“MCR-Click” synthesis of coumarin-tagged macrocycles with large Stokes shift values and cytotoxicity against human breast cancer cell line MCF-7

A three step “MCR-Click” strategy has been developed for the synthesis of a library of coumarin-tagged macrocycles with varying ring size from 11 to 18. The coumarin moiety connected to the peptidomimetic macrocycles thorough a keto-methylenic spacer helps the molecules to become optical systems with controlled emission properties. All the twelve macrocycles developed are emitting in the green region with high Stokes shift values indicating the potential of these molecules as probes for bioimaging applications. Similarly, the excellent cytotoxicity exhibited by the molecules toward human breast cancer cell line (MCF-7) further indicating the possibilities of these new macrocycles as potential anticancer/antitumor agents.     

Kinetics of hydroformylation of 1-decene using carbon-supported ossified HRh(CO)(TPPTS)3 catalyst

The kinetics of hydroformylation of 1-decene has been investigated using a carbon-supported ossified HRh(CO)(TPPTS)₃/Ba catalyst in a temperature range of 343–363 K. The effect of concentration of 1-decene, catalyst loading, partial pressure of H₂ and CO, and stirring speed on the reaction rate has been investigated. A first-order dependence was observed for catalyst concentration and hydrogen partial pressure. The rate showed a typical case of substrate inhibition for high 1-decene concentration. The rate varied with a linear dependence on P_CO up to a CO partial pressure of 5–6 MPa in contrast to the general trends; for most of the rhodium-phosphine catalyzed hydroformylation reactions, severe inhibition of rate is observed with an increase in CO pressure. A rate equation has been proposed, which was found to be in good agreement with the observed rate data within the limit of experimental errors. The kinetic parameters and activation energy values have been reported.     

Crystallization,non-isothermal kinetics and structural analysis of nanocrystalline multiferroic bismuth ferrite (BiFeO3) synthesized by combustion method

Journal of Thermal Analysis and Calorimetry - The aim of this study was to evaluate the effect of curing and microwave power levels on energy analysis, drying characteristics, modeling and quality...     

A model for charge transport in semicrystalline polymer thin films

A model for simulating the charge transport properties of semicrystalline polymer (SCrP) using Monte Carlo simulation is reinvented. The model is validated by reproducing the experimentally observed field and temperature dependence of mobility in Poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) thin films. This study also provides a new physical insight to the origin of much debated negative field dependence of mobility (NFDM) observed at low electric field strengths in P3HT thin films. The observed NFDM, which is not explainable with the mechanisms proposed earlier, is attributed to the weak dependence of transit time on the applied electric field strengths. In the semicrystalline films, the charge transport takes place mostly through the crystalline regions, in which the charge transport is weakly dependent on the strength of the applied electric field. In addition, a possible explanation for the origin of Arrhenius temperature dependence of mobility (lnμ ∝ 1/T) commonly observed in SCrP thin films is also proposed. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 137–141     

High-performance thin-layer chromatographic—densitometric determination of the major triterpene saponins and their aglycones from Centella asiatica

JPC – Journal of Planar Chromatography – Modern TLC - Centella asiatica (L.) Urban, Apiaceae, is a medicinal plant, rooted in the Ayurvedic medicine with wide and potent health...     

Development and Validation of a High-Performance Thin-Layer Chromatography Method for the Quantification of Rutin in the Fruit Pulp of Benincasa hispida (Thunb.) Cogniaux

JPC – Journal of Planar Chromatography – Modern TLC - The fruits of Benincasa hispida (Thunb.) Cogniaux, a ‘rasayana’ in ‘Ayurveda’, are enriched with several...     

A theoretical kinetic study of the reactions of NH2 radicals with methanol and ethanol and their implications in kinetic modeling

Amino (NH₂) radicals play a central role in the pyrolysis and oxidation of ammonia. Several reports in the literature highlight the importance of the reactions of NH₂ radicals with fuel in NH₃-dual-fuel combustion. Therefore, we investigated the reactions of NH₂ radicals with methanol (CH₃OH) and ethanol (C₂H₅OH) theoretically. We explored the various reaction pathways by exploiting CCSD(T)/cc-pV(T, Q)Z//M06-2X/aug-cc-pVTZ level of theory. The reaction proceeds via complex formation at the entrance and exit channels in an overall exothermic process. We used canonical transition state theory to obtain the high-pressure limiting rate coefficients for various channels over the temperature range of 300–2000 K. We discerned the role of various channels in the potential energy surface (PES) of NH₂ + CH₃OH/C₂H₅OH reactions. For both reactions, the hydrogen abstraction pathway at the OH-site of alcohols plays a minor role in the entire T-range investigated. By including the title reactions into an extensive kinetic model, we demonstrated that the reaction of NH₂ radicals with alcohols plays a paramount role in accurately predicting the low-temperature oxidation kinetics of NH₃-alcohols dual fuel systems (e.g., shortening the ignition delay time). On the contrary, these reactions have negligible importance for high-temperature oxidation kinetics of NH₃-alcohol blends (e.g., not affecting the laminar flame speed). In addition, we calculated the rate coefficients for NH₂ + CH₄ = CH₃ + NH₃ reaction that are in excellent agreement with the experimental data.