scholarly journals Spectroscopic and Theoretical Study of the Intramolecular π-Type Hydrogen Bonding and Conformations of 2-Cyclopenten-1-ol

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1106
Author(s):  
Esther J. Ocola ◽  
Jaan Laane
Keyword(s):  
Hydrogen Bonding ◽  
Internal Rotation ◽  
Energy Surface ◽  
Theoretical Study ◽  
Conformational Dynamics ◽  
The Other ◽  
Basis Set ◽  
Ring Puckering ◽  
High Level ◽  
Calculated Distance

The conformations of 2-cyclopenten-1-ol (2CPOL) have been investigated by high-level theoretical computations and infrared spectroscopy. The six conformational minima correspond to specific values of the ring-puckering and OH internal rotation coordinates. The conformation with the lowest energy possesses intramolecular π-type hydrogen bonding. A second conformer with weaker hydrogen bonding has somewhat higher energy. Ab initio coupled-cluster theory with single and double excitations (CCSD) was used with the cc-pVTZ (triple-ζ) basis set to calculate the two-dimensional potential energy surface (PES) governing the conformational dynamics along the ring-puckering and internal rotation coordinates. The two conformers with the hydrogen bonding lie about 300 cm−1 (0.8 kcal/mole) lower in energy than the other four conformers. The lowest energy conformation has a calculated distance of 2.68 Å from the hydrogen atom on the OH group to the middle of the C=C double bond. For the other conformers, this distance is at least 0.3 Å longer. The infrared spectrum in the O-H stretching region agrees well with the predicted frequency differences between the conformers and shows the conformers with the hydrogen bonding to have the lowest values. The infrared spectra in other regions arise mostly from the two hydrogen-bonded species.

scholarly journals The S66 Non-Covalent Interactions Benchmark Reconsidered Using Explicitly Correlated Methods Near the Basis Set Limit

2018 ◽  
Vol 71 (4) ◽  
pp. 238 ◽  
Author(s):  
Manoj K. Kesharwani ◽  
Amir Karton ◽  
Nitai Sylvetsky ◽  
Jan M. L. Martin
Keyword(s):  
Computational Cost ◽  
The Other ◽  
Basis Set ◽  
Basis Sets ◽  
Explicitly Correlated ◽  
Non Covalent Interactions ◽  
Explicitly Correlated Methods ◽  
The One ◽  
High Level ◽  
Covalent Interactions

The S66 benchmark for non-covalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 ‘high-level corrections’ are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66×8 problem set in particular, and for accurate calculations on non-covalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, whereas half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.

THE H2NO POTENTIAL ENERGY SURFACE EXPLORED WITH HIGH LEVEL AB INITIO AND DENSITY FUNCTIONAL THEORY METHODS

2007 ◽  
Vol 06 (03) ◽  
pp. 549-562
Author(s):  
ABRAHAM F. JALBOUT
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Hybrid Methods ◽  
Transition States ◽  
Basis Set ◽  
Functional Theory ◽  
High Level

The transition states for the H 2 NO decomposition and rearrangements mechanisms have been explored by the CBS-Q method or by density functional theory. Six transition states were located on the potential energy surface, which were explored with the Quadratic Complete Basis Set (CBS-Q) and Becke's one-parameter density functional hybrid methods. Interesting deviations between the CBS-Q results and the B1LYP density functional theory lead us to believe that further study into this system is necessary. In the efforts to further assess the stabilities of the transition states, bond order calculations were performed to measure the strength of the bonds in the transition state.

Theoretical study of the Cl(2P) + SiH4 reaction: Global potential energy surface and product pair-correlated distributions. Comparison with experiment.

2021 ◽  
Author(s):  
J. Espinosa-Garcia ◽  
Jose Carlos Corchado
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Theoretical Study ◽  
Title Reaction ◽  
Comparison With Experiment ◽  
Explicitly Correlated ◽  
High Level ◽  
First Time ◽  
Product Pair

For the theoretical study of the title reaction, an analytical full-dimensional potential energy surface named PES-2021 was developed for the first time, by fitting high-level explicitly-correlated ab initio data. This...

A theoretical study of the hydrogen bonding properties of H2BNH2: Some considerations on the basis set superposition error issue

2011 ◽  
Vol 967 (1) ◽  
pp. 147-151 ◽  
Author(s):  
Ibon Alkorta ◽  
Cristina Trujillo ◽  
Jose Elguero ◽  
Mohammad Solimannejad
Keyword(s):  
Hydrogen Bonding ◽  
Theoretical Study ◽  
Basis Set ◽  
Basis Set Superposition Error ◽  
Bonding Properties

scholarly journals Estimating Relative Disulfide Energies: An Accurate Ab Initio Potential Energy Surface

2010 ◽  
Vol 63 (3) ◽  
pp. 379 ◽  
Author(s):  
Naomi L. Haworth ◽  
Jason Y. Liu ◽  
Samuel W. Fan ◽  
Jill E. Gready ◽  
Merridee A. Wouters
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Redox Potential ◽  
Good Predictor ◽  
Web Application ◽  
Energy Surface ◽  
Basis Set ◽  
Dihedral Angles ◽  
High Level ◽  
Highly Strained

Disulfide torsional energy, a good predictor of disulfide redox potential in proteins, may be estimated by interpolation on a potential energy surface (PES) describing the twisting of diethyl disulfide through its three central dihedral angles. Here we update PES calculations at the M05-2X level of theory with the 6-31G(d) basis set. Although the surface shows no qualitative differences from an earlier MP2(full) PES, energy differences greater than 1 kJ mol–1 were seen for conformations with χ2 between –60° and 30°, or with χ3 below 60° or above 130°. This is particularly significant for highly strained disulfides that are likely to be spontaneously reduced by mechanical means. In benchmarking against the high-level G3X method, M05-2X showed significantly reduced root mean squared deviation compared with MP2(full) (1.0 versus 2.0 kJ mol–1 respectively). Results are incorporated into a web application that calculates relative torsional energies from disulfide dihedral angles (http://www.sbinf.org/applications/pes.html).

High Level Theoretical Study of Benzene−Halide Adducts: The Importance of C−H−Anion Hydrogen Bonding

2009 ◽  
Vol 113 (8) ◽  
pp. 1578-1585 ◽  
Author(s):  
Cecilia Coletti ◽  
Nazzareno Re
Keyword(s):  
Hydrogen Bonding ◽  
Theoretical Study ◽  
High Level

scholarly journals Theoretical Study of Reaction Between Nitrilimine and 1,4 Oxazine 2 Carboxylate by MP2 and DFT Methods

2018 ◽  
Vol 34 (6) ◽  
pp. 2992-2997
Author(s):  
H. El-Hadki ◽  
F. Hlimi ◽  
M. Salah ◽  
K. Marakchi ◽  
N. Komiha ◽  
...  
Keyword(s):  
Energy Surface ◽  
Theoretical Study ◽  
Basis Set ◽  
Dft Methods ◽  
Reactivity Indices ◽  
B3lyp Method ◽  
Transition Structures ◽  
Potential Energy Surface Calculation ◽  
Good Agreement ◽  
Surface Calculation

The regioselectivity of the reaction between phenyldiazen-1-ium-1-ylidene p-tolyl methanide and ethyl 4-benzoyl-4H-benzo [1,4]oxazine-2-carboxylate were studied by means of the DFT/B3LYP method coupled by the 6-31g(d) basis and MP2 in connection with 6-31G(d) and 6-31G+(d,p) basis set. The mechanism of this regioselectif reaction has performed by transition state optimization, evaluation of the potential energy surface, calculation of IRC and reactivity indices. Location and verification of minima and transition structures have been realized by using the Berny's algorithm. The process of formation of the two regioisomers is achieved through concerted and asynchronous mechanism. The results are in good agreement with the experimental data.

scholarly journals Theoretical study of the reaction mechanism and kinetics of the phenyl + propargyl association

2020 ◽  
Vol 22 (13) ◽  
pp. 6868-6880 ◽  
Author(s):  
Alexander N. Morozov ◽  
Alexander M. Mebel
Keyword(s):  
Reaction Mechanism ◽  
Energy Surface ◽  
Theoretical Study ◽  
Recombination Reaction ◽  
Propargyl Radical ◽  
Dependent Rate ◽  
Mechanism And Kinetics ◽  
Temperature And Pressure ◽  
High Level ◽  
Kinetics Of

Potential energy surface for the phenyl + propargyl radical recombination reaction has been studied using high-level ab initio calculations and temperature- and pressure-dependent rate constants and product yields have been computed employing RRKM-ME.

scholarly journals The S66 noncovalent interactions benchmark reconsidered using explicitly correlated methods near the basis set limit

2017 ◽  
Author(s):  
Manoj Kumar Kesharwani ◽  
Amir Karton ◽  
Nitai Sylvetsky ◽  
Jan M. L. Martin
Keyword(s):  
Noncovalent Interactions ◽  
Computational Cost ◽  
The Other ◽  
Basis Set ◽  
Basis Sets ◽  
Other Hand ◽  
Explicitly Correlated ◽  
Explicitly Correlated Methods ◽  
The One ◽  
High Level

<p>The S66 benchmark for noncovalent interactions has been re-evaluated using explicitly correlated methods with basis sets near the one-particle basis set limit. It is found that post-MP2 “high-level corrections” are treated adequately well using a combination of CCSD(F12*) with (aug-)cc-pVTZ-F12 basis sets on the one hand, and (T) extrapolated from conventional CCSD(T)/heavy-aug-cc-pV{D,T}Z on the other hand. Implications for earlier benchmarks on the larger S66x8 problem set in particular, and for accurate calculations on noncovalent interactions in general, are discussed. At a slight cost in accuracy, (T) can be considerably accelerated by using sano-V{D,T}Z+ basis sets, while half-counterpoise CCSD(F12*)(T)/cc-pVDZ-F12 offers the best compromise between accuracy and computational cost.</p>

High level theoretical study of binding and of the potential energy surface in benzene–hydride system

2012 ◽  
Vol 398 ◽  
pp. 168-175 ◽  
Author(s):  
Cecilia Coletti ◽  
Nazzareno Re
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Theoretical Study ◽  
High Level
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