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Hypothetical heterocyclic carbenes

  • Brian F. Yates ORCID logo EMAIL logo
Published/Copyright: June 20, 2025
Pure and Applied Chemistry
From the journal Pure and Applied Chemistry Volume 97 Issue 9

Abstract

Density functional theory is used to explore the geometries and properties of 55 heterocyclic carbenes containing N, P, As, Sb, Bi, O, S, Se, Te and Po. Planar and non-planar structures have been systematically evaluated and a variety of measures (including Wiberg bond indices, orbital occupancies, HOMO–LUMO gaps, proton affinities, J(13C–1H) coupling constants and isodesmic reaction energies) have been considered for all systems. The main conclusions are that the heavier heteroatoms can be effective π-donors towards the carbene carbon if planarity can be attained, and that the cost of attaining this planarity is actually quite low for the majority of the heterocyclic carbenes considered.

Keywords: π donation from heavy elements; indenylidene and fluorenylidene heterocyclic carbene analogues; planarity; quantum science and technology
Corresponding author: Brian F. Yates, University of Tasmania, Private Bag 75, Hobart, TAS 7001, Australia, e-mail:
Article note: A collection of invited papers to celebrate the UN’s proclamation of 2025 as the International Year of Quantum Science and Technology.

Funding source: Australian Research Council

Award Identifier / Grant number: DP180100904

Acknowledgments

This research was supported by the University of Tasmania high performance computing facility and a grant from the Australian Research Council.

  1. Research ethics: Not applicable.

  2. Informed consent: Not applicable.

  3. Author contributions: The author has accepted responsibility for the entire content of this manuscript and approved its submission.

  4. Use of Large Language Models, AI and Machine Learning Tools: None declared.

  5. Conflict of interest: The author states no conflict of interest.

  6. Research funding: This study was supported by the Australian Research Council through grant number DP180100904.

  7. Data availability: Data is available in the Supplementary Material accompanying this manuscript.

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Supplementary Material

This article contains supplementary material (https://doi.org/10.1515/pac-2025-0472).

Received: 2025-03-31
Accepted: 2025-06-06
Published Online: 2025-06-20
Published in Print: 2025-09-25

© 2025 IUPAC & De Gruyter

Articles in the same Issue

  1. Frontmatter
  2. IUPAC Technical Report
  3. Acid dissociation constants in selected dipolar non-hydrogen-bond-donor solvents (IUPAC Technical Report)
  4. Preface
  5. Introduction to the Special Issue of “The International Year of Quantum”
  6. Review Articles
  7. Quantum chemistry of molecules in solution. A brief historical perspective
  8. From Hückel to Clar: a block-localized description of aromatic systems
  9. Exploring potential energy surfaces
  10. Unlocking the chemistry facilitated by enzymes that process nucleic acids using quantum mechanical and combined quantum mechanics–molecular mechanics techniques
  11. Hypothetical heterocyclic carbenes
  12. Is relativistic quantum chemistry a good theory of everything?
  13. When theory came first: a review of theoretical chemical predictions ahead of experiments
  14. Research Articles
  15. Exploring reaction dynamics involving post-transition state bifurcations based on quantum mechanical ambimodal transition states
  16. Molecular aromaticity: a quantum phenomenon
  17. Using topology for understanding your computational results
  18. The role of ion-pair on the olefin polymerization reactivity of zirconium bis(phenoxy-imine) catalyst: quantum mechanical study and its beyond
  19. Theoretical insights on the structure and stability of the [C2, H3, P, O] isomeric family
https://doi.org/10.1515/pac-2025-0472
Keywords for this article
π donation from heavy elements; indenylidene and fluorenylidene heterocyclic carbene analogues; planarity; quantum science and technology

Articles in the same Issue

  1. Frontmatter
  2. IUPAC Technical Report
  3. Acid dissociation constants in selected dipolar non-hydrogen-bond-donor solvents (IUPAC Technical Report)
  4. Preface
  5. Introduction to the Special Issue of “The International Year of Quantum”
  6. Review Articles
  7. Quantum chemistry of molecules in solution. A brief historical perspective
  8. From Hückel to Clar: a block-localized description of aromatic systems
  9. Exploring potential energy surfaces
  10. Unlocking the chemistry facilitated by enzymes that process nucleic acids using quantum mechanical and combined quantum mechanics–molecular mechanics techniques
  11. Hypothetical heterocyclic carbenes
  12. Is relativistic quantum chemistry a good theory of everything?
  13. When theory came first: a review of theoretical chemical predictions ahead of experiments
  14. Research Articles
  15. Exploring reaction dynamics involving post-transition state bifurcations based on quantum mechanical ambimodal transition states
  16. Molecular aromaticity: a quantum phenomenon
  17. Using topology for understanding your computational results
  18. The role of ion-pair on the olefin polymerization reactivity of zirconium bis(phenoxy-imine) catalyst: quantum mechanical study and its beyond
  19. Theoretical insights on the structure and stability of the [C2, H3, P, O] isomeric family
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