Chromatographic Separation Studies of Carbapenem Antibiotics on Silica Gel G Layers with Different Solvent Systems

JPC – Journal of Planar Chromatography – Modern TLC -     

A new eco-friendly strategy for the synthesis of novel antimicrobial spiro-oxindole derivatives via supramolecular catalysis

Novel spiro-oxindole derivatives were synthesised by one-pot multicomponent reaction using isatins, urea and 1,3-dicarbonyls. β-Cyclodextrin, an oligosaccharide, catalysed the reaction and can be reused for further reaction after recovery. This developed synthetic route is environmentally benign in which water is used as solvent to produce excellent yields of products. The synthesised compounds were evaluated for their antimicrobial activities against two bacteria and two fungi. All the synthesised spiro-oxindoles exhibit significant antimicrobial activity.     

Study of carbon encapsulated iron oxide/iron carbide nanocomposite for hyperthermia

Magnetic nanocomposite has been synthesized successfully using biopolymer route which acts as a source of carbon for carbide formation. The present approach based on thermal decomposition represents a considerable advance over previous reports that often use high-energy procedures or costly and hazardous precursors. X-ray diffraction, high-resolution transmission electron microscopy and vibrating sample magnetometer have been used to characterize the composites. Multi phase formation is evident from X-ray diffraction in the as-prepared samples. Phase confirmation was further done from M (magnetization) versus T (temperature) curve indicating presence of different phases of carbide along with iron oxide. TEM study suggests formation of cuboidal shape nanocomposite using two different quenching conditions. Transmission electron microscopy also confirmed the formation of carbon layer in the vicinity of the Fe₃O₄/Fe₃C nanoparticles. The magnetic measurement shows that the composite nanoparticles exhibit a maximum magnetization of 60 emu g⁻¹ at room temperature. Biocompatibility study with three different cell lines (HeLa, MCF-7 and L929) confirms that these nanocomposites are biocompatible. Temperature versus time measurement in an AC field suggests good heating ability of the samples. These investigations indicate that these nanocomposites may be useful for bioapplications, in particular for hyperthermia.     

Mapping the inhomogeneity of the U and Th distributions — using sample size concept in the field conditions

Indigenously fabricated portable gamma-ray spectrometer (PGRS) is used for the measurement of gamma activity of ²¹⁴Bi (1.76 MeV) and ²⁰⁸TI (2.62 MeV), under field conditions in Mohar area, Shivpuri Distt. (MP). The energies are discriminated by using a Nal (TI) crystal of size 1.75″ × 2″. PGRS used to map the primordial elemental distributions shows reversals of concentration of thorium and uranium (represented by radium group) in field and lab analysis in many samples, which is attributed to the inhomogenity of distribution of these elements in the area. The concept of difference in the volume of dish shaped field sample and the randomly picked up sample from the field grid point (400 gm in lab analysis) is utilized to interpret the inhomogenity of these elements. However interpretations are based on the assumption that these primordial elements (U, Th) are in secular equilibrium and the terrain has low topographic relief.      

SYNTHETIC,SPECTRAL AND BIOLOGICAL STUDIES OF ORGANOSILICON (IV) COMPLEXES WITH SCHIFF BASES OF SULFA DRUGS

Abstract

In the present paper synthetic and structural studies of six-coordinated Me₂Si(NN)₂ type of organosilicon(IV) complexes of Schiff bases (NN) have been described. The complexes were characterized by elemental analyses, conductance measurements, molecular weight determinations and electronic, infrared, ¹H, ¹³C and ²⁹Si NMR spectral studies. A few representative complexes were also screened for antimicrobial activity and found to be quite active in this respect.     

Hydroisomerization of n -hexane over Mo-loaded Pt/H-Mor catalysts

Three Mo-Pt/H-Mor catalysts, HM-2, HM-3 and HM-4 were prepared by loading 0.05, 0.10 and 0.15 wt.% of Mo, respectively, on the Pt/H-Mor (HM-1) support. Effect of the Mo loading on the n-hexane hydroisomerization reaction was studied by comparing the products obtained on the parent Pt/H-Mor support and the three Mo-loaded catalysts. The n-hexane conversions were increased with a Mo loading up to 0.10 wt.% Mo (HM-2), and a further increase of the Mo content to 0.15 wt.% (HM-3) caused a decrease in the conversion. Among the catalysts, HM-3 prepared by 0.10 wt.% Mo loading on Pt-HM provided the highest isomer yield of 57.4 wt.%, with the highest di-branched isomer selectivity of 11.7 wt.%. The catalytic activity of Mo-loaded catalysts was greatly influenced by the reaction temperature, i.e., the catalysts exhibited an increase in the isomer yields with increasing reaction temperatures, i.e. from 250°C to 310°C.     

A gadolinium(III) complex: synthesis,structure, photophysical profile and its role in the degradation of nitroaromatics

The synthesis and structural characterization of a gadolinium(III) complex with phenanthroline and thiocyanate ligands have been accomplished. The X-ray crystal structure reveals that Gd(III) in a slightly distorted square anti-prism coordinated with four thiocyanate ions and two phenanthroline molecules; one phenanthroline is protonated which compensates the charge of Gd(III) center. The crystal structure shows chemically significant non-covalent interactions like hydrogen bonding involving the thiocyanate ligand and π–π interactions between uncoordinated phenanthrolinium and coordinated phen. Investigation on the intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that close contacts are mainly associated with weak interactions. The fingerprint plots demonstrate that these weak interactions are important for crystal packing. The Gd(III) complex shows photophysical activity. The compound is capable of degrading toxic pollutants like nitroaromatics and may have far reaching consequences for cleaning these toxic pollutants from industrial effluents.     

Dielectric relaxation studies of four aliphatic esters in benzene at 30°, 40°, 50° and 60°

The complex permittivity at 9.92 GHz, the static permittivity and the high frequency limiting permittivity have been determined for n-butyl-acrylate, allyl-methacrylate, isobutyl-methacrylate and isobutyl-acrylate monomers in benzene at 30°, 40°, 50° and 60°C. The relaxation time values and the dipole moment values calculated from these data employing different methods, are interpreted in terms of the molecular and the intramolecular rotations. Various thermodynamic parameters calculated for the dielectric relaxation as well as the viscous flow processes also suggest the existence of both the intramolecular and the overall orientations in these monomer esters. The comparative study of enthalpies of activation for the dipolar relaxation and the viscous flow suggests the absence of any solid rotator phase in these molecules. Values of the Debye's factor and the Kalman's factor show that the Kalman's equation represents the relation between the dielectric relaxation and the viscosity, more satisfactorily than the Debye's equation.