scholarly journals Gas–liquid interactions in solution

2005 ◽  
Vol 77 (3) ◽  
pp. 653-665 ◽  
Author(s):  
M. F. Costa Gomes ◽  
A. A. H. Pádua
Keyword(s):  
Molecular Structure ◽  
Computer Simulation ◽  
Ionic Liquids ◽  
Quantum Chemical ◽  
Molecular Structures ◽  
Gas Solubility ◽  
Free Energies ◽  
Solvent Interactions ◽  
Macroscopic Properties

Two approaches are followed to understand how molecular interactions influence the macroscopic properties of solutions: (1) experiment, through the determination of gas solubility, and (2) computer simulation, used to evaluate microscopic properties (structural and energetic). Examples of application of these approaches are considered in order to explain the properties of solutions containing fluorinated fluids or ionic liquids. The molecular structures and interactions are described by force fields built from ab initio quantum chemical calculations. These models allow the determination of free energies from computer simulations by using appropriate energy routes provided by statistical mechanics. The macroscopic properties related to the process of dissolution of several gases are interpreted in terms of the molecular structure of the solutions and of the solute–solvent interactions.

Quantum chemical calculations for the determination of the molecular structure of conjugated compounds

1979 ◽  
Vol 51 ◽  
pp. 99-105 ◽  
Author(s):  
Roland Benedix ◽  
Peter Birner ◽  
Frieder Birnstock ◽  
Horst Hennig ◽  
Hans-Jörg Hofmann
Keyword(s):  
Molecular Structure ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Conjugated Compounds

Determination of the molecular structure of gaseous proline by electron diffraction, supported by microwave and quantum chemical data

2015 ◽  
Vol 26 (5-6) ◽  
pp. 1489-1500 ◽  
Author(s):  
Alexander V. Belyakov ◽  
Maxim A. Gureev ◽  
Alexander V. Garabadzhiu ◽  
Vitalii A. Losev ◽  
Anatolii N. Rykov
Keyword(s):  
Molecular Structure ◽  
Electron Diffraction ◽  
Quantum Chemical ◽  
Chemical Data ◽  
Quantum Chemical Data

The Importance of Ionic Liquids and Applications on Their Molecular Modeling

2019 ◽  
pp. 206-230
Author(s):  
Sefa Celik ◽  
Ali Tugrul Albayrak ◽  
Sevim Akyuz ◽  
Aysen E. Ozel
Keyword(s):  
Ionic Liquids ◽  
Molecular Modeling ◽  
Biological Activities ◽  
Theoretical Models ◽  
Molecular Structures ◽  
Modeling Methods ◽  
Therapeutic Properties ◽  
Antibacterial And Antifungal ◽  
Large Cation

Ionic liquids are salts with melting points generally below 100 °C made of entirely ions by the combination of a large cation and a group of anions. Some ionic liquids are found to have therapeutic properties due to their toxic effects (e.g., anticancer, antibacterial, and antifungal properties). The determination of the most stable molecular structures, that is, the lowest energy conformer of these ionic liquids with versatile biological activities, is of particular importance. Density function theory (DFT) based on quantum mechanical calculation method, one of the molecular modeling methods, is widely used in physics and chemistry to determine the electronic structures of these stable geometries and molecules. With the theory, the energy of the molecule is determined by using the electron density instead of the wave function. It is observed that the theoretical models developed on the ionic liquids in the literature are in agreement with the experimental results because of electron correlations included in the calculation.

scholarly journals Crystal structure and quantum-chemical calculations of a trimethylaluminium–THF adduct

2018 ◽  
Vol 74 (2) ◽  
pp. 267-270 ◽  
Author(s):  
Lukas Brieger ◽  
Andreas Hermann ◽  
Christian Unkelbach ◽  
Carsten Strohmann
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Quantum Chemical Calculations ◽  
Title Compound ◽  
Quantum Chemical ◽  
Addition Product ◽  
Molecular Structures ◽  
Dimeric Structure

The title compound, trimethyl(tetrahydrofuran-κO)aluminium(III), [Al(CH3)3(C4H8O)], is an addition product of trimethylaluminium and tetrahydrofuran (THF). Instead of a dimeric structure, which is very common for these types of compounds, a monomeric molecular structure is observed. The C—Al—C angles in the molecule are very different from the C—Al—C angles found in dimeric molecular structures, leading to a different symmetry around the AlIII atom. The reasons for these differences are discussed.

Crystal Structure Determination of the Nonclassical 2-Norbornyl Cation

Science ◽  
2013 ◽  
Vol 341 (6141) ◽  
pp. 62-64 ◽  
Author(s):  
F. Scholz ◽  
D. Himmel ◽  
F. W. Heinemann ◽  
P. v. R. Schleyer ◽  
K. Meyer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Data Collection ◽  
Quantum Chemical ◽  
Molecular Structures ◽  
X Ray ◽  
Disorder Phase Transition ◽  
Carbonium Ion ◽  
Phase Data

After decades of vituperative debate over the classical or nonclassical structure of the 2-norbornyl cation, the long-sought x-ray crystallographic proof of the bridged, nonclassical geometry of this prototype carbonium ion in the solvated [C7H11]+[Al2Br7]–• CH2Br2salt has finally been realized. This achievement required exceptional treatment. Crystals obtained by reacting norbornyl bromide with aluminum tribromide in CH2Br2undergo a reversible order-disorder phase transition at 86 kelvin due to internal 6,1,2-hydride shifts of the 2-norbornyl cation moiety. Cooling with careful annealing gave a suitably ordered phase. Data collection at 40 kelvin and refinement revealed similar molecular structures of three independent 2-norbornyl cations in the unit cell. All three structures agree very well with quantum chemical calculations at the MP2(FC)/def2-QZVPP level of theory.

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