Superatomic nature of metal encapsulated dodecahedrane: The case of M@C₂₀H₂₀ (M = Li, Na, Mg⁺)

Abstract

The idea of designing unprecedented materials made of superatomic building blocks, motivated the present study on endohedral M@C 20 H 20 (M = Li, Na, Mg + ) species. Ground and excited electronic structures of M@C 20 H 20 (M = Li, Na, Mg + ) were analyzed by means of high-level quantum calculations. In their ground states, one electron occupies a defuse superatomic s-orbital that lies around the C 20 H 20 cage. These entities populate higher angular momentum p-, d-, f-, g-superatomic orbitals in their low-lying electronic states. The proposed superatomic Aufbau shell model for Li@C 20 H 20 and Na@C 20 H 20 is 1s, 1p, 1d, 2s, 1f, 2p, 2d, 1g, 2f slightly different from that of Mg@C 20 H 20 + which is 1s, 1p, 1d, 2s, 1f, 2p, 2d, 1g, 3s, 2f, 2g, 3p. These introduced superatomic orbital series resemble the Aufbau principle of solvated electron precursors.

Ground and excited electronic structures of electride and alkalide units: The cases of Metal‐Tren, ‐Azacryptand, and ‐TriPip222 complexes

“…Our past investigations disclosed their Aufbau shell model, which is chiefly 1S, 1P, 1D, 1F, 2S, and 2P (in some instances 2S populates prior to the 1F). 22,23 Similar orders are observed in a series of other Rydberg-like systems as well, namely, endohedral M@C 20 H 20 (M = Li, Na, K, Rb), 26,27 M(NH 3 ) 4 (M = Li, Na), 28 and M(H 2 O) 6 (M = Mg + , Ca + ). 29,30 Complexes with such expanded electron clouds tend to carry extremely low ionization potentials and can also be recognized as "Superalkalis."…”

A fresh perspective on metal ammonia molecular complexes and expanded metals: opportunities in catalysis and quantum information

“…74,75 The replacement of oxygen with nitrogen (crown ethers → aza-crown ethers or cyclams) or polydentate nitrogen-anchored ligands (such as cryptands) should be a better choice. 11,64 Less conventional suggestions are a dodecahedrane metal complex 76 or the “inverted” SEPs XM 4 (X = N, P and M = Li, Na). 76 Finally, species containing no metal atoms have been studied in the literature as well.…”

“…11,64 Less conventional suggestions are a dodecahedrane metal complex 76 or the “inverted” SEPs XM 4 (X = N, P and M = Li, Na). 76 Finally, species containing no metal atoms have been studied in the literature as well. 77–80…”

Electronic structure analysis and DFT benchmarking of Rydberg-type alkali-metal-crown ether, -cryptand, and -adamanzane complexes

“…Atom and molecule encapsulated macromolecules or molecular cages often possess unique physicochemical properties compared to their isolated fragments. 1–6 In this regard, development and structural modification of metal-encapsulable macrocyclic ligands for achieving the desired host–guest environments is an ongoing effort especially due to their potential applications in medicine, catalysis, and material science. 5–11 Macrocyclic-polyethers and -polyamines are ideal hosts for the encapsulation of metal atoms.…”

“…, M(NH 3 ) 4 (M = Li, Na, Be + ), 22,23 M(H 2 O) 6 (M = Mg + , Ca + ), 24,25 and M@C 20 H 20 (M = Li, Na, K, Rb, Mg + , Ca + ). 1,2 It should be noted that accurate computational analysis of the excited states of such systems is rather challenging due to the extensively diffuse nature of the peripheral electron which requires the implementation of high-level of quantum chemical methods with highly diffuse basis sets. 26–32 This could be the major reason for the scarcity of excited state studies available on such systems in the literature.…”