Cage-Like La4B24 and Core-Shell La4B290/+/-: Perfect Spherically Aromatic Tetrahedral Metallo-Borospherenes

Abstract

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 Td La4B24 (1) and core-shell Td La4B29 (2), Td La4B29+ (3), and Td La4B29- (4) which all possess the same geometrical symmetry as their carbon fullerene counterpart Td 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 Td 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 Td CH4 (B-~C). Detailed orbital and bonding analyses indicate that these Td 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.

Geometric and electronic diversity of metal doped boron clusters

“…For example, the highly symmetric di-lanthanide metal-boron clusters Ln(B 8 )Ln (Ln = La, Pr) [106], [La(η x −B x )La] − (x = 7-9) [107], and La 3 B 14 − clusters consist of two connected B 8 rings which form an inverse three-layer configuration [108], while metallo-borospherene La 3 B 18 − has a fullerene-like structure [109]. A number of different geometrical configurations of the lanthanum-boron clusters were discovered by the Li group using first-principles calculations; namely, a half-sandwiching configuration [110] and a tubular configuration of D 9d symmetry for La 2 [B 18 ] 0/2− , a configuration of C 2h symmetry for core-shell La 2 [B 2 @B 18 ] with two lanthanum atoms in a trans position [111], a cubic configuration of O h symmetry for La 6 [La@B 24 ] 0/+ [112], a caged structure of T d symmetry for La 4 B 24 and a core-shell structure of T d symmetry for La 4 B 29 [113]. In 2021, Jin et al performed a systematic study of neutral and anionic smallsized B n clusters (n = 9-20) doped with a single cesium atom by using a structure prediction method and DFT calculations [114].…”

Sc@B28−, Ti@B28, V@B28+, and V@B292−: Spherically Aromatic Endohedral Seashell-like Metallo-Borospherenes

“…Perfect transition-metal-centered wheel-like D and Tb 3 B 18 − have also been reported in experiments [36,37]. With inspirations from these experimental observations, our group predicted the smallest core-shell spherical trihedral metallo-boronospherene D 3h La 3 [B 2 @B 18 ] − , perfect spherically aromatic tetrahedral metallo-borospherenes T d La 4 B 24 and core-shell T d La 4 B 29 0/+/− (La 4 [B@B 4 @B 24 ] 0/+/− ), endohedral metallo-borospherenes O h La 6 &[La@B 24 ] +/0 , and the spherically aromatic trihedral metallo-borospherene D 3h La 6 B 30 in a series of recent papers [38][39][40][41]. Spherical trihedral metallo-borospherenes and endohedral Complexes of B 20 TM n (TM = Sc, Y; n = 3, 4) were predicted recently [42].…”