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Abstract Throughout the halogen bonding literature, electron withdrawing groups are relied upon heavily for tuning the interaction strength between the halogen bond donor and acceptor; however, the interplay of electronic effects associated with various substituents is less of a focus. This work utilizes computational techniques to study the degree ofσ‐ andπ‐electron donating/accepting character of electron withdrawing groups in a prescribed set of halo‐alkyne, halo‐benzene, and halo‐ethynyl benzene halogen bond donors. We examine how these factors affect theσ‐hole magnitude of the donors as well as the binding strength of the corresponding complexes with an ammonia acceptor. Statistical analyses aid the interpretation of how these substituents influence the properties of the halogen bond donors and complexes, and show that the electron withdrawing groups that are bothσ‐ andπ‐electron accepting form the strongest halogen bond complexes.
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This content will become publicly available on February 11, 2026
Methyl‐π Interactions. Nature of Bonding and Limits of Strength
Abstract Both methyl groups and benzene rings are exceedingly common, and they lie near one another in many chemical situations. DFT calculations are used to gauge the strength of the attractive forces between them, and to better understand the phenomena that underlie this attraction. Methane and benzene are taken as the starting point, and substituents of both electron‐withdrawing and donating types are added to each. The interaction energy varies between 1.4 and 5.0 kcal/mol, depending upon the substituents placed on the two groups. The nature of the binding is analyzed via Atoms in Molecules (AIM), Natural Bond Orbital (NBO), Symmetry‐Adapted Perturbation Theory (SAPT), nuclear magnetic resonance (NMR) chemical shifts, and electron density shift diagrams. While there is a sizable electrostatic component, it is dispersion that dominates these interactions, particularly the weaker ones. As such, these interactions cannot be categorized unambiguously as either H‐bonds or tetrel bonds.
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- Award ID(s):
- 1954310
- PAR ID:
- 10572606
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 31
- Issue:
- 19
- ISSN:
- 0947-6539
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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