Spectroscopic and Computational Evidence of Intramolecular Au(I)DOT OPERATOR DOT OPERATOR DOT OPERATOR H+-N Hydrogen Bonding
Abstrakt
Despite substantial evidence of short AuH-X contacts derived from a number of X-ray structures of Au-I compounds, the nature of (AuH)-H(I) bonding in these systems has not been clearly understood. Herein, we present the first spectroscopic evidence for an intramolecular (AuH(+))-H(I)-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 (AuH(+))-H(I)-N bond. Quantum chemical calculations reproduce the experimental IRPD spectra and allow to characterize the intramolecular AuH(+)-N bonding with a short r(Au(H)) distance of 2.17 angstrom and an interaction energy of approximately -10kcal.mol(-1).
Various theoretical descriptors of chemical bonding calculated for the AuH(+)-N interaction provide strong evidence for a hydrogen bond of moderate strength.