Perfect cubic La-doped boron clusters La₆&[La@B₂₄]^+/0as the embryos of low-dimensional lanthanide boride nanomaterials

Abstract

Perfect cubic clusters Oh La6&[La@B24]+/0 are predicted at first-principles levels to be the embryos of 1D La10B32, 2D La3B10, and 3D LaB6 lanthanide boride nanomaterials in a bottom-up approach.

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

“…These results are well comparable with the corresponding values of a = 8.66 Å, a = b = 4.17 Å, and a = b = c = 4.16 Å calculated for their lanthanide boride counterparts 1D La 10 B 32 , 2D La 3 B 10 , and 3D LaB 6 at the same theoretical level. 32 The calculated La–B distances of r Ac–B = 3.10 Å for 3D AcB 6 ( 13′ ), r Ac–B( x ) = r Ac–B( y ) = 3.08 Å, and r Ac–B( z ) = 3.10 Å for 2D Ac 3 B 10 ( 12′ ) also correspond well with the corresponding values in their lanthanide boride counterparts. 32 Similar Ac–B distances are obtained for 1D Ac 10 B 32 ( 11′ ).…”

“…32 The calculated La–B distances of r Ac–B = 3.10 Å for 3D AcB 6 ( 13′ ), r Ac–B( x ) = r Ac–B( y ) = 3.08 Å, and r Ac–B( z ) = 3.10 Å for 2D Ac 3 B 10 ( 12′ ) also correspond well with the corresponding values in their lanthanide boride counterparts. 32 Similar Ac–B distances are obtained for 1D Ac 10 B 32 ( 11′ ). It is worth noticing that cubic B 24 frameworks with six conjoined B 8 rings in O h Ac 7 B 24 + ( 6′ ) and O h Ac 7 B 24 are well maintained in its 1D, 2D, and 3D nanostructures with infinite conjoined B 8 rings in periodical arrangements (Fig.…”

“…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.…”

La@[La5&B30]0/−/2−: endohedral trihedral metallo-borospherenes with spherical aromaticity

“…26 Highly stable endohedral metallo-borospherenes O h La 6 &[La@B 24 ] +/0 have been predicted to be embryos of low-dimensional lanthanide boride nanomaterials. 27 However, whether larger endohedral metallo-borospherenes with spherical aromaticity exist or not and if such clusters can be used as building blocks to form low-dimensional boron nanomaterials still remain unknown to date in both theory and experiments.…”