Proximal noncovalent forces are commonplace in natural systems and understanding the consequences of their juxtaposition is critical. This paper experimentally quantifies for the first time a Hydrogen Bond‐Enhanced Halogen Bond (HBeXB) without the complexities of protein structure or preorganization. An HBeXB is a halogen bond that has been strengthened when the halogen donor simultaneously accepts a hydrogen bond. Our theoretical studies suggest that electron‐rich halogen bond donors are strengthened most by an adjacent hydrogen bond. Furthermore, stronger hydrogen bond donors enhance the halogen bond the most. X‐ray crystal structures of halide complexes (X−=Br−, I−) reveal that HBeXBs produce shorter halogen bonds than non‐hydrogen bond analogues.19F NMR titrations with chloride highlight that the HBeXB analogue exhibits stronger binding. Together, these results form the foundation for future studies concerning hydrogen bonds and halogen bonds in close proximity.
The lone pair of the N atom is a common electron donor in noncovalent bonds. Quantum calculations examine how various aspects of the base on which the N is located affect the strength and other properties of complexes formed with Lewis acids FH, FBr, F2Se, and F3As that respectively encompass hydrogen, halogen, chalcogen, and pnicogen bonds. In most cases the halogen bond is the strongest, followed in order by chalcogen, hydrogen, and pnicogen. The noncovalent bond strength increases in the sp
- Award ID(s):
- 1954310
- PAR ID:
- 10422834
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ChemPhysChem
- Volume:
- 24
- Issue:
- 15
- ISSN:
- 1439-4235
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Proximal noncovalent forces are commonplace in natural systems and understanding the consequences of their juxtaposition is critical. This paper experimentally quantifies for the first time a Hydrogen Bond‐Enhanced Halogen Bond (HBeXB) without the complexities of protein structure or preorganization. An HBeXB is a halogen bond that has been strengthened when the halogen donor simultaneously accepts a hydrogen bond. Our theoretical studies suggest that electron‐rich halogen bond donors are strengthened most by an adjacent hydrogen bond. Furthermore, stronger hydrogen bond donors enhance the halogen bond the most. X‐ray crystal structures of halide complexes (X−=Br−, I−) reveal that HBeXBs produce shorter halogen bonds than non‐hydrogen bond analogues.19F NMR titrations with chloride highlight that the HBeXB analogue exhibits stronger binding. Together, these results form the foundation for future studies concerning hydrogen bonds and halogen bonds in close proximity.
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