Fluorine Gauche Effect Explained by Electrostatic Polarization Instead of Hyperconjugation: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

Thacker, Joseph C. R.; Popelier, Paul L. A.

doi:10.1021/acs.jpca.7b11881

Cited by 68 publications

(49 citation statements)

References 51 publications

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“…These, together with the rcp-to-bcp connectivity appearing in the intermolecular regions are consistent with that described by the overlapping MESP model for (C 6 F 6 ) 2 , Figure 5, showing a further advantage in using QTAIM's bond path topology. There is no straightforward and convenient way that can assist to quantify the stabilization energy of each of the three individual F···F interactions in each dimer, although this could be done computationally using the so-called Interacting Quantum Atom (IQA) model of Pendás and coworkers [106,107] and employed by Tognetti et al [52,108,109] to study halogen bonding; however, this is computationally very expensive for larger systems. QTAIM does provide another means of quantifying individual F···F interactions through the magnitude of ρ b at a bcp, a property which has been shown to correlate with the binding energy [110,111].…”

Section: Qtaim and Rdg Descriptions Of Chemical Bondingmentioning

confidence: 99%

Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective

Varadwaj

Marques

et al. 2018

Computation

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The divergence of fluorine-based systems and significance of their nascent non-covalent chemistry in molecular assemblies are presented in a brief review of the field. Emphasis has been placed to show that type-I and -II halogen-centered F···F long-ranged intermolecular distances viable between the entirely negative fluorine atoms in some fluoro-substituted dimers of C 6 H 6 can be regarded as the consequence of significant non-covalent attractive interactions. Such attractive interactions observed in the solid-state structures of C 6 F 6 and other similar fluorine-substituted aromatic compounds have frequently been underappreciated. While these are often ascribed to crystal packing effects, we show using first-principles level calculations that these are much more fundamental in nature. The stability and reliability of these interactions are supported by their negative binding energies that emerge from a supermolecular procedure using MP2 (second-order Møller-Plesset perturbation theory), and from the Symmetry Adapted Perturbation Theory, in which the latter does not determine the interaction energy by computing the total energy of the monomers or dimer. Quantum Theory of Atoms in Molecules and Reduced Density Gradient Non-Covalent Index charge-density-based approaches confirm the F···F contacts are a consequence of attraction by their unified bond path (and bond critical point) and isosurface charge density topologies, respectively. These interactions can be explained neither by the so-called molecular electrostatic surface potential (MESP) model approach that often demonstrates attraction between sites of opposite electrostatic surface potential by means of Coulomb's law of electrostatics, nor purely by the effect of electrostatic polarization. We provide evidence against the standalone use of this approach and the overlooking of other approaches, as the former does not allow for the calculation of the electrostatic potential on the surfaces of the overlapping atoms on the monomers as in the equilibrium geometry of a complex. This study thus provides unequivocal evidence of the limitation of the MESP approach for its use in gaining insight into the nature of reactivity of overlapped interacting atoms and the intermolecular interactions involved.

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Section: Qtaim and Rdg Descriptions Of Chemical Bondingmentioning

confidence: 99%

Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective

Varadwaj

Marques

et al. 2018

Computation

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“…From a different point of view,

V_{c l} (A, B)

term can be divided into charge‐transfer,

V_{c t} (A, B)

, and polarization,

V_{p o l} (A, B)

, with terms defined as

true V_{c t} (A, B) = \frac{Q_{00} ((), A) Q_{00} ((), B)}{r_{A B}}

true V_{p o l} (A, B) = V_{c l} (A, B) - V_{c t} (A, B)

…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…From a different point of view, V cl ðA; BÞ term can be divided into charge-transfer, V ct ðA; BÞ, and polarization, V pol ðA; BÞ, with terms defined as [26]…”

Section: Interacting Quantum Atomsmentioning

confidence: 99%

Directionality of Halogen Bonds: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

et al. 2019

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Interacting Quantum Atoms (IQA) and Interacting Quantum Fragments (IQF) analyses are used to study normalF3C-X⋯NnormalH3 (X=Cl and Br) model complexes in order to determine the origin of halogen bond directionality. IQA allows for the calculation of intra‐ and interatomic classical and exchange‐correlation energies, which can be used to determine the energetic nature of the changes that occur when deviating from the preferred halogen bond approach. The Relative Energy Gradient (REG) method is also applied to rank the IQA energies and reveal which energy contributions best describe the total behavior of the system. Indeed, all the pairwise interactions and atomic self‐energies are angularly dependent; some terms favor the linear structure and some tend toward nonlinear arrangements. For instance, when the C−X−N angle is altered, the halogen‐nitrogen interaction energy behaves like the total energy of the system while the carbon‐nitrogen interaction works against the total energy profile. Furthermore, the REG values reveal that the contribution of the halogen‐nitrogen interaction to the total behavior of the system is small. Instead, the secondary interactions (e. g., fluorine‐nitrogen and carbon‐hydrogen interactions) and atomic self‐energies are mainly responsible for the angular preference of these halogen bonds. Finally, IQF calculations followed by REG analysis reveal the importance of the self‐energy of the fragments.

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“…The IQA partitioning scheme is an attractive candidate to serve as a bridge between chemical insight and present‐day wavefunctions. A combination of IQA and the newly proposed Relative Energy Gradient (REG) method has delivered crisp chemical insight explaining the chemical nature of a traditional hydrogen bond, enzymatic hydrolysis, the fluorine gauche effect and the origin of rotation barriers in biphenyl . IQA provides four types of energy, which are all well‐defined at atomistic level: intra‐atomic energy (which we showed corresponds to sterics), electrostatic energy (with a link to multipole moments), exchange energy (related to bond order) and correlation energy (expanding dispersion).…”

Section: Introductionmentioning

confidence: 99%

Does the Intra‐Atomic Deformation Energy of Interacting Quantum Atoms Represent Steric Energy?

et al. 2019

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We show that the mutual, through‐space compression of atomic volume experienced by approaching topological atoms causes an exponential increase in the intra‐atomic energy of those atoms, regardless of approach orientation. This insight was obtained using the modern energy partitioning method called interacting quantum atoms (IQA). This behaviour is consistent for all atoms except hydrogen, which can behave differently depending on its environment. Whilst all atoms experience charge transfer when they interact, the intra‐atomic energy of the hydrogen atom is more vulnerable to these changes than larger atoms. The difference in behaviour is found to be due to hydrogen's lack of a core of electrons, which, in heavier atoms, consistently provide repulsion when compressed. As such, hydrogen atoms do not always provide steric hindrance. In accounting for hydrogen's unusual behaviour and demonstrating the exponential character of the intra‐atomic energy in all other atoms, we provide evidence for IQA's intra‐atomic energy as a quantitative description of steric energy.

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Fluorine Gauche Effect Explained by Electrostatic Polarization Instead of Hyperconjugation: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

Cited by 68 publications

References 51 publications

Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective

Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective

Directionality of Halogen Bonds: An Interacting Quantum Atoms (IQA) and Relative Energy Gradient (REG) Study

Does the Intra‐Atomic Deformation Energy of Interacting Quantum Atoms Represent Steric Energy?

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