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 rst-principles theory calculations, we predict herein the perfect tetrahedral cage-like T d La 4 B 24 (1) and core-shell T d La 4 B 29 (2), T d La 4 B 29 + (3), and T d La 4 B 29 -(4) which all possess the same geometrical symmetry as their carbon fullerene counterpart T d C 28 , with four equivalent interconnected B 6 triangles on the cage surface and four nona-coordinate La centers in four conjoined η 9 -B 9 rings. In these tetra-La-doped boron complexes, La 4 [B@B 4 @B 24 ] 0/+/-(2/3/4) in the structural motif of1+4+28 contain a B-centered tetrahedral T d B@B 4 core in a La-decorated tetrahedral La 4 B 24 shell, with the negatively charged tetra-coordinate Bat the center being the boron analog of tetrahedral C in T d CH 4 (B -C). Detailed orbital and bonding analyses indicate that these T d lanthanide boride complexes are spherically aromatic in nature with a universal La--B 9 (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.

Lanthanide/actinide boride nanoclusters and nanomaterials based on boron frameworks consisting of conjoined Bnrings (n= 7–9)

“…Further increasing the cluster sizes, our group reported in two recent papers on singlet O h La 7 B 24 + ( 6 ) and doublet O h La 7 B 24 with six conjoined B 8 rings, tetrahedral T d La 4 B 24 ( 8 ) with four conjoined B 9 rings, and tetrahedral T d La 4 B 29 − ( 10 ) with four conjoined B 9 rings encapsulating a tetrahedral BB 4 core at the center. 31,32 We focus here on their actinide analogues O h Ac 7 B 24 + ( 6′ ), O h Ac 7 B 24 , T d Ac 4 B 24 ( 8′ ), T d Ac 4 B 29 − ( 10′ ), and the newly obtained core–shell C 1 M 5 B 24 + ( 9/9′ ) (M = La, Ac). Both the endohedral singlet Ac 7 B 24 + ( 6′ ) and doublet O h Ac 7 B 24 which can be viewed as six embedded La 2 B 8 inverse sandwiches in a cube sharing a La vertex at the center possess perfect body-centered structures with six equivalent octa-coordinate Ac atoms on the surface and one Ac atom at the center, T d Ac 4 B 24 ( 8′ ) as an ideal tetrahedral metallo-borospherene contains a boron framework consisting of four conjoined B 9 rings with four equivalent nona-coordinate Ac atoms as integrated parts of the cage surface, C 1 La 5 B 24 + ( 9 ) and C 1 Ac 5 B 24 + ( 9′ ) are slightly distorted endohedral tetrahedral metallo-borospherenes with four nona-coordinate metal atoms on the surface and one metal atom slightly off-centered, while T d Ac 4 B 29 − ( 10′ ) has a perfect tetrahedral core–shell structure with a tetrahedral T d BB 4 unit encapsulated at the center.…”

“…29 Based on extensive global minimum (GM) searches and first-principles theory calculations, our group recently proposed a series of novel lanthanide boride nanoclusters including the smallest double-ring tubular molecular rotor C 2h La 2 [B 2 @B 18 ] with a B 2 dumb-bell inside, 30 perfect endohedral cubic O h La 7 B 24 + ( 6 ) and O h La 7 B 24 with six conjoined inverse La 2 B 8 sandwiches sharing a La atom at the center, perfect tetrahedral metallo-borospherene T d La 4 B 24 ( 8 ) with four nona-coordinate La atoms on the cage surface, perfect tetrahedral core–shell metallo-borospherene T d La 4 B 29 0/+/− ( 10 ) (B@B 4 @La 4 B 24 ) with a tetrahedral BB 4 unit at the center, and endohedral trihedral metallo-borospherenes D 3h La@[La 5 &B 30 ] 0/2− with spherical aromaticity. 31–33 However, tetra-La-doped boride complexes La 4 B n −/0 ( n = 13–18) with conjoined B 7 , B 8 , and B 9 rings as ligands still remain unknown in both experiments and theory, and more importantly, the chemistry and materials science of the corresponding actinide boride nanoclusters and their low-dimensional nanomaterials have not been explored to date in either experiments or theory possibly due to the radioactivity of actinide. Modern quantum chemistry provides powerful means to fulfil the gaps in such situations.…”

“…(8) with four nona-coordinate La atoms on the cage surface, perfect tetrahedral core-shell metallo-borospherene T d La 4 B 29 0/+/À (10) (B@B 4 @La 4 B 24 ) with a tetrahedral BB 4 unit at the center, and endohedral trihedral metallo-borospherenes D 3h La@[La 5 &B 30 ] 0/2À with spherical aromaticity [31][32][33]. However, tetra-La-doped boride complexes La 4 B n À/0 (n = 13-18) with conjoined B 7 , B 8 , and B 9 rings as ligands still remain unknown in both experiments and theory, and more importantly, the chemistry and materials science of the corresponding actinide boride nanoclusters and their low-dimensional nanomaterials have not been explored to date in either experiments or…”

OsB9−: An Aromatic Osmium-Centered Monocyclic Boron Ring

“…These unusual structural and electronic properties can be regarded as a consequence of the electron deficiency of boron atom, which gives rise to the extraordinary ability of boron to form delocalized multi-center bonds with itself and other elements. Indeed, the introduction of heteroatoms in boron clusters has created a variety of intriguing doped boron clusters, including metal-centered monocyclic ring/tubular/cage structures, (Romanescu et al, 2011;Jian et al, 2016;Dong et al, 2018;Liang et al, 2018;Chen et al, 2019;Lu et al, 2021), half-sandwich structures, (Chen et al, 2018;Ren et al, 2019), inverse sandwich structures, (Cui et al, 2020;Jiang et al, 2021), metallo-borophenes (Li et al, 2016;Zhang et al, 2016) and metallo-borospherenes, (Chen et al, 2020;Zhang et al, 2021), strongly leading to a new direction of research on boron chemistry and pushing the limit of structural chemistry as well as the record of coordination number in 2D and 3D environments for central metal atoms. (Islas et al, 2007;Liu et al, 2007;Miao et al, 2009;Popov et al, 2014;Pan et al, 2018;Chen et al, 2019).…”

TM4B180/− (TM = Hf, Ta, W, Re, Os): new structure construction with TM doped B wheel units

“…The perfect core–shell La 4 [B@B 4 @B 24 ] 0/+/− clusters have been theoretically proposed to possess four equivalentinter-connected B 6 triangles on the cage surface. 38 …”