The interplay between hydrogen and halogen bonding: substituent effects and their role in the hydrogen bond enhanced halogen bond.

Autor: Sun J; Department of Chemistry and Biochemistry, University of Montana, 32 Campus Drive Missoula MT 59812 USA orion.berryman@umontana.edu., Decato DA; Department of Chemistry and Biochemistry, University of Montana, 32 Campus Drive Missoula MT 59812 USA orion.berryman@umontana.edu., Bryantsev VS; Chemical Sciences Division, Oak Ridge National Laboratory Oak Ridge TN 37831 USA., John EA; Department of Chemistry and Biochemistry, University of Montana, 32 Campus Drive Missoula MT 59812 USA orion.berryman@umontana.edu., Berryman OB; Department of Chemistry and Biochemistry, University of Montana, 32 Campus Drive Missoula MT 59812 USA orion.berryman@umontana.edu.
Jazyk: angličtina
Zdroj: Chemical science [Chem Sci] 2023 Jul 21; Vol. 14 (33), pp. 8924-8935. Date of Electronic Publication: 2023 Jul 21 (Print Publication: 2023).
DOI: 10.1039/d3sc02348f
Abstrakt: The hydrogen bond enhanced halogen bond (HBeXB) has recently been used to effectively improve anion binding, organocatalysis, and protein structure/function. In this study, we present the first systematic investigation of substituent effects in the HBeXB. NMR analysis confirmed intramolecular HBing between the amine and the electron-rich belt of the XB donor (N-H⋯I). Gas-phase density functional theory studies showed that the influence of HBing on the halogen atom is more sensitive to substitution on the HB donor ring (R 1 ). The NMR studies revealed that the intramolecular HBing had a significant impact on receptor performance, resulting in a 50-fold improvement. Additionally, linear free energy relationship (LFER) analysis was employed for the first time to study the substituent effect in the HBeXB. The results showed that substituents on the XB donor ring (R 2 ) had a competing effect where electron donating groups strengthened the HB and weakened the XB. Therefore, selecting an appropriate substituent on the adjacent HB donor ring (R 1 ) could be an alternative and effective way to enhance an electron-rich XB donor. X-ray crystallographic analysis demonstrated that intramolecular HBing plays an important role in the receptor adopting the bidentate conformation. Taken together, the findings imply that modifying distal substituents that affect neighboring noncovalent interactions can have a similar impact to conventional para substitution substituent effects.
Competing Interests: There are no conflicts to declare.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
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