Interpretation of Electron Delocalization in Benzene, Cyclobutadiene, and Borazine Based on Visualization of Individual Molecular Orbital Contributions to the Induced Magnetic Field
Abstract
The magnetic response of the valence molecular orbitals (MOs) of benzene, cyclobutadiene, and borazine to an external magnetic field has been visualized by calculating the chemical shielding in two-dimensional grids of points on the molecular plane and on a plane perpendicular to it, using gauge-including atomic orbitals (GIAOs). The visualizations of canonical MO contributions to the induced magnetic field (CMO-IMF) provide a clear view of the spatial extension, the shape, and the magnitude of shielding and deshielding areas within the vicinity of the molecule, originating from the induced currents of each valence orbital. The results are used to investigate the delocalization of each valence MO and to evaluate its contribution to the aromatic character of systems under study. The differentiation of the total magnetic response among the three molecules originates exclusively from π-HOMO orbitals because the magnetic response of the subsets of the remaining MOs is found to be almost identical. Borazine is classified as nonaromatic as the four electrons that occupy the π-HOMO are found to be strongly localized on nitrogen centers. CMO-IMF can clarify the interpretation of various NICS indexes and can be applied for the investigation of various types of electron delocalization.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The p_in orbitals of C6 induce a weak short-range diatropic response with a paratropic sphere inside the ring (+19.2 ppm at ring center), which is representative of localized CC σ bonding.
“The p in orbitals of C 6 induce a weak short range diatropic response with a paratropic sphere inside the ring (+19.2 ppm at ring center), which is representative of localized CC s bonding.43”
From Induced magnetic field in sp-hybridized carbon rings: analysis of double aromaticity and antiaromaticity in cyclo[2 <i>N</i> ]carbon allotropes (2020) · cites this paper as [43]
Lower energy valence orbitals induce a diatropic response, whereas the highest occupied orbitals dictate the overall magnetic response.
“Dissection of the induced magnetic field to CMO contributions reveals that lower energy valence orbitals induce a diatropic response, whereas the highest occupied orbitals dictate the overall magnetic response.43,44”
From Induced magnetic field in sp-hybridized carbon rings: analysis of double aromaticity and antiaromaticity in cyclo[2 <i>N</i> ]carbon allotropes (2020) · cites this paper as [43]
The CMO-IMF method allows through-space visualization of shielding and deshielding cones induced by different sets of orbitals, as well as from each CMO.
“by means of canonical orbital contributions to the induced magnetic field (CMO-IMF) that allows the through-space visualization of shielding and deshielding cones induced by different sets of orbitals, as well as from each CMO.[43][44][45][46]”
From Induced magnetic field in sp-hybridized carbon rings: analysis of double aromaticity and antiaromaticity in cyclo[2 <i>N</i> ]carbon allotropes (2020) · cites this paper as [43]
Cites
Nucleus-Independent Chemical Shifts (NICS) as an Aromaticity Criterion
Chen, Z., Wannere, C. S., Corminboeuf, C., Puchta, R., & Schleyer, P. V. R. (2005) · Chemical Reviews · doi:10.1021/cr030088+ · Cited by 3,847 · see citing works
Which NICS Aromaticity Index for Planar π Rings Is Best?
Fallah-Bagher-Shaidaei, H., Wannere, C. S., Corminboeuf, C., Puchta, R., & Schleyer, P. V. R. (2006) · Organic Letters · doi:10.1021/ol0529546 · Cited by 1,257 · see citing works
The Induced Magnetic Field in Cyclic Molecules
Merino, G., Heine, T., & Seifert, G. (2004) · Chemistry – A European Journal · doi:10.1002/chem.200400457 · Cited by 340 · see citing works
Islas, R., Heine, T., & Merino, G. (2012) · Accounts of Chemical Research · doi:10.1021/ar200117a · Cited by 299 · see citing works
Double Aromaticity in Monocyclic Carbon, Boron, and Borocarbon Rings Based on Magnetic Criteria
Wodrich, M. D., Corminboeuf, C., Park, S. S., & Schleyer, P. V. R. (2007) · Chemistry - A European Journal · doi:10.1002/chem.200700154 · Cited by 71 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Charistos, N. D., & Muñoz-Castro, A. (2020) · Physical Chemistry Chemical Physics · doi:10.1039/d0cp01252a · Cited by 88 · see citing works
Self-citation
- Authors
- Charistos, N. D., Papadopoulos, A. G., & Sigalas, M. P.
- Affiliations
- Aristotle University of Thessaloniki (GR)
- Corresponding author
- Charistos, Nickolas D.
- Sigalas, Michael P.
- Venue
- The Journal of Physical Chemistry A
- Publisher
- American Chemical Society (ACS)
- Published
- 2014-01-30
- Volume
- 118
- Issue
- 6
- Pages
- 1113-1122
- ISSN
- 1089-5639 (ISSN-L)
- 1520-5215
- OpenAlex
- W2313677087
- Cited by
- 80
- References
- 5
- Citations by year
- 2026: 9 · 2025: 8 · 2024: 5 · 2023: 8 · 2022: 3 · 2021: 10 · 2020: 11 · 2019: 4 · 2018: 4 · 2017: 7 · 2016: 3 · 2015: 6 · 2014: 2
- FWCI
- 2.64
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- The Journal of Physical Chemistry A (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Physical Sciences › Chemistry › Organic Chemistry › Synthesis and Properties of Aromatic Compounds
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Advanced Chemical Physics Studies
- Physical Sciences › Chemistry › Spectroscopy › Molecular spectroscopy and chirality
- Keywords
- electron delocalization, benzene, cyclobutadiene, borazine, induced magnetic field, chemical shielding, gauge-including atomic orbitals, aromaticity, NICS, valence molecular orbitals
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
