Scaled‐up,selective and green synthesis of sulfoxides under mild conditions using (CeIII‐MoVI)Ox/aniline hybrid rods as an efficient catalyst

A novel hybrid material, (Ce^III‐Mo^VI)O_x/aniline, with rod‐like morphology is synthesized through a wet chemical method using Mo₃O₁₀(C₆H₅NH₃)₂.2H₂O nanowires as precursor. The synthesized materials are characterized by XRD, XPS, SEM, TEM, FTIR, Raman, UV–Vis, TGA, and elemental analysis. Also, their catalytic activities as a hybrid catalyst are tested in the selective oxidation of sulfides using hydrogen peroxide as a green oxidant. The proposed novel hybrid catalyst shows an excellent performance under green conditions at mild temperature. Furthermore, the scalability of the oxidation reaction is shown by making multi‐gram quantities at optimized conditions.     

Optimization and characterization of electrospun chitosan/poly(vinyl alcohol) nanofibers as a phenol adsorbent via response surface methodology

Fabrication and characterization of chitosan/poly(vinyl alcohol) electrospun nanofibers for adsorption of phenol from water were investigated. The effects of voltage (15–30 kV), solution injection flow rate (0.5–1.5 ml/hr), distance of needle and collector (10–20 cm) and chitosan/poly(vinyl alcohol) ratio (25/75, 50/50, 75/25) were studied to obtain the optimum electrospinning conditions for the maximum adsorption capacity of phenol. Central composite design (CCD) was used to investigate and optimize the processing factors for production of chitosan/poly(vinyl alcohol) nanofibers from aqueous solutions. The nanofibers were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR). Uniform beadless nanofibers with the minimum diameters of 3–11 nm were obtained at chitosan/poly(vinyl alcohol) ratio of 50/50, voltage of 22.5 kV, distance of 15 cm and injection flow rate of 1.99 ml hr^?1. Fourier transform infrared spectrum of chitosan/poly(vinyl alcohol) exhibited the existence of relevant functional groups of both poly(vinyl alcohol) and chitosan in the blends. Results of CCD show that among all processing factors, rate of electrospinning will highly affect the nanofiber adsorption. The response surface quadratic order model presented correlation coefficient explaining 69.5% of the variability in the adsorption. Copyright © 2017 John Wiley & Sons, Ltd.     

Theoretical study on alkaloid encapsulating via cyclopentano-cucurbit[n]uril (n = 8, 10)/graphene oxide heterojunction

Here, physical chemistry properties of the inclusion complexes of some alkaloids and cyclopentano-cucurbit[8, 10]urils (Cy-CB[8, 10]) were investigated via molecular dynamic (MD) simulations and density functional theory (DFT) calculations. The possibility of the heterojunction formation between cyclopentano-cucurbit[8, 10]urils and graphene oxide was investigated via MD simulation. Based on the results, an effective role of graphene oxide on the encapsulation complex formation, especially in the presence of codeine and morphine was confirmed. DFT (M06-2X) and DFT-D3 (M06-2X-D3) functionals were applied for geometry optimization of the complexes. To have an insight into the atomic level, different analyses, such as natural bond orbital and quantum theory of atoms in molecule analyses were applied and discussed. DFT results confirm that Cy-CB[8] makes a stronger interaction with alkaloids in comparison with Cy-CB[10]. Thermodynamic studies show that the complexation process of codeine inside Cy-CB[n] is more favorable than other complexes. Moreover, energy analysis showed that the van der Walls part plays an important role in alkaloid stabilization inside the Cy-CB[n] cavity.     

Synthesis of spiroindolo[2,1‐b]quinazolines from Huisgen zwitterions and tryptanthrin‐malononitrile adducts

Functionalized spiroindolo[2,1‐b]quinazolines are obtained from the reaction between tryptanthrin‐malononitrile adducts and Huisgen zwitterionic intermediates, generated by addition reaction of aromatic N‐heterocycles with acetylenic esters. The reaction is diastereoselective leading to the formation of a single diastereoisomer. The structure of a typical product established by X‐ray crystallography.     

Synergistic Effect of Sarocladium sp. and Cryptococcus sp. Co-Culture on Crude Oil Biodegradation and Biosurfactant Production

This study was conducted to evaluate the co-culture ability of two yeast (Sarocladium sp. and Cryptococcus sp.) isolates as compared to their individual cultures in surfactant production and oil degradation. The results showed that individual culture of each strain was capable of producing surfactant, degrading oil, and pyrene; also, a synergistic effect was observed when a co-culture was applied. Oil removal and biomass production were 28 and 35% higher in the co-culture than in individual cultures, respectively. To investigate the synergistic effects of mix culture on oil degradation, the surface tension, emulsification activity (EA), and cell surface hydrophobicity of individual and co-culture were studied. A comparison between the produced biosurfactant and chemical surfactants showed that individual culture of each yeast strain could reduce the surface tension like SDS and about 10% better than Tween 80. The results showed that the microbial consortium could reduce the surface tension more, by 10 and 20%, than SDS and Tween 80, respectively. Both individual cultures of Sarocladium sp. and Cryptococcus sp. showed good emulsification activity (0.329 and 0.412, respectively) when compared with a non-inoculated medium. Emulsification activity measurement for the two yeast mix cultures showed an excellent 33 and 67% increase as compared to the individual culture of Sarocladium sp. and Cryptococcus sp., respectively. The cell surface hydrophobicity of Sarocladium sp. and Cryptococcus sp. increased (38 and 85%) when the cells were treated with pyrene as a hydrophobic substrate for four generations. Finally, a 40% increase for pyrene degradation was measured in a co-culture of the two yeast mix culture. According to the results of the present study, the co-culture system exhibited better performance and this study will enhance the understanding of the synergistic effects of yeast co-culture on oil degradation.

     

Highly Sensitive Electrochemical Sensor Based on Pt Doped NiO Nanoparticles/MWCNTs Nanocomposite Modified Electrode for Simultaneous Sensing of Piroxicam and Amlodipine

In this paper, a high‐sensitivity electrochemical sensor based on platinum (Pt) doped nickel oxide (NiO) nanoparticles and multi‐walled carbon nanotubes (MWCNTs) modified glassy carbon electrode (Pt?NiO/MWCNTs/GCE) has been developed to determine piroxicam (PIR) and amlodipine (AML) simultaneously. The electrochemical behavior of PIR and AML at the proposed sensor has been investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) methods. Pt doped NiO nanoparticles were synthesized by the sol‐gel procedure and were investigated using X‐ray diffraction (XRD), energy dispersive X‐ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM) techniques. DPV responses of PIR and AML increased linearly with their concentration in wide linear dynamic ranges of 0.6–320.0 μM and 1.0–250.0 μM, respectively. The limits of detection were 0.061 μM for PIR and 0.092 μM for AML. The excellent analytical figure of merits of the proposed modified electrode leads to application of it promising electrochemical sensor to determine PIR and AML in human serum and urine with satisfactory results.     

Three-component reaction between amines,carbon disulfide and electron-deficient derivatives of chloropyridine or chlorobenzene: synthesis of 3,6-diazaspiro[4.5]deca-2,7,9-trien-6-ium chloride and dithioylcarbamates derivatives

In this study, three-component reaction of some primary and secondary amines with carbon disulfide in the presence of electron-deficient derivatives of chloropyridine or chlorobenzene in the CH₃CN as a solvent is reported. The reaction of primary amines with carbon disulfide and electron-deficient compounds of chloropyridine or chlorobenzene after 6–8 h afforded the three-component addition product. The reaction of secondary amines with carbon disulfide and electron-deficient compounds of chloropyridine or chlorobenzene after 3–4 h afforded the two-component addition product. The product(s) of reactions were purified by recrystallization or column chromatography and their structures were identified by spectroscopy techniques such as ¹H-NMR, ¹³C-NMR, IR, UV and elemental analysis. The reactions were carried out under mild conditions and without using a catalyst.     

Theoretical evaluation of symmetrical α,α′,δ,δ′-tetramethyl cucurbit[6]uril for haloalkane 1-(3-chlorophenyl)-4-(3-chloropropyl)-piperazinium and chloroform encapsulation

In the present study, structures and electronic properties of inclusion complexes of TMeQ[6] with PZ⁺ and CHCl₃ were investigated, using the density functional theory calculations and molecular dynamic (MD) simulations. Theoretical results at the M05-2X-D3/6-31G(d) level clearly confirm that the inclusion complex formation is energetically feasible, and PZ⁺@TMeQ[6] formation is more favorable than CHCl₃@TMeQ[6]. Natural bond orbital and quantum theory of atoms in molecules analyses were applied to investigate the electron transfer and topological properties of the interactions of TMeQ[6] and guest compounds. Non-covalence nature, van der Waals, of the host–guest interactions was confirmed by non-covalent interactions–reduced density gradient method. Finally, the effect of solvent was taken into account by using the MD simulations. According to H-bond analysis in the MD simulations, the importance of hydrogen bonding interactions was confirmed only in PZ⁺@TMeQ[6] complex, the studied inclusion complexes are more stable in chloroform, because of a high value of van der Waals interactions. This study show that TMeQ[6] as a good candidate for sensing.

Graphical Abstract

A joint MD/QM study confirms the side chain effect of PZ⁺ on the response ability improvement of TMeQ[6].

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Understanding the role of noncovalent interactions on the rate of some Diels-Alder reactions in different solvents

In this article, the role of noncovalent interactions (NCI) on four types of cycloaddition reactions in different solvents was investigated by employing quantum chemistry calculations. For this purpose, explicit and implicit solvation models were applied in the experimental conditions of temperature and pressure. NCI analysis indicates that van der Waals (vdW) interactions, as a part of NCI, change the stability and Gibbs energy of the transition states (TSs), which in turn affects the rate of the reaction. On the basis of NCI analysis, a partial covalent nature of the forming C C bonds at the TSs was confirmed. Energy analysis confirms that vdW interactions can be considered as the main part of the solute-solvent interactions in the cycloaddition reactions. Moreover, cycloaddition reactions of the polar reactants are faster in polar solvents, while nonpolar solvents induce a contrast effect on the rate of these reactions.