From an Icosahedron to a Plane: Flattening Dodecaiodo‐dodecaborate by Successive Stripping of Iodine

Farràs, Pau; Vankova, Nina; Liu, Lei; Warneke, Jonas; Dülcks, Thomas; Heine, Thomas; Viñas, Clara; Teixidor, Francesç; Gabel, Detlef

doi:10.1002/chem.201200828

Cited by 32 publications

(33 citation statements)

References 46 publications

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“…Therefore, we computed the Gibbs free energies, ΔG, for both open-and close-B12X7 − at 300, 1500, and 5000 K, through the harmonic approximations for the minimum structures on the potential energy surface at 0 K. The Gibbs free energies were computed by ΔG = Gico -Gope = ΔU + RT -TΔS (U is the internal energy, T is the temperature, R is the gas constant and S is the entropy), and the data are given in Table 1. Previously, it was found that for the B12 cluster with seven iodine substituents, the temperature dependence of ΔG is important, 9 and here we have found the same phenomenon. cage.…”

Section: Resultssupporting

confidence: 88%

“…The transition between the icosahedral and planar structures is found be n = 5 to 7 depending on the temperatures. 9 Later, a combined experimental and theoretical infrared (IR) spectroscopy study was carried out to narrow down the region of transition. 19 The results showed that the simulated IR spectra matches the experimental IR spectra based on the icosahedral structures for n ≥ 8.…”

Section: Introductionmentioning

confidence: 99%

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The effects of halogen elements on the opening of an icosahedral B12 framework

Gong

Osorio

et al. 2017

The Journal of Chemical Physics

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Abstract:The fully halogenated or hydrogenated B12X12 2− (X = H, F, Cl, Br and I) clusters are confirmed to be icosahedral. On the other hand, the bare B12 cluster is shown to have a planar structure. A previous study showed that a transformation from an icosahedron to a plane happens when 5 to 7 iodine atoms are substituted (Chem. Eur. J. 18 (41), 13208-13212).Later, the transition was confirmed to be seven iodine substitutions based on an infrared spectroscopy study (Chem. Phys. Lett. 625,[48][49][50][51][52]. In this study, we investigated the effects of different halogen atoms on the opening of the B12 icosahedral cage by means of density functional theory calculations. We found that the halogen elements do not have significant effects on the geometries of the clusters. The computed IR spectra show similar representative peaks for all halogen substituted clusters. Interestingly, we found a blue-shift in the IR spectra with the increase in the mass of the halogen atoms. Further, we compared the Gibbs free energies at different temperatures for different halogen atoms. The results show that the Gibbs free energy differences between open and close structures of B12X7 − become larger when heavier halogen atoms are present. This interesting finding was subsequently investigated by energy decomposition analysis.Keywords: boron clusters; density functional theory calculations; infrared spectroscopy; Gibbs free energyThe effects of halogen elements on the opening of an icosahedral B12 framework have been investigated by density functional theory calculations and infrared spectroscopy.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The effects of halogen elements on the opening of an icosahedral B12 framework

Gong

Osorio

et al. 2017

The Journal of Chemical Physics

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“…Upon substitution with halogen atoms, this 2D‐to‐3D structural transition occurs earlier with fewer boron atoms. For example, a B 12 cluster was confirmed to be a bowl‐shaped quasi‐planar structure, but it preferred to be a 3D cage structure when more seven iodine atoms were substituted . The earlier 2D‐to‐3D transition in anionic boron clusters also occurs upon addition of transition metals.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Central Location of a Hexagonal Hole in a B₃₆ Cluster

Liu

Osorio

Heine

2016

Chemistry An Asian Journal

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The most stable form of a B cluster has a central hexagonal hole. Such an interesting finding has led to the possible synthesis of a 2D boron sheet by employing the B cluster as the building unit. Herein, a DFT study to investigate the reason for the central location of the hexagonal hole in the B cluster is presented. The results show that the B cluster with a central hexagonal hole is highly thermodynamically and kinetically stable. More importantly, such high stability is further understood through chemical bonding analysis.

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“…In the solid state, boron compounds often adopt threedimensional (3D) structures [6][7][8][9][10]. One heavily studied type is boranes of general form B n H n .…”

Section: Planar Boron Clustersmentioning

confidence: 99%

“…In this circular planar structure, a central boron atom is surrounded by a pentagonal unit, which is directly bonded to the outer B 13 ring. Interestingly, AdNDP (Adaptive Natural Density Partitioning) chemical bonding analysis showed that this cluster is characterized by a unique double π-aromaticity involving ten π-electrons delocalized between the inner pentagon and the outer B 13 ring, similar to the case of cyclodecapentaene, and another two π-electrons delocalized over the central B 6 , and B 30 − anions are also confirmed to be planar [20][21][22][23]. The chemical bonding analysis reveals that the bonding in B 22 − is similar to that in anthracene, and the bonding in B 23 − is analogous to that in phenanthrene.…”

Section: Planar Boron Clustersmentioning

confidence: 99%

Geometries and Electronic Structures of Boron Clusters: Planar Structures and All-boron Fullerenes

Liu¹

2016

J Apl Theol

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[5]. Thus, they attract the interests of interdisciplinary researchers. A primary task in the research of boron clusters is to find the most stable structures of clusters containing given numbers and types of atoms. In this mini-review, we summarize the geometries and electronic structures of two commonly studied boron clusters, planar boron clusters and all-boron fullerenes. Planar Boron ClustersIn the solid state, boron compounds often adopt threedimensional (3D) structures [6][7][8][9][10]. One heavily studied type is boranes of general form B n H n . Most of the boranes are shown to be cage-like, referred as deltahedra [11]. The representative example is B 12 H 12 2− , which was first theoretically investigated by Longuet-Higgins and Roberts using molecular orbital theory [12]. They concluded that the B 12 H 12 structure could be stable only as a di-anion, B 12 H 12 2− , having 13 skeletal bonding orbitals and 12 outward pointing external orbitals. This hypothesis was confirmed later by experimental data, and the structure of B 12 H 12 2− anion was shown to be icosahedral [13]. Unlike 3D cage structures, which are the dominant configurations of boron compounds in the solid state, the pure small boron clusters (n ≤ 40) are found to be two-dimensional (2D) planar or quasi-planar in the gas phase, and the chemical bonding analysis suggests that this planarity is a consequence of π bonding in the cluster forms [9,10]. The simplest pure boron cluster is the diatomic B 2 , which serves as the first example of unusual chemical bonding in the boron species. On the basis of Hartree-Fock and UMP4 (unrestricted fourth order Møller-Plesset perturbation theory) calculations [14], the next pure boron cluster, B 3 , is shown to exist in cationic or anionic forms with a triangular structure of D 3h symmetry.In 2004, Zubarev et al concluded that pure boron clusters containing up to 15 atoms retain planar or quasi-planar conformation [15]. However, there still remains a strong interest to determine the critical size at which structural transition from 2D to 3D occurs. This, however, is a challenging task due to the complexity of these systems and the existence of a large number of isomers. Such 2D-to-3D structural transition is also strongly affected by the charges of boron clusters. For cationic boron clusters (B n + ), the largest planar or quasi-planar structure was established for n=15, and the transition from planar to cylindrical structure takes place for B 16 + [16]. Combining experiment (photoelectron spectroscopy) with computational studies (global minimum search), Kiran et al [17]found that the neutral B 20 cluster undergoes a 2D-to-3D structural transition, resulting in formation of a stable double-ring tubular structure with a diameter of 5.2 Å (Figure 1). The tubular structure was considered as the embryo of the thinnest single-walled boron nanotubes.However, the upper limit for the B n − anionic clusters still remains an open question. Through a joint study of photoelectron spectroscopy and ab initio computatio...

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From an Icosahedron to a Plane: Flattening Dodecaiodo‐dodecaborate by Successive Stripping of Iodine

Cited by 32 publications

References 46 publications

The effects of halogen elements on the opening of an icosahedral B12 framework

The effects of halogen elements on the opening of an icosahedral B12 framework

Understanding the Central Location of a Hexagonal Hole in a B₃₆ Cluster

Geometries and Electronic Structures of Boron Clusters: Planar Structures and All-boron Fullerenes

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From an Icosahedron to a Plane: Flattening Dodecaiodo‐dodecaborate by Successive Stripping of Iodine

Cited by 32 publications

References 46 publications

The effects of halogen elements on the opening of an icosahedral B12 framework

The effects of halogen elements on the opening of an icosahedral B12 framework

Understanding the Central Location of a Hexagonal Hole in a B36 Cluster

Geometries and Electronic Structures of Boron Clusters: Planar Structures and All-boron Fullerenes

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Understanding the Central Location of a Hexagonal Hole in a B₃₆ Cluster