The layered sodium cobalt oxide Na x CoO 2 is studied by electron diffraction for a wide range of sodium contents, 0.15Ͻ x Ͻ 0.75. An extensive series of ordered Na ion-Na vacancy superlattices is found beyond the simple hexagonal average structure. The most strongly developed superlattice is found for the composition Na 0.5 CoO 2 , which displays Co 3+ /Co 4+ charge ordering at low temperatures. The structural principle for some of the observed ordering schemes, particularly near x = 0.5, is, surprisingly, the presence of lines of Na ions and vacancies rather than simply maximized Na-Na separations.

Heavily F-doped SnO(2) nanocrystals were successfully prepared by a novel synthetic approach involving low-temperature oxidation of a Sn(2+)-containing fluoride complex KSnF(3) as the single-source precursor with H(2)O(2). The F-doped SnO(2) powder was characterized by powder X-ray diffraction, TG-MS, BET surface area, diffuse reflectance spectroscopy, XPS, PL, FTIR spectroscopy, Raman spectroscopy, EPR spectroscopy, SEM, and TEM. Broadening of the diffracted peaks, signifying the low crystallite size of the products, was quite evident in the powder X-ray diffraction pattern of SnO(2) obtained from KSnF(3). It was indexed in a tetragonal unit cell with lattice constants a = 4.7106 (1) Å and c = 3.1970 (1) Å. Agglomeration of particles, with an average diameter of 5-7 nm, was observed in the TEM images whose spotwise EDX analysis indicated the presence of fluoride ions. In the core level high-resolution F 1s spectrum, the peak observed at 685.08 eV was fitted by the Gaussian profile yielding the fluoride ion concentration to be 21.23% in the SnO(2) lattice. Such a high fluoride ion concentration is reported for the first time in powders. SnO(2):F nanocrystals showed greater thermal stability up to 300 °C when heated in a thermobalance under flowing helium, after which generation of small quantities of HF was observed in the TG coupled mass spectrometry analysis. The band gap value, estimated from the Kubelka-Munk function, showed a large shift from 3.52 to 3.87 eV on fluoride ion doping, as observed in the diffuse reflectance spectrum. Such a large shift was corroborated to the overdoped situation due to the Moss-Burstein effect with an increase in the carrier concentration. In the photoluminescence (PL) spectrum, SnO(2):F nanocrystals exhibited a broad green emission arising from the singly ionized oxygen vacancies created due to higher dopant concentration. The evidence for singly ionized vacancies was arrived from the presence of a signal with a g value of 1.98 in the ESR spectrum of SnO(2):F at room temperature. The disordered nature of the rutile lattice and the enormous oxygen vacancies created due to fluoride ion doping were evident from the broad bands observed at 455, 588, and 874 cm(-1) in the room-temperature Raman spectrum of SnO(2):F. As the consequence of the oxygen vacancies, F-doped SnO(2) was examined for the function as a photocatalyst in the degradation of aqueous RhB dye solution under UV irradiation. A very high photocatalytic efficiency was observed for the F-doped SnO(2) nanocrystals as compared to pure SnO(2). The BET surface area of pure SnO(2) was quite high (207.81 m(2)/g) as compared to the F-doped SnO(2) nanocrystals (45.16 m(2)/g). Pore size analysis showed a mean pore diameter of 1.97 and 13.97 nm for the pure and doped samples. The increased photocatalytic efficiency was related to the very high concentration of oxygen vacancies in SnO(2) induced by F doping.

The current outbreak of a novel coronavirus, named as SARS-CoV-2 causing COVID-19 occurred in 2019, is in dire need of finding potential therapeutic agents. Recently, ongoing viral epidemic due to coronavirus (SARS-CoV-2) primarily affected mainland China that now threatened to spread to populations in most countries of the world. In spite of this, there is currently no antiviral drug/ vaccine available against coronavirus infection, COVID-19. In the present study, computer-aided drug design-based screening to find out promising inhibitors against the coronavirus (SARS-CoV-2) leads to infection, COVID-19. The lead therapeutic molecule was investigated through docking and molecular dynamics simulations. In this, binding affinity of noscapines(23B)-protease of SARS-CoV-2 complex was evaluated through MD simulations at different temperatures. Our research group has established that noscapine is a chemotherapeutic agent for the treatment of drug resistant cancers; however, noscapine was also being used as anti-malarial, anti-stroke and cough-suppressant. This study suggests for the first time that noscapine exerts its antiviral effects by inhibiting viral protein synthesis. ARTICLE HISTORY

Rock-salt-based honeycomb structures containing Te(VI) and Sb(V) with innumerable prospects of properties and applications were realized in the two new series of mixed-metal oxides of lithium, Li(8)M(2)Te(2)O(12) (M(II) = Co, Ni, Cu, Zn) and Li(8)M(2)Sb(2)O(12) (M(III) = Cr, Fe, Al, Ga). The structures of Li(8)Co(2)Te(2)O(12) and Li(8)Cu(2)Te(2)O(12) were determined by single-crystal X-ray diffraction for the first time, and mixed-occupancy Li/M was identified.

Coronavirus disease-2019 (COVID-19) is a global health emergency and the matter of serious concern, which has been declared a pandemic by WHO. Till date, no potential medicine/ drug is available to cure the infected persons from SARS-CoV-2. This deadly virus is named as novel 2019-nCoV coronavirus and caused coronavirus disease, that is, COVID-19. The first case of SARS-CoV-2 infection in human was confirmed in the Wuhan city of the China. COVID-19 is an infectious disease and spread from man to man as well as surface to man . In the present work, in silico approach was followed to find potential molecule to control this infection. Authors have screened more than one million molecules available in the ZINC database and taken the best two compounds based on binding energy score. These lead molecules were further studied through docking against the main protease of SARS-CoV-2. Then, molecular dynamics simulations of the main protease with and without screened compounds were performed at room temperature to determine the thermodynamic parameters to understand the inhibition. Further, molecular dynamics simulations at different temperatures were performed to understand the efficiency of the inhibition of the main protease in the presence of the screened compounds. Change in energy for the formation of the complexes between the main protease of novel coronavirus and ZINC20601870 as well ZINC00793735 at room temperature was determined on applying MM-GBSA calculations. Docking and molecular dynamics simulations showed their antiviral potential and may inhibit viral replication experimentally.

Ion-exchange reactions of Na2Cu2TeO6 with excess of lithium nitrate at low temperature (300 °C) readily resulted in an isostructural honeycomb ordered monoclinic layered structure Li2Cu2TeO6, otherwise inaccessible by direct solid state high temperature reactions. Similarly, Li2Ni2TeO6(I) stabilized approximately in equal amounts in both of the known P2-type polymorphs (P6(3)/mcm and P6(3)22) was synthesized as an ion-exchange reaction product from Na2Ni2TeO6 using a melt of lithium nitrate. Additionally, a unique tellurium containing oxide Li2Ni2TeO6(II) without the honeycomb ordering of Ni(2+)/Te(6+) ions has been obtained for the first time by the direct high temperature (800-900 °C) synthesis. The oxides were investigated by refinement of powder X-ray diffraction patterns, room temperature magnetization experiments along with Raman spectroscopy and photoluminescence measurements. A structural model has been suggested for the metastable Li2Ni2TeO6(II) and the presence of structural disorder was evidenced in the broadening of the Raman bands and the intense broad photoluminescence (PL) spectra obtained for Li2Ni2TeO6(II).

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For the better management and control of the viral replication, it is essential to discover a potential molecule to combat Chikungunya virus (CHIKV). The work aims to find a potential antiviral molecule via its interactions with the non-structural protease (nsP3) of CHIKV. It plays a crucial role in intracellular replication. The best molecular interaction is based on the minimum total binding energy of hydrogen bonding, electrostatic interaction and van der Waals forces. It was found that Erythro-noscapines showed good binding affinity with nsP3 protease of CHIKV (PDB ID: 3GPO) and minimum total binding energy (-149.964 kcal/mol) to form a more stable complex i. e. 109-nsP3 protease of CHIKV. Erythro-noscapines (109, one of the derivatives of erythro-noscapine) showed better interaction than the reported molecules by different reseach groups via docking. The parameters for bioactivity score and Lipinski "Rule of Five" were calculated to estimate the pharmacokinetic properties of antiviral Erythro-noscapines and compared to others. 109 can be considered as a good candidate for antiviral replication against nsP3 protease of CHIKV. Molecular dynamics simulations on nsP3 protease of CHIKV with or without 109 was performed and studied. Further, binding free energies of potential noscapine-nsP3 protease of CHIKV based on Molecular Mechanics-Generalized Born Suface Area (MM-GBSA) was calculated. Further, toxicity of top 10 noscapines and reported molecules by different research groups was determined and then, density functional theory was applied to understand the singlet and triplet states of the 109.