A Quantum Theory Atoms in Molecules Study about the Inductive Effect of Substituents in Methane Derivatives

Macedo, Gabriel K; Haiduke, Roberto Luiz Andrade

doi:10.1021/acsomega.0c01081

Cited by 11 publications

(9 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, it does not account for the σ-hole formation once a substituent like fluorine bonded to a more polarizable and less electronegative halogen (F−X) acquires a negative charge and, in principle, should deform the electronic cloud of X away from the bond by means of simple electrostatic arguments based on polarizations. Hence, these polarizations are probably transmitted through space (field effect), 52 but the electrons in chemical bonds appear to be the ones really affected by this field. In other words, the polarization in molecular systems seems to be more complicated than expected, and quantum effects may be associated with this unusual behavior.…”

Section: Atomic Interpretation Of Electronicmentioning

confidence: 99%

A Charge–Charge Flux–Dipole Flux Analysis of Simple Molecular Systems with Halogen Bonds

Martins Filho,

Haiduke

2024

J. Phys. Chem. A

View full text Add to dashboard Cite

The presence of halogen bonds (R−X•••B; R = substituent group, X = halogen, and B = Lewis base) provides quite amazing molecular systems for electronic structure investigations, presenting unique characteristics of fundamental relevance to supramolecular chemistry among other areas. Here, we use a double-hybrid approach from Density Functional Theory and triple-ζ basis sets augmented with diffuse functions (B2PLYP/def2-TZVPD) to deal with a large group of simple molecular systems containing halogen bonds (XBs), focusing on geometrical structures, binding energies, harmonic vibrational frequencies, and fundamental infrared intensities. Next, the electron densities and their variations on vibrations are carefully studied with the Quantum Theory of Atoms in Molecules (QTAIM) formalism and the charge−charge flux− dipole flux (CCFDF) model. We notice that the R−X stretching mode usually shows vibrational frequency decrements and infrared intensifications during the XB formation. Such features were also observed in hydrogen bonds, although the explanation for the band strengthening is different. Surprisingly, the most important contribution to these intensity increments due to complexation is now the interaction term between the charge flux and dipole flux (CF × DF). Thus, the use of atomic dipoles is mandatory to fully understand this phenomenon. In fact, the huge charge flux contributions to changes in dipole moment derivatives of R−X stretchings on halogen bonding are no longer accompanied by opposite variations of similar magnitudes in polarizations described by atomic dipole fluxes, which provided nearly unaltered values during the XB formation. Thus, the electronic charge flux direction change that takes place in complexes (from B to R) now reinforces dipole moment derivative terms from such atomic polarizations (mainly from the X atom). This intermolecular charge flux seems to be responsible for the unusual features noticed in the R−X stretching mode with the CCDDF/QTAIM model.

show abstract

Section: Atomic Interpretation Of Electronicmentioning

confidence: 99%

A Charge–Charge Flux–Dipole Flux Analysis of Simple Molecular Systems with Halogen Bonds

Martins Filho,

Haiduke

2024

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…If the electronegativity of X is more than that of C, the electron pair of C–X bond will be biased to X, resulting in X with partial negative charge and C with partial positive charge. Thus, it is considered that inductive effect originates polar bonds (i.e., the electronegativities are unequal for the adjacent atoms), and weakens as the distance from the substituent increase and is transmitted through the σ-bonds of the molecule. , That is, the inductive effect is due to polarization changes driven by substituent charges . Here, take n -C 4 H 9 F for example: its charge distribution diagram is as shown in Figure , which shows that the farther the carbon atom is from the fluorine atom, the less positive charge it carries.…”

Section: Teaching Processmentioning

confidence: 99%

“…3,4 That is, the inductive effect is due to polarization changes driven by substituent charges. 14 Here, take n-C 4 H 9 F for example: its charge distribution diagram is as shown in Figure 2, which shows that the farther the carbon atom is from the fluorine atom, the less positive charge it carries.…”

Section: Step 1: To Establish the Inductive Effect Conceptuallymentioning

confidence: 99%

Three-Step Method to Teach Inductive Effect

Cao

2023

J. Chem. Educ.

View full text Add to dashboard Cite

The inductive effect is one of the very important concepts of electronic effects in organic chemistry. In traditional teaching methods, only the origin, transmission mode, and decay of the inductive effect are introduced briefly, which is not conducive to students' complete understanding of the inductive effect. This work developed a new method to teach inductive effect, named the "Three-step Method" (TsM): (1) establishing the concept of inductive effect; (2) evaluating the transmission distance of inductive effect qualitatively; and (3) determining the attenuation factor of inductive effect quantitatively. In the TsM, the group electronegativity, nuclear magnetic resonance chemical shift of H atom, and data fitting method are employed to discuss the origin, transmission mode, transmission distance, and attenuation factor of the inductive effect. The TsM of this paper is intuitive and simple, and takes less than 10 minutes in the classroom, which can help students to understand the concept of inductive effect indepth and to cultivate students' molecular structure−property reasoning ability.

show abstract

“…nuclei, the electron density, and the energy density of the carbon and hydrogen bonds (Macedo and Haiduke 2020). Others, like Mendoza et al (2013), calculate methane's electron charge distributions by applying the kinetic theory to the DFT method (figure 2).…”

Section: Chemical Bonds Are Real Patternsmentioning

confidence: 99%

“…However, there are more efficient ways of describing methane. For example, it can be described using the QTAIM, which calculates the electric field at carbon nuclei, the electron density, and the energy density of the carbon and hydrogen bonds (Macedo and Haiduke 2020). Others, like Mendoza et al (2013), calculate methane’s electron charge distributions by applying the kinetic theory to the DFT method (figure 2).…”

Section: Chemical Bonds Are Real Patternsmentioning

confidence: 99%