scholarly journals Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6441
Author(s):  
Justyna Krupa ◽  
Maria Wierzejewska ◽  
Jan Lundell
Keyword(s):  
Quantum Chemical ◽  
Van Der Waals ◽  
Spectroscopic Properties ◽  
Van Der Waals Interactions ◽  
Basis Set ◽  
Isolation Technique ◽  
The Matrix ◽  
Argon Matrices ◽  
Solid Argon ◽  
Ir Spectroscopic

FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO…SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van der Waals structures. Upon annealing, complexes of the 1:2 stoichiometry were detected, as well.

scholarly journals Matrix Isolation FTIR and Theoretical Study of Weakly Bound Complexes of Isocyanic Acid with Nitrogen

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 495
Author(s):  
Justyna Krupa ◽  
Maria Wierzejewska ◽  
Jan Lundell
Keyword(s):  
Van Der Waals ◽  
Matrix Isolation ◽  
Lone Pair ◽  
Nitrogen Molecule ◽  
Van Der Waals Interactions ◽  
Isocyanic Acid ◽  
Weakly Bound ◽  
Isolation Technique ◽  
Weak Complexes ◽  
Argon Matrices

Weak complexes of isocyanic acid (HNCO) with nitrogen were studied computationally employing MP2, B2PLYPD3 and B3LYPD3 methods and experimentally by FTIR matrix isolation technique. The results show that HNCO interacts specifically with N2. For the 1:1 stoichiometry, three stable minima were located on the potential energy surface. The most stable of them involves a weak, almost linear hydrogen bond from the NH group of the acid molecule to nitrogen molecule lone pair. Two other structures are bound by van der Waals interactions of N⋯N and C⋯N types. The 1:2 and 2:1 HNCO complexes with nitrogen were computationally tracked as well. Similar types of interactions as in the 1:1 complexes were found in the case of the higher stoichiometry complexes. Analysis of the HNCO/N2/Ar spectra after deposition indicates that the 1:1 hydrogen-bonded complex is prevalent in argon matrices with a small amount of the van der Waals structures also present. Upon annealing, complexes of the 1:2 and 2:1 stoichiometry were detected as well.

scholarly journals Identification of the early intermediates formed in ozonolysis of cis-2-butene and limonene: a theoretical and matrix isolation study

RSC Advances ◽  
2019 ◽  
Vol 9 (35) ◽  
pp. 20100-20106
Author(s):  
Shan-shan Li ◽  
Xiao-yang Yang ◽  
Yi-sheng Xu ◽  
Lei Jiang
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Matrix Isolation ◽  
Isolation Technique ◽  
The Matrix

This study combined quantum chemical calculations and the matrix isolation technique to identify the formation of primary intermediates from the ozonolysis of cis-2-butene and limonene.

scholarly journals 2019-nCoV vs. SARS-CoV: Which Truly Has a Higher ACE2 Affinity? A Quantum Chemical Perspective on Virus-Receptor Noncovalent Interactions

2020 ◽  
Author(s):  
Nitai Sylvetsky
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Force Field ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Van Der Waals ◽  
Noncovalent Interaction ◽  
Van Der Waals Interactions ◽  
Virus Receptor ◽  
Electronic Structure Methods

Noncovalent interaction energetics associated with ACE2 affinity differences are investigated using electronic structure methods; Our results were found to challenge previous predictions – claiming a higher affinity for 2019-nCoV compared to SARS-CoV based merely on "chemical intuition". In addition, we demonstrate that a broadly-used classical molecular dynamics force field – MMFF94 – is clearly incapable of reproducing DFT-based noncovalent interaction energetics for the systems at hand (despite being specifically parameterized for van der Waals interactions).

Theoretical Study of the Complexation of Lidocaine by α- and β-Cyclodextrins

2021 ◽  
Vol 43 (4) ◽  
pp. 429-429
Author(s):  
Nourredine Meddah Araibi Nourredine Meddah Araibi ◽  
Teffaha Fergoug Teffaha Fergoug ◽  
Mansour Azayez Mansour Azayez ◽  
Cherifa Zelmat Cherifa Zelmat ◽  
Jendara Ali Cherif and Youcef Bouhadda Jendara Ali Cherif and Youcef Bouhadda
Keyword(s):  
Inclusion Complex ◽  
Quantum Chemical ◽  
Driving Forces ◽  
Minimum Energy ◽  
Geometry Optimization ◽  
Empirical Method ◽  
Van Der Waals Interactions ◽  
Basis Set ◽  
The Stability ◽  
Complexation Reactions

Structure and stability of an eventual inclusion complex formed by Lidocaine and two cyclodextrins (α- and β-CD) were investigated using molecular mechanics and quantum-chemical methods in the gas phase and in water. The molecular docking and quantum chemical calculations results show that no inclusion complex is formed between α-CD and Lidocaine molecule, while the conformational research allowed observing two minimum-energy structures between this molecule and β-CD. From a potential energy scan, a partial inclusion of the two ends of Lidocaine by the secondary face of the cavity of β-CD is observed with a better stability for the complex including the ((-N(C2H5)2) group in it. The minimum energy conformers, obtained by semi empirical method (PM3), have been exposed to fully geometry optimization employing ONIOM2 calculations by combining PM3 method with B3LYP, M06-HF and WB97XD functionals at 6-311G (d,p) basis set. The results show that complexation reactions are thermodynamically favored (Gand#176; ˂ 0) and the inclusion complexes are energetically stables and well structured (Sand#176; ˂ 0). According to the analysis of natural bond orbitals, the Van der Waals interactions are the sole driving forces that ensure the stability of the formed complexes.

ELECTRON DENSITY ANALYSIS OF WEAK VAN DER WAALS COMPLEXES

2006 ◽  
Vol 05 (03) ◽  
pp. 621-631 ◽  
Author(s):  
A. H. PAKIARI ◽  
S. FAKHRAEE
Keyword(s):  
Electron Density ◽  
Van Der Waals ◽  
Closed Shell ◽  
Van Der Waals Interactions ◽  
Basis Set ◽  
Total Energy Density ◽  
Atmospheric Molecules ◽  
Density Analysis ◽  
Polyatomic Systems ◽  
Electron Density Analysis

The nature of weak van der Waals interactions in different complexes of some atmospheric molecules such as CO 2, N 2 O , and N 2 was examined. Ab initio calculation was carried out at MP2 level of theory using Dunning's aug-cc-pVTZ basis set. Bader's theory of atoms in molecules (AIM) was employed to analyze electron density and to characterize the nature and properties of van der Waals interactions. A set of criteria, having been proposed in the context of AIM theory, was examined for these complexes. In spite of the parameter kinetics energy, per electron density is expected to be greater than unity for closed-shell interactions; we obtained values less than unity for many of these polyatomic systems. A set of limitations has also been outlined for the values of two AIM quantities: total energy density, H(r), and Laplacian of electron density, ∇2ρ, which correspond to different bond natures.

scholarly journals 2019-nCoV vs. SARS-CoV: Which Truly Has a Higher ACE2 Affinity? A Quantum Chemical Perspective on Virus-Receptor Noncovalent Interactions

2020 ◽  
Author(s):  
Nitai Sylvetsky
Keyword(s):  
Molecular Dynamics ◽  
Electronic Structure ◽  
Force Field ◽  
Quantum Chemical ◽  
Noncovalent Interactions ◽  
Van Der Waals ◽  
Noncovalent Interaction ◽  
Van Der Waals Interactions ◽  
Virus Receptor ◽  
Electronic Structure Methods

Noncovalent interaction energetics associated with ACE2 affinity differences are investigated using electronic structure methods; Our results were found to challenge previous predictions – claiming a higher affinity for 2019-nCoV compared to SARS-CoV based merely on "chemical intuition". In addition, we demonstrate that a broadly-used classical molecular dynamics force field – MMFF94 – is clearly incapable of reproducing DFT-based noncovalent interaction energetics for the systems at hand (despite being specifically parameterized for van der Waals interactions).

Electron attachment products of methylene chloride in solid argon: an experimental and quantum chemical IR spectroscopic study

1997 ◽  
Vol 214 (2-3) ◽  
pp. 321-328 ◽  
Author(s):  
Andreas Richter ◽  
Hermann Meyer ◽  
Thorsten Kausche ◽  
Thomas Müller ◽  
Walter Sporleder ◽  
...  
Keyword(s):  
Spectroscopic Study ◽  
Quantum Chemical ◽  
Methylene Chloride ◽  
Electron Attachment ◽  
Solid Argon ◽  
Ir Spectroscopic

The photochemistry of RDX in solid argon at 10 K

1991 ◽  
Vol 69 (10) ◽  
pp. 1535-1538 ◽  
Author(s):  
Jeff Alix ◽  
Susan Collins
Keyword(s):  
Ftir Spectroscopy ◽  
Key Words ◽  
Gas Phase ◽  
Condensed Phase ◽  
Thermal Reactions ◽  
The Matrix ◽  
Intermolecular Reactions ◽  
Argon Matrices ◽  
Solid Argon ◽  
Kinetics Of

The photochemistry of RDX was studied in argon matrices at 10 K and examined by FTIR spectroscopy. The spectra and kinetics of product growth indicate that there are two decomposition pathways: [I]        RDX → 4NO + 2CH2O + N2 + CH2 → 4NO + 2CO + N2 +CH4 + H2 [II]        RDX → N2O + [O3 + N2] or [N2O3] + CO2 + C2H2 +N2 + 2H2 The mechanism II nitrogen products can easily be rationalized for the chair configuration of RDX with axial NO2 groups adjacent (Cs symmetry). When considering the carbon products of II, it may be necessary to postulate intermolecular reactions. Our studies gave no evidence for the symmetric triple fission path, which leads to N2O and CH2O, nor for the NO2 stripping mechanism reported for the gas-phase thermal reactions, which leads to the formation of NO2 and HCN. Rather, our findings were more consistent with the known condensed phase products. The production of CH4, C2H2, N2O3, and O3 are unique to the matrix study. Key words: RDX, photochemistry, argon matrices.

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