Probing the Hydrogen Bonding in Microsolvated Clustersof Au 1,2 – (Solv) n (Solv = C 2 H 5 OH, n ‑C 3 H 7 OH; n = 1–3 for Au – ; n =1 for Au 2 – )

The microsolvation of gold anion in different alcohol solvents is demonstrated by the combination of anion photoelectron spectroscopy and quantum chemical calculations on the Au1,2-(Solv)n (Solv=C2H5OH, n-C3H7OH; n=1-3 for Au-; n=1 for Au2-). The microsolvation structures of these clusters and their corresponding neutrals are assigned by comparing calculations with experiments. In terms of overall regularity, the increasing solvation number (n) and carbon chain extension both can increase the stability of the anion. When n ≥ 2, these clusters have low-energy isomers, where conventional hydrogen bonds (HBs) compete with nonconventional hydrogen bonds (NHBs). NHBs are dominant when n ≤ 2 and when n is increased, vice versa. Interestingly, a variety of theoretical calculations show that after the hydroxy H atom of ethanol molecule forms a weak ionic hydrogen bond with Au-, there are two lowest conformations of ethanol, that are trans and gauche, could be coexist in the molecular beams. Some theoretical methods also suggest that the gauche isomer is more stable than the trans one, which indicating that Au- may be exist a gold gauche effect similar to fluorine.