Hypothetical planar and nanotubular crystalline structures with five interatomic bonds of Kepler nets type

The possibility of metastable existence of planar and non-chiral nanotubular crystalline lattices in the form of Kepler nets of 34324, 3342, and 346 types (the notations are given in Schläfly symbols), using ab initio calculations, has researched. Atoms of P, As, Sb, Bi from 15th group and atoms of S, Se, Te from 16th group of the periodic table were taken into consideration. The lengths of interatomic bonds corresponding to the steadiest states for such were determined. We found that among these new composed structures crystals encountered strong elastic properties. Besides, some of them can possess pyroelectric and piezoelectric properties. Our results can be used for nanoelectronics and nanoelectromechanical devices designing

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

Ab Initio Insight into the Interaction of Metal-Decorated Fluorinated Carbon Fullerenes with Anti-COVID Drugs

We theoretically investigated the adsorption of two common anti-COVID drugs, favipiravir and chloroquine, on fluorinated C60 fullerene, decorated with metal ions Cr3+, Fe2+, Fe3+, Ni2+. We focused on the effect of fluoridation on the interaction of fullerene with metal ions and drugs in an aqueous solution. We considered three model systems, C60, C60F2 and C60F48, and represented pristine, low-fluorinated and high-fluorinated fullerenes, respectively. Adsorption energies, deformation of fullerene and drug molecules, frontier molecular orbitals and vibrational spectra were investigated in detail. We found that different drugs and different ions interacted differently with fluorinated fullerenes. Cr3+ and Fe2+ ions lead to the defluorination of low-fluorinated fullerenes. Favipiravir also leads to their defluorination with the formation of HF molecules. Therefore, fluorinated fullerenes are not suitable for the delivery of favipiravir and similar drugs molecules. In contrast, we found that fluorine enhances the adsorption of Ni2+ and Fe3+ ions on fullerene and their activity to chloroquine. Ni2+-decorated fluorinated fullerenes were found to be stable and suitable carriers for the loading of chloroquine. Clear shifts of infrared, ultraviolet and visible spectra can provide control over the loading of chloroquine on Ni2+-doped fluorinated fullerenes