Stability, edge passivation effect, electronic and transport properties of POPGraphene nanoribbons.

POPGraphene is a theoretically predicted 2D carbon allotrope which presents a unit cell with 5-8-5 carbon rings. It presents metallic behavior and has a low diffusion energy barrier, which suggests applications as an anode material in batteries. Motivated by the fact that nanoribbons present different properties to their 2D counterparts, in this work two kinds of POPGraphene nanoribbons were proposed, with (POPGNRH) and without (POPGNR) hydrogen edge passivation, and their electronic and transport properties were investigated, in order to characterize them and verify the influence of hydrogen edge passivation. Density functional theory was employed for structure optimization and combined with the Non-Equilibrium Green's Function to obtain the electronic transport properties. We predict that both nanoribbons are stable and can be obtained experimentally. Furthermore, hydrogen passivation reduces the bands around the Fermi level and shift them toward the region of negative energies, which can be seen from the presence of NDR in the transport properties of the hydrogenated device. The electronic transport properties suggest that POPGNR shows Field effect transistor behavior in the analyzed range and POPGNRH shows the same behavior, but in the range of -0.70 V to 0.70 V. Also, due to the presence of NDR, POPGNRH presents Resonant Tunneling Diode behavior in the range of ±0.70 V to ±1.00 V. Therefore, the results suggest applications for both nanoribbons in the field of molecular electronics.

SARS-CoV-2 external structures interacting with nanospheres using docking and molecular dynamics.

Coronavirus is caused by the SARS-CoV-2 virus has shown rapid proliferation and scarcity of treatments with proven effectiveness. In this way, we simulated the hospitalization of carbon nanospheres, with external active sites of the SARS-CoV-2 virus (M-Pro, S-Gly and E-Pro), which can be adsorbed or inactivated when interacting with the nanospheres. The computational procedures performed in this work were developed with the SwissDock server for molecular docking and the GROMACS software for molecular dynamics, making it possible to extract relevant data on affinity energy, distance between molecules, free Gibbs energy and mean square deviation of atomic positions, surface area accessible to solvents. Molecular docking indicates that all ligands have an affinity for the receptor's active sites. The nanospheres interact favorably with all proteins, showing promising results, especially C60, which presented the best affinity energy and RMSD values ​​for all protein macromolecules investigated. The C60 with E-Pro exhibited the highest affinity energy of -9.361 kcal/mol, demonstrating stability in both molecular docking and molecular dynamics simulations. Our RMSD calculations indicated that the nanospheres remained predominantly stable, fluctuating within a range of 2 to 3 Å. Additionally, the analysis of other structures yielded promising results that hold potential for application in other proteases.Communicated by Ramaswamy H. Sarma.