Single‐Metal‐Encapsulated Double‐Cage [Pt@Sn₁₇]⁴⁻: An Exception from Group 14 Endohedral Clusters

Abstract

Group 14 endohedral clusters containing a metal center inside usually possess a single cage topological structure, but here an unexpected single-metal-filled doublecage cluster, [Pt@Sn 17 ] 4À (1 a) is reported. It can be seen as a combination of the more extended Pt-filled [Pt@Sn 9 ] cage and hollow [Sn 9 ] cage sharing a central Sn atom, which is offset from the central position. This double-cage species represents the largest group 14 intermetalloid cluster encapsulating a single transition metal atom. DFT calculations show that the capsule-like architecture of [Sn 17 ] 4À , similar to that found in [Pt 2 @Sn 17 ] 4À , is unstable if filled with a single Pt atom and collapses to the title cluster 1 a upon geometry optimization. Deviation of the central Sn atom occurs due to the vibronic coupling as a consequence of pseudo-Jahn-Teller distortion leading to the bent C s -symmetrical structure, in contrast to the more symmetrical D 2d cage previously reported in [Ni 2 @Sn 17 ] 4À .

Bonding character, electronic properties, and electronic transitions of perfluorocubane as a small electron acceptor

“…In order to further elucidate the nature of the chemical bonding of perfluorocubane, the adaptive natural density partitioning (AdNDP) method proposed by Zubarev and Boldyrev 24 was utilized here. The AdNDP method has been found to be very efficient for gaining insight into bonding features and has been successfully employed to explore the bonding natures of metal clusters, [43][44][45] boron compounds, [46][47][48][49] organic materials, [50][51][52] and so on. The principle of the AdNDP method focuses on the electron pairs in a molecule and represents the chemical bonding in terms of n-center two-electron bonds (nc-2e), in which n ranges from one (lone-pairs) to the maximum number of atoms.…”