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Publication Abstract from PubMed

The halogen bond (X-bond) has become an important design element in chemistry, including medicinal chemistry and biomolecular engineering. Although oxygen is the most prevalent and best characterized X-bond acceptor in biomolecules, the interaction is seen with nitrogen, sulfur, and aromatic systems as well. In this study, we characterize the structure and thermodynamics of a Br...S X-bond between a 5-bromouracil base and a phosphorothioate in a model DNA junction. The single-crystal structure of the junction shows the geometry of the Br...S to be variable, while calorimetric studies show that the anionic S acceptor is comparable to or slightly more stable than the analogous O acceptor, with a -3.5 kcal/mol difference in DeltaDeltaH(25( degrees )C) and -0.4 kcal/mol DeltaDeltaG(25( degrees )C) (including an entropic penalty DeltaDeltaS(25( degrees )C) of -10 cal/(mol K)). Thus sulfur is shown to be a favorable acceptor for bromine X-bonds, extending the application of this interaction for the design of inhibitors and biological materials.

Sulfur as an Acceptor to Bromine in Biomolecular Halogen Bonds.,Ford MC, Saxton M, Ho PS J Phys Chem Lett. 2017 Sep 7;8(17):4246-4252. doi: 10.1021/acs.jpclett.7b01725., Epub 2017 Aug 24. PMID:28796521^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.