Substituent Effects on the σ···π Interactions Between Au6 Cluster and Substituted Benzene

To facilitate computational investigation of intermolecular interactions in the solution phase, we report the development of ALMO-EDA(solv), a scheme that allows the application of continuum solvent models within the framework of energy decomposition analysis (EDA) based on absolutely localized molecular orbitals (ALMOs). In this scheme, all the quantum mechanical states involved in the variational EDA procedure are computed with the presence of solvent environment so that solvation effects are incorporated in the evaluation of all its energy components. After validation on several model complexes, we employ ALMO-EDA(solv) to investigate substituent effects on two classes of complexes that are related to electrochemical CO2 reduction catalysis. For [FeTPP(CO2−κC)]2− (TPP = tetraphenylporphyrin), we reveal that two ortho substituents which yield most favorable CO2 binding, −N(CH3)3+ (TMA) and −OH, stabilize the complex via through-structure and through-space mechanisms, respectively. The Coulombic interaction between the positively charged TMA group and activated CO2 is found to be largely attenuated by the polar solvent. Furthermore, we also provide computational support for the design strategy of utilizing bulky, flexible ligands to stabilize activated CO2 via long-range Coulomb interactions, which creates biomimetic solvent-inaccessible “pockets” in that electrostatics is unscreened. For the reactant and product complexes associated with the electron transfer from the p-terphenyl radical anion to CO2 , we demonstrate that the double terminal substitution of p-terphenyl by electron-withdrawing groups considerably strengthens the binding in the product state while moderately weakens that in the reactant state, which are both dominated by the substituent tuning of the electrostatics component. These applications illustrate that this new extension of ALMO-EDA provides a valuable means to unravel the nature of intermolecular interactions and quantify their impacts on chemical reactivity in solution.

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Contribution of Nitrogen Heteroatom to Anion-π Interaction of N-heterocyclic Anthracene C14-2mH10-2mN2m (m = 1, 2, and 3) with Chloride Anion

10.22541/au.162556179.91340820/v1 ◽

2021 ◽

Author(s):

Huan Zhang ◽

Bingqiang Wang ◽

Shuangli Du ◽

Pingyu Kuai ◽

Baojing Guo

Keyword(s):

Aromatic Ring ◽

Electrostatic Interactions ◽

Decomposition Analysis ◽

Chloride Anion ◽

Energy Decomposition Analysis ◽

Dispersion Forces ◽

Biological Processes ◽

Energy Decomposition ◽

Present Contribution ◽

Π Interactions

N-heterocyclic aromatic in anion-π interaction has been playing a crucial role in a host of chemical and biological processes. In the present contribution, several different complexes composed of N-heterocyclic anthracene C14-2mH10-2mN2m (m = 1, 2, and 3) and chloride anion are investigated at the atomic level. We find that anion-π interactions are enhanced with the increasing number of N atoms. In addition, positions of nitrogen heteroatoms also have a significant effect on this interaction. Contributions of α, β and γ N atoms are in order of Nβ>Nγ>Nα. Moreover, energy decomposition analysis indicates that electrostatic interactions are the dominant stabilizing forces when chloride anion locates above aromatic ring, while the influence of other terms becomes significant when chloride anion deviates from aromatic ring. It is worth noting that dispersion forces play an important role in those anion-π interactions.

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Consistent Inclusion of Continuum Solvation in Energy Decomposition Analysis: Theory and Application to Molecular CO2 Reduction Catalysts

10.26434/chemrxiv.13065290.v1 ◽

2020 ◽

Author(s):

Yuezhi Mao ◽

Matthias Loipersberger ◽

Kareesa Kron ◽

Jeffrey Derrick ◽

Christopher Chang ◽

...

Keyword(s):

Intermolecular Interactions ◽

Chemical Reactivity ◽

Decomposition Analysis ◽

Substituent Effects ◽

Co2 Reduction ◽

Energy Decomposition Analysis ◽

Energy Decomposition ◽

Coulombic Interaction ◽

Model Complexes ◽

Localized Molecular Orbitals

To facilitate computational investigation of intermolecular interactions in the solution phase, we report the development of ALMO-EDA(solv), a scheme that allows the application of continuum solvent models within the framework of energy decomposition analysis (EDA) based on absolutely localized molecular orbitals (ALMOs). In this scheme, all the quantum mechanical states involved in the variational EDA procedure are computed with the presence of solvent environment so that solvation effects are incorporated in the evaluation of all its energy components. After validation on several model complexes, we employ ALMO-EDA(solv) to investigate substituent effects on two classes of complexes that are related to electrochemical CO2 reduction catalysis. For [FeTPP(CO2−κC)]2− (TPP = tetraphenylporphyrin), we reveal that two ortho substituents which yield most favorable CO2 binding, −N(CH3)3+ (TMA) and −OH, stabilize the complex via through-structure and through-space mechanisms, respectively. The Coulombic interaction between the positively charged TMA group and activated CO2 is found to be largely attenuated by the polar solvent. Furthermore, we also provide computational support for the design strategy of utilizing bulky, flexible ligands to stabilize activated CO2 via long-range Coulomb interactions, which creates biomimetic solvent-inaccessible “pockets” in that electrostatics is unscreened. For the reactant and product complexes associated with the electron transfer from the p-terphenyl radical anion to CO2 , we demonstrate that the double terminal substitution of p-terphenyl by electron-withdrawing groups considerably strengthens the binding in the product state while moderately weakens that in the reactant state, which are both dominated by the substituent tuning of the electrostatics component. These applications illustrate that this new extension of ALMO-EDA provides a valuable means to unravel the nature of intermolecular interactions and quantify their impacts on chemical reactivity in solution.

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