The nature of closed-shell AuI···AuI attraction is still a conundrum in theoretical chemistry. However, for Au2F2 with a zigzag conformation, the d10–d10 closed-shell interaction between the AuF monomers is demonstrated as a coordinate covalent bond. Chemical bonding analysis reveals that the strong AuI···AuI attraction is caused by the participation of the extraordinary active 5d orbital of Au. Based on our study, one of the 5d orbitals of the Au atom is activated to hybridize with its 6s and 6p orbitals to form hybridized dsp2 orbitals, where each Au atom is both an electron donor (Lewis base) and acceptor (Lewis Acid) in dimerization. Actually, the closed-shell AuI···AuI interaction in the zigzag conformation of Au2X2 (X = F, Cl, Br, I, or NH2) is covalent. Our results provide a rather simple but clear-cut example, where mysterious AuI···AuI attractions can be possibly explained by the covalent bond theory.

Utilizing a customized metal cluster source in tandem with a flow tube reactor and a reflectron time-of-flight mass spectrometer, we have obtained well-resolved pure metal clusters Pt n − and observed their gas-phase reactions with a few small gas molecules. Interestingly, the remarkable inertness of Pt 10 − was repeatedly observed in different reactions. Meanwhile, we have determined the structure of Pt 10 − within a regular tetrahedron. Considering that Pt possesses 5d 9 6s 1 electron configuration, the tetrahedral Pt 10 − exhibits unexpected stability at neither a magic number of valence electrons nor a shell closure of geometric structure. Comprehensive theoretical calculations unveil the stability of Pt 10 − is significantly associated with the allmetal aromaticity. In addition to the classical total aromaticity, which is mainly due to 6s electrons, there is unique beta-aromaticity ascribed to spin-polarized beta 5d electrons pertaining to singly occupied multicenter bonds. Further, we demonstrate the superatomic feature of such a transition metal cluster Pt 10 − , as Pt 6 @Pt 4 − , in mimicking methane.

No abstract

The synthesis and application of compounds with Cr-Cr and V-V d-d quintuple bonds (σ, 2π, 2δ) have led to a new thinking about whether d-d multiple bonds also exist between...