| 1. |
- Poater, Jordi, et al.
(författare)
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Single-Not Double-3D-Aromaticity in an Oxidized Closo Icosahedral Dodecaiodo-Dodecaborate Cluster
- 2023
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 145:41, s. 22527-22538
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Tidskriftsartikel (refereegranskat)abstract
- 3D-aromatic molecules with (distorted) tetrahedral, octahedral, or spherical structures are much less common than typical 2D-aromatic species or even 2D-aromatic-in-3D systems. Closo boranes, [BnHn](2-) (5 = n = 14) and carboranes are examples of compounds that are singly 3D-aromatic, and we now explore if there are species that are doubly 3D-aromatic. The most widely known example of a species with double 2D-aromaticity is the hexaiodobenzene dication, [C6I6](2+). This species shows p-aromaticity in the benzene ring and s-aromaticity in the outer ring formed by the iodine substituents. Inspired by the hexaiodobenzene dication example, in this work, we explore the potential for double 3D-aromaticity in [B12I12](0/2+). Our results based on magnetic and electronic descriptors of aromaticity together with B-11{H-1} NMR experimental spectra of boron-iodinated o-carboranes suggest that these two oxidized forms of a closo icosahedral dodecaiodo-dodecaborate cluster, [B12I12] and [B12I12](2+), behave as doubly 3D-aromatic compounds. However, an evaluation of the energetic contribution of the potential double 3D-aromaticity through homodesmotic reactions shows that delocalization in the I-12 shell, in contrast to the 10s-electron I-6(2+) ring in the hexaiodobenzene dication, does not contribute to any stabilization of the system. Therefore, the [B12I12](0/2+) species cannot be considered as doubly 3D-aromatic.
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| 2. |
- Matxain, Jon M, et al.
(författare)
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New solids based on B12N12 fullerenes
- 2007
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Ingår i: The Journal of Physical Chemistry C. - Washington, DC : American Chemical Society. - 1932-7447 .- 1932-7455. ; 111:36, s. 13354-60
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, BN fullerenes have been synthesized experimentally. As their carbon counterparts, these BN fullerenes could be assembled in molecular solids, but this possibility has been studied little in the literature. In this work, we focus on the smallest synthesized BN fullerene, B12N12, which is built by squares and hexagons. First, the interaction between two of these fullerenes has been analyzed, using the hybrid B3LYP and MPW1PW91 density functional methods. Two different interactions have been studied in the dimer, a square facing a square (S−S) and a hexagon facing a hexagon (H−H). In both cases, a B is facing a N. The most stable dimer was found to be S−S facing, with covalent interactions between the monomers, but other dimers with weak interactions have been found as well, which opens possibilities of new systems, as in the case of fullerene dimers and solids. The solids resulting from the infinite repetition of the characterized dimers were optimized, finding two different solids, with covalent and weak interactions between monomers, respectively. The solid with covalent interactions is a nanoporous material that is more stable by around 12 eV. Because of the nanoporous character of this solid, it could be used for heterogeneous catalysis, molecular transport, and so forth. The SIESTA code with the GGA-PBE density functional method has been used for the solid-state calculations.
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