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Structural Variations and Bonding in Gold Halides: A Quantum Chemical Study of Monomeric and Dimeric Gold Monohalide and Gold Trihalide Molecules, AuX, Au 2 X 2 , AuX 3 , and Au 2 X 6 (X=F, Cl, Br, I)
Author(s) -
Schulz Axel,
Hargittai Magdolna
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010903)7:17<3657::aid-chem3657>3.0.co;2-q
Subject(s) - trihalide , chemistry , molecule , halogen , dimer , crystallography , halide , acceptor , molecular geometry , iodide , computational chemistry , chemical physics , inorganic chemistry , physics , alkyl , organic chemistry , condensed matter physics
The molecular structures of all gold mono‐ and trihalides and of their dimers have been calculated at the B3LYP, MP2, and CCSD(T) levels of theory by using relativistic pseudopotentials for all atoms except fluorine. Our computations support the experimental observation that the relative stability of the monohalides increases from the fluoride toward the iodide, while the stability trend of the trihalides is the opposite. The potential energy surface (PES) of all gold trihalides has been investigated. These molecules are typical Jahn–Teller systems; the trigonal planar D 3h ‐symmetry geometry does not correspond to the minimum energy structure for any of them. At the same time, the amount and character of their Jahn–Teller distortion changes gradually from AuF 3 to AuI 3 . The minimum energy geometry is a T‐shaped structure for AuF 3 and AuCl 3 , with a Y‐shaped transition‐state structure. For AuI 3 , the Y‐shaped structure lies lower than the T‐shaped structure on the PES. For AuBr 3 and AuI 3 , neither of them is the global minimum but instead an L‐shaped structure, which lies outside the Jahn–Teller PES. This structure can be considered to be a donor–acceptor system, or a closed‐shell interaction, with I 2 acting as donor and AuI as acceptor. The dimers of gold monohalides have very short gold–gold distances and demonstrate the aurophilic interaction. The dimers of the trihalides are planar molecules with two bridging halogen atoms.