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Spectroscopic and Computational Evidence of Intramolecular Au I ⋅⋅⋅H + −N Hydrogen Bonding
Author(s) -
Straka Michal,
Andris Erik,
Vícha Jan,
Růžička Aleš,
Roithová Jana,
Rulíšek Lubomír
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201811982
Subject(s) - intramolecular force , chemistry , hydrogen bond , photodissociation , carbene , protonation , crystallography , chemical bond , infrared spectroscopy , spectral line , hydrogen , computational chemistry , molecule , photochemistry , stereochemistry , physics , ion , biochemistry , organic chemistry , astronomy , catalysis
Despite substantial evidence of short Au⋅⋅⋅H−X contacts derived from a number of X‐ray structures of Au I compounds, the nature of Au I ⋅⋅⋅H bonding in these systems has not been clearly understood. Herein, we present the first spectroscopic evidence for an intramolecular Au I ⋅⋅⋅H + −N hydrogen bond in a [Cl−Au−L] + complex, where L is a protonated N‐heterocyclic carbene. The complex was isolated in the gas phase and characterized with helium‐tagging infrared photodissociation (IRPD) spectra, in which H + −N‐mode‐derived bands evidence the intramolecular Au I ⋅⋅⋅H + −N bond. Quantum chemical calculations reproduce the experimental IRPD spectra and allow to characterize the intramolecular Au⋅⋅⋅H + −N bonding with a short r Au⋅⋅⋅H distance of 2.17 Å and an interaction energy of approximately −10 kcal mol −1 . Various theoretical descriptors of chemical bonding calculated for the Au⋅⋅⋅H + −N interaction provide strong evidence for a hydrogen bond of moderate strength.