Isotope shift studies in the second spectrum of neodymium in UV region

Isotope shift (IS) Δσ (142–150) have been measured in 92 spectral lines of Nd⁺ in the region 3290–3955 Å, employing recording Fabry-Perot spectrometer and highly enriched isotopic samples excited in a liquid-nitrogen cooled hollow cathode. Earlier IS measurement in UV region of Nd II spectrum is available for only a few lines, New classification has been made for several of the spectral lines studied presently. We have also revised the earlier suggested classification for some of the Nd II lines on the basis of observed isotope shifts. The transitions presently studied mostly involve high lying odd parity energy levels above 30,000 cm^?1 having neither electronic configuration assignment nor term isotope shifts (ΔT) evaluated. The present study would thus enable to evaluate ΔT values of some of these high lying odd levels, which should be helpful in suggesting possible electronic configurations.     

A Validated HPTLC Method for Simultaneous Analysis of Eugenol and Piperine in a Siddha Formulation

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatographic (HPTLC) method has been established for simultaneous analysis of eugenol and piperine...     

Isoreticular Expansion of Metal–Organic Frameworks via Pillaring of Metal Templated Tunable Building Layers: Hydrogen Storage and Selective CO2 Capture

The deliberate construction of isoreticular eea-metal–organic frameworks (MOFs) ( Cu-eea-1 , Cu-eea-2 and Cu-eea-3 ) and rtl-MOFs ( Co-rtl-1 and Co-rtl-2 ) has been accomplished based on the ligand-to-axial pillaring of supermolecular building layers. The use of different metal ions resulted in two types of supermolecular building layers (SBLs): Kagome (kgm) and square lattices (sql) which further interconnect to form anticipated 3D-MOFs. The isoreticular expansion of (3,6)-connected Cu-MOFs has been achieved with desired eea-topology based on kgm building layers. In addition, two (3,6)-connected Co-rtl-MOFs were also successfully constructed based on sql building layers. The Cu-eea-MOFs were shown to act as hydrogen storage materials with appreciable amount of hydrogen uptake abilities. Moreover Cu-eea-MOFs have also exhibited remarkable CO₂ capture ability at ambient condition compared to nitrogen and methane, due to the presence of amide functionalities.     

Radiative lifetime measurements in neutral zirconium using time-resolved laser induced fluorescence in supersonic free-jet

Radiative lifetimes of 20 odd-parity excited energy levels in Zr I, out of which 10 for the first time, have been investigated in the energy range 17 400-29 300 cm⁻¹. The levels belong to the 4d²5s5p and 4d³5p electronic configurations. Time-resolved laser-induced fluorescence spectroscopy technique in supersonic free-jet has been employed in the present work to circumvent the effects of collision in lifetime measurements.     

Laser-Induced Fluorescence Molecular Beam Investigation of New Singlet and Triplet Electronic States of Yttrium Monohydride

The yttrium monohydride spectrum in the range 12 500-25 000 cm⁻¹ has been studied by various laser-induced fluorescence (LIF) techniques. YH (YD) molecules have been produced in a free jet molecular beam apparatus by a laser vaporizing yttrium metal in the presence of He doped with H₂ (D₂) or NH₃ (ND₃). Low-resolution (∼0.04 cm⁻¹) excitation spectra have been recorded in the entire studied range. Four green bands (19 300-19 900 cm⁻¹) of the YH isotopomer have been studied in more detail: (1) high-resolution (∼120 MHz, ∼0.004 cm⁻¹) excitation spectra have been recorded, (2) dispersed fluorescence spectra have been obtained, and (3) lifetimes of the selected rotational levels of the upper states have been measured. Our observations have confirmed that the ground state of yttrium monohydride has ¹Σ⁺ symmetry and have provided a link between the singlet and triplet manifolds. The upper states of the observed transitions have been tentatively assigned to five electronic states, d0⁺, f³Π, f′1, D¹Π, E0⁺, and Fl. The low-energy excited electronic state observed in the dispersed fluorescence experiment has been assigned as the a³Δ state.     

Solid-State Isolation of Cyclic Alkyl(Amino) Carbene (cAAC)-Supported Structurally Diverse Alkali Metal-Phosphinidenides

Cyclic alkyl(amino) carbene (cAAC)-supported, structurally diverse alkali metal-phosphinidenides 2 – 5 of general formula ((cAAC)P-M)_n(THF)_x [ 2 : M=K, n=2, x=4; 3 : M=K, n=6, x=2; 4 : M=K, n=4, x=4; 5 : M=Na, n=3, x=1] have been synthesized by the reduction of cAAC-stabilized chloro-phosphinidene cAAC=P-Cl ( 1 ) utilizing metallic K or KC₈ and Na-naphthalenide as reducing agents. Complexes 2 – 5 have been structurally characterized in solid state by NMR studies and single crystal X-ray diffraction. The proposed mechanism for the electron transfer process has been well-supported by cyclic voltammetry (CV) studies and Density Functional Theory (DFT) calculations. The solid state oligomerization process has been observed to be largely dependent on the ionic radii of alkali metal ions, steric bulk of cAAC ligands and solvation/de-solvation/recombination of the dimeric unit [(cAAC)P-M(THF)_x]₂.     

Facile synthesis of highly functionalized novel pyrazolopyridones using oxoketene dithioacetal and their anti-HIV activity

A series of novel 3-amino-4,5-dihydro-6-methyl-4-oxo-N-aryl-1H-pyrazolo[4,3-c]pyridine-7-carboxamide have been synthesized starting from various oxoketene dithioacetals. The cyclocondensation reaction of 2-(bis(methylthio)methylene)-3-oxo-N-arylbutanamide 2a–w with cyanoacetamide using NaOiPr as base under reflux condition afforded novel highly functionalized pyridone 3a–w derivatives. Further, [3?+?2] cyclocondensation reaction of pyridones with hydrazine in the presence of alcohol was yielded pyrazolopyridones (23 nos) 4a–w with excellent yields. All newly synthesized compounds were evaluated for in vitro anti-HIV activity using MTT method. Most of these compounds have showed moderate to potent activity against HIV-1 (III_B) and HIV-2 (ROD) strains with an IC₅₀ ranging from >18 IC₅₀[µg/ml] to <100 IC₅₀[µg/ml]. Among them, compounds 4j and 4v were identified as the most promising compound for both types of HIV strains. (IC₅₀?=?18?µg/ml). Three compounds 4l, 4m, and 4p have been found potent anti-HIV 1 and 2 activity against MT-4 cells.