{"entity": "publication", "iuid": "7124e92b71b74c53a6b0673e31f27a91", "timestamp": "2026-07-18T15:30:55.222Z", "links": {"self": {"href": "https://publications.scilifelab.se/publication/7124e92b71b74c53a6b0673e31f27a91.json"}, "display": {"href": "https://publications.scilifelab.se/publication/7124e92b71b74c53a6b0673e31f27a91"}}, "title": "Halogen Bond Asymmetry in Solution.", "authors": [{"family": "Lindblad", "given": "Sofia", "initials": "S"}, {"family": "Mehmeti", "given": "Krenare", "initials": "K"}, {"family": "Veiga", "given": "Alberte X", "initials": "AX"}, {"family": "Nekoueishahraki", "given": "Bijan", "initials": "B"}, {"family": "Gr\u00e4fenstein", "given": "J\u00fcrgen", "initials": "J"}, {"family": "Erd\u00e9lyi", "given": "M\u00e1t\u00e9", "initials": "M", "orcid": "0000-0003-0359-5970", "researcher": {"href": "https://publications.scilifelab.se/researcher/f772b571449e417ca6fda2eee361a0c3.json"}}], "type": "journal article", "published": "2018-10-17", "journal": {"volume": "140", "issn": "1520-5126", "issue": "41", "pages": "13503-13513", "title": "J. Am. Chem. Soc.", "issn-l": "0002-7863"}, "abstract": "Halogen bonding is the noncovalent interaction of halogen atoms in which they act as electron acceptors. Whereas three-center hydrogen bond complexes, [D\u00b7\u00b7\u00b7H\u00b7\u00b7\u00b7D] + where D is an electron donor, exist in solution as rapidly equilibrating asymmetric species, the analogous halogen bonds, [D\u00b7\u00b7\u00b7X\u00b7\u00b7\u00b7D]+, have been observed so far only to adopt static and symmetric geometries. Herein, we investigate whether halogen bond asymmetry, i.e., a [D-X\u00b7\u00b7\u00b7D]+ bond geometry, in which one of the D-X bonds is shorter and stronger, could be induced by modulation of electronic or steric factors. We have also attempted to convert a static three-center halogen bond complex into a mixture of rapidly exchanging asymmetric isomers, [D\u00b7\u00b7\u00b7X-D]+ \u21c4 [D-X\u00b7\u00b7\u00b7D]+, corresponding to the preferred form of the analogous hydrogen bonded complexes. Using 15N NMR, IPE NMR, and DFT, we prove that a static, asymmetric geometry, [D-X\u00b7\u00b7\u00b7D]+, is obtained upon desymmetrization of the electron density of a complex. We demonstrate computationally that conversion into a dynamic mixture of asymmetric geometries, [D\u00b7\u00b7\u00b7X-D]+ \u21c4 [D-X\u00b7\u00b7\u00b7D]+, is achievable upon increasing the donor-donor distance. However, due to the high energetic gain upon formation of the three-center-four-electron halogen bond, the assessed complex strongly prefers to form a dimer with two static and symmetric three-center halogen bonds over a dynamic and asymmetric halogen bonded form. Our observations indicate a vastly different preference in the secondary bonding of H+ and X+. Understanding the consequences of electronic and steric influences on the strength and geometry of the three-center halogen bond provides useful knowledge on chemical bonding and for the development of improved halonium transfer agents.", "doi": "10.1021/jacs.8b09467", "pmid": "30234293", "labels": {"Swedish NMR Centre": "Service"}, "xrefs": [{"db": "pmc", "key": "PMC6209183"}], "notes": [], "created": "2018-10-31T13:03:34.950Z", "modified": "2025-10-17T13:03:58.487Z"}