Structure, stability and bonding of the leapfrogB₂₄^0,±1,±2

Abstract

Two new structural motifs of the B 24 clusters are constructed by use of the leapfrog transformation. The resulting leapfrog B 24 has either a bowl shape with a square vacancy or a quasi-planar 2D close-packed triangular boron sheet. The neutral and ionic forms of the latter are found to be more stable than their homologous leapfrog bowl clusters, with the exception of the dicationic B 24 +2. While the leapfrog isomer is less stable than the tubular double ring in the neutral state, it becomes competitive in some ionic states. The nucleus independent chemical shift, electron localization function, ring current maps and the electronic structure of leapfrog B 24 clusters reveal them to behave as aromatics.

Theoretical Study on the Regioselectivity of Leapfrog B18 and B30 Boron Sheets in Electrophilic and Nucleophilic Reactions Using DFT-Based Reactivity Indices

“…In addition, B 18 is nearly planar, whereas B 30 has a curved surface. The intermediate leapfrog B 24 has not been observed experimentally yet and exists only in silico . These two clusters display most structural aspects of the higher leapfrog B 6 n clusters.…”

“…35 Several boron sheets and cages were reported to resemble those of carbon, including leapfrog boron clusters, which can be built by combining omnicapping and dual operations. 8,11 It should be clear from what has been discussed so far that boron, being an electron-deficient atom, can display fascinating bonding properties and geometries. Significant efforts have also been made to explore the chemistry of boron sheets.…”

Structural transformations in boron clusters induced by metal doping

“…21). 207,221 The fact that the tubular form is the most energetically favorable also for the neutral system, B 24 , was assumed as early as 1997 and confirmed six years later by Born–Oppenheimer MD simulations. 222,223 The story is different for the anionic cases.…”

“…21). 207,221 Unsurprisingly, the GM of B 24 2+ and B 24 + adopt such a structure ( 24-1 in Fig. 21).…”

“…224 The same irregular quasi-planar structure is the most stable isomer for B 24 2− and B 24 3− . 221,225…”