Zn/MCM-41-catalyzed unsymmetrical Hantzsch reaction and the evaluation of optical properties and anti-cancer activities of the polyhydroquinoline products

The three-component Hantzsch condensation of various aryl aldehydes, dimedone, and methyl 3-aminocrotonate was investigated in the presence of MCM-41-supported ZnNO3. The polyhydroquinoline products which were obtained under mild conditions and very easy workup were evaluated for anti-cancer activities against MCF-7, SK-BR-3, and HT-29 of breast and colon cancer cells. The fluorescence emission of some products was also studied and their optical parameters were reported.     

Au‐dimercaprol functionalized cellulose aerogel: Synthesis,characterization and catalytic application

A new derivative of cellulose aerogel was prepared via functionalization of cellulose with dimercaprol. Dimercaprol, as a chelating agent of Au(III), was applied for the loading of Au(III) on cellulose aerogel. The new organogold compound after characterization was used as an efficient heterogeneous catalyst in the oxidation reactions of aliphatic alcohols, benzyl alcohol, and ethylbenzene. Excellent selectivities and good conversions were obtained in the green oxidation reactions of alcohols and ethylbenzene. The high porosity of cellulose aerogel led to the good conversions with the low catalyst amounts. The significance of the presented work is the introducing of an environmentally benign process for the oxidation reactions based on a biocompatible catalyst.     

Synthesis and catalytic application of Pd/PdO/Fe3O4@polymer-like graphene quantum dots

A novel approach was achieved for growing citric acid towards polymer-like graphene quantum dots (PGQD) with high efficiency in the presence of sodium hydroxide as a base catalyst. This protocol is completely safe, simple, fast, and efficient by a bottom up strategy. Thermal treatment of a mixture containing citric acid with NaOH at 300 °C gave PGQD during 5 min. The reaction afforded a new heterogeneous catalyst, Pd/PdO/Fe₃O₄@PGQD, in the presence of Pd and Fe₃O₄. The magnetically recoverable catalyst showed high activity in the oxidation of alkylarenes and alcohols using H₂O₂ as a green oxidant at room temperature. Comparison of the results with previous reports showed the efficiency of the catalyst to have high turnover numbers in mild reaction conditions.     

Constraint Qualifications and Stationary Conditions for Mathematical Programming with Non-differentiable Vanishing Constraints

This paper aims at studying a broad class of mathematical programming with non-differentiable vanishing constraints. First, we are interested in some various qualification conditions for the problem. Then, these constraint qualifications are applied to obtain, under different conditions, several stationary conditions of type Karush/Kuhn–Tucker.     

Computational Study on Interactions between CO2 and (TiO2)n Clusters at Specific Sites

The energetic pathways of adsorption and activation of carbon dioxide (CO₂) on low-lying compact (TiO₂)_n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). Our calculated results show that CO₂ is adsorbed preferably on the bridge O atom of the clusters, forming a "chemisorption" carbonate complex, while the CO is adsorbed preferably to the Ti atom of terminal Ti-O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggests that CO₂ in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO-LUMO gap, and density of states (DOS) confirm the charge transfer and interaction between CO₂ and the cluster. From the predicted energy profiles, CO₂ can be easily adsorbed and activated, while the activation of CO₂ on (TiO₂)_n clusters are structure-dependent and energetically more favorable than that on the bulk TiO₂. Overall, this study critically highlights how the small (TiO₂)_n clusters can influence the CO₂ adsorption and activation which are the critical steps for CO₂ reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.     

Nonlinear excitation and stability analysis of ion-acoustic waves in a magnetized quantum plasma with exchange-correlation effects of degenerate electrons

The nonlinear ion-acoustic wave excitation and its stability analysis are investigated in a magnetized quantum plasma with exchange-correlation and Bohm diffraction effects of degenerate electrons in the model. Using reductive perturbation technique, the Zakharov-Kuznetsov (ZK) equation is derived for two dimensional propagation of ion-acoustic wave in a magnetized quantum plasma. It is found that the phase speed, amplitude and width of the nonlinear ion-acoustic wave structures are affected in the presence of exchange-correlation potential in the model. The stability analysis of the 2D ion-acoustic wave pulse is also presented. It is found that growth rate of the first and second order instabilities of 2D ion acoustic wave soliton is enhanced with the inclusion of exchange-correlation potential effect in the model.     

Thermo-bioconvection transport of nanofluid over an inclined stretching cylinder with Cattaneo–Christov double-diffusion

In this paper, Newtonian nanofluid flow is observed under the effects of the magnetic field, activation energy and motile microorganisms over an inclined stretchable cylinder. The magnificent aspects of nanoliquid are demonstrated by enduring the Brownian motion and thermophoresis diffusion features.Nonlinear higher order partial differential equations are transformed into first-order ordinary differential equations with suitable similarity variables. The attained sets of governing equations are then cracked by bvp4 c procedure in MATLAB mathematical software. The numerical and graphical outcomes of controlling parameters such as Prandtl number, mixed convection, activation energy, thermophoresis,Brownian parameter, Biot number, Lewis number, Peclet number and motile concentration parameter against the velocity, temperature, volumetric concentration and motile concentration of nanoparticles of the fluid are discussed. The velocity is enhanced with the growth valuation in mixed convection and decay by rising variation of buoyancy ratio parameter, magnetic parameter and bio-convective Rayleigh parameter. The evolution in motile microorganisms is due to the increasing values of microorganisms Biot number. The presented data can be helpful in enhancement of manufacturing processes, biomolecules, extrusion systems applications and energy production improvement.     

Structural,Optical and Electrical Properties of Cu0.6CoxZn0.4−xFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4) Soft Ferrites

A series of cobalt-inserted copper zinc ferrites, Cu_0.6Co_xZn_0.4−xFe₂O₄ (x = 0.0, 0.1, 0.2, 0.3, 0.4) having cubic spinel structure were prepared by the coprecipitation method. Various characterization techniques, including XRD, FTIR, UV-vis and I–V were used to investigate structural optical and electrical properties, respectively. The lattice constant was observed to be decreased as smaller ionic radii Co²⁺ (0.74 Å) replaced the higher ionic radii Zn²⁺ (0.82 Å). The presence of tetrahedral and octahedral bands was confirmed by FTIR spectra. Optical bandgap energy was determined in the range of 4.44–2.05 eV for x = 0.0 to 0.4 nanoferrites, respectively. DC electrical resistivity was measured and showed an increasing trend (5.42 × 10⁸ to 6.48 × 10⁸ Ω·cm) with the addition of cobalt contents as cobalt is more conductive than zinc. The range of DC electrical resistivity (10⁸ ohm-cm) makes these nanomaterials potential candidates for telecommunication devices.     

Unprecedented Strong Panchromic Absorption from Proton‐Switchable Iridium(III) Azoimidazolate Complexes

Two new heteroleptic iridium(III) complexes bearing an aryldiazoimidazole ligand are reported. These complexes differ structurally with respect to the protonation state of the imidazole ring, but can be independently accessed by varying the synthetic conditions. Their structures have been unequivocally confirmed by X‐ray crystal structure analysis, with surprising differences in the structural parameters of the two complexes. The strongly absorbing nature of the free diazoimidazole ligand is enhanced in these iridium complexes, with the protonated cationic complex demonstrating extraordinarily strong panchromic absorption up to 700 nm. The absorption profile of the deprotonated neutral complex is blueshifted by about 100 nm and thus the interconversion between the two complexes as a function of the acidity/basicity of the environment can be readily monitored by absorption spectroscopy. Theoretical calculations revealed the origins of these markedly different absorption properties. Finally, the protonated analogue has been targeted as an acceptor material for organic photovoltaic (OPV) applications, and preliminary results are reported.     

One-pot isocyanide-based five-component reaction: Synthesis of highly functionalized N-cyclohexyl-2-(2,4-dioxo-2,3,4,5 tetrahydro-1H-benzo[b][1,5]diazepin-3-yl)-2-phenylacetamides

A new protocol has been developed for the efficient synthesis of structurally diverse N-cyclohexyl-2-(2,4-dioxo-2,3,4,5-tetrahydro-1H-benzo[b][1,5]diazepin-3-yl)-2-phenylacetamides through a one-pot, five-component condensation reaction of an aromatic diamine, an aromatic aldehyde, an isocyanide, ethyl malonyl chloride, and water in dichloromethane with good yields, at ambient temperature, in the presence of MgCl₂ as a catalyst.