Infrared intensity analysis of hydroxyl stretching modes in carboxylic acid dimers by means of the charge–charge flux–dipole flux model

Silva, Natieli Alves da; Haiduke, Roberto Luiz Andrade

doi:10.1002/jcc.26024

Cited by 6 publications

(5 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One can notice that the harmonic frequencies always decrease because of the XB formation (red shift), from 3.9 to 419.8 cm –1 , while the infrared intensities tend to increase up to 907.0 km mol –1 (HI···I – ). Similar features were observed before during halogen bonding ,,, and also in the X-H stretchings of donor monomers during dimerization by hydrogen bond formation. − Only a few of the systems investigated here show slightly weaker R–X bands due to halogen bonding, namely, HCl···Br – , HCl···I – , and HBr···NCH. Once again, the CCFDF/QTAIM model provides a nice description of the infrared intensities for this mode, with deviations up to 3.8 km mol –1 or 11% (CF 3 Cl···Br – ).…”

Section: Resultssupporting

confidence: 82%

“…Hence, this feature is quite different from the picture that emerged on hydrogen bonding, where infrared intensity increments on dimerization are usually dominated by the C × CF contribution. 18,20 In fact, the dynamic terms now seem to be much more important for systems with XBs. Moreover, the CCFDF/QTAIM analysis shows that a model lacking atomic dipole fluxes is not able of properly describing this intensity strengthening for the R−X stretching during the XB formation, as done in the past with effective charges.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Despite many similarities observed between XBs and hydrogen bonds, the interpretation for the infrared intensification of the R–X stretching on complexation by XB formation is different from the mechanism discussed for a similar band strengthening also seen for X–H stretchings of the HB donors. Hence, while the charge–charge flux term is usually the most important one for HBs, , the charge flux–dipole flux contribution predominates for XB systems. Thus, the atomic dipole moment fluxes are crucial to really understand this infrared intensification, and models neglecting this contribution will lead to incomplete or misleading conclusions.…”

Section: Discussionmentioning

confidence: 99%

“…The CCFDF/QTAIM model has being applied to several systems, including dimers with hydrogen bonds (X–H···Y). − These studies were focused on understanding the origin of the large infrared strengthening normally observed in the X–H stretching mode due to dimerization, which indicates that the charge–charge flux term normally plays a major role. In other words, the presence of an HB induces a charge flux change in the dimer that is coordinated with the static charge movement in this vibrational mode.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Martins Filho,

Haiduke

2024

J. Phys. Chem. A

Self Cite

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: Resultssupporting

confidence: 82%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Martins Filho,

Haiduke

2024

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Theoretical predictions of vibrational intensities required an accurate dipole moment functions and vibrational wavefunctions, which became available only in recent decades due to significant improvement of computational methods and techniques 48,49 . At the moment there are a few theories describing the mechanism of intensification of the stretching mode upon formation of hydrogen bond based on QTAIM theory and charge transfer model 50,52,61 …”

Section: Introductionmentioning

confidence: 99%

Estimations of FH···X hydrogen bond energies from IR intensities: Iogansen's rule revisited

et al. 2021

View full text Add to dashboard Cite

In this work the possibility of using the IR intensity of the stretching vibration νs of proton donor group for estimation of hydrogen bond strength was investigated. For a set of complexes with FH···X (X = F, N, O) hydrogen bonds in the wide range of energies (0.1–49.2 kcal/mol) vibrational frequencies νs and their intensities A were calculated (CCSD at complete basis set limit). The validity of the previously proposed linear proportionality between the intensification of the stretching vibration νs in IR spectra and hydrogen bond enthalpy –ΔH = 12.2 ∆A (A. V. Iogansen, Spectrochimica Acta A 1999) was examined. It is shown that for a range of similar hydrogen bond types with complexation energies ∆E <15 kcal/mol the ∆E(∆A) function remains similar to that proposed in the Iogansen's work, while upon strengthening this dependency becomes significantly nonlinear. We examined two other parameters (∆Aνs and ∆A∙mR) related to IR intensity as descriptors of hydrogen bond strength which are proportional to transition dipole moment matrix element and mass‐independent dipole moment derivative. It was found that the dependency ∆E(∆Aνs) stays linear in the whole studied range of complexation energies and it can be used for evaluation of ∆E from infrared spectral data with the accuracy about 2 kcal/mol. The mass‐independent product ∆A∙mR is an appropriate descriptor for sets of complexes with various hydrogen bond types. Simple equations proposed in this work can be used for estimations of hydrogen bond strength in various systems, where experimental thermodynamic methods or direct calculations are difficult or even impossible.

show abstract

Successive Protonation of Decaniobate, [Nb10O28]6−: Electronic Properties and Spectra

Steffler,

Haiduke

2023

J Clust Sci

View full text Add to dashboard Cite

Infrared intensity analysis of hydroxyl stretching modes in carboxylic acid dimers by means of the charge–charge flux–dipole flux model

Cited by 6 publications

References 47 publications

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

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

Estimations of FH···X hydrogen bond energies from IR intensities: Iogansen's rule revisited

Successive Protonation of Decaniobate, [Nb10O28]6−: Electronic Properties and Spectra

Contact Info

Product

Resources

About