Investigation of the substituted-titanium nanocages using computational chemistry.

We are investigated substitution effects of titanium heteroatoms on band gap, charge and local reactivity of C20-nTin heterofullerenes (n = 1-5), at different levels and basis sets. The C18Ti2-2 nanocage is considered as the most kinetically stable species with the widest band gap of 2.86 eV, in which two carbon atoms are substituted by two Ti atoms in equatorial position, individually. The charges on carbon atoms of C20 are roughly zero, while high positive charge (1.256) on the surface of C19Ti1 prompts this heteofullerene for hydrogen storage. The positive atomic charge on Ti atoms and negative atomic charge on their adjacent C atoms implies that these sites can be influenced more readily by nucleophilic and electrophilic regents, respectively. We examined the usefulness of local reactivity descriptors to predict the reactivity of Ti-C atomic sites on the external surface of the heterofullerenes. The properties determined include Fukui function (F.F.); f (k) and local softness s (k) on the surfaces of the investigated hollow cages. Geometry optimization results reveal that titanium atoms can be comfortably incorporated into the CC network of fullerene. It is most likely associated with the triple-coordination characteristic of titanium atoms, which can well match with the sp2-hybridized carbon bonding structure. According to the values of f (k) and s (k) for the C15Ti5 heterofullerene; the carbon atoms in the cap regions exhibit a different reactivity pattern than those in the equatorial portion of the heterofullerene. The titanium impurity can significantly improve the fullerene's surface reactivity and it allows controlling their surface properties. The band gap of C20-nTin …..(H2)n structures is decreased with increasing n. Hence, C15Ti5 is found as the best hydrogen adsorbent.

DFT calculations, structural analysis, solvent effects, and non-covalent interaction study on the para-aminosalicylic acid complex as a tuberculosis drug: AIM, NBO, and NMR analyses.

In this study, the effect of non-covalent interactions on the para-aminosalicylic acid complex is explored using density functional theory (DFT) in the gas phase and the solution. Our findings exhibit that the achieved binding energies considerably change on going from the gas phase to the solution. Based on the obtained results, the absolute value of the binding energy of the complex in the polar solvents is lower than the non-polar ones while in the gas phase it is higher than the solution. The atoms in molecules (AIM) and the natural bond orbital (NBO) analyses are applied to estimate the topological properties and the charge transfer during complexation, respectively. The results indicate that the presence of the cation-π interaction increases the strength of the intramolecular hydrogen bond in the studied complex. Finally, the various electronic descriptors such as energy gap, hardness, softness, and electronic chemical potential are investigated to gain further insight into these interactions. According to the achieved results, the high energy gap of the complex in the water solvent indicates high chemical stability and low reactivity compared to the others. On the other hand, the most reactive as well as the softest complex belongs to the gas phase.

Theoretical investigation of the titanium-nitrogen heterofullerenes evolved from the smallest fullerene.

In this survey, we are performed kinetic stability, global reactivity, atomic polar tensor (APT) charge and counter plots of Ti-N heterofullerenes developed from C20 fullerene with the molecular formula of C20-2nTinNn (n = 1-8), at B3PW91/6-311+G∗ level of theory. Also, we are investigated substituent effect of titanium and nitrogen heteroatoms on deuterium adsorption of the heterofullerenes according to density functional theory (DFT). Substituting of Ti-N units with various topology in the cap or equatorial position of heterofullerenes, changes significantly their electronic properties and causes different frontier molecular orbital energy separation (ΔEHOMO-LUMO). Hence, C18Ti1N1 and C10Ti5N5 are found as the best insulated species, while C12Ti4N4 and C4Ti8N8 are considered as the strongest conductive nanocage. Also, C14Ti3N3 cage shows the highest positive APT charge on Ti atom (+1.357, +1.053), while C12Ti4N4 cage shows the lowest positive APT charge on Ti atom (+0.031, -0.292). Accordingly, C14Ti3N3, and C12Ti4N4 exhibit the lowest, and the highest global electrophilicity; ω of 2.58, and 7.01 eV, respectively. As six D2 molecules are approached the C14Ti3N3 heterofullerene, its ΔEHOMO-LUMO (Eg) is increased from 1.29 eV in C14Ti3N3 heterofullerene to 2.11 eV in D2/C14Ti3N3 complex (∼+63.57%) indicating high sensitivity of it to adsorption of six D2 molecules through an exothermic process. As sixteen D2 molecules approaches the C4Ti8N8 nanocage, its Eg reduces from 0.97 to 0.73 eV (∼-24.74%) indicating high electrical conductivity of D2/C4Ti8N8 complex. Therefore, C4Ti8N8 as hopeful sensor, can be generate electrical signals when the D2 molecules approach.

Novel CoFe2O4@ZnO-CeO2 ternary nanocomposite: Sonochemical green synthesis using Crataegus microphylla extract, characterization and their application in catalytic and antibacterial activities.

In this study, CoFe2O4@ZnO-CeO2 magnetic nanocomposite (CoFe@Zn-Ce MNC) was successfully prepared by facile sonochemical method for the first time. CoFe@Zn-Ce MNC was obtained by green and cost-effective process in the presence of Crataegus microphylla (C. microphylla) fruit extract. Influence of some parameters like capping agents (C. microphylla, SDS and CTAB), sonication time (10, 30 and 60 min) and sonication power (40, 60 and 80 W) were studied to achieve optimum condition. The as-obtained products were characterized by FT-IR, FESEM, TEM, DRS, VSM, EDS, TGA and XRD analysis. Results showed that high magnetic properties (20.38 emug-1), 70-80 nm size and spherical morphology were unique characteristics of synthesized nanocomposite. Antibacterial activity of CoFe@Zn-Ce MNC was examined against E. coli, P. aeruginoss and S. aureus bacteria. Among theme, S. aureus as gram-positive bacteria showed excellent antibacterial activity. Furthermore, photocatalytic performance of the CoFe@Zn-Ce MNC was investigated by degradation of humic acid (HA) molecules under visible and UV light irradiations. The influence of morphology of products and incorporation of cerium oxide with CoFe2O4@ZnO on photocatalytic activity of CoFe2O4@ZnO was performed. After 100 min illumination, the decomposition of HA pollutant by magnetic nanocomposite were 97.2% and 72.4% under exposure of UV and visible light irradiations, respectively. Also, CoFe@Zn-Ce MNC demonstrated high stability in the cycling decomposition experiment after six times cycling runs.

Enhanced catalytic and antibacterial efficiency of biosynthesized Convolvulus fruticosus extract capped gold nanoparticles (CFE@AuNPs).

Scientists are interested in biosynthesis of gold nanoparticles owing to their catalytic and biological features. In this research, the extract of Convolvulus fruticosus (C. fruticosus; CFE) extract was applied to synthesize spherical-like gold nanoparticles (CFE@AuNPs). As-prepared CFE@AuNPs was characterized by TEM, FE-SEM, XRD, FT-IR, EDS, UV-Vis and DLS analysis. Identification analysis revealed that the properties of as-prepared CFE@AuNPs with spherical morphology were homogeneous, regular, high dispersibility and low agglomeration. The particle size of biogenic gold nanoparticles (about 35 nm) was obtained using FE-SEM, TEM and DLS techniques. Photocatalytic experiment of CFE@AuNPs determined by degradation of basic violet 10 (BV10), basic blue 9 (BB9) and acid red 51 (AR51) pollutants with percent degradation of 94.3%, 90.2%, 85.4% under UV and 80.6%, 79.8%, 73.3% under visible light irradiation, respectively. As well as, as-prepared CFE@AuNPs illustrated as a significant inhibitory influence against ATCC strain for both gram-positive and gram-negative bacteria. Owing to the antibacterial results, CFE@AuNPs enhanced antibacterial activity against E. coli, A. baumannii, P. aeruginosa, S. aureus, K. pneumonia, P. mirabilis and E. faecalis with MIC of 0.075, 0.075, 0.075, 0.075, 0.15, 0.075 and 0.037 mg/ml, respectively. All in all, results of the findings showed that C. fruticosus capped gold nanoparticles can find applications in the various arena including biological and removal of toxic pollutants for water purification.

S, N co-doped carbon quantum dots/TiO2 nanocomposite as highly efficient visible light photocatalyst.

In this paper, we report on the preparation of S, N co-doped carbon quantum dots (CQDs)/TiO2 nanocomposite using a hydrothermal process where S, N-CQDs were concurrently synthesized and anchored to the surface of the TiO2. The prepared nanocomposite was carefully characterized to identify the morphology and structure, crystallinity, chemical composition and optical properties. The photocatalytic activity of the nanocomposite was investigated for degradation of acid red 88 (AR88) under visible light irradiation. The capability of the S, N-CQDs/TiO2 nanocomposite to remove AR88 (77.29%) was higher than that of pure TiO2 (23.7%). In order to determine the influencing factors on the photocatalytic activity of the prepared nanocomposite, we studied various contents of the photocatalyst, the effect of pH and the content of H2O2. Further investigations were conducted to reveal the mechanism of photocatalytic degradation using radical scavenging agents. The stability and reusability of the S, N-CQDs/TiO2 photocatalyst was tested in four reaction cycles (870 min) which showed a 25% loss of photoactivity after the fourth photocatalytic reaction.

Modified Fe3O4/HAp Magnetically Nanoparticles as the Carrier for Ibuprofen: Adsorption and Release Study.

The adsorption capacity and release attributes of magnetic Fe3O4@hydroxyapatite (Fe3O4/HAp) nanoparticles for drug molecules can be improved by modified their surfaces with logical chosen organic groups. The internal surface of nanoparticles was functionalized with (3-aminopropyl) trimethoxysilane (APTS). Comparative studies of their adsorption and release properties for various model drug molecules (such as pure hydroxyapatite, Fe3O4@hydroxyapatite and functionalized Fe3O4@hydroxyapatite) were then conducted. The characteristic of the obtained materials was performed with X-ray-diffraction (XRD), energy dispersive X-ray microanalysis (EDS), fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-Vis analysis, vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Results show that functionalized magnetic Fe3O4@hydroxyapatite nanoparticles leads than a substantial decrease of the drug delivery rate in pH=6.8 after investigated drug release in intestine environment. In addition, the results demonstrate that high adsorption capacity for drug and slower drug release rate was obtained after functionalized nanoparticles than Fe3O4@hydroxyapatite and pure hydroxyapatite.