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Title: Bond-bending isomerism of Au2I3-: Competition between covalent bonding and aurophilicity

We report a joint photoelectron spectroscopy and theoretical investigation of the gaseous Au2I3 cluster, which is found to exhibit two types of isomers due to competition between Au–I covalent bonding and Au–Au aurophilic interactions. The covalent bonding favors a bent IAuIAuI structure with an obtuse Au–I–Au angle (100.7°), while aurophilic interactions pull the two Au atoms much closer, leading to an acutely bent structure (72.0°) with an Au–Au distance of 3.08 Å. The two isomers are separated by a small barrier and are nearly degenerate with the obtuse isomer being slightly more stable. At low temperature, only the obtuse isomer is observed; distinct experimental evidence is observed for the co-existence of a combination of isomers with both acute and obtuse bending angles at room temperature. As a result, the two bond-bending isomers of Au2I3 reveal a unique example of one molecule being able to oscillate between different structures as a result of two competing chemical forces.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [4] ;  [5] ;  [1] ;  [3] ;  [1]
  1. Tsinghua Univ., Beijing (China)
  2. Chinese Academy of Sciences (CAS), Shanghai (China)
  3. Brown Univ., Providence, RI (United States)
  4. Tsinghua Univ., Beijing (China); Chinese Academy of Sciences (CAS), Shanghai (China)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
1239322
Report Number(s):
LA-UR--15-21694
Journal ID: ISSN 2041-6520; CSHCBM
Grant/Contract Number:
1263745; 21433005, 21201106, and 21221062; AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY ab initio calculation; bond-bending isomer; aurophilicity; photoelectron spectroscopy; chemical bonding