Synthesis, Structural Characterization and Crystal Structure of Selenium Bearing 3-(Phenylseleno) Propylammonium Acetate Salt and its Cleavage on Reaction with Mercury(II) and Tin(IV) Salts

Abstract  

3-(Phenylseleno) propylammonium acetate, C₉H₁₄NSe⁺ C₂H₃O₂ ^–, L ¹ , the first example of a selenium bearing acetate salt has been synthesized and characterized by spectroscopic, NMR, DSC and single crystal X-ray crystallographic techniques. L ¹ crystallizes with one cation–anion pair in the asymmetric unit. Reactions of L ¹ with four different metal salts revealed four new selenium bearing compounds (1–4) whose identities are characterized by spectroscopic and NMR techniques. The crystal structure of Compound 1, [C₉H₁₄NSe]₂⁺ [ClO₄]₂^–, whose crystal structure has been confirmed. It crystallizes with two independent cation–anion pairs in the asymmetric unit. Both L ¹ and Compound 1 display strong N–H···O hydrogen bond intermolecular interactions which help stabilize crystal packing in the unit cell.     

Vibrational spectra of H2O and CF4 molecules using Lie algebraic approach

In this paper, we introduce one dimensional vibron model to analyze the fundamental, overtone and combination modes of CF₄ molecule and both stretching, bending vibrational mode of bent H₂O molecule up to first overtone with few algebraic parameters. Using the model Hamiltonian, we reported here better results for the vibrational spectra of H₂O. Our analysis suggests some reassignments of levels and predicts location of states in case of CF₄ molecule which was not yet observed.     

Evaluation of soil to tea plant elemental correlation using instrumental neutron activation analysis

Instrumental neutron activation analysis using relative and k ₀-based internal monostandard methods were employed for determination of concentrations of 12 elements in soil and tea plants collected from three different tea producing regions in India namely Assam, Darjeeling and Kangra. A total of 17 tea leaf samples along with corresponding soil samples were analyzed for elemental content. The obtained concentration data was used for the soil–plant elemental correlation studies. Positive correlation was observed between elemental concentrations of tea plants and the associated soil with Pearson correlation coefficient values in the range 0.6–0.9 for ten elements. Variations in transfer factor values were also observed according to the geo-chemical variation.     

Plutonium-239+240 selectivity for pseudo-colloids of iron in subsurface aquatic environment having elevated level of dissolved organic carbon

Laboratory simulated experiments have been conducted to study the association of ^239,240Pu with pseudo-colloids of iron in groundwater samples having dissolved organic carbon (DOC) in the range of 10–60 mg L⁻¹. Ultra-filtration membranes have been used to partition colloidal components into seven different size range of <0.45 μm-1.1 nm. Elevated levels of Fe, DOC and ^239,240Pu were observed in the fractions concentrated with 1.6 nm (10,000 NMWL) and 1.1 nm (500 NMWL) compared to the other dissolved fractions. To ascertain the fact that, the formation of pseudo-colloids of Fe in the size range 1.6 nm and 1.1 nm was assisted by the presence of DOC, experiments have been conducted under similar experimental conditions with uniform Fe concentration and varying the DOC in the range of 10–60 mg L⁻¹. Seven to eight times higher concentration of Fe was observed in fractions concentrated with 1.6 nm and 1.1 nm having DOC ≥30 mg L⁻¹, whereas Fe was equally distributed in all the fractions in groundwater having DOC ≥10 mg L⁻¹. The surface morphology and composition of the residue left on the ultra-filtration membranes was examined using scanning electron microscope (SEM) coupled with energy dispersive X-ray spectrometer (EDS). The EDS results validate the observation that the residue left on filter paper membrane of 10000 and 500 NMWL with pore size 1.6 and 1.1 nm respectively, shows elevated levels of carbon and Fe contents as compared to other fractions. Understanding the association of ^239,240Pu with Fe and DOC will facilitate in predicating the long term integrity of underground waste storage facilities of alpha emitting radioactive material.     

Biophysical,spectroscopic vis-à-vis biochemical investigation on DNA–metalloprotein interaction: a model study involving cobalt(II)-glutathione complex

Abstract  The interaction of cobalt(II)-glutathione (CoGSH) with deoxyribonucleic acid (DNA) has been studied by UV–vis, fluorescence, circular dichroism (CD), thin-film infrared (IR), and viscometric techniques. From the UV-spectroscopic method, binding constant (K _b) was determined and was found to be 2.3 × 10⁶ M⁻¹. In fluorimetric analysis, the quenching of fluorescence intensity of DNA bound to ethidium bromide (EB) was investigated. The Stern–Volmer quenching constant (K _sv) was also estimated from this study and was found to be 2.8 × 10⁶ M⁻¹at 37 °C. The solution CD spectra of DNA and DNA–CoGSH indicate that in each case, DNA exists in the ‘B’ conformation and suggested an intercalative binding mode. Thin-film IR data also reveal that DNA attains the ‘B’ family of conformations after interaction with CoGSH complex. The increase in DNA viscosity in the presence of CoGSH complexes is attributed to the lengthening of DNA helix due to intercalation. Graphical Abstract  The spectrophotometric, CD, thin film IR, viscometric and fluorimetric studies on the interaction of CoGSH with DNA indicated an intercalative binding mode with the retention of ‘B’ conformation of DNA.      

Individual and simultaneous voltammetric determination of ascorbic acid,uric acid and folic acid by using a glassy carbon electrode modified with gold nanoparticles linked to bentonite via cysteine groups

A voltammetric sensor for both the individual and the simultaneous determination of ascorbic acid (AA), uric acid (UA) and folic acid (FA) is described. It is based on a glassy carbon electrode (GCE) that was modified with bentonite (Bnt) that was first functionalized with cysteine (Cys) to which gold nanoparticles were linked. The resulting material (referred to as Au-Cys-Bnt) and the other materials were characterized by UV-vis spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray analysis and electrochemical methods. The XRD peak positions of bentonite and Cys-functionalized bentonite prove the incorporation of Cys into bentonite. The XPS spectrum of Au-Cys-Bnt confirms the interaction of gold nanoparticles with the thiol group of Cys. The modified GCE displays high electrocatalytic activity for the oxidation of AA, UA and FA, typically at 0.19, 0.41, and 0.73 V (vs. SCE), respectively. Differential pulse voltammetric data show a linear response that covers the 1 μM to 25 mM concentration range for AA, the 1 to 200 μM concentration range for UA, and two linear ranges for FA, one from 5 to 100 μM and one from 100 μM to 1.5 mM. The sensor was applied to the determination of AA, UA and FA in (spiked) multi-vitamin syrup, bird serum and milk samples.

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Graphical abstract Schematic of a sensor for simultaneous and individual electrochemical determination of ascorbic, uric, and folic acids in real samples. The sensor consists of a glassy carbon electrode that was modified with a nanocomposite prepared from bentonite that was first functionalized with cysteine to which gold nanoparticles were linked.

     

Nonlinear normal modes and quanta in the β Fermi-Pasta-Ulam lattice

We enumerate simple periodic orbits for the well-known Fermi-Pasta-Ulam (FPU) problem. Using these solutions as simple modes for the problem, we construct quantum solutions of the corresponding problem. These studies present a natural generalization of the concept of phonon in the nonlinear realm.