scholarly journals Temperature and Pressure Dependence of the Infrared Spectrum of 1-Ethyl-3-Methylimidazolium Trifluoromethanesulfonate Ionic Liquid

2020 ◽  
Vol 10 (12) ◽  
pp. 4404
Author(s):  
Francesco Trequattrini ◽  
Anna Celeste ◽  
Francesco Capitani ◽  
Oriele Palumbo ◽  
Adriano Cimini ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Infrared Spectrum ◽  
Density Functional ◽  
Room Temperature ◽  
Polar Solvent ◽  
Ambient Pressure ◽  
Infrared Absorption Spectrum ◽  
Functional Theory ◽  
Temperature And Pressure ◽  
Good Agreement

The infrared absorption spectrum of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI–TfO) was investigated at ambient pressure and variable temperatures between 120 and 330 K, or at room temperature and variable pressures up to 10 GPa. Upon cooling, the ionic liquid crystallizes; on the contrary, upon compression no evidence of crystallization can be obtained from the infrared spectra. Moreover, Density Functional Theory (DFT) calculations were applied to gain a better description of the ionic couple. The ωB97X-D functional, including not only the empirical dispersion corrections but also the presence of a polar solvent, gives a good agreement with the infrared spectrum and suggests that TfO resides above the plane of the imidazolium, with the shorter distance between the O atom of the anion and the C2 atom of the imidazolium ring equal to 2.23 Å.

scholarly journals Investigation of the absorption of CO2 in ionic liquid

2016 ◽  
Vol 29 (1) ◽  
pp. 41-46
Author(s):  
Kalyan Dhar ◽  
Syed Fahim
Keyword(s):  
Ionic Liquid ◽  
Binding Sites ◽  
Density Functional ◽  
Room Temperature ◽  
Minimum Energy ◽  
Environmental Concerns ◽  
Co2 Absorption ◽  
Solvation Model ◽  
Functional Theory ◽  
The Density Functional Theory

Due to environmental concerns, current interest is the development of technologies that may be able to remove CO2 efficiently from exhaust gases and thus avoid its dispersion in the atmosphere. The density functional theory (DFT) calculations with the modern continuum solvation model (IEFPCM-SMD) was used to study the mechanism of CO2 absorption in room temperature ionic liquid such as, [EMIM][BF4] (1-ethyl-3- methylimidazolium tetrafluoroborate). We determine the minimum energy structures and to determine the possible binding sites for CO2 absorption process in [EMIM][BF4]; by comparing the relative minimum energy of [EMIM][BF4] in the presence and absence of CO2.Bangladesh J. Sci. Res. 29(1): 41-46, June-2016

scholarly journals Synthesis of Pyrazolo-Fused 4-Azafluorenones in an Ionic Liquid. Mechanistic Insights by Joint Studies Using DFT Analysis and Mass Spectrometry

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 820
Author(s):  
Efraín Polo ◽  
Valentina Arce-Parada ◽  
Xaviera A. López-Cortés ◽  
Jesús Sánchez-Márquez ◽  
Alejandro Morales-Bayuelo ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Density Functional ◽  
Room Temperature ◽  
Theoretical Study ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Conceptual Density Functional Theory ◽  
Functional Theory ◽  
Three Component Reaction ◽  
Work Up

A series of pyrazolo-fused 4-azafluorenones (indeno[1,2-b]pyrazolo[4,3-e]pyridines, IPP) were synthesized via the three-component reaction between arylaldehydes, 3-methyl-1H-pyrazol-5-amine and 1,3-indanedione in an ionic liquid as a catalyst at room temperature. The applied synthetic route has the advantages of easy work-up under mild reaction conditions presenting moderate yields and an environmentally benign procedure. A theoretical study based on conceptual-density functional theory has been done, bond reactivity indices have been calculated and an electrophilic and nucleophilic character of localized orbitals has been determined to analyze the possible electronic mechanisms.

Does Osmium Carbide Exist? Ab initio Investigation

2006 ◽  
Vol 987 ◽  
Author(s):  
M. Zemzemi ◽  
M. Hebbache ◽  
D. Zivkovic ◽  
L Stuparevic
Keyword(s):  
Mechanical Properties ◽  
Density Functional Theory ◽  
Transition Metals ◽  
Ab Initio ◽  
Density Functional ◽  
Ambient Pressure ◽  
Hexagonal Structure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Good Agreement

AbstractTransition metals of the platinum group (Os, Ir, Pt, Ru, Re, Rh) do not form carbides and nitrides at ambient pressure. Osmium carbide seems to have been synthesized at zero pressure by Kempter and Nadler forty six years ago. According to the authors, OsC crystallizes in WC-type structure and has a hardness equal to 2000 kg mm-2. Up to date, no other experimental confirmation is available. We studied the electronic and mechanical properties of this hypothetical carbide using an approach based on the density-functional theory. We found that the work of the above mentioned authors is sound. The calculated lattice parameters are in good agreement with that given by those authors and a rough estimate also showed that the hardness given by them is reasonable. However, we found that the hexagonal structure of osmium carbide is electronically and mechanically unstable.

Surface Study of Ni2MnGa(100)

2011 ◽  
Vol 684 ◽  
pp. 215-230 ◽  
Author(s):  
S.W. D'Souza ◽  
R.S. Dhaka ◽  
Abhishek Rai ◽  
M. Maniraj ◽  
J. Nayak ◽  
...  
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Room Temperature ◽  
Compositional Variation ◽  
Ferromagnetic Shape Memory Alloy ◽  
Functional Theory ◽  
Band Spectra ◽  
Ferromagnetic Shape Memory ◽  
Good Agreement

The (100) surface of Ni2MnGa ferromagnetic shape memory alloy exhibits intrinsic surface property dissimilar to the bulk as well as influence of compositional variation at the surface. It is shown that by sputtering at room temperature and annealing at high temperature, it is possible to obtain a clean, ordered and stoichiometric surface. However, for even higher annealing temperatures, the surface becomes Mn rich. The (100) surface of Ni2MnGa is found to have Mn–Ga termination. A surface reconstruction to p4gm symmetry is observed in the austenite phase, while the expected bulk truncated symmetry at surface is p4mm. For the stoichiometric surface, the XPS valence band is compared with our calculations based on first principles density functional theory and good agreement is obtained. The ultraviolet photoelectron spectroscopy (UPS) valence band spectra depend sensitively on composition varying from Ni rich to Mn rich surfaces. A satellite feature observed in both Ni 2p core-level and valence band spectra is related to the narrow 3d valence band in Ni2MnGa.

scholarly journals Pressure-dependent X-ray diffraction of the multiferroics RMn2O5

2019 ◽  
Vol 75 (4) ◽  
pp. 687-696 ◽  
Author(s):  
Wei Peng ◽  
Victor Balédent ◽  
Marie-Bernadette Lepetit ◽  
Antoine Vaunat ◽  
Elisa Rebolini ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Room Temperature ◽  
Exchange Interactions ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Scattering ◽  
Pressure Evolution ◽  
Good Agreement

The room-temperature structural properties of the RMn2O5 multiferroics have been investigated under pressure, using powder X-ray scattering and density functional theory (DFT) calculations. It was possible to determine the lattice parameters and the main atomic positions as a function of pressure. Good agreement was observed between the X-ray and DFT results for most of the determined crystallographic data. From the DFT calculations, it was possible to infer the pressure evolution of the exchange interactions, and this analysis led to the conclusion that the onset of the q = (½, 0, ½) magnetic structure under pressure is related to the increase in the J 1 super-exchange terms (due to the reduction in the Mn—O distances) compared with the Mn—R exchange interactions. In addition, the 1D antiferromagnetic character of the compounds should be reinforced under pressure.

scholarly journals Mechanism of the Absorption of CO2 in Ionic Liquid Dimer

2019 ◽  
Vol 45 (1) ◽  
pp. 137-144
Author(s):  
Kalyan Dhar
Keyword(s):  
Ionic Liquid ◽  
Binding Sites ◽  
Density Functional ◽  
Room Temperature ◽  
Minimum Energy ◽  
Co2 Absorption ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Anions And Cations ◽  
Multiple Interactions

The density functional theory (DFT) calculations with the modern continuum solvation model (IEFPCM-SMD) was used to study the mechanism of CO2 absorption at room temperature using ionic liquid such as, [EMIM][BF4] (1-ethyl-3-methylimidazolium tetrafluoroborate) monomer and dimer ionic liquid [IL] dimer comprises two couple of anions and cations, so that more intermolecular interactions are established than in the single IL pair. In this paper, we determined the minimum energy structures and to determine the possible binding sites for CO2 absorption in [EMIM][BF4] monmer and dimer; by comparing the relative minimum energy of [EMIM][BF4] in the presence and in absence of CO2. It was found that CO2 is stabilized by the multiple interactions with several anions. When CO2 penetrates the IL monomer or dimer, through gas-to-liquid diffusion, the O-C-O (CO2)-BF4 intermolecular bond is likely to be formed immediately and bind the CO2 molecule. This result suggests that ionic liquid dimer is suitable for the absorption of CO2. Asiat. Soc. Bangladesh, Sci. 45(1): 137-144, June 2019

INFRARED-ABSORPTION SPECTRUM OF ELECTRON BUBBLES IN LIQUID HELIUM

2006 ◽  
Vol 20 (30n31) ◽  
pp. 5291-5300 ◽  
Author(s):  
M. PI ◽  
M. BARRANCO ◽  
V. GRAU ◽  
R. MAYOL
Keyword(s):  
Liquid Helium ◽  
Excited States ◽  
Infrared Absorption ◽  
Density Functional ◽  
Infrared Absorption Spectrum ◽  
Functional Theory ◽  
Electron Bubbles ◽  
Transition Energies ◽  
Solidification Pressure ◽  
Good Agreement

Within finite temperature Density Functional Theory, we have calculated the energy of the transitions from the ground state to the first two excited states in the electron bubbles in liquid helium at pressures from zero to about the solidification pressure. For 4 He at low temperatures, our results are in very good agreement with infrared absorption experiments. We have found that the 1s – 2p transition energies are sensitive not only to the size of the electron bubble, but also to its surface thickness. We also present results for the infrared transitions in the case of liquid 3 He .

Structure of Cu6PbO8

2000 ◽  
Vol 56 (1) ◽  
pp. 22-26 ◽  
Author(s):  
Björn Winkler ◽  
Michael Chall ◽  
Chris J. Pickard ◽  
Victor Milman ◽  
Jim White
Keyword(s):  
Density Functional ◽  
Structural Parameters ◽  
Ambient Pressure ◽  
Lattice Parameter ◽  
Functional Theory ◽  
Close Packed Structure ◽  
Packed Structure ◽  
The Stability ◽  
Parameter Density ◽  
Good Agreement

First-principles quantum mechanical calculations based on density functional theory were performed for Cu_6PbO_8, hexacopper lead octaoxide, murdochite. The computed lattice parameter, density and bond lengths at ambient pressure are in good agreement with experimental data for murdochite. At about 18 GPa a phase transition is predicted, when a polymorph with a Suzuki-type structure, i.e. a close-packed structure with ordered vacancies, is proposed to become stable. The pressure dependence of the structural parameters has been calculated for the two polymorphs and their bulk moduli have been predicted. It is argued that the incorporation of halogen atoms is not a precondition for the stability of murdochite.

Synthesis of New α-Amino Phosphonates Containing 3-Amino-4(3H) Quinazolinone Moiety as Anticancer and Antimicrobial Agents: DFT, NBO, and Vibrational Studies

2018 ◽  
Vol 15 (2) ◽  
pp. 286-296 ◽  
Author(s):  
Mohamed K. Awad ◽  
Mahmoud F. Abdel-Aal ◽  
Faten M. Atlam ◽  
Hend A. Hekal
Keyword(s):  
Biological Activity ◽  
Cell Line ◽  
Quantum Chemical ◽  
Density Functional ◽  
Carcinoma Cell ◽  
Liver Carcinoma ◽  
Anticancer Activities ◽  
Functional Theory ◽  
Ft Ir ◽  
Good Agreement

Aim and Objective: Synthesis of new .-aminophosphonates containing quinazoline moiety through Kabachnik-Fields reaction in the presence of copper triflate catalyst [32], followed by studying their antimicrobial activities and in vitro anticancer activities against liver carcinoma cell line (HepG2) with the hope that new anticancer agents could be developed. Also, the quantum chemical calculations are performed using density functional theory (DFT) to study the effect of the changes of molecular and electronic structures on the biological activity of the investigated compounds. Materials and Method: The structures of the synthesized compounds are confirmed by FT-IR, 1H NMR, 13C NMR, 31P NMR and MS spectral data. The synthesized compounds show significant antimicrobial and also remarkable cytotoxicity anticancer activities against liver carcinoma cell line (HepG2). Density functional theory (DFT) was performed to study the effect of the molecular and electronic structure changes on the biological activity. Results: It was found that the electronic structure of the substituents affects on the reaction yield. The electron withdrawing substituent, NO2 group 3b, on the aromatic aldehydes gave a good yield more than the electron donating substituent, OH group 3c. The electron deficient on the carbon atom of the aldehydic group may increase the interaction of the Lewis acid (Cu(OTf)2) and the Lewis base (imine nitrogen), and accordingly, facilitate the formation of imine easily, which is attacked by the nucleophilic phosphite species to give the α- aminophosphonates. Conclusion: The newly synthesized compounds exhibit a remarkable inhibition of the growth of Grampositive, Gram-negative bacteria and fungi at low concentrations. The cytotoxicity of the synthesized compounds showed a significant cytotoxicity against the liver cancer cell line (HepG 2). Also, it was shown from the quantum chemical calculations that the electron-withdrawing substituent increases the biological activity of the α-aminophosphonates more than the electron donating group which was in a good agreement with the experimental results. Also, a good agreement between the experimental FT-IR and the calculated one was found.

Sign in / Sign up

Export Citation Format

Share Document