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New Science of Boron Allotropes, Compounds, and Nanomaterials

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 27696

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Special Issue Editors


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Guest Editor
Department of Materials Science, Faculty of Pure and Applied Sciences University of Tsukuba, Ibaraki 305-8577, Japan
Interests: surface science; molecular beam scattering; nitrogen-doped carbon; hydrogen boride; boron hydride; borophene; borophane; two-dimensional materials; reaction dynamics

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Guest Editor
Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
Interests: atomic layer; surface; spectroscopy

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Guest Editor
Physical Chemistry Institute “Rocasolano”, CSIC, Serrano 119, ES-28006 Madrid, Spain
Interests: electronic structure; quantum chemistry; boron chemistry; chemical bond; computational chemistry

Special Issue Information

Dear Colleagues,

Boron is known to have a large number of allotropes. Boron compounds and boron nanomaterials are also known to show polymorphs because, compared to other compounds, they form a wide variety of chemical bonds with each other. Thus, there are several important research subjects in theoretical, computational, and experimental physics and chemistry. A recent example is the realization of two-dimensional planar boron nanomaterials (borophene), showing polymorphisms as expected. This Special Issue aims to provide a forum for the dissemination of the latest information on boron allotropes, compounds, and nanomaterials.

Dr. Takahiro Kondo
Prof. Dr. Iwao Matsuda
Dr. Josep M. Oliva-Enrich
Guest Editors

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Keywords

  • Boron nanomaterials
  • Borophene
  • Borophane
  • 2D boron compounds
  • Borane
  • Boride
  • Planar 2D
  • boron molecules
  • Hybrid boron–carbon 2D system
  • Boron clusters
  • Bonding in boron 2D compounds and molecules
  • Interaction of boron 2D and 3D systems with light and electrons

Published Papers (13 papers)

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Research

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15 pages, 5898 KiB  
Article
Accelerated Synthesis of Borophane (HB) Sheets through HCl-Assisted Ion-Exchange Reaction with YCrB4
by Xiaoni Zhang, Miwa Hikichi, Takushi Iimori, Yuki Tsujikawa, Mei Yuan, Masafumi Horio, Kunio Yubuta, Fumio Komori, Masahiro Miyauchi, Takahiro Kondo and Iwao Matsuda
Molecules 2023, 28(7), 2985; https://doi.org/10.3390/molecules28072985 - 27 Mar 2023
Cited by 7 | Viewed by 1750
Abstract
We present an enhanced method for synthesizing sheets of borophane. Despite the challenges associated with low efficiency, we discovered that incorporating hydrochloric acid into the ion-exchange reaction significantly improved the production yield from 20% to over 50%. After a thorough examination of the [...] Read more.
We present an enhanced method for synthesizing sheets of borophane. Despite the challenges associated with low efficiency, we discovered that incorporating hydrochloric acid into the ion-exchange reaction significantly improved the production yield from 20% to over 50%. After a thorough examination of the reaction, we gained insight into the underlying mechanisms and found that the use of hydrochloric acid provides two key benefits: accelerated production of borophene and isolation of high-purity products. This method has the potential to pave the way for the production of novel topological 2D materials with potential industrial applications. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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9 pages, 1541 KiB  
Communication
Rhombohedral Boron Monosulfide as a p-Type Semiconductor
by Norinobu Watanabe, Keisuke Miyazaki, Masayuki Toyoda, Kotaro Takeyasu, Naohito Tsujii, Haruki Kusaka, Akiyasu Yamamoto, Susumu Saito, Masashi Miyakawa, Takashi Taniguchi, Takashi Aizawa, Takao Mori, Masahiro Miyauchi and Takahiro Kondo
Molecules 2023, 28(4), 1896; https://doi.org/10.3390/molecules28041896 - 16 Feb 2023
Cited by 6 | Viewed by 1874
Abstract
Two-dimensional materials have wide ranging applications in electronic devices and catalysts owing to their unique properties. Boron-based compounds, which exhibit a polymorphic nature, are an attractive choice for developing boron-based two-dimensional materials. Among them, rhombohedral boron monosulfide (r-BS) has recently attracted considerable attention [...] Read more.
Two-dimensional materials have wide ranging applications in electronic devices and catalysts owing to their unique properties. Boron-based compounds, which exhibit a polymorphic nature, are an attractive choice for developing boron-based two-dimensional materials. Among them, rhombohedral boron monosulfide (r-BS) has recently attracted considerable attention owing to its unique layered structure similar to that of transition metal dichalcogenides and a layer-dependent bandgap. However, experimental evidence that clarifies the charge carrier type in the r-BS semiconductor is lacking. In this study, we synthesized r-BS and evaluated its performance as a semiconductor by measuring the Seebeck coefficient and photo-electrochemical responses. The properties unique to p-type semiconductors were observed in both measurements, indicating that the synthesized r-BS is a p-type semiconductor. Moreover, a distinct Fano resonance was observed in Fourier transform infrared absorption spectroscopy, which was ascribed to the Fano resonance between the E(2) (TO) phonon mode and electrons in the band structures of r-BS, indicating that the p-type carrier was intrinsically doped in the synthesized r-BS. These results demonstrate the potential future application prospects of r-BS. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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13 pages, 6230 KiB  
Article
Prediction of a Cyclic Hydrogenated Boron Molecule as a Promising Building Block for Borophane
by Yasunobu Ando, Takeru Nakashima, Heming Yin, Ikuma Tateishi, Xiaoni Zhang, Yuki Tsujikawa, Masafumi Horio, Nguyen Thanh Cuong, Susumu Okada, Takahiro Kondo and Iwao Matsuda
Molecules 2023, 28(3), 1225; https://doi.org/10.3390/molecules28031225 - 26 Jan 2023
Cited by 2 | Viewed by 1952
Abstract
We have extensively searched for a cyclic hydrogenated boron molecule that has a three-center two-electron bond at the center. Using first-principles calculations, we discovered a stable molecule of 2:4:6:8:-2H-1,5:1,5-μH-B8H10 and propose its existence. This molecule can be regarded as a [...] Read more.
We have extensively searched for a cyclic hydrogenated boron molecule that has a three-center two-electron bond at the center. Using first-principles calculations, we discovered a stable molecule of 2:4:6:8:-2H-1,5:1,5-μH-B8H10 and propose its existence. This molecule can be regarded as a building block for sheets of topological hydrogen boride (borophane), which was recently theoretically proposed and experimentally discovered. The electronic structure of the cyclic hydrogenated boron molecule is discussed in comparison with that of cyclic hydrogenated carbon molecules. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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25 pages, 6799 KiB  
Article
Hall Effect Anisotropy in the Paramagnetic Phase of Ho0.8Lu0.2B12 Induced by Dynamic Charge Stripes
by Artem L. Khoroshilov, Kirill M. Krasikov, Andrey N. Azarevich, Alexey V. Bogach, Vladimir V. Glushkov, Vladimir N. Krasnorussky, Valery V. Voronov, Natalya Y. Shitsevalova, Volodymyr B. Filipov, Slavomir Gabáni, Karol Flachbart and Nikolay E. Sluchanko
Molecules 2023, 28(2), 676; https://doi.org/10.3390/molecules28020676 - 9 Jan 2023
Cited by 2 | Viewed by 1251
Abstract
A detailed study of charge transport in the paramagnetic phase of the cage-cluster dodecaboride Ho0.8Lu0.2B12 with an instability both of the fcc lattice (cooperative Jahn–Teller effect) and the electronic structure (dynamic charge stripes) was carried out at temperatures [...] Read more.
A detailed study of charge transport in the paramagnetic phase of the cage-cluster dodecaboride Ho0.8Lu0.2B12 with an instability both of the fcc lattice (cooperative Jahn–Teller effect) and the electronic structure (dynamic charge stripes) was carried out at temperatures 1.9–300 K in magnetic fields up to 80 kOe. Four mono-domain single crystals of Ho0.8Lu0.2B12 samples with different crystal axis orientation were investigated in order to establish the singularities of Hall effect, which develop due to (i) the electronic phase separation (stripes) and (ii) formation of the disordered cage-glass state below T*~60 K. It was demonstrated that a considerable intrinsic anisotropic positive component ρanxy appears at low temperatures in addition to the ordinary negative Hall resistivity contribution in magnetic fields above 40 kOe applied along the [001] and [110] axes. A relation between anomalous components of the resistivity tensor ρanxyanxx1.7 was found for H||[001] below T*~60 K, and a power law ρanxyanxx0.83 for the orientation H||[110] at temperatures T < TS~15 K. It is argued that below characteristic temperature TS~15 K the anomalous odd ρanxy(T) and even ρanxx(T) parts of the resistivity tensor may be interpreted in terms of formation of long chains in the filamentary structure of fluctuating charges (stripes). We assume that these ρanxy(H||[001]) and ρanxy(H||[110]) components represent the intrinsic (Berry phase contribution) and extrinsic (skew scattering) mechanism, respectively. Apart from them, an additional ferromagnetic contribution to both isotropic and anisotropic components in the Hall signal was registered and attributed to the effect of magnetic polarization of 5d states (ferromagnetic nano-domains) in the conduction band of Ho0.8Lu0.2B12. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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15 pages, 3575 KiB  
Article
Electrochemical Characterization and Voltammetric Determination of Methylisothiazolinone on a Boron-Doped Diamond Electrode
by Magdalena Jakubczyk, Slawomir Michalkiewicz, Agata Skorupa and Kinga Krajcarz
Molecules 2022, 27(24), 9013; https://doi.org/10.3390/molecules27249013 - 17 Dec 2022
Viewed by 1732
Abstract
The electrochemical properties of methylisothiazolinone (MIT), the most widely used preservative, were investigated by cyclic (CV) and differential pulse voltammetry (DPV) to develop a new method for its determination. To our knowledge, this is the first demonstration of a voltammetric procedure for the [...] Read more.
The electrochemical properties of methylisothiazolinone (MIT), the most widely used preservative, were investigated by cyclic (CV) and differential pulse voltammetry (DPV) to develop a new method for its determination. To our knowledge, this is the first demonstration of a voltammetric procedure for the determination of MIT on a boron-doped diamond electrode (BDDE) in a citrate–phosphate buffer (C-PB) environment. The anodic oxidation process of methylisothiazolinone, which is the basis of this method, proved to be diffusion-controlled and proceeded with an irreversible two-electron exchange. The radical cations, as unstable primary products, were converted in subsequent chemical reactions to sulfoxides and sulfones, and finally to more stable final products. Performed determinations were based on the DPV technique. A linear calibration curve was obtained in the concentration range from 0.7 to 18.7 mg L−1, with a correlation coefficient of 0.9999. The proposed procedure was accurate and precise, allowing the detection of MIT at a concentration level of 0.24 mg L−1. It successfully demonstrated its suitability for the determination of methylisothiazolinone in household products without the need for any separation steps. The proposed method can serve as an alternative to the prevailing chromatographic determinations of MIT in real samples. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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12 pages, 3034 KiB  
Article
Highly Dispersed Ni Nanoclusters Spontaneously Formed on Hydrogen Boride Sheets
by Natsumi Noguchi, Shin-ichi Ito, Miwa Hikichi, Yohei Cho, Kazuho Goto, Atsushi Kubo, Iwao Matsuda, Takeshi Fujita, Masahiro Miyauchi and Takahiro Kondo
Molecules 2022, 27(23), 8261; https://doi.org/10.3390/molecules27238261 - 26 Nov 2022
Cited by 4 | Viewed by 2197
Abstract
Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonal boron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1. Herein, we report the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets. The spontaneous reduction reaction [...] Read more.
Hydrogen boride (HB) sheets are two-dimensional materials comprising a negatively charged hexagonal boron network and positively charged hydrogen atoms with a stoichiometric ratio of 1:1. Herein, we report the spontaneous formation of highly dispersed Ni nanoclusters on HB sheets. The spontaneous reduction reaction of Ni ions by the HB sheets was monitored by in-situ measurements with an ultraviolet-visible spectrometer. Acetonitrile solutions of Ni complexes and acetonitrile dispersions of the HB sheets were mixed in several molar ratios (the HB:Ni molar ratio was varied from 100:0.5 to 100:20), and the changes in the absorbance were measured over time. In all cases, the results suggest that Ni metal clusters grow on the HB sheets, considering the increase in absorbance with time. The absorbance peak position shifts to the higher wavelength as the Ni ion concentration increases. Transmission electron microscopy images of the post-reaction products indicate the formation of Ni nanoclusters, with sizes of a few nanometers, on the HB sheets, regardless of the preparation conditions. These highly dispersed Ni nanoclusters supported on HB sheets will be used for catalytic and plasmonic applications and as hydrogen storage materials. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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8 pages, 1162 KiB  
Communication
Structure of χ3-Borophene Studied by Total-Reflection High-Energy Positron Diffraction (TRHEPD)
by Yuki Tsujikawa, Makoto Shoji, Masashi Hamada, Tomoya Takeda, Izumi Mochizuki, Toshio Hyodo, Iwao Matsuda and Akari Takayama
Molecules 2022, 27(13), 4219; https://doi.org/10.3390/molecules27134219 - 30 Jun 2022
Cited by 1 | Viewed by 1683
Abstract
We have investigated the structure of χ3-borophene on Ag(111), a monolayer material of boron atoms, via total-reflection high-energy positron diffraction (TRHEPD). By comparing the experimental rocking-curves with ones for several structures calculated by using dynamical diffraction theory, we confirmed that the [...] Read more.
We have investigated the structure of χ3-borophene on Ag(111), a monolayer material of boron atoms, via total-reflection high-energy positron diffraction (TRHEPD). By comparing the experimental rocking-curves with ones for several structures calculated by using dynamical diffraction theory, we confirmed that the χ3-borophene layer has a flat structure. The distance from the topmost layer of the metal crystal is 2.4 Å, which is consistent with results reported by X-ray standing wave-excited X-ray photoelectron spectroscopy. We also demonstrated that the in-plane structure of χ3-borophene is compatible with the theoretical predictions. These structural properties indicate that χ3-borophene belongs to a group of epitaxial monolayer sheets, such as graphene, which have weak interactions with the substrates. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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14 pages, 1843 KiB  
Article
Electrochemistry of Cobalta Bis(dicarbollide) Ions Substituted at Carbon Atoms with Hydrophilic Alkylhydroxy and Carboxy Groups
by Lukáš Fojt, Bohumír Grüner, Jan Nekvinda, Ece Zeynep Tűzűn, Luděk Havran and Miroslav Fojta
Molecules 2022, 27(6), 1761; https://doi.org/10.3390/molecules27061761 - 8 Mar 2022
Cited by 1 | Viewed by 1709
Abstract
In this study we explore the effect on the electrochemical signals in aqueous buffers of the presence of hydrophilic alkylhydroxy and carboxy groups on the carbon atoms of cobalta bis(dicarbollide) ions. The oxygen-containing exo-skeletal substituents of cobalta bis(dicarbollide) ions belong to the [...] Read more.
In this study we explore the effect on the electrochemical signals in aqueous buffers of the presence of hydrophilic alkylhydroxy and carboxy groups on the carbon atoms of cobalta bis(dicarbollide) ions. The oxygen-containing exo-skeletal substituents of cobalta bis(dicarbollide) ions belong to the perspective building blocks that are considered for bioconjugation. Carbon substitution provides wider versatility and applicability in terms of the flexibility of possible chemical pathways. However, until recently, the electrochemistry of compounds substituted only on boron atoms could be studied, due to the unavailability of carbon-substituted congeners. In the present study, electrochemistry in aqueous phosphate buffers is considered along with the dependence of electrochemical response on pH and concentration. The compounds used show electrochemical signals around −1.3 and +1.1 V of similar or slightly higher intensities than in the parent cobalta bis(dicarbollide) ion. The signals at positive electrochemical potential correspond to irreversible oxidation of the boron cage (the C2B9 building block) and at negative potential correspond to the reversible redox process of (CoIII/CoII) at the central atom. Although the first signal is typically sharp and its potential can be altered by a number of substituents, the second signal is complex and is composed of three overlapping peaks. This signal shows sigmoidal character at higher concentrations and may be used as a diagnostic tool for aggregation in solution. Surprisingly enough, the observed effects of the site of substitution (boron or carbon) and between individual groups on the electrochemical response were insignificant. Therefore, the substitutions would preserve promising properties of the parent cage for redox labelling, but would not allow for the further tuning of signal position in the electrochemical window. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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20 pages, 3871 KiB  
Article
Relative Stability of Boron Planar Clusters in Diatomic Molecular Model
by Levan Chkhartishvili
Molecules 2022, 27(5), 1469; https://doi.org/10.3390/molecules27051469 - 22 Feb 2022
Cited by 2 | Viewed by 1664
Abstract
In the recently introduced phenomenological diatomic molecular model imagining the clusters as certain constructions of pair interatomic chemical bonds, there are estimated specific (per atom) binding energies of small all-boron planar clusters Bn, n = 1–15, in neutral single-anionic and single-cationic [...] Read more.
In the recently introduced phenomenological diatomic molecular model imagining the clusters as certain constructions of pair interatomic chemical bonds, there are estimated specific (per atom) binding energies of small all-boron planar clusters Bn, n = 1–15, in neutral single-anionic and single-cationic charge states. The theoretically obtained hierarchy of their relative stability/formation probability correlates not only with results of previous calculations, but also with available experimental mass-spectra of boron planar clusters generated in process of evaporation/ablation of boron-rich materials. Some overestimation in binding energies that are characteristic of the diatomic approach could be related to differences in approximations made during previous calculations, as well as measurement errors of these energies. According to the diatomic molecular model, equilibrium binding energies per B atom and B–B bond lengths are expected within ranges 0.37–6.26 eV and 1.58–1.65 Å, respectively. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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7 pages, 17602 KiB  
Article
Vibrational Property of α-Borophene Determined by Tip-Enhanced Raman Spectroscopy
by Ping Zhang, Xirui Tian, Shaoxiang Sheng, Chen Ma, Linjie Chen, Baojie Feng, Peng Cheng, Yiqi Zhang, Lan Chen, Jin Zhao and Kehui Wu
Molecules 2022, 27(3), 834; https://doi.org/10.3390/molecules27030834 - 27 Jan 2022
Cited by 5 | Viewed by 2835
Abstract
We report a Raman characterization of the α borophene polymorph by scanning tunneling microscopy combined with tip-enhanced Raman spectroscopy. A series of Raman peaks were discovered, which can be well related with the phonon modes calculated based on an asymmetric buckled α structure. [...] Read more.
We report a Raman characterization of the α borophene polymorph by scanning tunneling microscopy combined with tip-enhanced Raman spectroscopy. A series of Raman peaks were discovered, which can be well related with the phonon modes calculated based on an asymmetric buckled α structure. The unusual enhancement of high-frequency Raman peaks in TERS spectra of α borophene is found and associated with its unique buckling when landed on the Ag(111) surface. Our paper demonstrates the advantages of TERS, namely high spatial resolution and selective enhancement rule, in studying the local vibrational properties of materials in nanoscale. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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11 pages, 2089 KiB  
Article
Fabrication of Hydrogen Boride Thin Film by Ion Exchange in MgB2
by T. Hirabayashi, S. Yasuhara, S. Shoji, A. Yamaguchi, H. Abe, S. Ueda, H. Zhu, T. Kondo and M. Miyauchi
Molecules 2021, 26(20), 6212; https://doi.org/10.3390/molecules26206212 - 14 Oct 2021
Cited by 6 | Viewed by 2314
Abstract
In this study, hydrogen boride films are fabricated by ion-exchange treatment on magnesium diboride (MgB2) films under ambient temperature and pressure. We prepared oriented MgB2 films on strontium titanate (SrTiO3) substrates using pulsed laser deposition (PLD). Subsequently, these [...] Read more.
In this study, hydrogen boride films are fabricated by ion-exchange treatment on magnesium diboride (MgB2) films under ambient temperature and pressure. We prepared oriented MgB2 films on strontium titanate (SrTiO3) substrates using pulsed laser deposition (PLD). Subsequently, these films were treated with ion exchangers in acetonitrile solution. TOF-SIMS analysis evidenced that hydrogen species were introduced into the MgB2 films by using two types of ion exchangers: proton exchange resin and formic acid. According to the HAXPES analysis, negatively charged boron species were preserved in the films after the ion-exchange treatment. In addition, the FT-IR analysis suggested that B-H bonds were formed in the MgB2 films following the ion-exchange treatment. The ion-exchange treatment using formic acid was more efficient compared to the resin treatment; with respect to the amount of hydrogen species introduced into the MgB2 films. These ion-exchanged films exhibited photoinduced hydrogen release as observed in a powder sample. Based on the present study, we expect to be able to control the morphology and hydrogen content of hydrogen boride thin films by optimising the ion-exchange treatment process, which will be useful for further studies and device applications. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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Review

Jump to: Research

14 pages, 1475 KiB  
Review
History of Cobaltabis(dicarbollide) in Potentiometry, No Need for Ionophores to Get an Excellent Selectivity
by Anca-Iulia Stoica, Clara Viñas and Francesc Teixidor
Molecules 2022, 27(23), 8312; https://doi.org/10.3390/molecules27238312 - 29 Nov 2022
Cited by 3 | Viewed by 1813
Abstract
This work is a mini-review highlighting the relevance of the θ metallabis(dicarbollide) [3,3′-Co(1,2-C2B9H11)2] with its peculiar and differentiating characteristics, among them the capacity to generate hydrogen and dihydrogen bonds, to generate micelles and vesicles, [...] Read more.
This work is a mini-review highlighting the relevance of the θ metallabis(dicarbollide) [3,3′-Co(1,2-C2B9H11)2] with its peculiar and differentiating characteristics, among them the capacity to generate hydrogen and dihydrogen bonds, to generate micelles and vesicles, to be able to be dissolved in water or benzene, to have a wide range of redox reversible couples and many more, and to use these properties, in this case, for producing potentiometric membrane sensors to monitor amine-containing drugs or other nitrogen-containing molecules. Sensors have been produced with this monoanionic cluster [3,3′-Co(1,2-C2B9H11)2]. Other monoanionic boron clusters are also discussed, but they are much fewer. It is noteworthy that most of the electrochemical sensor species incorporate an ammonium cation and that this cation is the species to be detected. Alternatively, the detection of the borate anion itself has also been studied, but with significantly fewer examples. The functions of the borate anion in the membrane are different, even as a doping agent for polypyrrole which was the conductive ground on which the PVC membrane was deposited. Apart from these cases related to closo borates, the bulk of the work has been devoted to sensors in which the θ metallabis (dicarbollide) [3,3′-Co(1,2-C2B9H11)2] is the key element. The metallabis (dicarbollide) anion, [3,3′-Co(1,2-C2B9H11)2], has many applications; one of these is as new material used to prepare an ion-pair complex with bioactive protonable nitrogen containing compounds, [YH]x[3,3′-Co(1,2-C2B9H11)2]y as an active part of PVC membrane potentiometric sensors. The developed electrodes have Nernstian responses for target analytes, i.e., antibiotics, amino acids, neurotransmitters, analgesics, for some decades of concentrations, with a short response time, around 5 s, a good stability of membrane over 45 days, and an optimal selectivity, even for optical isomers, to be used also for real sample analysis and environmental, clinical, pharmaceutical and food analysis. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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13 pages, 7519 KiB  
Review
Electronic Structures of Polymorphic Layers of Borophane
by Ikuma Tateishi, Xiaoni Zhang and Iwao Matsuda
Molecules 2022, 27(6), 1808; https://doi.org/10.3390/molecules27061808 - 10 Mar 2022
Cited by 10 | Viewed by 2837
Abstract
The search for free-standing 2D materials has been one of the most important subjects in the field of studies on 2D materials and their applications. Recently, a free-standing monolayer of hydrogenated boron (HB) sheet has been synthesized by hydrogenation of borophene. The HB [...] Read more.
The search for free-standing 2D materials has been one of the most important subjects in the field of studies on 2D materials and their applications. Recently, a free-standing monolayer of hydrogenated boron (HB) sheet has been synthesized by hydrogenation of borophene. The HB sheet is also called borophane, and its application is actively studied in many aspects. Here, we review recent studies on the electronic structures of polymorphic sheets of borophane. A hydrogenated boron sheet with a hexagonal boron frame was shown to have a semimetallic electronic structure by experimental and theoretical analyses. A tight-binding model that reproduces the electronic structure was given and it allows easy estimation of the properties of the material. Hydrogenated boron sheets with more complicated nonsymmorphic boron frames were also analyzed. Using the symmetry restrictions from the nonsymmorphic symmetry and the filling factor of hydrogenated boron sheets, the existence of a Dirac nodal line was suggested. These studies provide basic insights for research on and device applications of hydrogenated boron sheets. Full article
(This article belongs to the Special Issue New Science of Boron Allotropes, Compounds, and Nanomaterials)
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