scholarly journals London dispersion effects in the coordination and activation of alkanes in σ-complexes: a local energy decomposition study

2019 ◽  
Vol 21 (22) ◽  
pp. 11569-11577 ◽  
Author(s):  
Qing Lu ◽  
Frank Neese ◽  
Giovanni Bistoni
Keyword(s):  
Coupled Cluster ◽  
Local Energy ◽  
Energy Decomposition ◽  
Dispersion Effects ◽  
London Dispersion

The coupled-cluster-based local energy decomposition (LED) analysis is used to elucidate the nature of the TM–alkane interaction in alkane σ-complexes.

scholarly journals Cobalt-catalyzed C–H cyanations: Insights into the reaction mechanism and the role of London dispersion

2018 ◽  
Vol 14 ◽  
pp. 1537-1545 ◽  
Author(s):  
Eric Detmar ◽  
Valentin Müller ◽  
Daniel Zell ◽  
Lutz Ackermann ◽  
Martin Breugst
Keyword(s):  
Reaction Mechanism ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Local Energy ◽  
Energy Decomposition ◽  
Functional Theory ◽  
London Dispersion ◽  
Cobalt Center

Carboxylate-assisted cobalt(III)-catalyzed C–H cyanations are highly efficient processes for the synthesis of (hetero)aromatic nitriles. We have now analyzed the cyanation of differently substituted 2-phenylpyridines in detail computationally by density functional theory and also experimentally. Based on our investigations, we propose a plausible reaction mechanism for this transformation that is in line with the experimental observations. Additional calculations, including NCIPLOT, dispersion interaction densities, and local energy decomposition analysis, for the model cyanation of 2-phenylpyridine furthermore highlight that London dispersion is an important factor that enables this challenging C–H transformation. Nonbonding interactions between the Cp* ligand and aromatic and C–H-rich fragments of other ligands at the cobalt center significantly contribute to a stabilization of cobalt intermediates and transition states.

scholarly journals Local energy decomposition analysis of hydrogen-bonded dimers within a domain-based pair natural orbital coupled cluster study

2018 ◽  
Vol 14 ◽  
pp. 919-929 ◽  
Author(s):  
Ahmet Altun ◽  
Frank Neese ◽  
Giovanni Bistoni
Keyword(s):  
Hydrogen Fluoride ◽  
Decomposition Analysis ◽  
Energy Decomposition Analysis ◽  
Intermolecular Distance ◽  
Local Energy ◽  
Natural Orbital ◽  
Energy Decomposition ◽  
Potential Wells ◽  
Dynamic Charge ◽  
London Dispersion

The local energy decomposition (LED) analysis allows for a decomposition of the accurate domain-based local pair natural orbital CCSD(T) [DLPNO-CCSD(T)] energy into physically meaningful contributions including geometric and electronic preparation, electrostatic interaction, interfragment exchange, dynamic charge polarization, and London dispersion terms. Herein, this technique is employed in the study of hydrogen-bonding interactions in a series of conformers of water and hydrogen fluoride dimers. Initially, DLPNO-CCSD(T) dissociation energies for the most stable conformers are computed and compared with available experimental data. Afterwards, the decay of the LED terms with the intermolecular distance (r) is discussed and results are compared with the ones obtained from the popular symmetry adapted perturbation theory (SAPT). It is found that, as expected, electrostatic contributions slowly decay for increasing r and dominate the interaction energies in the long range. London dispersion contributions decay as expected, as r −6. They significantly affect the depths of the potential wells. The interfragment exchange provides a further stabilizing contribution that decays exponentially with the intermolecular distance. This information is used to rationalize the trend of stability of various conformers of the water and hydrogen fluoride dimers.

scholarly journals Local Energy Decomposition Analysis and Molecular Properties of Encapsulated Methane in Fullerene (CH4@C60)

2021 ◽  
Author(s):  
Aleksander Jaworski ◽  
Niklas Hedin
Keyword(s):  
Decomposition Analysis ◽  
Chem Phys ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Energy Decomposition Analysis ◽  
Local Energy ◽  
Energy Decomposition ◽  
Endohedral Complexes ◽  
London Dispersion ◽  
Phys Chem Chem Phys

Methane has been successfully encapsulated within cages of C<sub>60</sub> fullerene, and it is an appropriate model system to study confinement effects. Its chemistry and physics is also relevant for theoretical model descriptions. Here we provided insights into intermolecular interactions and predicted spectroscopic responses of the CH<sub>4</sub>@C<sub>60</sub> complex and compared with results from other methods and with literature data. Local energy decomposition analysis (LED) within the domain-based local pair natural orbital coupled cluster singles, doubles, and perturbative triples (DLPNO-CCSD(T)) framework was used, and an efficient protocol for studies of endohedral complexes of fullerenes is proposed. This approach allowed us to assess energies in relation to electronic and geometric preparation, electrostatics, exchange, and London dispersion for the CH<sub>4</sub>@C<sub>60</sub> endohedral complex. The calculated stabilization energy of CH<sub>4</sub> inside the C<sub>60</sub> fullerene was −13.5 kcal/mol and its magnitude was significantly larger than the latent heat of evaporation of CH<sub>4</sub>. Evaluation of vibrational frequencies and polarizabilities of the CH<sub>4</sub>@C<sub>60</sub> complex revealed that the infrared (IR) and Raman bands of the endohedral CH<sub>4</sub> were essentially “silent” due to dielectric screening effect of the C<sub>60</sub>, which acted as a molecular Faraday cage. Absorption spectra in the UV-Vis domain and ionization potentials of the C<sub>60</sub> and CH<sub>4</sub>@C<sub>60</sub> were predicted. They were almost identical. The calculated <sup>1</sup>H/<sup>13</sup>C NMR shifts and spin-spin coupling constants were in very good agreement with experimental data. In addition, reference DLPNO-CCSD(T) interaction energies for complexes with noble gases<br>(Ng@C60 ; Ng = He, Ne, Ar, Kr) were calculated. The values were compared with those derived from supermolecular MP2/SCS-MP2 calculations and estimates with London-type formulas by Pyykkö and coworkers [Phys. Chem. Chem. Phys., 2010, 12, 6187-6203], and with values derived from<br>DFT-based symmetry-adapted perturbation theory (DFT SAPT) by Hesselmann & Korona [Phys. Chem. Chem. Phys., 2011, 13, 732-743]. Selected points at the potential energy surface of the endohedral He<sub>2</sub>@C<sub>60</sub> trimer were considered. In contrast to previous theoretical attempts with the DFT/MP2/SCS-MP2/DFT-SAPT methods, our calculations at the DLPNO-CCSD(T) level of theory predicted the He<sub>2</sub>@C<sub>60</sub> trimer to be thermodynamically stable, which is in agreement with experimental observations.

scholarly journals Local Energy Decomposition Analysis and Molecular Properties of Encapsulated Methane in Fullerene (CH4@C60)

2021 ◽  
Author(s):  
Aleksander Jaworski ◽  
Niklas Hedin
Keyword(s):  
Decomposition Analysis ◽  
Chem Phys ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Energy Decomposition Analysis ◽  
Local Energy ◽  
Energy Decomposition ◽  
Endohedral Complexes ◽  
London Dispersion ◽  
Phys Chem Chem Phys

Methane has been successfully encapsulated within cages of C<sub>60</sub> fullerene, and it is an appropriate model system to study confinement effects. Its chemistry and physics is also relevant for theoretical model descriptions. Here we provided insights into intermolecular interactions and predicted spectroscopic responses of the CH<sub>4</sub>@C<sub>60</sub> complex and compared with results from other methods and with literature data. Local energy decomposition analysis (LED) within the domain-based local pair natural orbital coupled cluster singles, doubles, and perturbative triples (DLPNO-CCSD(T)) framework was used, and an efficient protocol for studies of endohedral complexes of fullerenes is proposed. This approach allowed us to assess energies in relation to electronic and geometric preparation, electrostatics, exchange, and London dispersion for the CH<sub>4</sub>@C<sub>60</sub> endohedral complex. The calculated stabilization energy of CH<sub>4</sub> inside the C<sub>60</sub> fullerene was −13.5 kcal/mol and its magnitude was significantly larger than the latent heat of evaporation of CH<sub>4</sub>. Evaluation of vibrational frequencies and polarizabilities of the CH<sub>4</sub>@C<sub>60</sub> complex revealed that the infrared (IR) and Raman bands of the endohedral CH<sub>4</sub> were essentially “silent” due to dielectric screening effect of the C<sub>60</sub>, which acted as a molecular Faraday cage. Absorption spectra in the UV-Vis domain and ionization potentials of the C<sub>60</sub> and CH<sub>4</sub>@C<sub>60</sub> were predicted. They were almost identical. The calculated <sup>1</sup>H/<sup>13</sup>C NMR shifts and spin-spin coupling constants were in very good agreement with experimental data. In addition, reference DLPNO-CCSD(T) interaction energies for complexes with noble gases<br>(Ng@C60 ; Ng = He, Ne, Ar, Kr) were calculated. The values were compared with those derived from supermolecular MP2/SCS-MP2 calculations and estimates with London-type formulas by Pyykkö and coworkers [Phys. Chem. Chem. Phys., 2010, 12, 6187-6203], and with values derived from<br>DFT-based symmetry-adapted perturbation theory (DFT SAPT) by Hesselmann & Korona [Phys. Chem. Chem. Phys., 2011, 13, 732-743]. Selected points at the potential energy surface of the endohedral He<sub>2</sub>@C<sub>60</sub> trimer were considered. In contrast to previous theoretical attempts with the DFT/MP2/SCS-MP2/DFT-SAPT methods, our calculations at the DLPNO-CCSD(T) level of theory predicted the He<sub>2</sub>@C<sub>60</sub> trimer to be thermodynamically stable, which is in agreement with experimental observations.

scholarly journals Local energy decomposition analysis and molecular properties of encapsulated methane in fullerene (CH4@C60)

2021 ◽  
Author(s):  
Aleksander Jaworski ◽  
Niklas Hedin
Keyword(s):  
Decomposition Analysis ◽  
Model System ◽  
Molecular Properties ◽  
C60 Fullerene ◽  
Energy Decomposition Analysis ◽  
Local Energy ◽  
Energy Decomposition ◽  
Confinement Effects

Methane has been successfully encapsulated within cages of C60 fullerene, and it is an appropriate model system to study confinement effects. Its chemistry and physics is also relevant for theoretical...

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