Simultaneous high-performance thin-layer chromatography analysis of phytoconstituents and antioxidant potential of Inula grandiflora Willd. from India

JPC – Journal of Planar Chromatography – Modern TLC - The Inula genus has been used for the cure of pulmonary, heart diseases and also acts as a rejuvenator, immunomodulator in...     

Colossal Stability of SiB11(BO)12−: An Implication as Potential Electrolyte in High-Voltage Alkali-ion Battery

High-voltage alkali metal-ion batteries (AMIBs) require a non-hazardous, low-cost, and highly stable electrolyte with a large operating potential and rapid ion conductivity. Here, we have reported a halogen-free high-voltage electrolyte based on SiB₁₁(BO)₁₂⁻. Because of the weak π-orbital interaction of −BO as well as the mixed covalent and ionic interaction between SiB₁₁-cage and −BO ligand, SiB₁₁(BO)₁₂⁻ has colossal stability. SiB₁₁(BO)₁₂⁻ possesses extremely high vertical detachment energy (9.95 eV), anodic voltage limit (∼10.05 V), and electrochemical stability window (∼9.95 V). Furthermore, SiB₁₁(BO)₁₂⁻ is thermodynamically stable at high temperatures, and its large size allows for faster cation movement. The alkali salts MSiB₁₁(BO)₁₂ (M=Li, Na, and K) are easily dissociated into ionic components. Electrolytes based on SiB₁₁(BO)₁₂⁻ greatly outperform commercial electrolytes. In short, SiB₁₁(BO)₁₂⁻-based compound is demonstrated to be a high-voltage electrolyte for AMIBs.     

Synthesis,Spectroscopy, Semi‐empirical and Biological Activities of Organotin(IV) Complexes with o‐Isopropyl Carbonodithioic Acid

New organotin(IV) complexes have been synthesized by treating potassium o‐isopropyl carbonodithioate with R₂SnCl₂/R₃SnCl in 1 : 2/1 : 1 M/L ratio. All complexes have been characterized by IR and NMR (¹H, ¹³C) spectroscopy. IR results shows that ligand acts as bidentate which is also confirmed by semi‐empirical study. NMR data reveals four coordinated geometry in solution. Computed positive heat of formation shows that complex 5 is thermodynamically unstable. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that complex 5 exhibits higher binding constant as compared to complex 3 . In protein kinase inhibition assay, compound 3 was found most active, while other biological activities shows that triorganotin(IV) complexes are biologically more active as compared to diorganotin(IV) complexes.     

SH-waves in viscoelastic heterogeneous layer over half-space with self-weight

The effect of gravity, heterogeneity and internal friction on propagation of SH-waves (horizontally polarised shear waves) in viscoelastic layer over a half-space has been studied. Using the method of separation of variables, dispersion equation has been obtained and used to recover the damped velocity of SH-waves. Both the real and imaginary parts of dispersion equation are in well agreement with the classical Love wave equation. It has been observed that heterogeneity of the medium affects the velocity profile of SH-wave significantly. Some other peculiarities have been observed and discussed in our study.     

Nanocrystalline NaNbO3 and NaTaO3: Rietveld studies,Raman spectroscopy and dielectric properties

Nanocrystalline NaNbO₃ and NaTaO₃ have been synthesized by the reverse micellar technique for the first time. The particle size of NaNbO₃ was found to be 18 nm while that of NaTaO₃ was found to be 40 nm (much smaller size than most of the earlier reports on NaTaO₃). Rietveld refinement of X-ray diffraction data and Raman spectroscopy confirm that the nanoparticles of NaNbO₃ and NaTaO₃ have orthorhombically distorted structures with Pmc2₁ and Pbnm space groups, respectively. The dielectric constant at 25 °C of NaNbO₃ and NaTaO₃ was found to be 209 and 147 at 1 kHz, respectively. The antiferroelectric transition in NaNbO₃ shifts to lower temperature (325 °C) in the nanocrystalline solid.     

Synthesis,Characterization, and Semi-Empirical Study of Organotin(IV) Complexes with 4-(Hydroxymethyl)piperidine-1-carbodithioic Acid: X-Ray Structure of Chlorodimethyl-(4-hydroxymethyl piperidine-1-carbodithioato-S,S′)tin(IV)

Abstract

Organotin complexes with the general formulae R₂SnL₂, R₂Sn(Cl)L, and R₃SnL have been synthesized where R = CH₃, n-C₄H₆, C₆H₅, C₆H₁₁, and L = 4-(hydroxy methyl)piperidine-1-carbodithioic acid. The newly synthesized complexes have been characterized by elemental analysis, IR, NMR (¹H, ¹³C and ¹¹⁹Sn), and, for one example, a single crystal x-ray structure. The FT-IR data shows the bidentate nature of the ligand. This coordination behavior is also confirmed by semi-empirical study. In the solid state, diorganotin complexes exhibit the penta/hexacoordinated geometry, whereas the triorganotin(IV) complexes show the five coordinated geometry. ¹¹⁹Sn NMR data reveal that triorganotin(IV) complexes exhibit the four coordinated geometry in solution, whereas the diorganotin(IV) compounds show the higher coordination, probably five or six. X-ray diffraction analysis of complex (2) shows a square pyramidal geometry around the tin atom on the basis of τ value.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

GRAPHICAL ABSTRACT      

Organotin(IV) Complexes of 2-[(2′,4′,6′- Trichlorophenylamido)]benzoic Acid: Synthesis,Coordination Chemistry,and Semi-Empirical Study

A new series of organotin(IV) complexes of aniline derivatives, R₂SnL₂ and R₃SnL [where R = Me, n-Bu, n-Oct, and Ph], have been synthesized by the reaction of ligand acid with respective organotin halides in the presence of triethylamine as base or dioctyltin oxide using a Dean–Stark trap for the removal of water under reflux conditions. Experimental details for the preparation and characterization, including elemental analysis, IR, semi-empirical study, multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn spectra and EI mass spectral studies) of all reported complexes are provided. The IR data indicate that in both di- and triorganotin(IV) carboxylates, the ligand moiety ?COO acts as a bidentate group in the solid state. Multinuclear NMR data show that triorganotin complexes exhibits a four-coordinated geometry, while diorganotin(IV) complexes show a coordination number greater than four, probably five or six, in solution state.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Prebiotically Plausible Autocatalytic Peptide Amyloids

The prebiotic emergence of molecules capable both of self-replication and of storing information was a defining event at the dawn of life. Still, no plausible prebiotic self-replication of biologically relevant molecules has been demonstrated. Building upon the known templating nature of amyloids, we present two systems in which the products of a peptide-bond-forming reaction act as self-replicators to enhance the yield and stereoselectivity of their formation. This first report of an amino acid condensation that can undergo autocatalysis further supports the potential role of amyloids in prebiotic molecular evolution as an environment-responsive and information-coding system capable of self-replication.     

Applying green analytical chemistry for development and validation of RP-HPLC stability indicating assay method for estimation of fenoverine in bulk and dosage form using quality by design approach

A green and robust reverse-phase liquid chromatographic method has been developed for the determination of fenoverine (FEN), by applying combined principles of green analytical chemistry and quality by design approaches on a Spherisorb C18 column (150?×?4.6?mm, 3?µm) with UV detection at 262?nm. A two level fractional factorial design (2^^7-3) Res IV was used for screening of influential chromatographic factors. The critical method parameters actively affecting critical quality attributes (CQAs) were identified and further optimized using Box–Behnken design. The predicted optimum assay conditions comprised of methanol and ammonium acetate buffer 20?mM, in an extent of 81:19% v/v individually having a flow rate of 1.0?mL/min with a column oven temperature of 33°C. The drug was stressed in hydrolytic, oxidative, reductive, thermal, and photolytic conditions. The developed method was validated successfully. The detector response was linear in the concentration of 0.5–160?µg/mL with a limit of detection (LOD) and limit of quantitation (LOQ) as 0.1 and 0.3?µg/mL, respectively. The % recovery was found to be 99.7%. The analytical method volume intensity value for developed method was 45?mL and the environment assessment tool (EAT) score was 41.07. The method is simple, environmentally benign, rapid, and robust for the determination of FEN in bulk and in its dosage form.