Indexed on: 17 Feb '17Published on: 30 Jan '17Published in: New Journal of Chemistry
The synthesis of the first all-metal aromatic sandwich by Pan et al. (J. Am. Chem. Soc., 2015, 137, 10954) was an important breakthrough in chemistry and is indicative of the possible existence of other similar complexes. In this study, an all-metal aromatic sandwich species with D3h symmetry, [Bi3Au3Bi3]3−, was designed and investigated via density functional theory. Analysis of the bonding nature indicated that the Bi–Bi bond is a nonpolar σ covalent bond, which is mainly attributed to the p orbitals of Bi atoms; the Bi–Au bond is a polar σ covalent bond, which mainly consists of 6s AOs of Au and 6pz AOs of Bi; and the Au–Au bond has a typical aurophilic interaction dominated by 5sAu→6pAu character. Furthermore, charge decomposition analysis indicated an intermolecular electron transfer between cyclo-Bi3 and cyclo-Au3 that explained the weak Jahn–Teller effect in cyclo-Bi3. In addition, the large Egap and small ΔEavgR indicated the stability and potential application of the species as a semiconductor material. Nucleus-independent chemical shift values and molecular orbital analysis indicated that cyclo-Bi3 constitutes uncommon multiple aromaticity (both σ and π aromaticities), and cyclo-Au3 has conflicting aromaticity (σ and δ aromaticity and weak π antiaromaticity).