Nonconventional hydrogen bonding between clusters of gold and hydrogen fluoride.
The bonding patterns between small neutral gold Au(3 < or = n < or = 7) and hydrogen fluoride (HF)(1 < or = m < or = 4) clusters are discussed using a high-level density functional approach. Two types of interactions, anchoring Au-F and F-H...Au, govern the complexation of these clusters. The F-H...Au interaction exhibits all the characteristics of nonconventional hydrogen bonding and plays a leading role in stabilizing the lowest-energy complexes. The anchor bonding mainly activates the conventional F-H...F hydrogen bonds within HF clusters and reinforces the nonconventional F-H...Au one. The strength of the F-H...Au bonding, formed between the terminal conventional proton donor group FH and an unanchored gold atom, depends on the coordination of the involved gold atom: the less it is coordinated, the stronger its nonconventional proton acceptor ability. The strongest F-H...Au bond is formed between a HF dimer and the singly coordinated gold atom of a T-shape Au4 cluster and is accompanied by a very large red shift (1023 cm(-1)) of the nu(F-H) stretch. Estimations of the energies of formation of the F-H...Au bonds for the entire series of the studied complexes are provided.
Kryachko
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Department of Chemistry, Bat. B6c, University of Liège, Sart-Tilman, B-4000, Liège, Belgium. eugene.kryachko@ulg.ac.be
Karpfen
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A
Remacle
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