Physico-chemical and spectroscopic investigation of flavonoid dispersed C
            
              n
            
            TAB micelles

In this study, kaempferol (0.2 m/mmol kg −1 ) dispersed cationic surfactant micelles were prepared as a function of alkyltrimethylammonium bromide (C n TAB) hydrophobicity (C = 12 to C = 16). The dispersion study of kaempferol in different C n TAB, i.e. dodecyltrimethylammonium bromide (C = 12), tetradecyltrimethylammonium bromide (C = 14) and hexadecyltrimethylammonium bromide (C = 16), was conducted with the physico-chemical properties of density, sound velocity, viscosity, surface tension, isentropic compressibility, acoustic impedance, surface excess concentration and area occupied per molecule and thermodynamic parameters Gibbs free energy, enthalpy and activation energy measured at 298.15 K. These properties were measured with varying concentration of C n TAB from 0.0260 to 0.0305 mol kg −1 in a 10% (w/w) aqueous dimethyl sulfoxide solvent system. The variations in these measured properties have been used to infer the kaempferol dispersion stability via hydrophobic–hydrophilic, hydrophilic–hydrophilic, van der Waals, hydrogen bonding and other non-covalent interactions.

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Physico-chemical Properties of Solutions of Lithium Bis(fluorosulfonyl)imide (LiFSI) in Dimethyl Carbonate, Ethylene Carbonate, and Propylene Carbonate

10.31219/osf.io/kgmwn ◽

2021 ◽

Author(s):

Johannes Neuhaus ◽

Erik von Harbou ◽

Hans Hasse

Keyword(s):

Experimental Data ◽

Electrical Conductivity ◽

Propylene Carbonate ◽

Dimethyl Carbonate ◽

Ethylene Carbonate ◽

Chemical Properties ◽

Lithium Ion ◽

Solvent System ◽

Empirical Correlations ◽

Physico Chemical

Battery performance strongly depends on the choice of the electrolyte-solvent system. Lithium bis(fluorosulfonyl)imide (LiFSI) is a highly interesting novel electrolyte. Information on physico-chemical properties of solutions of LiFSI, however, is scarce. Therefore, the density, shear viscosity, and electrical conductivity of solutions of LiFSI in three pure solvents that are interesting for battery applications: dimethyl carbonate (DMC), ethylene carbonate (EC), and propylene carbonate (PC), were studied experimentally at temperatures between 273 K and 333 K at 1 bar and concentrations of LiFSI up to 0.45 mol mol−1 in the present work. Empirical correlations of the experimental data are provided. The comparison of the data of this work with the corresponding LiPF6 data underpins the attractiveness of LiFSI as an electrolyte in lithium ion batteries.

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Mesoscale Assembly of Bisteroidal Esters from Terephthalic Acid

Molecules ◽

10.3390/molecules25051213 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1213 ◽

Cited By ~ 1

Author(s):

Gabriel Guerrero-Luna ◽

María Guadalupe Hernández-Linares ◽

Sylvain Bernès ◽

Alan Carrasco-Carballo ◽

Diana Montalvo-Guerrero ◽

...

Keyword(s):

Self Assembly ◽

Terephthalic Acid ◽

Van Der Waals ◽

Solvent System ◽

Van Der Waals Interactions ◽

Show Evidence ◽

Non Covalent Interactions ◽

Solvent Systems ◽

High Yields ◽

Covalent Interactions

A new series of bisteroidal esters was synthesized using a spacer group, sterols and sapogenins as substrates. Steroidal dimers were prepared in high yields employing diesters of terephthalic acid as linkages at the 3β, 3′β steroidal positions. In all attempts to crystallize bisteroids, it was observed that the compounds tended to self-organize in solution, which was detected when employing various solvent systems. The non-covalent interactions (van der Waals) of the steroidal moieties of this series of symmetrical bisteroids, the polarity of the solvents systems, and the different solubilities of the bisteroid aggregates, indeed induce the molecules to self-assemble into supramolecular structures with well-defined organization. Our results show that the self-assembled structures for the bisteroidal derivatives depend on the solvent system used: with hexane/EtOAc, membrane-shaped structures were obtained, while pure EtOAc afforded strand-shaped arrangements. In the CHCl3/CH3OH system, thin strands were formed, since van der Waals interactions are lowered in this system, as a consequence of the increased solubility of the bisteroids in CHCl3. Based on the characterization by SEM and XRD, we show evidence that the phenomenon of self-assembly of bisteroids occurs presenting different morphologies depending on the solvent used. The new steroidal dimer derivatives were characterized by NMR, TGA, DSC, SEM, and XRD. Finally, the molecular structure of one bisteroid was confirmed by single-crystal X-ray analysis.

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Study of Acoustical and Physico-chemical Properties for the Ternary Mixture of (Toluene+ Chlorobenzene + Cyclohexane) at 298.15 K Temperature

Journal of Ultra Chemistry ◽

10.22147/juc/170201 ◽

2021 ◽

Vol 17 (2) ◽

pp. 9-15

Author(s):

SONU DWIVEDI ◽

Keyword(s):

Ultrasonic Velocity ◽

Acoustic Impedance ◽

Ternary Mixture ◽

Chemical Properties ◽

Isentropic Compressibility ◽

Excess Properties ◽

Acoustical Parameters ◽

Free Length ◽

Physico Chemical ◽

Kister Equation

Ultrasonic velocity (U), density (ρ) for the ternary mixture of (Toluene + Chlorobenzene + Cyclohexane) in the various range of composition has been carried out at 298.15K. The observed data have been utilized to calculate various acoustical parameters like Isentropic compressibility (KS), Intermolecular free length (Lf) and acoustic impedance (Z). The various excess properties like excess ultrasonic velocity(UE ), excess acoustic impedance (ZE ), excess Isentropic compressibility (KS E ) and excess Inter molecular free length (Lf E ) have been calculated and using standard relations to the Redlich-Kister equation. The trend of acoustical and physicochemical parameters confirm the dynamics of molecules at temperature and the magnitude of intermolecular interactions among the constituents of the mixture always reflects the nature of substance. The variations in sign and values of these parameters are help us to know the interaction between component molecules and structural arrangement of the liquid mixture.

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Small Molecules, Non-Covalent Interactions, and Confinement

Molecules ◽

10.3390/molecules25143311 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3311 ◽

Cited By ~ 5

Author(s):

Gerd Buntkowsky ◽

Michael Vogel

Keyword(s):

Role Models ◽

Organic Molecules ◽

Guest Molecules ◽

Analytical Technique ◽

Host Interactions ◽

Functionalized Mesoporous Silica ◽

Current Trends ◽

Physico Chemical ◽

Non Covalent Interactions ◽

Covalent Interactions

This review gives an overview of current trends in the investigation of small guest molecules, confined in neat and functionalized mesoporous silica materials by a combination of solid-state NMR and relaxometry with other physico-chemical techniques. The reported guest molecules are water, small alcohols, and carbonic acids, small aromatic and heteroaromatic molecules, ionic liquids, and surfactants. They are taken as characteristic role-models, which are representatives for the typical classes of organic molecules. It is shown that this combination delivers unique insights into the structure, arrangement, dynamics, guest-host interactions, and the binding sites in these confined systems, and is probably the most powerful analytical technique to probe these systems.

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On the Use of Popular Basis Sets: Impact of the Intramolecular Basis Set Superposition Error

Molecules ◽

10.3390/molecules24203810 ◽

2019 ◽

Vol 24 (20) ◽

pp. 3810 ◽

Cited By ~ 2

Author(s):

Ángel Vidal Vidal ◽

Luis de Vicente Poutás ◽

Olalla Nieto Faza ◽

Carlos Silva López

Keyword(s):

Small Molecules ◽

Chemical Properties ◽

Basis Set ◽

Basis Sets ◽

Basis Set Superposition Error ◽

Large Molecules ◽

Molecular Complexation ◽

Non Covalent Interactions ◽

Covalent Interactions ◽

Structure Calculations

The magnitude of intramolecular basis set superposition error (BSSE) is revealed via computing systematic trends in molecular properties. This type of error is largely neglected in the study of the chemical properties of small molecules and it has historically been analyzed just in the study of large molecules and processes dominated by non-covalent interactions (typically dimerization or molecular complexation and recognition events). In this work we try to provide proof of the broader prevalence of this error, which permeates all types of electronic structure calculations, particularly when employing insufficiently large basis sets.

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Physico-chemical properties of binary systems involving modifier (methanol or propionic acid) and an acidic extractant di (2-ethylhexyl) phosphoric acid (DEHPA): volumetric, acoustic and viscometric routes

Biointerface Research in Applied Chemistry ◽

10.33263/briac104.880885 ◽

2020 ◽

Vol 10 (4) ◽

pp. 5880-5885

Keyword(s):

Solvent Extraction ◽

Molar Volume ◽

Propionic Acid ◽

Binary Mixtures ◽

Acoustic Impedance ◽

Molecular Interaction ◽

Chemical Properties ◽

Isentropic Compressibility ◽

Intermolecular Free Length ◽

Physico Chemical

In solvent extraction, a suitable modifier, basically polar liquid is used with extractant like DEHPA, TBP, TOPO and MIBK to enhance the efficiency in extraction processes. This paper is related to the study of physico-chemical properties of polar – polar binary mixtures at 303.15K and 0.1 MPa. Molar volume, free volume, isentropic compressibility, intermolecular free length, specific acoustic impedance, relaxation time, Rao’s constant, Wada’s constant, absorption coefficient have been calculated from the experimentally measured data of density, ultrasonic velocity and viscosity of pure components and binary mixtures of methanol/ propionic acid + DEHPA. In addition, excess molar volume, excess Gibb’s energy of activation of viscous flow, deviations in viscosity, isentropic compressibility, free volume, intermolecular free length and acoustic impedance were also computed from the experimental data. The observed variations of excess/deviation functions with the composition of DEHPA have been discussed in terms of molecular interaction between unlike molecules in two binary mixtures due to chemical, physical and structural effects. It is found that the molecular interaction of methanol with extractant DEHPA is better than that of propionic acid and so methanol may be used as a suitable modifier with DEHPA in the solvent extraction process.

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Decoration of specific sites on freeze-fractured membranes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081565 ◽

1978 ◽

Vol 36 (2) ◽

pp. 140-141

Author(s):

H. Gross ◽

H. Moor

Keyword(s):

Pure Water ◽

Freeze Fracture ◽

Chemical Properties ◽

Surface Forces ◽

Sulfate Pentahydrate ◽

Copper Sulfate Pentahydrate ◽

Physico Chemical ◽

Water Of Hydration ◽

Small Container ◽

Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

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PHYSICO CHEMICAL PROPERTIES OF NICKEL OXIDE AT HIGH TEMPERATURE

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1976798 ◽

1976 ◽

Vol 37 (C7) ◽

pp. C7-438-C7-442 ◽

Cited By ~ 2

Author(s):

R. FARHI ◽

G. PETOT-ERVAS

Keyword(s):

High Temperature ◽

Nickel Oxide ◽

Chemical Properties ◽

Physico Chemical

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Physico-Chemical Properties of Recombinant Desulphatohirudin

Thrombosis and Haemostasis ◽

10.1055/s-0038-1645073 ◽

1990 ◽

Vol 63 (03) ◽

pp. 499-504 ◽

Cited By ~ 4

Author(s):

A Electricwala ◽

L Irons ◽

R Wait ◽

R J G Carr ◽

R J Ling ◽

...

Keyword(s):

Molecular Weight ◽

Gel Filtration ◽

Chemical Properties ◽

Alpha Helix ◽

Apparent Molecular Weight ◽

Correlation Spectroscopy ◽

Nmr Studies ◽

Recombinant Hirudin ◽

Physico Chemical ◽

Recombinant Molecule

SummaryPhysico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. (13) for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies (17)

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