Interaction between photons, “trapped electron” and vibronic excitation

The role of “trapped electron,” photon, and vibronic state coupling has been worked out in relation to an aspect of cancer, namely, to the activity of an anticancer drug. The main emphasis for such study comes from the fact that in cancerous systems the participation of usual electronic states of the molecule may not be sufficient. Because of disorder in the cancer tumour, additional states, viz. trapped electron states, could be formed in the manner of localised states in solids. The drug activity of mitomycin C obtained in this way agrees with the experimental values. An additional feature of the study is that it shows that it will be effective mainly in the initial phases of cancer.     

Order-disorder transition in Nd2−yGdyZr2O7 pyrochlore solid solution: An X-ray diffraction and Raman spectroscopic study

Powder X-ray diffraction (XRD) and Raman spectroscopic study of order-disorder-phase transition with increase in the content of Gd in Nd_2−yGd_yZr₂O₇ solid solution is being reported. It has been observed from Rietveld analysis that with increase in concentration of Gd in Nd_2−yGd_yZr₂O₇, the value of the x parameter of the 48f oxygen changes from 0.332(1) to 0.343(1) with a sudden change in the slope for y=1.8, which indicates that the structure is transforming from ordered pyrochlore to disordered pyrochlore. In addition to that a sudden and drastic change in the Raman spectra including changes in the position and width of several Raman modes beyond y?1.8 has also been observed which has been correlated with increasing disorder. Based on these studies, it is suggested that there is a discontinuous order-disorder transition from ‘perfect pyrochlore’ to ‘defect pyrochlore’ phase in Nd_2−yGd_yZr₂O₇ solid solution.     

Template synthesis, spectroscopic studies and biological screening of macrocyclic complexes derived from thiocarbohydrazide and benzil

A novel series of complexes of the type [M(TML)X₂]; where TML is a tetradentate macrocyclic ligand; M = Co(II), Ni(II), Cu(II) or Zn(II); X = Cl⁻, CH₃COO⁻ or NO ₃ ⁻ have been synthesized by template condensation of benzil and thiocarbohydrazide in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. Electronic spectra along with magnetic moments suggest the six coordinate octahedral geometry for these complexes. The low value of molar conductance indicates them to be non-electrolytes. The biological activities of metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibiting potential.     

Study of phase transition and volume thermal expansion in a rare-earth (RE) oxyfluoride system by high-temperature XRD (RE=La, Nd, Sm, Eu and Gd)

Volume thermal expansion behaviour of a number of rare-earth oxyfluorides (REOF) have been studied using high-temperature X-Ray diffractometry (HT-XRD) in the 298–1075 K range in air. The studies revealed an anomalous expansion for each compound associated with phase transition. The phase transition temperature and the coefficient of volume thermal expansion of five compounds in REOF series determined by this method are reported and compared with our earlier results obtained by dilatometry.     

A Spectrophotometric Study of Fe(III) Chelates of Some Hydroxy Coumarin Derivatives

Chelates formation of Fe(III) with 7–hydroxy–4–methyl coumarin–6–carboxylic acid (HMCCH)₂ and 8–amino–7–hydroxy–4–methyl coumarin (AHMCH) have been studied. It has been observed that Fe(III) forms 1:2 (metal:ligand) chelates with HMCCH₂ and AHMCH. The stability constants of these chelates at different ionic strengths and the effect of temperature on the stability constants of these chelates have been studied. The thermodynamic parameters such as entropy change (ΔS), free energy of formation (ΔG) and enthalpy change (ΔH) have also been calculated. The effect of dielectric constant oh the stability constants of these chelates have been studied. Estimation of nanogram quantities of Fe(III) with these ligands and the effect of diverse ions have also been studied and the results have been compared with other methods used for estimation of Fe(III).     

Amberlite IR-120 catalysed efficient synthesis of glycosyl enamines and their application

β-Keto esters and acetyl acetone on condensation with glycosylated amino esters in the presence of IR-120 resin resulted in high yields of glycosyl enamino esters or ketones. The latter on cyclisation with NaH in toluene at reflux gave 6-glycosyl-5,6-dihydro-1H-pyridin-4-ones in fair to good yields.     

Sensitive and selective methods for determination of antipsychotic drug olanzapine in pharmaceuticals

Two simple and sensitive spectrophotometric methods have been developed for analysis of the antipsychotic drug olanzapine in pharmaceuticals. Method A is based on liberation of iodine by reaction between the drug and potassium iodate, followed by reaction with leuco crystal violet (LCV), the color of oxidized LCV being measured at 598 nm. Method B is based on oxidation of olanzapine with chloramine-T (CAT) in acidic medium, the unconsumed CAT being determined with rhodamine B, measuring the absorbance at 550 nm. Calibration graphs were linear over the ranges of 0.05–2.0 and 0.1–1.6 μg mL^?1 olanzapine for method A and B, respectively. The molar absorptivity, Sandell’s sensitivity, detection limit, and quantitation limit were found to be 1.59 × 10⁵, 0.00132, 0.038, and 0.117, respectively, for method A and 0.953 × 10⁵, 0.00221, 0.064, and 0.192, respectively, for method B. The optimum conditions and other analytical parameters were evaluated. The proposed methods have been applied successfully for analysis of olanzapine in pure form and its dosage forms, and no interference was observed from common excipients present in pharmaceutical formulations.     

Electrochemical studies of novel olivine-layered (LiFePO4-Li2MnO3) dual composite as an alternative cathode material for lithium-ion batteries

Journal of Solid State Electrochemistry - In the present work, olivine-layered composites, i.e., LiFePO4-Li2MnO3, are successfully synthesized in the form of a single monolithic electrode and layer...     

Transition Metal Complexes of Dis(thiosemicarbazone): Synthesis and Spectral,and Antifungal Studies

Mn(II), Co(II), Ni(II), and Cu(II) complexes have been synthesized with benzil bis(thiosemicarbazone) (L) and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, thermogravimetric studies, infrared (IR), electronic, and electron paramagnetic resonance (eEPR) spectral studies. The molar conductance measurements of the complexes in DMF correspond to the non-electrolytic nature of the complexes. Thus these complexes may be formulated as [M(L)X₂] (where M = Mn(II), Co(II), Ni(II), Cu(II) and X = Cl^? and NO₃ ^?). On the basis of IR, electronic, and EPR spectral studies, an octahedral geometry has been assigned for Mn(II), Co(II), and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes is presumed. The free ligand and its metal complexes were tested against the phytopathogenic fungi (i.e., Rhizoctonia baticola, Alternaria alternata) in vitro.