Carbon monoxide interactions with pure and doped B₁₁XN₁₂ (X = Mg, Ge, Ga) nano-clusters: a theoretical study

The goal of this investigation was to study a novel sensor for detecting the toxic gas compounds of CO using B₁₁XN₁₂ (X = Ge, Mg, and Ga) nano-clusters in terms of its energetic, geometric, and electronic structure using DFT calculations by the PBE-D method. The reaction of CO gas with these doping atoms results in a weak interaction and an elongation of X-N bond of B₁₁XN₁₂ nano-clusters. After the adsorption of CO gas over the doped positions of B₁₁XN₁₂ nano-cluster, the conductivity of the adsorbent and the atomic charges in some of the nearby B and N atoms around X atoms were dramatically enhanced. These calculations represent the capabilities of the B₁₁XN₁₂ nano-clusters in designing novel materials based on B₁₁XN₁₂ for potential applications in gas sensing. © The Royal Society of Chemistry

A comparative theoretical study on the interaction of pure and carbon atom substituted boron nitride fullerenes with ifosfamide drug

Anticancer drug delivery is now becoming an important scientific challenge as it allows localizing drug release near the tumor cell and avoiding secondary side effects. Based on the density functional theory (DFT) calculations, the adsorption of Ifosfamide (IFO) on a series of pure B12N12 and carbon-doped boron nitride, including B12N6C6 and B6N6C12 fullerenes, was carried out both in vacuum and solvent (water) environment conditions by means of PBE-1 and M06-2X functionals and 6-311 + G (d,p) basis set. The most stable chemisorption state for the IFO was through phosphoryl group (�1.21 eV) onto the B12N12 in comparison with chloroalkyl (�0.35 eV) and nitrogen atom of oxazaphosphorine ring (�1.14 eV) groups. To compare both environments, the computed results indicate that the adsorption of IFO in the solvent environment is more stable on the B12N12 (�1.27 eV), B12N6C6 (�1.86 eV), and B6N6C12 (�1.99 eV) fullerenes than in the vacuum environment. Our computational simulations represent that the amount of IFO loading is higher for the fullerenes, on the other hand, the interaction energy of IFO with B6N6C12 is greater, which can reduce its release rate. © 2019 Elsevier B.V

Optical and Electronic Properties of Al-Doped Mg12O12 Nanocluster: A Theoretical Study

Effects of A doping on the structural, optical, and electronic properties of Mg12O12 nanocluster have been investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. It is found that for all stable structures, the doped nanocluster with five Al atoms has a larger binding energy of �5.22 and �5.06 eV evaluated by M06-2X and B97D functional, respectively. Both M06-2X and B97D functional exhibited that the Al substituted at the Mg-site can alter the energy gap of the nanocluster in comparison with unstable O sites. With substituting four Al atoms at the Mg sites of the nanocluster, the changes in the energy gap is significantly large than other states. More details on the dopant effects, charge population and electronic structure evolution with the variation of the Al concentration of doping are discussed in the context. © 2019, Pleiades Publishing, Ltd

Adsorption of chemical warfare agents over C24 fullerene: Effects of decoration of cobalt

The present theoretical study suggests the adsorption of the chemical warfare agents (Soman, Chlorosoman, Sarin, and Chlorosarin) over the pure and cobalt-decorated C24 fullerenes by using PBE functional. For all four species, adsorption on the C24 fullerene takes place via a Co–OdbndP dative covalent bond between a cobalt-decorated site. It has been indicated that the interaction between the chemical warfare agents and the cobalt-decorated C24 fullerene is more stable than that of the pure C24 fullerene. We found that the cobalt-decorated C24 fullerene is the most favorable site for Sarin and Soman in comparison with Chlorosarin and Chlorosoman. In addition, the interactions of chemical warfare agents with cobalt-decorated C24 fullerene can be responsible to alter of the structural and electronic properties. © 2017 Elsevier B.V

Effect of the embedded atom on the electronic, optical properties and kinetic stability of 3,6silaprismane

Using ab initio calculations it is found that endohedral complexes C@Si18H12, Si@Si18H12 and Ge@Si18H12 are less kinetically stable than pure [3,6]silaprismane Si18H12. Moreover, kinetic stability of Si18H12 is higher than the stability of its carbon molecular analogue C18H12. The height of the minimum energy barrier preventing the Si18H12 isomerization is found to be 1.09 eV and its lifetime at room temperature will reach several hours that is acceptable not only for its immediate experimental observation but for the laboratory synthesis without using the extreme temperature conditions as well. It is also found that embedded atoms can significantly change the electronic properties of Si18H12 cage that is directly affect the optical characteristics of the systems considered. Thus, the doped Si18H12s can be experimentally divided from each other due to the changes in their optical spectra. © 2017 Elsevier B.V

Kinetic Stability and Reactivity of Silicon and Fluorine-Containing CL-20 Derivatives

A CL-20 based cages in which carbon/oxygen atoms are replaced by silicon/fluorine ones are studied using the ab initio molecular dynamics, density functional theory, and time-dependent density functional theory. In contrast to the pristine CL-20, the first step of pyrolysis of these cages is the migration of oxygen/fluorine atoms to silicon. Molecules containing fluorine are unstable at room temperature. The high-energy silicon-containing molecule (CSi5H6N12O12) is approximately as stable as pristine CL-20. Energy barrier preventing its decomposition is about 200 kJ/mol. Energies of the frontier orbitals and reactivity descriptors of CSi5H6N12O12 are very close to the corresponding values of pure CL-20. All studied cages can form covalent dimers via the methylene molecular bridges. It is found that the reactions of dimerization are exothermic. Dimers� isomers in which silicon atoms are located closer to the methylene bridges possess lower internal energies. It is found that the mechanisms of dimers� thermal decomposition are similar to the analog mechanisms of corresponding monomers. Dimerization of the cages results in the redshifts of their ultraviolet spectra. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinhei

A DFT study of adsorption of glycine onto the surface of BC2N nanotube

A theoretical study of structure and the energy interaction of amino acid glycine (NH2CH2COOH) with BC2N nanotube is crucial for apperception behavior occurring at the nanobiointerface. Herein, we studied the adsorption of glycine in their radical and zwitterionic forms upon the surface of BC2N nanotube using M06 functional and 6-311G∗∗standard basis set. We also considered the different orientations of the glycine amino acid on the surface of adsorbent. Further, we found out that the stability of glycine from its carbonyl group is higher than hydroxyl and amine groups. Our results also indicated that the electronic structure of BC2N nanotube on the adsorption of glycine from its amine group is more altered than the other groups. Our study exhibits that opto-electronic property of adsorbent is changed after the glycine adsorption. © 2016 Elsevier B.V. All rights reserved

Theoretical study on pure and doped B12N12 fullerenes as thiophene sensor

The physisorption and chemisorption of Thiophene (C4H4S) onto the B12N12, B11AlN12, and B11SiN12 fullerenes have been investigated in both gas and solvent environments by means of density functional theory calculation. We found that the higher physisorption of C4H4S in the top site of boron atom of B12N12 fullerene is − 0.14 eV (II), while in the top sites of Si and Al in B11AlN12 and B11SiN12 fullerenes were − 0.58 (VII) and − 1.08 eV (V), respectively. We believe that B11AlN12 fullerene is responsible for the increase of binding energy and reduction of the energy band gap in comparison with B11SiN12 fullerene. This data demonstrates that the increase of charge transfer and dipole moment led to the accretion of binding energy. Therefore, B11AlN12 fullerene will give additional insights of reducing sulfur contents and it also can serve as an adsorbent in the detection of the C4H4S molecule. © 2018, Springer Science+Business Media, LLC, part of Springer Nature

Ga-doped and antisite double defects enhance the sensitivity of boron nitride nanotubes towards Soman and Chlorosoman

Adsorption of Soman and Chlorosoman over the outer surface of boron nitride nanotube (BNNT) was studied using density functional theory (DFT) calculations to consider its sensitivity toward mentioned nerve agents. Then, we studied the sensitivity of Ga-doped BNNT and double-antisite defective BNNT (d-BNNT) effects towards adsorbed molecule resulting in eye-catching sensitivity of defected adsorbents representing strong chemical adsorption on the Ga-doped BNNT, while they are mainly physisorbed on the pure BNNT with negligible electronic properties. Density of states (DOSs) was analyzed for further understanding of electronic properties of the applied configurations. Charges were moved from BNNT to the single molecules while in case of Ga-doped and d-BNNT; the charges were transferred from single molecules to the defected adsorbents. These along with outcomes of quantum molecular descriptors, difference in energy gap (Eg), and dipole moments clearly reveal that the d-BNNT is a promising sensor material for the detection of these nerve agents. © 2017 Elsevier B.V

Adsorption of HCOH and H 2 S molecules on Al 12 P 12 fullerene: a DFT study

In this study, we have investigated the adsorption and dissociation of four small gas molecules including HCOH, H 2 S, NH 3 , and O 2 on Al 12 P 12 fullerene using density functional theory (DFT). The computations have been performed with B3LYP-D and M06-2X levels of theory and have been calculated with the 6-311++G** basis set. The adsorption of HCOH, H 2 S, NH 3 , and O 2 molecules can be attributed to the chemical and physical behavior of these molecules. The computational results show that the dissociation energies of HCOH and H 2 S on the surface of Al 12 P 12 fullerene were found more negative than those of their adsorption. On the contrary, the adsorption energies of O 2 and NH 3 on the surface of Al 12 P 12 fullerene were found to be more negative than those of their dissociation. The results also indicate that the differences between calculated energies at both levels are negligible. The complex bonds between all molecules and Al 12 P 12 fullerene have been formed due to the charge transfer that occurred during these interactions. According to the computations and the plots of total density of state (TDOS), the results indicate that Al 12 P 12 fullerene is slightly sensitive toward HCOH and H 2 S molecules. © 2019, Springer Science+Business Media, LLC, part of Springer Nature