Theory of collective motion of interacting gas of polyvalent Hg atoms at 3.0, 6.3 and 9.0 particles per nm

Collective dynamics of interacting gaseous mercury at high temperatures and pressures having densities of 3.0, 2.1 and 1.0 g cm⁻³, as determined very recently by the measurement of dynamical structure factor using the inelastic X-ray scattering, have been successfully explained, making use of the recently modified microscopic theory of a simple fluid. It also turns out that in determining the collective dynamics of all the three systems of the mercury vapor, the two body interactions, as prevalent in a weakly interacting system, play a dominant role.     

Xyloccensin X and Y, two new limonoids from xylocarpus molluccensis: NMR investigation in mixture

Two new limonoids, xyloccensin X (1) and xyloccensin Y (2), have been identified in mixture using NMR spectroscopy. Both limonoids were isolated in mixture from the fruit of the plant Xylocarpus molluccensis. The structures of these were proposed after extensive 2D NMR analyses in mixture.     

Facile one-pot synthesis of 5-amino-1H-pyrazole-4-carbonitriles using alumina–silica-supported MnO2 as recyclable catalyst in water

Research on Chemical Intermediates - A novel, facile, one-pot, multicomponent protocol for the synthesis of 5-amino-1H-pyrazole-4-carbonitrile derivatives has been developed using...     

Extra‐Framework Aluminum Species of Zeolite that Surrogate the Growth of Metal Organic Framework from Zeolite Matrix

Constructing a robust hybrid material with a porous inorganic and a porous organic framework is highly intriguing owing to its diverse functionality and porosity. However, the line of synthesis is not straightforward, since their nucleation and crystal growth processes are incompatible. Here, a simple method for the fabrication of hybrid zeolite/metal–organic framework of different framework structures is developed wherein the less‐useful extra‐framework aluminum species present in the zeolite surrogate the growth of metal organic framework (MOF) from the zeolite matrix in the presence of organic linkers of the corresponding MOF. An NMR study confirms that all the octahedral Al species are converted to Al‐MOF. TGA analysis shows that 32 % Al of H‐Beta is converted to Al‐MOF. Furthermore, NH₃ TPD analysis shows that most of the weak acid sites disappear but strong acid sites are preserved suggesting the utilization of weakly bound Al species of H‐Beta in the growth of Al‐MOF. The synthesis strategy is successfully demonstrated using H‐Beta, H‐ZSM‐5, and H‐Y zeolites for the growth of MIL‐53 and MIL‐96 MOFs from the zeolite matrix. This synthesis strategy enables application‐based engineering of the framework structures, functionality, and porosity of the materials.     

Heat capacity and phonons in poly(L-leucine)

Poly(L-leucine) is one of the polyamino acids having a bulky hydrophobic side-chain. For want of full phonon dispersion curves and density-of-states on this biopolymer Roleset al have interpreted their specific heat data in a limited way. In the present communication we report an analysis of the normal modes and their dispersion for poly(L-leucine) which leads to a very good agreement of the specific heat calculations with experimental measurements. It is observed that the main contribution to specific heat comes from the coupling of the back-bone skeletal and side-chain modes. Several other assignments have been revised. A special feature of some dispersion curves is their tendency to bunch in the neighbourhood of helix angle. It has been attributed to the presence of strong intramolecular interactions. Repulsion between the dispersion curves is also observed.     

Synthesis of quinazolinophanes containing bridgehead nitrogen atoms from quinazoline‐2,4(1H, 3H)‐dione

Quinazoline‐2,4(1H,3H)‐dione (1) reacts with α,ω‐dihaloalkanes to generate three types of quinazolinophanes. When the number of carbon atoms in the dihaloalkanes is 9 , a mixture of all the three types of quinazolinophanes ( 2 ), ( 3 ) and ( 4 ) was produced; and when the number of carbon atoms in the dihaloalkane used is from 4 to 7, a mixture of only two types of quinazolinophanes ( 2 ) and ( 3 ) were produced. When the number of carbon atoms of the dihaloalkane used is odd ( 5, 7 and 9 ), the different structural types of quinazolinophanes produced were easily identifiable and distinguishable on the basis of ¹³C NMR and mass spectral data.     

1,5-Stereocontrol in tin(IV) halide promoted reactions of 2-alkoxy-1-(2-tributylstannylethylidene)cyclohexanes with aldehydes

2-Methoxy- and 2-(p-methoxybenzyloxy)-1-(2-tributylstannylethylidene)cyclohexanes 22 and 23 were prepared from 2-methoxy- and 2-(p-methoxybenzyloxy)cyclohexanones 12 and 13. The allylstannane 22 was transmetallated stereoselectively with tin(IV) chloride at −78 °C to generate an allyltin trihalide, which reacted with aldehydes to give (Z)-(3-hydroxyalkylidene)-2-methoxycyclohexanes 24 with excellent 1,5-syn-stereocontrol. Similar reactions with aldehydes were observed for the 2-(p-methoxybenzyloxy) substituted allylstannane 23. The structure of the product 24f prepared from p-nitrobenzaldehyde was confirmed by an X-ray structure determination of its p-nitrobenzoate ester 27.     

Determination of trace amounts of nitrogen in uranium based samples by ion chromatography (IC) without Kjeldahl distillation

A simple, sensitive and fast ion chromatographic (IC) method with suppressed conductivity detection is described for the determination of traces of nitrogen in uranium based fuel materials. Initially a method was developed to determine nitrogen as NH₄⁺ using cation exchange column after matrix separation by Kjeldahl distillation. The method was then improved by eliminating this distillation. Matrix separation after sample dissolution was done by hydrolyzing and filtering off the polyvalent cations. This had helped in reducing both the sample size and analysis time. Optimization of dissolution conditions for various kinds of uranium based samples was done to keep acid content minimum; a prerequisite chromatographic condition. The calibration plot for nitrogen was linear in the concentration range of 0.02-1 mg L⁻¹ with regression coefficient of 0.9999. The relative standard deviation (R.S.D.) obtained in this method (100 μL injected) was 3% and 2% in 9 replicates at nitrogen level of 28 and 55 ng g⁻¹, respectively. Detection limit based on S/N = 3 (100 μL injected) as well as three times of variation in blank value was 4 ng g⁻¹. The developed method was authenticated by comparison with certified uranium-alloy standard as well as with independent indophenol photometry method. The developed method was applied to uranium-alloy, uranium-metal, sintered UO₂ pellets and sintered UO₂ microspheres samples.     

Correction to: Evaluation of background radiation level and excess lifetime cancer risk in Doon valley,Garhwal Himalaya

Journal of Radioanalytical and Nuclear Chemistry -     

Superiority of thin-layer chromatography over high-performance liquid chromatography in enantioseparation

JPC – Journal of Planar Chromatography – Modern TLC - The scientific development in the area of enantioseparation during the last few decades has centered on the production of new...