Stabilizing Otherwise Unstable Anions with Halogen Bonding
Abstract
Both hydrogen bonding (HB) and halogen bonding (XB) are essentially electrostatic interactions, but whereas hydrogen bonding has a well-documented record of stabilizing unstable anions, little is known about halogen bonding's ability to do so. Herein, we present a combined anion photoelectron spectroscopic and density functional theory study of the halogen bond-stabilization of the pyrazine (Pz) anion, an unstable anion in isolation due to its neutral counterpart having a negative electron affinity (EA). The halogen bond formed between the σ-hole on bromobenzene (BrPh) and the lone pair(s) of Pz significantly lowers the energies of the Pz(BrPh)_1− and Pz(BrPh)_2− anions relative to the neutral molecule, resulting in the emergence of a positive EA for the neutral complexes. As seen through its charge distribution and electrostatic potential analyses, the negative charge on Pz− is diluted due to the XB. Thermodynamics reveals that the low temperature of the supersonic expansion plays a key role in forming these complexes.
Additional Information
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. Issue online: 2 August 2017; Version of record online: 18 July 2017; Accepted manuscript online: 29 June 2017; Manuscript Received: 6 June 2017. This material is based upon work supported by the (U.S.) National Science Foundation under Grant No. CHE-1664182. The authors declare no conflict of interest.Attached Files
Supplemental Material - anie201705738-sup-0001-misc_information.pdf
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Additional details
- Eprint ID
- 79146
- Resolver ID
- CaltechAUTHORS:20170718-091808141
- CHE-1664182
- NSF
- Created
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2017-07-18Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field