Simultaneous Quantitation of Piperine and Piperlongumine in the Fruit of Piper longum Linn. by Validated High-Performance Thin-Layer Chromatography—Densitometric Method

JPC – Journal of Planar Chromatography – Modern TLC - The fruit of Piper longum Linn. (family: Piperaceae), known as pippali in India, is a reputed drug of Ayurveda (the Indian system...     

Hydrophobic and oleophobic surface modification using fluorinated bis-urea and bis-amide gelators

A series of fluorinated bis-urea and bis-amide derivatives were synthesized from fluorinated amines and explored as surface modifiers for nonwoven substrates. A majority of these derivatives showed excellent gelation properties both in organic solvents as well as in supercritical carbon dioxide (scCO₂) at concentrations ranging from 0.3 to 3 wt%. Gelation in the presence of a nonwoven substrate led to a gel-impregnated surface, which upon drying produced a composite with porous microstructure morphology on the surface. The composites thus produced showed high water and hexadecane contact angles, indicative of excellent hydrophobic and lyophobic properties. The superior hydrophobic and oleophobic behaviors observed in these composites are attributed to a combination of increased surface roughness and the presence of fluoroalkyl functionalities in the gelator backbone.     

Triethanolamine‐catalyzed expeditious and greener synthesis of 2‐amino‐4H‐chromenes

Triethanolamine (TEOA), an inexpensive and eco‐friendly base, was used to efficiently catalyze the three‐component condensation reaction of heterocyclic/aromatic aldehyde, (α/β)‐naphthol, and malononitrile in water to give the corresponding substituted 2‐amino‐4H‐chromene derivatives with excellent yields.     

Poly (ethylene oxide) (PEO)-based,sodium ion-conducting‚ solid polymer electrolyte films,dispersed with Al<Subscript>2</Subscript>O<Subscript>3</Subscript> filler,for applications in sodium ion cells

The studies on solid polymer electrolyte (SPE) films with high ionic conductivity suitable for the realization of all solid-state Na-ion cells? form the focal theme of the work presented in this paper. The SPE films are obtained by the solution casting technique using the blend solution of poly (ethylene oxide) (PEO) with ethylene carbonate (EC) and propylene carbonate (PC) and complexed with sodium nitrate. Structural and thermal studies of SPE films are done by XRD, FTIR spectroscopy, and TGA techniques. Surface morphology of the films is studied using the FESEM. The ionic conductivity of SPE films is determined from the electrochemical impedance spectroscopy studies. For the SPE film with 16 wt% of NaNO₃ used for reacting with the polymer blend of PEO with EC and PC, the ionic conductivity obtained is around 1.08 × 10^?5 S cm^?1. Addition of the Al₂O₃ as the filler material is found to enhance the ionic conductivity of the SPE films. The studies on the Al₂O₃ modified SPE film show an ionic conductivity of 1.86 × 10^–4 S cm^?1, which is one order higher than that of the SPE films without the filler content. For the SPE film dispersed with 8 wt% of Al₂O₃, the total ion transport number observed is around 0.9895, which is quite impressive from the perspective of the applications in electrochemical energy storage devices. From the cyclic voltammetry studies, a wide electrochemical stability window up to 4 V is observed, which further emphasizes the commendable electrochemical behavior of these SPE films.     

A novel and efficient methodology for the C-C bond forming radical cyclization of hydrophobic substrates in water

[reaction: see text]. The combination of water-soluble radical initiator 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (VA-061), water-soluble chain carrier 1-ethylpiperidine hypophosphite (EPHP), and surfactant cetyltrimethylammonium bromide (CTAB) was found to be the most suitable condition for effective radical cyclization in water for a variety of hydrophobic substrates.     

Crystal and molecular structure studies of tris(2-hydroxy-3-t-butyl-5-methylbenzene)-methane trihydrate and N-benzyl-N-phenyl benzamide

The structures of the title compounds, tris(2-hydroxy-3-t-butyl-5-methylbenzene)-methane)C₃₄H₄₆O₃.3H₂O, 3) and N-benzyl-N-phenylbenzamide (C₂₀H₁₇NO, 6), have been investigated by X-ray crystallography. Compound 3 crystallizes in the trigonal space group with cell parameters a = 14.090(5) Å, b = 14.090(5)Å, c = 10.485(5)Å, Z = 2. Compound 6 crystallizes in the monoclinic space group C2/c with cell parameters a = 24.533(4)Å, b = 9.176(4)Å, c = 16.711(5)Å, = 125.88(2)°, Z = 8. Compound 3 has both intra-and intermolecular hydrogen bonds. It also exhibits a helical columnar arrangement of the molecules and goes into mesophase before melting into an isotropic liquid.     

Selective separation of strontium by multitopic ion‐pair receptor: A DFT exploration

Selective extraction of a radionuclide in the presence of other interfering ions is one of the vital steps in the back‐end‐of‐the‐nuclear fuel cycle. The presence of interfering cations (such as Ca²⁺) in the radioactive waste and involvement of multiple separation steps are known to be bottlenecks in the efficient Sr²⁺ extraction. Here, using free energy corrected density functional theory, we have proposed a two‐step Sr²⁺ extraction methodology in nitrate media in the presence of interfering Ca²⁺ ion using a multitopic ion‐pair receptor, which was earlier reported to be strongly selective for K⁺ (Kim et al. J. Am. Chem. Soc. 2012, 134 , 1782–1792). To depict the correct free energy trend in the proposed extraction processes, the most probable binding mode of the metal (Sr²⁺, Ca²⁺, and K⁺) nitrates in the host are identified. In excellent agreement with the previously reported experiment, Crown/Pyrrole (C/P) binding is noted to be the most preferable mode for KNO₃, where K⁺ and occupied the Crown (C) and Pyrrole (P) site, respectively. However, the divalent metal ions (Ca²⁺ and Sr²⁺) are noted to marginally prefer Crown/Crown‐Pyrrole (C/CP) mode, in which metal reside at the C site while two nitrates occupy the P site and also simultaneously bind at the outer sphere of C site to coordinate with the metal via monodentate motif. Based on the free energy of extraction, we predict that the selective separation of chemically alike Ca²⁺/Sr²⁺ pair is indeed achievable using this receptor. We propose that once [Sr(NO₃)₂] is extracted in organic media, the receptor's high affinity toward K⁺ in nitrate media can be used to back strip Sr²⁺ to the aqueous phase.     

Development of rapid solvent extraction based radioanalytical technique for estimation of 90Sr in the presence of natural and anthropogenic radionuclides

A radiochemical technique for estimation of ⁹⁰Sr concentration by direct extraction of ⁹⁰Y with bis (2-ethylhexyl) phosphate (HDEHP) in toluene was developed and standardized. About 90% ⁹⁰Sr retained in the aqueous phase at the optimized pH 4–4.5. Cerenkov counting with 0.04 g mL⁻¹ sodium salicylate as a wavelength shifter resulted in 7.5 fold increase its Cerenkov counting efficiency. The method was validated by estimating ⁹⁰Sr in certified reference materials like, IAEA TEL 2016-03 drinking water, Spruce needle and IAEA-156 Clover. The interference of naturally occurring Ra and its β progeny especially Pb was eliminated by means of Cerenkov counting. Conventional radiochemical separation was used to compare ⁹⁰Sr activity in effluent samples.

     

Studies on matrix interferences during uranium analysis by extractive liquid scintillation technique

Journal of Radioanalytical and Nuclear Chemistry - The efficiency of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) in reducing the influence of salinity and...     

Design,synthesis, characterization,photophysical and pH chemosensor studies of novel 2,4,6-trisubstituted pyridines

For the application in organic electronics as well as pH meters, a series of novel 2,4,6-trisubstituted pyridines have been synthesized by the reaction of substituted aromatic aldehydes and substituted 3-acetylcoumarin with ammonium acetate. The structures of all the new compounds were characterized by IR, NMR, and GC–MS analysis. The important photo physical prerequisites for organoelectronic such as optical absorption and thermal stability were determined for the synthesized molecules. Optical properties were studied by UV–visible absorption and fluorescence spectroscopy. Optical band gaps of the 2,4,6-trisubstituted pyridines were found to be around 3.01–3.06?eV as calculated from their onset absorption edge. The pH-dependent changes in the fluorescence intensity suggest that 2,4,6-trisubstituted pyridines are useful applicants in intracellular pH meters.