Catalytic Potential of [B₁₂X₁₁]^2– (X = F, Cl, Br, I, CN) Dianions

Abstract

Dodecaborate anions ([B12H12]2–) and their derivatives where hydrogen atoms are replaced by halogen, pseudohalogen, or superhalogen moieties belong to a class of very stable species, even in the gas phase. Their stability is attributed to Wade’s electron counting rule that requires n + 1 pairs of skeletal electrons, n being the number of boron atoms. Consequently, [B12 X 11]2– (X = H, F, Cl, Br, I, CN) dianions that carry one more electron than needed to satisfy Wade’s rule should not be stable, assuming that the rule applies to fragments as well. While this is the case for X = H, we show that [B12 X 11]2– (X = F, Cl, Br, I, CN) dianions are stable with the second electron in [B12(CN)11]2– bound by as much as 3.17 eV. More importantly, the stability of these dianions is found to have a significant effect on the activation of gas molecules such as CO2 and N2, providing a path toward the development of new catalysts.

Enhancement of Visible Light-Driven Water Splitting and CO2 Conversion Activities of SrTiO3 by Tuning the Dopant Charge State

“…The angular distortion is found to be more for the SrO-terminated surface except for the case of (Ni, 2F) doping. These observations are favorable for weakening the CO 2 molecule, thereby activating it, as reported by Kilic and Jena …”

Activation of Small Molecules by Modified Dodecaborate Anions

“…The geometries and total energies of [B 12 X 12 ], [B 12 X 11 ] n − , and [B 12 X 11 ] n − ( n = 0, 1, 2; X = H, F, CN) clusters interacting with small molecules, Y = H 2 , O 2 , CO, and NH 3 , are calculated using density functional theory (DFT) and the B3LYP exchange-correlation functional . We used the Gaussian 16 code with the 6-31+G­(d,p) basis set for all atoms as this choice has led to good agreement between theory and experiment . All the structures are fully optimized without any symmetry constraint.…”

“…In a recent article, we showed that if one of the ligands X from [B 12 X 12 ] 2– (X = F, CN) could be removed in neutral form, the resulting cluster, [B 12 X 11 ] 2– , can remain stable against the detachment of the second electron. This is consistent with an earlier experimental observation of [B 12 Br 11 ] 2– .…”

“…We had earlier shown that [B 12 X 11 ] 2– (X = F, CN) can activate CO 2 and N 2 more strongly than their monoanionic counterpart, [B 12 X 11 ] − . To understand the underlying reason for this enhanced reactivity, we examined the distribution of the second electron in [B 12 X 11 ] 2– .…”

Structural and Stress Response of Nanotwinned B13CN under Large Strains

“…Boron-rich carbides (e.g., B 4 C and B 13 C 2 ) are exemplary cases among boron-rich compounds that exhibit unique properties of high hardness (30–50 GPa) and low density (∼2.5·gcm –3 ), with applications in body armor, cutting tools, and neutron radiation absorbents. − However, owing to low fracture toughness (3–4 MPa·m 1/2 ), B 4 C exhibits brittle failure under high pressure while forming amorphous shear bands. − To design and synthesize lightweight materials with excellent mechanical properties, various boron-rich compounds have been extensively explored, e.g., B 6 O, B 13 C 2 , and B 13 CN. − In boron-rich compounds, a B 12 icosahedron serves as the skeleton unit in which two-center two-electron (2c-2e) and three-center two-electron (3c-2e) bonding configurations coexist and exhibits unique bonding characteristics because of its electron-deficient nature. − The mechanical properties of boron-rich compounds are highly sensitive to their electron-filling states because of the electron-deficient icosahedrons and electron-compensating atomic chains. Thus, understanding their mechanical properties under various electron-filling states is crucial.…”