SbCl3‐Al2O3–Catalyzed,Solvent‐Free,One‐Pot Synthesis of Benzo[b]1,4‐diazepines

This article explores the use of antimony(III) chloride adsorbed on neutral alumina as an efficient catalyst for the one‐pot synthesis of benzo[b]1,4‐diazepines (83–94%) under solvent‐free conditions. The process is easy, efficient, ecofriendly, and economical.     

Effect of Sodium Alkanoates on Micellization of Dodecylbenzyldimethylammonium Chloride in Aqueous Medium

The present study deals with the interaction of sodium alkanoates viz. sodium acetate, sodium propionate, sodium butanoate, sodium hexanoate and sodium benzoate on the micellization of dodecylbenzyldimethylammonium chloride using conductometeric and flourscence quenching experiments carried out at 25°C. The analysis has been made through study of variation of critical micelle concentration (cmc), degree of counterion binding (β), aggregation number (N), and micropolarity with the concentration of these hydrophobic salts. The differentiation between the effects of hydrophobic and inorganic salts was made by comparing the above results with the influence of NaCl on cmc, β, and N.     

Carbon black and propylene oxidation over Ru/CoxMgyAl2Oz catalysts

The effects of Co_xMg_yAl₂O_z mixed oxides composition and ruthenium addition on the oxidation of propylene and carbon black (CB) were investigated. Different reactive cobalt and ruthenium oxide species were formed following calcination at 600 °C. The addition of ruthenium was beneficial for the CB oxidation under “loose contact” conditions and for propylene oxidation when the cobalt content was intermediate to low. The calculated activation energy for CB oxidation was decreased from 151 kJ mol⁻¹ for the uncatalyzed reaction to 111 kJ mol⁻¹ over the best catalyst.     

Rheological response and small-angle neutron-scattering study of diester-bonded cationic biodegradable gemini surfactants in presence of different additives

Morphological changes and internal packing arrangements of planar dicationic-ester-bonded biodegradable gemini surfactants ethane-1, 2-diyl-bis(N,N-dimethyl-N-alkylammonium acetoxy) dichlorides (m-E2-m) have been explored by exploiting small-angle neutron-scattering (SANS) measurements. The data have been analyzed on the basis of Hayter and Penfold model for macroion solutions to obtain information about the aggregation behavior at the molecular level. The extent of micellar growth and structural changes of the micelles formed by these surfactants have been found to depend on the number of methylene units in their tail length. The growth and variation of micellar shape are more pronounced for the surfactant with longer tail length (m?=?16), whereas the surfactants with shorter tail length showed less variation of these properties in aqueous solution. Semi-major axes of the micelles show flexibility while varying the concentration and temperature of the systems; however, semi-minor axes remain rigid. Changes in the structural parameters of the micelles with addition of different salts were also inferred from SANS measurements. The intensity of scattered neutrons at the low Q region was found to increase while varying the nature of salt from monovalent to trivalent. On the basis of rheological responses, the rich aggregation behavior resulting from the addition of sodium salicylate (NaSal) is attributed to the special molecular structure of the gemini surfactant and the appropriate interaction between the surfactant and NaSal. This is inferred on the basis of behavior observed by varying the chain length (m) of the gemini surfactant that resulted in the formation of different types of microstructures.     

A concise synthesis of Hagen’s gland lactones

A short synthesis of Hagen’s gland lactones 1 and 2 from commercially available pentanal and heptanal, respectively, is outlined. The approach relies on sequential ring closing metathesis and intramolecular oxy-Michael addition as the key transformations.     

On the zeros of certain composite polynomials and an operator preserving inequalities

The Ramanujan Journal - If all the zeros of nth degree polynomials f(z) and $$g(z) = \sum _{k=0}^{n}\lambda _k\left( {\begin{array}{c}n\\ k\end{array}}\right) z^k$$ respectively lie in the cricular...     

Biocompatible fluorescent polyamine‐based cyclophosphazene hybrid nanospheres for targeted cell imaging

Fluorescent nanoprobes are highly desirable toolkit for bioimaging applications. This study reports the first example for the synthesis of a nontoxic prototypical fluorescent organic compound 2‐benzo[d]thiazol‐2‐yl)‐3‐(2‐chloro‐4‐(dimethylamino)phenyl)acrylonitrile (BCA) and its entrapment into the poly[cyclotriphosphazene‐co‐polyethyleneimine] cross‐linked (PCPEI) nanospheres named as BCA@PCPEI for targeted cell imaging application. The as‐prepared BCA@PCPEI nanospheres were thoroughly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and phosphorus‐31 nuclear magnetic resonance (³¹P‐NMR) analyses. The surface functional analysis of the nanospheres was performed by X‐ray photoelectron spectroscopy (XPS), which proves that the content ratios of elements belong to the precursors concentrations. The as‐prepared nanospheres displayed emission at 606 nm with bright orange fluorescence at any concentration. Moreover, the nanospheres were also less cytotoxic and maintained remarkable cell viability up to 100 μg/mL. Owing to the fluorescence with higher emission, this material has shown excellent cell imaging performance with better targeting ability to HeLa cells.     

A mini review on the generation of crimped ultrathin fibers via electrospinning: Materials,strategies, and applications

Structures modification of fibers has been attracting significant attention in various fields and applications. Among different techniques of fabricating ultrathin fibers, electrospinning is the most commonly adopted method because of the ease of forming fibers with a wide range of properties and its exceptional advantages, such as the ability to spin into different shapes and sizes, as well as the adaptable porosity of electrospun fiber webs. The crimped structure has been attracting the attention of scientific researchers owing to its unique properties (eg, spring‐like behavior, supreme strain, remarkable specific surface area, good piezoelectric properties, excellent biological properties, and so on). Therefore, this study summarizes a review of the strategies and methods, reported so far, of generating electrospun crimped ultrathin fibers of various polymers. The review focuses on the polymer types, formation methods, characterizations, and applications of the electrospun crimped ultrathin fibers. We believe this work can serve as an important reference for the materials, strategies, and applications of crimped fibers.     

Free‐Standing CoO‐POM Janus‐like Ultrathin Nanosheets

A single‐step solution‐based strategy is used to obtain 2D Janus‐like free‐standing ultrathin nanosheets build from two structurally unrelated species, that is, polyoxomolybdate (POM) and CoO. A controlled 2D‐to‐1D morphological transition was achieved by judiciously adjusting the solvent choice. These POM‐CoO heterostructures can behave as an ideal catalyst for the epoxidation of styrene. Benefiting from their amphiphilic nature, these 2D POM‐CoO nanosheets have also been used as surfactant to emulsify immiscible solvents. It is anticipated that structurally diverse polyoxometalates will offer promise as design elements for variety of structurally and compositionally tunable van der Waals integrated heteromaterials having a broad range applications.     

Stabilization of Highly Efficient and Stable Phase‐Pure FAPbI3 Perovskite Solar Cells by Molecularly Tailored 2D‐Overlayers

As a result of their attractive optoelectronic properties, metal halide APbI₃ perovskites employing formamidinium (FA⁺) as the A cation are the focus of research. The superior chemical and thermal stability of FA⁺ cations makes α‐FAPbI₃ more suitable for solar‐cell applications than methylammonium lead iodide (MAPbI₃). However, its spontaneous conversion into the yellow non‐perovskite phase (δ‐FAPbI₃) under ambient conditions poses a serious challenge for practical applications. Herein, we report on the stabilization of the desired α‐FAPbI₃ perovskite phase by protecting it with a two‐dimensional (2D) IBA₂FAPb₂I₇ (IBA=iso‐butylammonium overlayer, formed via stepwise annealing. The α‐FAPbI₃/IBA₂FAPb₂I₇ based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23 %. In addition, it showed excellent operational stability, retaining around 85 % of its initial efficiency under severe combined heat and light stress, that is, simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over 500 h.