Metalloporphyrin reduced C70 fullerenes as adsorbents and detectors of ethenone; A DFT, NBO, and TD-DFT study.

In the present work, the structure and electronic properties of Ti-, Cr-, Fe-, Ni-, Zn-, and Cu-inserted in porphyrin-reduced C70 fullerenes (TM-PIC70Fs) and their interactions with the ethenone were studied using DFT, NBO, and TD-DFT at CAM-B3LYP/6-31G(d) level of theory. 2.89-3.83 and 4.02-4.56 eV were obtained for the HOMO-LUMO gap energies and work functions of TM-PIC70Fs, respectively, compared with 3.76 and 4.54 eV for PIC70F. Among considered TM-PIC70Fs, the adsorption of the ethenone on Ti-PIC70F appreciably changed the HOMO-LUMO energy gap and work function. Consequently, Ti-PIC70F may be used as the ethenone's electronic conductivity and work function types sensor. According to calculated UV-visible spectra, the ethenone adsorption may change the color of Fe- and Ti-PIC70Fs. Therefore, they can be used as color-changing sensors of ethenone. In addition, Ti-, Cr-, Fe-, and Zn-PIC70Fs can be employed as suitable adsorbents of ethenone. Among proper sensors and adsorbents of ethenone, Cr-, Fe-, and Zn-PIC70Fs may be recovered and reused.

Carbon fixation of CO2 via cyclic reactions with borane in gaseous atmosphere leading to formic acid (and metaboric acid); A potential energy surface (PES) study.

Carbon dioxide (CO2), a stable gaseous species, occupies the troposphere layer of the atmosphere. Following it, the environment gets warmer, and the ecosystem changes as a consequence of disrupting the natural order of our life. Due to this, in the present reasearch, the possibility of carbon fixation of CO2 by using borane was investigated. To conduct this, each of the probable reaction channels between borane and CO2 was investigated to find the fate of this species. The results indicate that among all the channels, the least energetic path for the reaction is reactant complex (RC) to TS (A-1) to Int (A-1) to TS (A-D) to formic acid (and further meta boric acid production from the transformation of boric acid). It shows that use of gaseous borane might lead to controlling these dangerous greenhouse gases which are threatening the present form of life on Earth, our beautiful, fragile home.

Characterization of titanium influences on structure and thermodynamic stability of novel C20-nTin nanofullerenes (n=1-5): a density functional perspective.

In this survey, effects of titanium heteroatom(s) on structural parameters and thermodynamic stability of C20 fullerene and its C20-nTin derivatives (n = 1-5) are compared and contrasted, at DFT levels of theory. The results show that in going from C19Ti1 to C15Ti5, binding energy increases while absolute value heat of atomization decreases. According to vibrational frequency analysis, excepting C16Ti4-1, the other optimized structures give no imaginary frequency as true minima. The calculated binding energy of 887.12 kcal mol-1/atom displays C15Ti5 as the most thermodynamically stable heterofullerene. It has Cs symmetry and contains five titanium atoms alternatively in equatorial position. The substitutional doping of C20 fullerene leads to high Mülliken charge distribution upon the surfaces of the resulted heterofullerenes especially C19Ti1 as suitable hydrogen storage. The contour plots indicate the most negative electrostatic potential by red color for C atoms, whereas the most positive electrostatic potential by yellow color for Ti heteroatoms. The contour plots and multiwfn analysis exhibit charge transfer from titanium heteroatoms to the neighboring carbon atoms. Furthermore, the resulted electron density maps from multiwfn qualitatively confirm the contour plot's findings. The hydrogen adsorption is an endothermic process for C20 fullerene and exothermic process for C20-nTin heterofullerenes. Major criteria examined for thermodynamic stability; from C19Ti1 to C15Ti5, binding energy and hydrogen adsorption increase while heat of atomization decreases.

Thermodynamic stability, structural and electronic properties for the C20-nAln heterofullerenes (n = 1-5): a DFT study.

DFT calculations are utilized to compare and contrast the substituted aluminum-heterofullerenes, C20-nAln (with n = 1-5) from thermodynamically view point, at density functional theory (DFT). Vibrational frequency analysis confirms that apart from C15Al5, all studied species are true minima. Considering the optimized geometries shows that all heterofullerenes are isolated-pentagon cage and none collapse to open deformed as segregated structure. The highest binding energy (5.56 eV/atom) and absolute heat of atomization (3323.68 kcal mol-1) reveals open-shell C19Al1 as the most stable thermodynamic heterofullerene. The most NICS (0) (isotropic and anisotropic parameters, -49.58 and - 46.47 ppm, respectively) introduces closed-shell C18Al2-2 as the most aromatic structure. Also, closed-shell C16Al4-1 heterofullerene emerges with the most polarizability (307.71 a.u.) and hence activity to interact with the surrounding polar species. The lowest and the highest charge transfer on the surfaces of C20 and C16Al4-2 without weak Al-Al bond, as the worst and the best candidate, respectively, provokes further investigation on impossible and possible application for hydrogen storage, respectively. We wish that the present survey will stimulate new experiments.

The effect of soft repulsive interactions on the diffusion of particles in quasi-one-dimensional channels: A hopping time approach.

Fluids confined to quasi-one-dimensional channels exhibit a dynamic crossover from single file diffusion to normal diffusion as the channel becomes wide enough for particles to hop past each other. In the crossover regime, where hopping events are rare, the diffusion coefficient in the long time limit can be related to a hopping time that measures the average time it takes for a particle to escape the local cage formed by its neighbors. In this work, we show that a transition state theory (TST) that calculates the free energy barrier for two particles attempting to pass each other in the small system isobaric ensemble is able to quantitatively predict the hopping time in a system of two-dimensional soft repulsive disks [U(rij)=(σ/rij)α] confined to a hard walled channel over a range of channel radii and degrees of particle softness measured in terms of 1/α. The free energy barrier exhibits a maximum at intermediate values of α that moves to smaller values of 1/α (harder particles) as the channel becomes narrower. However, the presence of the maximum is only observed in the hopping times for wide channels because the interaction potential dependence of the kinetic prefactor plays an increasingly important role for narrower channels. We also begin to explore how our TST approach can be used to optimize and control dynamics in confined quasi-one-dimensional fluids.

Protective effects of isatin and its synthetic derivatives against iron, copper and lead toxicity.

INTRODUCTION: While some metals are required for physiological functions in the form of essential trace elements, they can cause toxicity in the excessive concentrations. Chelation therapy was used to reduce the adverse effects of acute and chronic poisoning by metals. Isatin derivatives form complexes with copper ions indicating that they may have protective activity against metal overload. METHOD: In this study, four compounds (isatin and three isatin-derivatives Mj1, TR and Mk1) were evaluated for drug-likeliness. Then their potency inhibiting cell proliferation was determined in HEK293 cell culture assay. Finally, IC50 values for lead, copper, and iron was evaluated in the absence and also the presence of isatin and its derivatives. RESULTS: Isatin and its derivatives used in this study complied with the Lipinski criteria for drug-likeliness. The greatest difference between the IC50 values and the non-toxic dose was obtained for TR and Mj1, respectively. Pretreatment with the Mj1 increased the IC50 values for lead, iron, and copper, by 2.1, 1.7 and 1.7 times, respectively. At non-toxic dose, TR has only increased the IC50 values for lead and copper by 1.4 and 1.3 times without affecting iron cytotoxicity. Mk1 increased the IC50 values for lead, copper, and iron by 1.3, 1.8 and 1.7 times, respectively. CONCLUSIONS: Mj1 is suggested as a lead compound for developing therapeutic agents for lead (Pb) toxicity and Mk1 for copper and iron.

A DFT study on nanocones, nanotubes (4,0), nanosheets and fullerene C60 as anodes in Mg-ion batteries.

In this article, we studied the interactions between Mg atom and Mg2+ ion and four nanostructures, including a nanocone, nanotube (4,0), nanosheet, and C60 nanocage, to obtain the cell voltages (V) for Mg-ion batteries (MIBs). Total energy, geometry optimization, frontier molecular orbital (FMO) and density of states (DOS) analyses have been performed using the ωB97XD level of theory and the 6-31G(d) basis set. The DFT calculations clarified that the changes in energy adsorption between Mg2+ ion and the nanostructures, E ad, are in the order tube > cone > sheet > cage. However, V cell for the nanocone is the highest. The changes in V cell of the MIBs are in the order cone > tube > sheet > cage. This study theoretically considers the possibilities of Mg as an anode in batteries due to its high V cell values.

Recent advances in the application of nano-catalysts for Hiyama cross-coupling reactions.

This mini-review highlights the recent developments in the field of metal nanoparticle (NP) catalyzed Hiyama cross-coupling reactions. Most of the nanocatalysts outlined here allow convenient and green synthetic pathways for the construction of carbon-carbon bonds in water and fluoride-free conditions. Literature has been surveyed from 2005 to February 2018.

Cross-Dehydrogenative C-H/S-H Coupling Reactions.

Carbon-sulfur bond formation represents a key step in the synthesis of thioethers, which are a common structural motif in many pharmaceutically compounds. The direct cross-dehydrogenative coupling of C-H/S-H bonds has become a powerful tool for C-S bond formation. As these coupling reactions avoid pre-functionalization of the starting materials, they are more atom-economical, practical, and environmentally friendly than traditional cross-coupling reactions. In this review, we will highlight the most important developments in this novel and interesting research arena with the emphasis on the mechanistic aspects of the reactions. The review is divided into three major sections: (1) C(sp3)-H/S-H bonds coupling reactions; (2) C(sp2)-H/S-H bonds coupling reactions; and (3) C(sp)-H/S-H bonds coupling reactions.

Diaryl ethers synthesis: nano-catalysts in carbon-oxygen cross-coupling reactions.

The diaryl ether moiety is not only prevalent in a significant number of natural products and synthetic pharmaceuticals but also widely found in many pesticides, polymers, and ligands. Ullmann-type cross-coupling reactions between phenols and aryl halides are regarded as one of the most important methods for the synthesis of this important and versatile structural motif. In recent years, the use of nano-sized metal catalysts in this coupling reaction has attracted a lot of attention because of these catalysts with their high surface-to-volume ratio, high surface energy, and reactive morphology allows for rapid C-O bond formation under mild and ligand-free conditions. In this review we will highlight the power of these catalysts in Ullmann-type C-O cross-coupling reactions.

Decarboxylative cross-coupling reactions for P(O)-C bond formation.

Phosphorus-containing compounds are one of the most important classes of organic compounds, which have wide applications in organic chemistry, medicinal chemistry, agricultural chemistry, and materials chemistry. In particular, organophosphorus compounds bearing a P(O)-C bond have attracted significant attention in recent decades due to their widespread biological and pharmacological activities. In this review, we will highlight the most important developments in the construction of P(O)-C bonds through decarboxylative C-P cross-coupling reactions. The literature has been surveyed from 2011 to May 2018.

Arylhydrazines: novel and versatile electrophilic partners in cross-coupling reactions.

Arylhydrazines are extremely valuable compounds in organic chemistry that are widely used for the synthesis of a variety of biologically active molecules such as indoles, indazoles, pyrazoles, aryltriazoles, ß-lactams and quinazolines. These compounds have also been widely utilized as arylation agents in oxidative cross-coupling reactions. In this review, we will highlight the most important explorations and developments in the carbon-carbon and carbon-heteroatom (nitrogen, phosphorus, sulfur, and selenium) cross-coupling of arylhydrazines. The literature has been surveyed from 2001 to June 2018.

Diffusion in quasi-one-dimensional channels: A small system n, p, T, transition state theory for hopping times.

Particles confined to a single file, in a narrow quasi-one-dimensional channel, exhibit a dynamic crossover from single file diffusion to Fickian diffusion as the channel radius increases and the particles begin to pass each other. The long time diffusion coefficient for a system in the crossover regime can be described in terms of a hopping time, which measures the time it takes for a particle to escape the cage formed by its neighbours. In this paper, we develop a transition state theory approach to the calculation of the hopping time, using the small system isobaric-isothermal ensemble to rigorously account for the volume fluctuations associated with the size of the cage. We also describe a Monte Carlo simulation scheme that can be used to calculate the free energy barrier for particle hopping. The theory and simulation method correctly predict the hopping times for a two-dimensional confined ideal gas system and a system of confined hard discs over a range of channel radii, but the method breaks down for wide channels in the hard discs' case, underestimating the height of the hopping barrier due to the neglect of interactions between the small system and its surroundings.