A cyclic (R2SnAu)3 anion (3−, R2Sn=2,2,5,5‐tetrakis(trimethylsilyl)‐1‐stannacyclopentane‐1,1‐diyl) has been synthesized as a stable blue salt with K+(THF)6 through the reaction of stable dialkylstannylene 1 with R′3PAuCl (R′=Et, Ph) followed by the reduction with KC8. Crystallographic and NMR analysis shows that the six‐membered (SnAu)3 ring of 3− is planar and highly symmetric with an equal distance of six Au−Sn bonds. A UV/Vis spectrum of 3− in hexane reveals an intense absorption maximum at 598 nm. While cyclic Au3− with four valence electrons is known as unstable anti‐aromatic anion, 3− with three divalent tin ligands is stable σ aromatic anion with an unprecedented Möbius orbital array as predicted by the perturbation MO and CCSD analysis of 3−.

The bonding between gold and main-group metallic elements (M) featuring Auδ−−Mδ+ polarity, has been studied recently. The gold in the bonds is expected to have the oxidation number of −1, and hence, nucleophilic. However, the knowledge of the reactivity of the gold-metal bonds remains limited. Here, we report digold-substituted germanes of the form of R’2Ge(AuPR3)(AuGeR’2) (3a; R = Me, 3b; R = Et), featuring two Au-Ge(IV) and one Au-Ge(II) bonds. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene pπ nature. A pendular motion of AuPR3 group between Ge(IV) and Ge(II) of 3 occurs in the NMR time scale, suggesting that the Ge(II) center has an enhanced electrophilicity to be attacked by the nucleophilic gold (−I) atom. 3a reacts with nucleophilic Cl− and electrophilic MeOTf reagents at Ge(II) and Ge(IV) centers, respectively.

A cyclic (R2SnAu)3 anion (3−, R2Sn=2,2,5,5‐tetrakis(trimethylsilyl)‐1‐stannacyclopentane‐1,1‐diyl) has been synthesized as a stable blue salt with K+(THF)6 through the reaction of stable dialkylstannylene 1 with R′3PAuCl (R′=Et, Ph) followed by the reduction with KC8. Crystallographic and NMR analysis shows that the six‐membered (SnAu)3 ring of 3− is planar and highly symmetric with an equal distance of six Au−Sn bonds. A UV/Vis spectrum of 3− in hexane reveals an intense absorption maximum at 598 nm. While cyclic Au3− with four valence electrons is known as unstable anti‐aromatic anion, 3− with three divalent tin ligands is stable σ aromatic anion with an unprecedented Möbius orbital array as predicted by the perturbation MO and CCSD analysis of 3−.

Fluoro(dialkyl)stannylenoid 2 exhibits unique reactivity towards ethynes with acetylenic hydrogen and those with trimethylsilyl groups, though the corresponding free dialkylstannylene 1 is inactive against those ethynes. Stannylenoid 2 reacts smoothly...