Fullerene B40 Research Articles

Borospherene in the Nanohoop: Complexation and Aromaticity of Neutral and Dioxidized Cycloparaphenylene Supramolecules with B40 and C60 Fullerenes.

Supramolecular complexes of carbon nanohoops with fullerenes play a key role for the design of novel nanomaterials with technological applications. Herein we investigate with density functional theory (DFT) methods the capability of neutral and dioxidized cycloparaphenylenes (CPPs) to encapsulate all-boron fullerene B40. Our results show that [9]CPP and [10]CPP are feasible host candidates to encapsulate B40 displaying comparable complexation energies with the all-carbon analog [10]CPP⊃C60. Upon dioxidation the host-guest interactions are not affected, whereas the positive charge is delocalized on the CPPs leading to global aromatic character of the hosts. Consequently, the dicationic complexes [n]CPP2+⊃B40 and [10]CPP2+⊃C60 display augmented global shielding cones that strongly shield the guests, as manifested by large upfield shifts in 11B-NMR and 13C-NMR signals. Hence, CPP complexes with carbon fullerenes can be extended borospherene B40 host-guest complexes, as well as to doubly oxidized species stabilized by global host aromaticity, expanding our understanding of carbon nanohoop complexes to boron-based fullerenes.

A Comparative Study on Electronic Transport Behavior of Silicene and B40-Nano Onions

Density Functional Theory is utilized to scrutinize the electronic state of silicene and boron nano-onion which is a round compact mass formed by placing an N20, C20, and B20 fullerene within its parent atom fullerene B40. The NEGF is used to investigate the quantum transport at both equilibrium and non-equilibrium. Firstly the I-V curve for both silicene and boron-based devices is studied. From the results, it is concluded that boron-based devices are better than silicene. Therefore to get deeper insights into why boron-based devices are better transport properties of boron-based devices are suited. Later on, the transport mechanism is analyzed by computing the DOS, transmission and molecular spectra, HLG, I-V curve, electron densities, and differential conductance. When the Boron nano-onion is placed between the pair of Au electrodes. The calculated results are evaluated and a comparative study is done. From the results, it is deduced that the N20 variant nano-onion has reduced the HOMO-LUMO gap (HLG) and highest value of current in comparison to other devices. Thus by infusing a smaller fullerene of N20 inside the hollow cage of B40 fullerene the amplification of current and conductance can be observed in Boron-nano-onion in comparison to other devices.

On the potential of all-boron fullerene B40 as a carrier for anti-cancer drug nitrosourea

The potential application of all-boron fullerene B40 as a drug carrier for anti-cancer nitrosourea (NU) has been explored by the means of density functional theory (DFT). Our results reveal that the NU drug tends to combine with the corner boron atom of B40 cage via its oxygen and nitrogen atoms with a moderate adsorption energy of −25.18 kcal/mol. Herein, the newly formed B-O and B-N bonds are proved to be strong polar covalent bonds by atoms in molecules (AIM) theory, localized molecular orbital (LMO), and electron localization function (ELF) analyses. A short recovery time of 52 s is predicted for the NU desorption process at 310.15 K, indicating that the desorption of NU from B40 is easy under body temperature. Moreover, it is found that B40 can simultaneously adsorb up to five NU drugs, exhibiting a high loading capacity. Finally, the substituent effect of C, N, Al, and Ga atoms on the drug delivery performance of this B40 nanocage has been considered. Our results not only suggest that B40 has a great potential to be used in drug delivery, but also signify that the substituent effect of foreign atoms can be employed to modulate the drug adsorption performance of B40.

Binary magnetic moments of all-boron fullerene B40 by positioning the Co atom

Recently, the all-boron fullerene B40 is experimentally observed and theoretically confirmed. As the second single-element fullerene after C60, further study about this novel fascinating fullerene is thus quite desirable. In this work, the structures, stability and magnetic properties of the Co-doped B40-based metallofullerenes were systematically studied. The results reveal different stable configurations of the endohedral Co@B40 and exohedral Co-B40 metallofullerenes depending on the doped sites of the Co atom. The spin-polarized calculations indicate that all the Co-doped metallofullerenes have an interesting characteristic of the magnetic properties: the magnetic moments having binary alternative between 2.98 μB and 1.00μB, corresponding to the Co atom resident inside the center of the unwoven double rings and inside the center of multiple-membered holes, respectively. This interesting finding of the binary magnetic moments implies that the Co-encapsulated B40-based metallofullerenes may be a promising candidate for the single molecular spin electronic devices.

Fe-Doped All-Boron Fullerene B40 with Tunable Electronic and Magnetic Properties as Single Molecular Devices**Supported by the National Basic Research Program of China under Grant No 2014CB931700, and the State Key Laboratory of Optoelectronic Materials and Technologies.

Systematic theoretical calculations are performed to investigate the dopant effect of Fe on stability, electronic and magnetic properties of the newly synthesized all-boron fullerene B40. The results reveal that as a typical ferromagnetic element, Fe atoms can either be chemically externally adsorbed on, or internally encapsulated in the cage of B40, with the binding energies ranging from 3.07 to 5.31 eV/atom. By introducing the dopant states from the doped Fe atom, the energy gaps of the Fe-doped B40-based metallofullerenes are decreased. Our spin-polarized calculations indicate that Fe-doped metallofullerenes have attractive magnetic properties: with alternative binary magnetic moments between 4.00μB and 2.00μB, depending on the resident sites of the doped Fe atom. The findings of the tunable electronic properties and binary magnetic moments of the Fe-doped B40-based metallofullerenes imply that this type of metallofullerene may be applied in single molecular devices.

The electronic transport properties of B40 fullerenes with chalcogens as anchor atoms.

Fullerenes are the most popular molecules to use in applications related to molecular electronics because of their superconductive nature. These molecules show a diverse range of properties, including optical, electronic, and structural characteristics. In this work, we focused on the electronic transport properties of molecular devices consisting of the fullerene B40 or B40 with different anchor atoms between two gold electrodes in a two-probe configuration. The elements used as anchor atoms in the B40 molecules were oxygen, selenium, and sulfur, i.e., chalcogens. The current characteristics of these fullerene-based molecular devices were calculated and analyzed. The analysis highlighted the superior electrical conductivity of the pure B40 device compared to the devices based on its chalcogen-anchored variants. The conductivities of the molecular devices were ranked as follows: pure B40 > selenium-anchored > sulfur-anchored > oxygen-anchored B40. It was also noted that the devices based on B40 and its chalcogen-anchored variants gave nonzero conductance values at zero bias. These results pave the way for the application of these molecules in future nanodevices utilizing extremely small bias voltages.

All-boron fullerene B40: a superatomic structure

By means of the first-principles calculations, we reveal that B40 presents superatomic properties. It not only has superatomic 1S, 1P, 1D and 1F orbitals, but also has superatomic orbitals 2S, 2P, 2D and 2F. The superatomic 2F orbital of B40 is partially occupied, thus adding six electrons to the cluster leads to a superatomic structure of fully occupied shells. The computed nucleus-independent chemical shift values suggest that the B406− is of higher electron delocalization than B40 itself. Our work opens up a new perspective for the superatomic physics in boron fullerene family.

Bonding the superalkali M3O (M = Li and K): An effective strategy to improve the electronic and nonlinear optical properties of the inorganic B40 nanocage

Inspired by the fascinating finding of all-boron fullerene B40 (Nat Chem, 2014, 6, 727), we propose a new and effective strategy to construct a series of typical Donor-Acceptor (D-A) frameworks via linking the superalkali M3O (M = Li and K) unit with the low ionization potential to the B40 nanocage with large electron affinity. By means of the density functional theory computations, we have systematically investigated the structures, electronic properties, the first and second hyperpolarizabilities of these modified B40 nanocage systems. Owing to the formation of a B–O chemical bond, these composite systems (M3O)n-B40 (M = Li and K, n = 1 and 2) can possess the considerably large binding energy ranging from 57.0 to 99.8kcal/mol, indicating their high structure stabilities. Compared with the pristine B40 nanocage, linking the superalkali M3O can effectively narrow the wide energy gap from the original 2.86eV to 0.61–1.11eV, and significantly increase the first and second hyperpolarizabilities to as large as 5.00 × 104–2.46 × 105 au and 1.48 × 107–4.85 × 108 au, respectively, owing to the occurrence of evident electron transfer process in this kind of typical D-A framework. These fascinating findings will be advantageous for promoting the potential applications of the inorganic boron-based nanosystems in the new type of electronic nanodevices and high-performance nonlinear optical materials.

The hydrogen storage capacity of Sc atoms decorated porous boron fullerene B40: A DFT study

The hydrogen storage capacity of transition metal Sc atoms decorated porous boron fullerene B40 is investigated by the pseudopotential density functional method. The B40 cage contains two B6 cavities (diameter: 3.36 Å) and four B7 holes (diameter: 3.68 Å). It is calculated that the structures with the Sc atom outside the hollow sites of these cavities are the most stable. The calculated binding energy of the Sc atom to the B6 and B7 cavities on the surface of B40 are 4.61 and 5.24 eV, much larger than the experimental cohesive energy of bulk Sc (3.90 eV/atom). Moreover, the distance between the neighboring two Sc atoms (5.61 Å) is considerably larger than that of the Sc2 dimer (3.20 Å), therefore, the problem of Sc atoms aggregative to form the Scn cluster is expected to be overcome. The average adsorption energies and consecutive adsorption energies reveal that each Sc atom can most adsorb five H2 molecules. The calculated average hydrogen adsorption energies per H2 for B40(Sc–nH2)6 (n = 1–5) are in the energy range from 0.33 to 0.58 eV, which is suitable for hydrogen storage under near-ambient conditions. The Dewar–Kubas interaction dominates the adsorption of H2 by B40Sc6. The calculated desorption temperature and molecular dynamic simulation indicate that the B40(Sc–5H2)6 structure is easy to desorb H2 molecules. The HGD of the bulk [B40(Sc–5H2)4]4 is 6.18 wt%, a little smaller than that for B40(Sc–5H2)6 (8.3%), however still exceeding the 5.5 wt% at 2017 specified by the US department of energy (DOE). Therefore, the stable B40 structure decorated by the Sc atoms can be applied as one candidate for hydrogen storage materials under near-ambient conditions.

B40 fullerene as a highly sensitive molecular device for NH3 detection at low bias: a first-principles study

The adsorption of small molecules (NH3, N2, H2 and CH4) on all-boron fullerene B40 is investigated by density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) for its potential application in the field of single-molecular gas sensors. The high adsorption energies (−1.09 to −0.75 eV) of NH3 on different adsorption sites of the B40 surface indicate that NH3 strongly chemisorbs to B40. The charge transfer induced by the NH3 adsorption results in a modification of the density of states (DOS) of B40 near the Fermi level, and therefore changes its electronic transport properties. For all possible adsorption sites, the adsorption of NH3 exclusively leads to a decrease of the conductance of B40. Taking into consideration that the non-polar gas molecules (e.g. N2, H2 and CH4) are only physisorbed and show negligible effect on the conductance properties of B40, we would expect that B40 can be used as a single-molecular gas sensor to distinguish NH3 from non-polar gas molecules at low bias.

Computational investigation on the endohedral borofullerenes M@B40 (M = Sc, Y, La)

Stimulated by the recent fascinating finding of all-boron fullerene B40 (Zhai et al. in Nat Chem 6:727–731, 2014), we systematically investigated the structures, stabilities and electronic properties of its endohedral derivatives M@B40 (M = Sc, Y, La) by means of density functional theory computations. The binding energies of M@B40 are closely comparable with the classical M@C 2v (9)–C82 family, suggesting the considerable possibility to experimentally achieve these endohedral borofullerenes. The paramagnetic M@B40 molecules can easily form stable dimers with quenched magnetism, which could be avoided by exohedral functionalization and promise potential applications in the design of nanodevices. Furthermore, the infrared absorption spectra and 11B nuclear magnetic resonance spectra were computed to assist future experimental characterization.

Electronic structures and electronic spectra of all-boron fullerene B40.

This study is motivated by the recent discovery of the first all-boron fullerene analogue, a B40 cluster with D(2d) point-group symmetry, dubbed borospherene (Nat. Chem., 2014, 6, 727). Insight into the electronic structures and spectral properties of B40 is timely and important to understand the borospherene and the transition from open-ended plate or ribbon-like structures to a hollow-cage structure at B40. Optimized geometries of borospherene B40 for both the ground state and the first excited state allow us to compute spectral properties including UV-vis absorption, infrared (IR) and Raman spectra. Highly resolved absorption and emission spectra are obtained, for the first time, for the fullerene at the time-dependent density-functional theory (TD-DFT) level within the Franck-Condon approximation and including the Herzberg-Teller effect. Assigned vibrational modes in absorption and emission spectra are readily compared with future spectroscopy measurements to distinguish the hollow-cage structure of D(2d)-B40 from other quasi-planar boron structures.

The boron conundrum: Bonding in the bowl B30 and B36, fullerene B40 and triple ring B42 clusters

Geometries and bonding of B30, B36, B40 and B42 clusters were studied using quantum chemical computations. The bowl B30 and B36 and planar B42 clusters exhibit disk aromaticity. Diatropic ring current is strong in B30 and weaker in B42. A fullerene-like B40 (D2d) having two hexagons and four heptagons was found as the lowest-lying isomer. Such a fullerene whose MOs closely mimic those of the buckyball B80, represents novel structural feature of boron clusters. The most stable B42 (C2h) isomer is a triple ring tube with consistent σ+π diatropic magnetic responses making it a tubular aromatic species.