Spectroscopic and Computational Evidence of Intramolecular AuI ???H+ -N Hydrogen Bonding.

ABSTRACT: Despite substantial evidence of short Au???H-X contacts derived from a number of X-ray structures of AuI compounds, the nature of AuI ???H bonding in these systems has not been clearly understood. Herein, we present the first spectroscopic evidence for an intramolecular AuI ???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 AuI ???H+ -N bond. Quantum chemical calculations reproduce the experimental IRPD spectra and allow to characterize the intramolecular Au???H+ -N bonding with a short rAu???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.

SUBMITTER: Straka M 

PROVIDER: S-EPMC6519277 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature