influence of Water–Methanol Solvation Assembly and the Key Consequences on the Photo Reduction of CoIII(L)33+(L = (NH3)2, en, pn) Complexes via Ion-Pair Formation". Zeitschrift für Physikalische Chemie 220, n.º 3_2006 (marzo de 2006): 335–48. http://dx.doi.org/10.1524/zpch.2006.220.3.335.

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31

Zhang, Zhenglin, Thien Lieu, Chia-Hua Wu, Xiqu Wang, Judy I. Wu, Olafs Daugulis y Ognjen Š. Miljanić. "Solvation-dependent switching of solid-state luminescence of a fluorinated aromatic tetrapyrazole". Chemical Communications 55, n.º 63 (2019): 9387–90. http://dx.doi.org/10.1039/c9cc03932e.

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32

Sharma, Suresh Kumar, Gurpreet Singh, Harsh Kumar y Ramesh Kataria. "Study of solvation consequences of glycine, L-alanine and L-valine in aqueous 1-butyl-4-methyl pyridinium chloride ionic liquid solutions probed by physicochemical approach in the temperature interval (288.15–308.15) K". Journal of Chemical Thermodynamics 110 (julio de 2017): 137–53. http://dx.doi.org/10.1016/j.jct.2017.02.021.

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33

Olsson, Mats H. M., Janez Mavri y Arieh Warshel. "Transition state theory can be used in studies of enzyme catalysis: lessons from simulations of tunnelling and dynamical effects in lipoxygenase and other systems". Philosophical Transactions of the Royal Society B: Biological Sciences 361, n.º 1472 (13 de julio de 2006): 1417–32. http://dx.doi.org/10.1098/rstb.2006.1880.

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The idea that enzyme catalysis involves special factors such as coherent fluctuations, quantum mechanical tunnelling and non-equilibrium solvation (NES) effects has gained popularity in recent years. It has also been suggested that transition state theory (TST) cannot be used in studies of enzyme catalysis. The present work uses reliable state of the art simulation approaches to examine the above ideas. We start by demonstrating that we are able to simulate any of the present catalytic proposals using the empirical valence bond (EVB) potential energy surfaces, the dispersed polaron model and the quantized classical path (QCP) approach, as well as the approximate vibronic method. These approaches do not treat the catalytic effects by phenomenological treatments and thus can be considered as first principles approaches (at least their ability to compare enzymatic reaction to the corresponding solution reactions). This work will consider the lipoxygenase reaction, and to lesser extent other enzymes, for specific demonstration. It will be pointed out that our study of the lipoxygenase reaction reproduces the very large observed isotope effect and the observed rate constant while obtaining no catalytic contribution from nuclear quantum mechanical (NQM) effects. Furthermore, it will be clarified that our studies established that the NQM effect decreases rather than increases when the donor–acceptor distance is compressed. The consequences of these findings in terms of the temperature dependence of the kinetic isotope effect and in terms of different catalytic proposals will be discussed. This paper will also consider briefly the dynamical effects and conclude that such effects do not contribute in a significant way to enzyme catalysis. Furthermore, it will be pointed out that, in contrast to recent suggestions, NES effects are not dynamical effects and should therefore be part of the activation free energy rather than the transmission factor. In view of findings of the present work and our earlier works, it seems that TST provides a quantitative tool for studies of enzyme catalysis and that the key open questions are related to the nature of the factors that lead to transition state stabilization.
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34

Kuranova, Natalia N., Dzhovidon N. Kabirov, Olga V. Kashina y Tatyana R. Usacheva. "THERMODYNAMICS OF QUERCETIN SOLVATION IN WATER-DIMETHYLSULFOXIDE SOLVENT". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, n.º 10 (8 de septiembre de 2020): 23–29. http://dx.doi.org/10.6060/ivkkt.20206310.6285.

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The distribution coefficients of quercetin (QCT) in water-dimethylsulfoxide solvents with a content of dimethylsulfoxide from 0.0 to 0.5 mol. fr. were determined by the method of interfacial distribution of the substance between two immiscible phases: aqueous or water-dimethylsulfoxide solution and n-hexane at 298.2 K. The distribution coefficients are less than one, which indicates a better solvation of quercetin in water and a water-dimethylsulfoxide solvent than in hexane. Changes in the distribution coefficients of quercetin are not correlated with a gradual increase in the content of dimethylsulfoxide (DMSO) in the solvent. Using the obtained values of the distribution coefficients, we calculated the changes in the Gibbs energy of re-solvation of quercetin in water-dimethylsulfoxide solvents. The dependence of the Gibbs energy of QCT re-solvation on the solvent composition has an extreme form with a minimum in the range of DMSO concentrations corresponding to 0.3 mol. fr. A comparative analysis of the effect of a water-dimethylsulfoxide solvent on the change in Gibbs energy of re-solvation of quercetin, nicotinamide and nicotinic acid was carried out. In the case of both nicotinamide and nicotinic acid, an extreme change is observed in the Gibbs energy of re-solvation of particles with a maximum in the region with a low content of non-aqueous component XDMSO ≈ 0.1 mol. fr. The main contribution to the weakening of the solvation of nicotinamide and nicotinic acid is due to the enthalpy component, and with increasing concentration of dimethylsulfoxide there is an increase in the contribution of entropy to the change in the Gibbs energy transfer. An extreme change in the Gibbs energy transfer of quercetin suggests that the minimum on the dependence ∆trGº(QCT) = F(χDMSO) is also a consequence of a change in the prevailing thermodynamic factor in the solvate state of quercetin.
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35

Závada, Jiří, Magdalena Pánková y Antonín Vítek. "On the origin of base concentration effect on stereo- and regioselectivity in alkoxide-promoted E2 reactions: A consequence of substrate solvation by metal ions". Collection of Czechoslovak Chemical Communications 55, n.º 3 (1990): 695–703. http://dx.doi.org/10.1135/cccc19900695.

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The title problem has been investigated in the reaction of 2-decyl bromide with t-C4H9OK/t-C4H9OH system employing 18-crown-6 ether and an "inert" salt (t-C4H9OLi) as mechanistic probes. From olefin-distribution data and a subsidiary kinetic evidence it has been inferred that the investigated effect originates from a concentration-dependent substrate solvation by metal ions in the transition state.
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36

Chan, Eric J., Simon A. Cotton, Jack M. Harrowfield, Brian W. Skelton, Alexandre N. Sobolev y Allan H. White. "Allan White and Solvento/Aqua Complexes: ScIII Solvation". Australian Journal of Chemistry 73, n.º 6 (2020): 468. http://dx.doi.org/10.1071/ch19130.

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Addition of various oxygen-donor ligands (L, all dipolar, aprotic solvents), to a solution of hydrated scandium picrate in weakly coordinating solvents (S), has yielded several crystalline adducts of the form Sc(pic)3(L)m(·nS) in which all ligands L are coordinated, subsequently characterised by a series of single crystal X-ray studies. For L=dmso, m=3 and the picrate anions are all bound as phenoxide-O donor units, while for nmp, dma, tmp, and hmpa, m=2 and one of the bound picrates becomes bidentate through phenoxide- and nitro-O donation. For L=ompa, m=2 and two picrate ligands are bound through phenoxide-O while one is displaced from the primary coordination sphere. All complexes contain six-coordinate ScIII, confirming that this coordination number is a consequence of ligand bulk.
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37

Cooper, A., D. Cameron, J. Jakus y G. W. Pettigrew. "Pressure perturbation calorimetry, heat capacity and the role of water in protein stability and interactions". Biochemical Society Transactions 35, n.º 6 (23 de noviembre de 2007): 1547–50. http://dx.doi.org/10.1042/bst0351547.

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It is widely acknowledged, and usually self-evident, that solvent water plays a crucial role in the overall thermodynamics of protein stabilization and biomolecular interactions. Yet we lack experimental techniques that can probe unambiguously the nature of protein–water or ligand–water interactions and how they might change during protein folding or ligand binding. PPC (pressure perturbation calorimetry) is a relatively new technique based on detection of the heat effects arising from application of relatively small pressure perturbations (±5 atm; 1 atm=101.325 kPa) to dilute aqueous solutions of proteins or other biomolecules. We show here how this can be related to changes in solvation/hydration during protein–protein and protein–ligand interactions. Measurements of ‘anomalous’ heat capacity effects in a wide variety of biomolecular interactions can also be related to solvation effects as part of a quite fundamental principle that is emerging, showing how the apparently unusual thermodynamics of interactions in water can be rationalized as an inevitable consequence of processes involving the co-operative interaction of multiple weak interactions. This leads to a generic picture of the thermodynamics of protein folding stabilization in which hydrogen-bonding plays a much more prominent role than has been hitherto supposed.
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38

Kuraeva, Yu G., D. A. Tugareva, L. A. Onuchak y T. S. Kapralova. "Thermodynamics of Sorption of Organic Compounds by Sorbents Based on Supramolecular Liquid Crystal HPFAB and β-Cyclodextrin Derivatives under Gas Chromatography Conditions". Физикохимия поверхности и защита материалов 59, n.º 6 (1 de noviembre de 2023): 593–601. http://dx.doi.org/10.31857/s0044185623700742.

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Using gas chromatography, we studied the influence of the nature of substituents in the β-cyclodextrin (CD) molecule on the sorption properties and the possibility of complex formation with the macrocycle of 26 organic compounds (hydrocarbons and alcohols) in binary sorbents based on the smectic–nematic supramolecular liquid crystal 4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) and four derivatives β-CD. It has been established that the nature of the substituents in the β-CD molecule significantly affects the manifestation of solvation interactions between LC and macrocyclic additive and, as a consequence, the mesomorphic, sorption, and selective properties of the studied composite sorbents.
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39

Dighe, Anish V. y Meenesh R. Singh. "Solvent fluctuations in the solvation shell determine the activation barrier for crystal growth rates". Proceedings of the National Academy of Sciences 116, n.º 48 (11 de noviembre de 2019): 23954–59. http://dx.doi.org/10.1073/pnas.1910691116.

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Solution crystallization is a common technique to grow advanced, functional crystalline materials. Supersaturation, temperature, and solvent composition are known to influence the growth rates and thereby properties of crystalline materials; however, a satisfactory explanation of how these factors affect the activation barrier for growth rates has not been developed. We report here that these effects can be attributed to a previously unrecognized consequence of solvent fluctuations in the solvation shell of solute molecules attaching to the crystal surface. With increasing supersaturation, the average hydration number of the glutamic acid molecule decreases and can reach an asymptotic limit corresponding to the number of adsorption sites on the molecule. The hydration number of the glutamic acid molecule also fluctuates due to the rapid exchange of solvent in the solvation shell and local variation in the supersaturation. These rapid fluctuations allow quasi-equilibrium between fully solvated and partially desolvated states of molecules, which can be used to construct a double-well potential and thereby to identify the transition state and the required activation barrier. The partially desolvated molecules are not stable and can attach spontaneously to the crystal surface. The activation barrier versus hydration number follows the Evans–Polanyi relation. The predicted absolute growth rates of the α-glutamic acid crystal at lower supersaturations are in reasonable agreement with the experimental observations.
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40

Ekka, Deepak, Tanusree Ray, Kanak Roy y Mahendra Nath Roy. "Exploration of Solvation Consequence of Ionic Liquid [Bu4PCH3SO3] in Various Solvent Systems by Conductance and FTIR Study". Journal of Chemical & Engineering Data 61, n.º 7 (10 de junio de 2016): 2187–96. http://dx.doi.org/10.1021/acs.jced.5b00670.

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41

Jay-Gerin, J. P. y C. Ferradini. "L'ion positif géminé intervient-il sur le destin de l'électron piégé incomplètement relaxé dans les liquides polaires irradiés?" Canadian Journal of Chemistry 70, n.º 6 (1 de junio de 1992): 1869–71. http://dx.doi.org/10.1139/v92-232.

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A model is proposed concerning the influence of the parent positive ion on the fate of the incompletely relaxed trapped electron (eir−) in irradiated polar liquids. This model is based on the release, by a tunneling and (or) a trap-hopping mechanism in the Coulomb field of the cation, of the electrons captured in preexisting shallow localized states below the bottom of the conduction band of the solvent. The released electrons would either recombine with the parent positive ion or get retrapped. The net effect would be an accumulation of electrons in deeper traps. The removal of weakly trapped electrons would contribute to the decrease of the infrared part of the optical absorption spectrum during the very early time dynamics of electron solvation. Such a process would imply, as a consequence, the existence of a maximum of the eir− absorption spectrum.
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42

Domingo, Luis R., Mar Ríos-Gutiérrez y María José Aurell. "Unveiling the Ionic Diels–Alder Reactions within the Molecular Electron Density Theory". Molecules 26, n.º 12 (14 de junio de 2021): 3638. http://dx.doi.org/10.3390/molecules26123638.

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The ionic Diels–Alder (I-DA) reactions of a series of six iminium cations with cyclopentadiene have been studied within the Molecular Electron Density Theory (MEDT). The superelectrophilic character of iminium cations, ω > 8.20 eV, accounts for the high reactivity of these species participating in I-DA reactions. The activation energies are found to be between 13 and 20 kcal·mol−1 lower in energy than those associated with the corresponding Diels–Alder (DA) reactions of neutral imines. These reactions are low endo selective as a consequence of the cationic character of the TSs, but highly regioselective. Solvents have poor effects on the relative energies, and an unappreciable effect on the geometries. In acetonitrile, the activation energies increase slightly as a consequence of the better solvation of the iminium cations than the cationic TSs. Electron localization function (ELF) topological analysis of the bonding changes along the I-DA reactions shows that they are very similar to those in polar DA reactions. The present MEDT study establishes that the global electron density transfer (GEDT) taking place at the TSs of I-DA reactions, and not steric (Pauli) repulsions such as have been recently proposed, are responsible for the features of these types of DA reactions.
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43

Fukunishi, Mika, Shunya Ishii, Yusuke Himata, Atsushi Kondo, Fumisato Ozawa y Morihiro Saito. "Li Pre-Doping into Si Negative Electrodes Using Li-Naphthalenide Solutions with Various Ether Solvents For Next-Generation Batteries". Journal of The Electrochemical Society 169, n.º 6 (1 de junio de 2022): 060534. http://dx.doi.org/10.1149/1945-7111/ac7673.

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Four ethers were compared as solvents of lithium naphthalenide (Li-NTL) solutions to pre-dope Li into Si electrodes. The solvents of the Li-NTL solutions affected the stability and equilibrium potential (V eq). X-ray diffraction, thermodynamic characterization and ultraviolet-visible (UV–vis) spectroscopy were used to clarify the effects of the solvation structure, the lowest unoccupied molecular orbital (LUMO) energy of the solvent molecule and the ion pair structure between Li+ ions and naphthalenide radical anions ([NTL]·−) on doping capacity. A Li-NTL solution having a low V eq and sufficient stability under potentials as low as that of Li metal was found to provide the highest pre-doping capacity. In particular, a 2-methyltetrahydrofuran (MeTHF) solution exhibiting the lowest V eq showed a pre-doping capacity as high as 3250 mAh g−1 after 24 h. UV–vis spectra and Walden plots indicated that a Li-NTL solution using MeTHF provided less dissociation than a tetrahydrofuran (THF) solution. The doping capacity is evidently determined by the V eq of the Li-NTL solution as a consequence of the dissociation equilibrium of the ion pair of the solvated Li+ ion and [NTL]·− radical ions.
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44

Štěpnička, Petr, Róbert Gyepes y Jaroslav Podlaha. "Synthesis, Characterization and Crystal Structure of [Tetra-μ3-iodotetrakis{1'-(diphenylphosphino)ferrocenecarboxylic Acid-P}tetracopper(I)]-Acetic Acid (1 : 2)". Collection of Czechoslovak Chemical Communications 63, n.º 1 (1998): 64–74. http://dx.doi.org/10.1135/cccc19980064.

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The title compound was prepared by the reaction of 1'-(diphenylphosphino)ferrocenecarboxylic acid with copper(I) iodide in acetic acid. It has the tetrameric structure of the heterocubane type and all four monomeric units are crystallographically independent. The central Cu4I4 core is severely distorted from the Oh symmetry as a consequence of disparate radii of the atoms; however, this does not lead to transformation of the core into a stepped arrangement, the feature otherwise common for similar tetrameric structures. The ligand behaves as a monodentate phosphine and completes the approximately tetrahedral coordination polyhedron around copper(I). The carboxyl groups remain undissociated and uncoordinated but participate in intermolecular hydrogen bonding. Two carboxyl groups link the molecules of the tetramer into a zig-zag chain; the remaining two are bonded to molecules of solvating acetic acid which act as spacers between the chains. As expected, the geometry of the flexible ligand is remarkably influenced by the hydrogen bonding, the main conformation changes taking place at the P-C bonds and in the mutual arrangement of the cyclopentadienyl rings.
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45

Pytela, Oldřich, Jiří Kulhánek, Miroslav Ludwig y Václav Říha. "Chemometrical Analysis of Substituent Effects. III. Additivity of Substituent Effects in Dissociation of 3,4-Disubstituted Benzoic Acids in Organic Solvents". Collection of Czechoslovak Chemical Communications 59, n.º 3 (1994): 627–38. http://dx.doi.org/10.1135/cccc19940627.

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Sixteen 3,4-disubstituted benzoic acids (with all combinations of CH3O, CH3, Cl/Br, and NO2 substituents) have been synthesized and their dissociation constants measured in seven organic solvents (methanol, acetone, dimethyl sulfoxide, dimethylformamide, acetonitrile, pyridine, 1,2-dichloroethane). The effect of disubstitution and the validity of additive correlation relationships based on the Hammett equation have been analyzed by means of the analysis of variance, comparison of overall residual standard deviations of correlation equations of additive and additive multiplicative type, and application of the Hammett equation with internal (latent, defined in various ways) parameters and external (taken from literature) parameters describing the substituent effects. The effect of disubstitution has been found to be additive and describable within the validity range of the substituent constants adopted - by applying the additivity principle without any additional correction for interactions between the two substituents. The same conclusion has been drawn from the comparison of overall residual deviations in correlation equations for mono- and disubstituted derivatives. The analysis of differences between the reaction constants of the Hammett equation applied to mono- and disubstituted benzoic acids has shown that in organic solvents the solvation of substituents makes various contributions. The substituent influence is stronger in polar aprotic solvents (acetone, dimethyl sulfoxide, dimethylformamide, acetonitrile) than that in the protic, basic, and less polar ones in which the stabilization by hydrogen bond becomes important, the role of proton donor being played either by the solvent itself (methanol) or by its conjugated acid (pyridine) or by a molecule of the dissociating acid as a consequence of homoconjugation (1,2-dichloroethane).
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46

Giancaspro, Mariangela, Annamaria Panniello, Nicoletta Depalo, Roberto Comparelli, Marinella Striccoli, Maria Lucia Curri y Elisabetta Fanizza. "Understanding the Effect of the Synthetic Method and Surface Chemistry on the Properties of CsPbBr3 Nanoparticles". Nanomaterials 14, n.º 1 (27 de diciembre de 2023): 81. http://dx.doi.org/10.3390/nano14010081.

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Over the last decade, the attractive properties of CsPbBr3 nanoparticles (NPs) have driven ever-increasing progress in the development of synthetic procedures to obtain high-quality NPs at high concentrations. Understanding how the properties of NPs are influenced by the composition of the reaction mixture in combination with the specific synthetic methodology is crucial, both for further elucidating the fundamental characteristics of this class of materials and for their manufacturing towards technological applications. This work aims to shed light on this aspect by synthesizing CsPbBr3 NPs by means of two well-assessed synthetic procedures, namely, hot injection (HI) and ligand-assisted reprecipitation (LARP) in non-polar solvents, using PbBr2 and Cs2CO3 as precursors in the presence of already widely investigated ligands. The overall goal is to study and compare the properties of the NPs to understand how each synthetic method influences the NPs’ size and/or the optical properties. Reaction composition and conditions are purposely tuned towards the production of nanocubes with narrow size distribution, high emission properties, and the highest achievable concentration. As a result, the formation of bulk crystals as precipitate in LARP limits the achievement of a highly concentrated NP solution. The size of the NPs obtained by LARP seems to be poorly affected by the ligands’ nature and the excess bromide, as consequence of bromide-rich solvation agents, effectively results in NPs with excellent emission properties. In contrast, NPs synthesized by HI exhibit high reaction yield, diffusion growth-controlled size, and less striking emission properties, probably ascribed to a bromide-deficient condition.
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47

Pukhovskaya, Svetlana G., Yulia B. Ivanova, Dmitry A. Erzunov, Aleksander S. Semeykin y Sergei A. Syrbu. "SYNTHESIS, COORDINATION AND ACID-BASE PROPERTIES OF MESO-DINITROSUBSTITUTED DERIVATIVES OF 5,15-DIPHENYL-β-OCTAALKYLPORPHINE". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, n.º 6 (6 de junio de 2018): 17. http://dx.doi.org/10.6060/tcct.20186106.5655.

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Presented work shows results of synthesis and spectrophotometric researches on properties of meso-dinitrosubstituted derivatives of 5,15-diphenyl-β-octaalkylporphyrin nitroderivatives in comparison with 2,8,12,18,3,7,13,17-octaethylporphyrin and 2,3,7,8,12,13,17,18-octaethyl-5,15-dinitroporphyrin. The method of spectrophotometric titration with perchloric acid (for determining the basicity constant) and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) was used in order to study the acid-base properties of porphyrins, namely to determine the acidity constant. The spectral characteristics of the ionized forms of 5,15-dinitro-10,20-diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporfin-F (I) and 5,15-dinitro-10,20-bis(4-nitrophenyl)-2,8,12,18-tetramethyl-3,7,13,17-tetraethylporphyrin (II) and the corresponding total constants of the acidic (pKa (I) = 6.00 and pKa (II) = 5.27) and the basic (pKb (I) = 19.78 and pKb (II) = 19.83) ionization were provided. The reaction of complexation of porphyrins with zinc acetate was studied by spectrophotometric method in pure acetonitrile and in mixed AN + DBU solvent. The influence of the degree of deformation of the tetrapyrrole macroring, the electronic effects of substituents and the acidity of the medium on the coordination and acid-base properties of porphyrins was analyzed. It was shown that the reactions of formation of metalloporphyrins with anionic porphyrin forms proceed with much higher rates compared to molecular ones, that is accompanied with a decrease in the energy parameters of the reaction. This is evidently due to the absence of energy costs for the deformation and cleaving N-H bonds of the reaction center, as well as the stronger polarization of the molecule, and as a consequence, the higher degree of solvation of anionic forms of porphyrins in the transition state. Thus, the determination of the conditions for the existence of dianionic forms of porphyrins gives grounds for the development of new sensor systems for the recognition and determination of the concentration of metal cations in liquid media due to a sharp increase in the rate of formation of metalloporphyrins in the presence of an organic base.Forcitation:Pukhovskaya S.G., Ivanova Yu.B., Erzunov D.A., Semeykin A.S., Syrbu S.A. Synthesis, coordination and acid-base properties of meso-dinitrosubstituted derivatives of 5,15-diphenyl-β-octaalkylporphine. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 17-28
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48

Caruana, Daren. "(Invited) Redox Chemistry Driven by Atmospheric Pressure Plasma Jet". ECS Meeting Abstracts MA2023-01, n.º 20 (28 de agosto de 2023): 1519. http://dx.doi.org/10.1149/ma2023-01201519mtgabs.

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Plasmas may be considered as mixed ionic and electronic conductors. From an electrochemical point of view, a conducting gas presents a wonderful opportunity to explore redox reactions without all the restrictions a solvent medium provides. Identifying a plasma medium suitable to allow electrochemical measurements can be technically challenging, often due to the electrical energy used to create the plasma. However, atmospheric pressure plasma jets (APPJ)1&2 have been shown to be accessible and convenient as laboratory plasma sources. They present a medium that may be considered as an electrode, due to the presence of electrons or as electrolytes, due to their electrical conduction.3 Although its definition is not too important, the presence of free electrons gives an opportunity to drive reduction processes. The interesting aspect of non-thermal plasmas, and the root of their interesting chemistry, is partly due to the imbalance of thermal kinetic energy distribution between the electron and all the other species, neutral or ionized. As a consequence plasma jets are found in routine industrial applications such as etching or cleaning of surfaces for adhesion promotion. Furthermore, there is a growing body of evidence to suggest that APPJ may be used for the treatment of solid tumors. These highly energized electrons can drive redox reactions, as well as other chemical reactions, at solid or liquid can be unexpected. In this presentation I will explore the use of APPJ for reduction of metal oxides under potentiostatic control and material synthesis.4-6 References Ratcliffe, L.V., et al., Surface analysis under ambient conditions using plasma-assisted desorption/ionization mass spectrometry. Analytical Chemistry, 2007. 79(16): p. 6094-6101. Golda, J., et al., Concepts and characteristics of the 'COST Reference Microplasma Jet'. Journal of Physics D-Applied Physics, 2016. 49(8). Rumbach, P.; Bartels, D. M.; Sankaran, R. M.; Go, D. B., The solvation of electrons by an atmospheric-pressure plasma. Nature Communications 2016, 6, 7248. Sener, M. E., Quesada Cabrera, R., Parkin, I.P., Caruana, D. J., Facile formation of black titania films using an atmospheric-pressure plasma jet, Green Chemistry 2022 , 24, 2499-2505. Sener, M. E., Palgrave, R., Quesada Cabrera, R., Caruana, D. J., Patterning of Metal Oxide thin Films using H2/He Atmospheric Pressure Plasma Jet. Green Chemistry 2020, 22, 1406-1413. Sener, M. E.; Caruana, D. J., Modulation of copper(I) oxide reduction/oxidation in atmospheric pressure plasma jet. Electrochemistry Communications 2018, 95, 38-42.
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49

Pant, Bhargavi, Soumyadip Mondal, Rajesh B. Jethwa, Rhys Bunting y Stefan A. Freunberger. "The Influence of Discharge Mediators on Singlet Oxygen Generation in Lithium-Air Batteries". ECS Meeting Abstracts MA2023-02, n.º 65 (22 de diciembre de 2023): 3082. http://dx.doi.org/10.1149/ma2023-02653082mtgabs.

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Next-generation metal-air batteries are limited by factors such as high overpotential, and low energy efficiency. These factors lead to significant electrode and electrolyte decomposition, and consequently, limit the cell life. The primary cause of these parasitic reactions has been identified as the generation of singlet oxygen (1O2) 1 from the disproportionation of superoxide during both charge and discharge.2 Nonetheless, in addition to singlet oxygen generation, in a lithium air battery the insulating products such as lithium peroxide (Li2O2) tend to accumulate on the cathode overtime and passivate the active surface. This results in early cell death and significantly hinders the overall efficiency of the battery. 3, 4 Redox mediators (RMs) are one potential solution to these problems. For example, by mediating the charge and discharge pathway, they can shuttle electrons back-and-forth between the electrodes and the charge and discharge products. This prevents passivation of the porous cathode by facilitating both a greater distribution of the discharge products, as well as an easier means by which to re-oxidise these insulating materials. The literature shows several examples of redox couples, including quinones, that inhibit the formation of a passivating film to some extent and result in higher rates, higher capacities and longer cycle lives.5, 6 Previously, our group has shown that the choice of RM can either enhance or suppress 1O2 formation during charge.7 We have now expanded this investigation to discharge mediators. In this work, we explore the primary reason for singlet vs triplet oxygen formation and identify if it is possible to suppress 1O2 formation completely via RMs. We leverage mass spectrometry, pressure cell measurements, and spectro-electrochemistry in this work to gain insight into the reaction kinetics and 1O2 generation mechanism. These experimental results are further supported by density functional theory (DFT) to help elucidate the reaction pathway. References: Mahne, N. et al.Singlet oxygen generation as a major cause for parasitic reactions during cycling of aprotic lithium–oxygen batteries. Nat Energy 2, 17036 (2017). Mourad, E. et al. Singlet oxygen from cation driven superoxide disproportionation and consequences for aprotic metal–O2 batteries. Energy Environ. Sci. 12, 2559 (2019). Liu, T. et al. Current Challenges and Routes Forward for Nonaqueous Lithium–Air Batteries. Chem. Rev. 120, 6558-6625 (2020). Mahne, N. et al. Electrochemical Oxidation of Lithium Carbonate Generates Singlet Oxygen. Angew. Chem. Int. Ed. 57, 5529-5533 (2018). Gao, X. et al. Promoting solution phase discharge in Li–O2 batteries containing weakly solvating electrolyte solutions. Nat. Mater. 15, 882–888 (2016). Liu, T. et al. The Effect of Water on Quinone Redox Mediators in Nonaqueous Li-O2 Batteries. J. Am. Chem. Soc. 140, 1428–1437 (2018). Petit, Y. K. et al. Mechanism of mediated alkali peroxide oxidation and triplet versus singlet oxygen formation. Nat Chem. 13, 465–471 (2021).
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50

Alvarez Ferrero, Guillermo, Gustav Åvall, Katherine Mazzio, Knut Janßen, Youhyun Son, Sebastian Risse y Philipp Adelhelm. "Co-Intercalation Batteries (CoIBs): The Use of TiS2 As Electrode for Solvent Co-Intercalation in Sodium-Ion Batteries". ECS Meeting Abstracts MA2023-01, n.º 5 (28 de agosto de 2023): 876. http://dx.doi.org/10.1149/ma2023-015876mtgabs.

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With the rising demand for lithium-ion batteries (LIBs), sodium-ion batteries (SIBs) have become an attractive alternative with the promise of improved safety, reduced cost, and lower environmental impact.1 However, the larger ion size of sodium cation has major consequence on the battery chemistry, which provides several challenges and opportunities for designing electrode materials and electrolyte solutions.2 Graphite is the currently most used anode material in LIBs. However, its use in SIBs, with traditional carbonate-based electrolytes, results in very poor specific capacities due to unfavorable thermodynamic processes.3 A strategy around this problem is to choose different solvents: Ethers and in particular glymes can exhibit a co-intercalation behavior into the graphite structure by forming ternary graphite intercalation compounds.4, 5 Although the co-intercalation of solvent molecules with sodium cation leads to a large increase in the graphite framework, the cycle life and rate capability of the reaction are excellent. Regardless of this, there is a lack of evidence for a comparable reaction with other electrode materials. Hence, it would be of interest to identify a cathode material that operates via this same mechanism. A battery based on solvent co-intercalation at both electrodes can have minimized charge-transfer resistances due to the absence of desolvation steps, and great cycle life. Thus, such a system can show high power density over many cycles. It has also been shown that stripping of the solvation shell can be the rate limiting step for battery operation, especially at subzero temperatures.6 Such a solvent co-intercalation battery (CoIB) could therefore be more energy efficient compared to other batteries or could enable a better low-temperature performance. Transition metal dichalcogenides (TMDs) have emerged as promising anode materials owing to their low cost, high electric conductivity, good thermal stability and environmental friendliness. Among them, titanium sulphide (TiS2), with a two-dimensional framework, exhibits several advantages such as a high conductivity (compare to other metal oxides), a larger interlayer distance (0.569 nm) compared to graphite (0.335 nm) and high stability. 7 Several papers have reported on the use of TiS2 as an anode material for SIBs, and observed that the voltage profiles and electrochemical behaviour of the system is highly dependent on the choice of electrolyte. However, this has seldomly been explicitly stated and the cause of the electrolyte dependence has never been investigated. By using operando and in-situ techniques such as Operando XRD and dilatometry, Na-diglyme complexes were showed to co-intercalate, similar as graphite, into TiS2. In contrast, no signs of solvent co-intercalation are observed in cyclic ethers and conventional carbonate-based electrolytes – where instead the redox reaction with TiS2 results in the formation of different NaxTiS2 compounds. As we identified TiS2 as “co-intercalation electrode” in glyme-based electrolytes it served to create the first ever solvent co-intercalation battery (CoIB – pronounced Co-IB) which was done by pairing TiS2 (positive electrode) with graphite (negative electrode).8 This work could enable the development of highly energy efficient batteries with minimum charge transfer resistances and References I. Hasa, S. Mariyappan, D. Saurel, P. Adelhelm, A. Y. Koposov, C. Masquelier, L. Croguennec and M. Casas-Cabanas, J. Power Sources, 2021, 482, 228872. P. Adelhelm, P. Hartmann, C. L. Bender, M. Busche, C. Eufinger and J. Janek, Beilstein Journal of Nanotechnology, 2015, 6, 1016-1055. B. Jache and P. Adelhelm, Angew. Chem., 2014, 126, 10333-10337. B. Jache, J. O. Binder, T. Abe and P. Adelhelm, Physical Chemistry Chemical Physics, 2016, 18, 14299-14316. M. Goktas, C. Bolli, J. Buchheim, E. J. Berg, P. Novák, F. Bonilla, T. f. Rojo, S. Komaba, K. Kubota and P. Adelhelm, ACS applied materials & interfaces, 2019, 11, 32844-32855. S. S. Zhang, K. Xu and T. R. Jow, Journal of Power Sources, 2003, 115, 137-140. Q. Yun, L. Li, Z. Hu, Q. Lu, B. Chen and H. Zhang, Adv. Mater., 2020, 32, 1903826. G. A. Ferrero, G. Avall, K. A. Mazzio, Y. Son, K. Janssen, S. Risse and P. Adelhelm, Adv. Energy Mater., 2022, 2202377. an improved low temperature performance, where the charge transfer can become rate limiting. Figure 1
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