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Title: Bond-bending isomerism of Au 2I 3 -: Competition between covalent bonding and aurophilicity

We report a joint photoelectron spectroscopy and theoretical investigation of the gaseous Au 2I 3 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 Au 2I 3 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:
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 Lab. (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
OSTI Identifier:
1239322