Ligand-stabilized aromatic three-membered gold rings and their sandwichlike complexes

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Ligand-stabilized aromatic three-membered gold rings and their sandwichlike complexes (EN)

Tsipis, A. C. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Tsipis, A. C. (EN)

Electronic structure calculations (DFT) suggest that ligand-stabilized three-membered gold(l) rings constituting the core structure in a series of cyclo-Au3LnH3-n (L = CH3, NH2, OH and Cl; n = 1, 2, 3) molecules exhibit aromaticity, which is primarily due to 6s and 5d cyclic electron delocalization over the triangular Au-3 framework (s- and d-orbital aromaticity). The aromaticity of the novel triangular gold(l) isocycles was verified by a number of established criteria of aromaticity. In particular, the nucleus-independent chemical shift, NICS(0), the upfield changes in the chemical shifts for Li+, Ag+, and TI+ cations over the Au-3 ring plane, and their interaction with electrophiles (e.g., H+, Li+, Ag+, and TI+) are indicative for the aromaticity of the three-membered gold(l) rings. Interestingly, unlike the respective substituted derivatives of cyclopropenium cation and the bora-cyclopropene carbacyclic analogues, the aromatic Au-3 rings, although exhibit comparable diatropicity, react with electrophiles in a different way affording 1:1 and 2:1 sandwichlike complexes. The bonding in the three-membered gold(I) rings is characterized by a common ring-shaped electron density, more commonly seen in aromatic organic molecules and in "all-metal" aromatics, such as the cyclo-[Hg-3](4-) tetraanion. Moreover, the cation-pi interactions in the 1:1 and 1:2 sandwichlike complexes formed upon reacting the Au-3 rings with electrophiles, depending on the nature of the cation, are predicted to be predominantly electrostatic (Li+, TI+) or covalent (H+, Ag+). The 1:2 complexes constitute a new class of sandwichlike complexes, which are expected to have novel properties and applications. (EN)

silver bromide clusters (EN)

J Am Chem Soc (EN)



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