M4 @Si28 (M=Al,Ga): metal-encapsulated tetrahedral silicon fullerene

Cu12@Au30Ag12: a magnetic pentakis icosidodecahedron molecule with core-shell configuration

A 54-atom trimetallic core-shell Cu₁₂@Au₃₀Ag₁₂ molecule has been identified by using first-principles calculations. This molecule with I_h symmetry consists of an icosahedral 12-atom Cu core (Cu₁₂) coated by a pentakis icosidodecahedral 42-atom Au-Ag shell (Au₃₀Ag₁₂) composed of an icosidodecahedral Au₃₀ and an icosahedral Ag₁₂. Both the molecular dynamics simulations and vibrational frequency analysis demonstrate the high stability of Cu₁₂@Au₃₀Ag₁₂. The analyses for electronic properties indicate that there exists spd hybridization which is crucial to maintain the geometrical configuration of Cu₁₂@Au₃₀Ag₁₂. Moreover, a total spin magnetic moment of Cu₁₂@Au₃₀Ag₁₂ is found to be 4 µ_B, which chiefly arises from the 6 s states of Au atoms. A new type of sugar gourd-like [Cu₁₂@Au₃₀Ag₁₁]_n nanowire is also proposed; the results demonstrate that the nanowire exhibits metallic and magnetic behaviors. The magnetic Cu₁₂@Au₃₀Ag₁₂ molecule and [Cu₁₂@Au₃₀Ag₁₁]_n nanowire can be promising candidates of novel magnetic nanomaterials and nanodevices.

Perfect Spherical Tetrahedral Metallo-Borospherene Ta4B18 as a Superatom Following the 18-Electron Rule

Cage-like metallo-borospherenes exhibit unique structures and bonding. Inspired by the newly reported smallest spherical trihedral metallo-borospherene D 3h Ta3B12 - (1), which contains two equivalent B3 triangles interconnected by three B2 units on the cage surface, we present herein a first-principles theory prediction of the perfect spherical tetrahedral metallo-borospherene T d Ta4B18 (2), which possesses four equivalent B3 triangles interconnected by six B atoms, with four equivalent nonacoordinate Ta centers in four η9-B9 rings as integrated parts of the cage surface. As the well-defined global minimum of the neutral, Ta4B18 (2) possesses four 10c-2e B9(π)-Ta(dσ) and eight 10c-2e B9(π)-Ta(dδ) coordination bonds evenly distributed over four Ta-centered Ta@B9 nonagons, with the remaining 18 valence electrons in nine 22c-2e totally delocalized bonds following the 18-electron principle (1S21P61D10) of a superatom. Such a bonding pattern renders spherical aromaticity to the tetrahedral complex, which can be used as building blocks to form the face-centered cubic crystal Ta4B15 (3). The IR, Raman, and UV-vis spectra of Ta4B18 (2) are theoretically simulated to facilitate its future experimental characterizations.

Cage-like La4B24 and Core-Shell La4B290/+/- : perfect spherically aromatic tetrahedral metallo-borospherenes

Cage-like and core-shell metallo-borospherenes exhibit interesting structures and bonding. Based on extensive global searches and first-principles theory calculations, we predict herein the perfect tetrahedral cage-like T_d La₄B₂₄ (1) and core-shell T_d La₄B₂₉ (2), T_d La₄B₂₉⁺ (3), and T_d La₄B₂₉^- (4) which all possess the same geometrical symmetry as their carbon fullerene counterpart T_d C₂₈, with four equivalent interconnected B₆ triangles on the cage surface and four nona-coordinate La centers in four conjoined η⁹-B₉ rings. In these tetra-La-doped boron complexes, La₄[B@B₄@B₂₄]^0/+/- (2/3/4) in the structural motif of 1 + 4 + 28 contain a B-centered tetrahedral T_d B@B₄ core in a La-decorated tetrahedral La₄B₂₄ shell, with the negatively charged tetra-coordinate B^- at the center being the boron analog of tetrahedral C in T_d CH₄ (B^- ~ C). Detailed orbital and bonding analyses indicate that these T_d lanthanide boride complexes are spherically aromatic in nature with a universal La--B₉ (d-p) σ and (d-p) δ coordination bonding pattern. The IR, Raman, and UV-Vis or photoelectron spectra of these novel metallo-borospherenes are computationally simulated to facilitate their spectral characterizations. Graphical abstract.

Transition from exohedral to endohedral structures of AuGen− (n = 2–12) clusters: photoelectron spectroscopy and ab initio calculations

AuGe₁₂⁻ has an I_h symmetric endohedral icosahedral structure. It also shows 3D aromaticity.

Discovery of a silicon-based ferrimagnetic wheel structure in V(x)Si(12)(-) (x = 1-3) clusters: photoelectron spectroscopy and density functional theory investigation

Our studies show that VSi(12)(-) adopts a V-centered hexagonal prism with a singlet spin state. The addition of the second V atom leads to a capped hexagonal antiprism for V(2)Si(12)(-) in a doublet spin state. Most interestingly, V(3)Si(12)(-) exhibits a ferrimagnetic, bicapped hexagonal antiprism wheel-like structure with a total spin of 4 μ(B).

Exohedral silicon fullerenes: SiNPtN∕2 (20⩽N⩽60)

Using density functional theory method we show that hollow silicon fullerene cages, SiN (20<or=N<or=60), can be fully stabilized by exohedrally coated platinum atoms (PtN/2), denoted as SiNPtN/2. The exohedral coating PtN/2 passivates the dangling bonds of the silicon cages, thereby making the silicon cages SiN to retain the symmetry and structure of homologous carbon fullerenes CN. In particular, the Ih symmetrical, 60-atom silicon buckminsterfullerene cage (Si60) can be fully stabilized by exohedrally coated 30 Pt atoms. Properties of SiNPtN/2, such as the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap and relative stability of cage isomers, are calculated and compared with their carbon counterparts. It is found that the HOMO-LUMO gaps of SiNPtN/2 are close to their carbon fullerene counterparts (CN). The trend in relative stability for exohedral fullerene isomers SiNPtN/2 is similar to that for the homologous carbon fullerenes (CN). The exohedral Pt coating offers a possible molecular design towards stabilizing the silicon fullerene cages.

To Achieve Stable Spherical Clusters: General Principles and Experimental Confirmations

General principles for designing stable highly symmetrical clusters are proposed. This approach takes advantage of both the extra stability of cage aromaticity and the good geometrical balance between the outer cage and the endohedral atom. The applicability of these design principles was confirmed by gas-phase experimental observations on group 14 element cages with endohedral Al's and also is illustrated by many literature examples of diverse systems.