Gas-Solid Reactions: Photochemical Oxidation of Thioketones in the Crystalline State

Photochemical oxidation of 11 diaryl thioketones (1-11) was conducted in the solid state. Quite interestingly, of these only six were oxidized to the corresponding carbonyl compound whereas the rest were photostable. However, in solution all were readily oxidized. The difference in behavior between the thioketones in the solid state has been rationalized on the basis of molecular arrangement in the crystal. X-ray crystal structure analyses of four thioketones were carried out in this connection.

On the valence state of molybdenum in Ce2MoO6

he valence state of molybdenum in cubic Ce2MoO6 was investigated using magnetic susceptibility measurements, electron spin resonance spectroscopy and X-ray absorption spectroscopy. The results are consistent with the formulation Ce3+Ce4+Mo5+O6.

Evidence for the involvement of a rapidly turning over protease in the degradation of cytochrome oxidase in Neurospora crassa

Treatment of N. crassa cultures with cycloheximide followed by washing and incubation in drug-free fresh medium results in a rapid decline in cytochrome oxidase activity. This is associated with the degradation of higher molecular weight subunits of cytochrome oxidase under these conditions. The protease activity associated with the mitochondrial preparation decreases during cycloheximide treatment and rapidly returns to normal levels on subsequent washing and transfer to drug-free fresh medium. It is suggested that the steady-state level of cytochrome oxidase is governed by a rapidly turning over cytoplasmically synthesized mitochondrial protease.

On the valence state of molybdenum in Ce2MoO6

The valence state of molybdenum in cubic Ce2MoO6 was investigated using magnetic susceptibility measurements, electron spin resonance spectroscopy and X-ray absorption spectroscopy. The results are consistent with the formulation Ce3+Ce4+Mo5+O6.

Nondiffusive Quantum Transport in a Dynamically Disordered Medium

For a dynamically disordered continuum it is found that the exact quantum mechanical mean square displacement 〈x2(t)〉∼t3, for t→∞. A Gaussian white-noise spectrum is assumed for the random potential. The result differs qualitatively from the diffusive behavior well known for the one-band lattice Hamiltonian, and is understandable in terms of the momentum cutoff inherent in the lattice, simulating a "momentum bath."

On a generalized dynamic model of bi-state social interaction processes

A non-linear model, construed as a generalized version of the models put forth earlier for the study of bi-state social interaction processes, is proposed in this study. The feasibility of deriving the dynamics of such processes is demonstrated by establishing equivalence between the non-linear model and a higher order linear model.

Conformational characterisation of valinomycin complexation with barium salts:A nuclear magnetic resonance spectroscopic study

Conformations of valinomycin and its complexes with Perchlorate and thiocyanate salts of barium, in a medium polar solvent acetonitrile, were studied using nuclear magnetic resonance spectroscopic techniques. Valinomycin was shown to have a bracelet conformation in acetonitrile. With the doubly charged barium ion, the molecule, at lower concentrations, predominantly formed a 1:1 complex. At higher concentrations, however, apart from the 1:1, peptide as well as ion sandwich complexes were formed in addition to a :final complex:. Unlike the standard 1:1 potassium complex, where the ion was centrally located in a bracelet conformation, the a 1:1 barium complex contained the barium ion at the periphery. The a :final complex: appeared to be an open conformation with no internal hydrogen bonds and has two bound barium ions. This complex was probably made of average of many closely related conformations that were exchanging very fast (on nuclear magnetic resonance time scale) among them. The conformation of the a:final complex a: resembled the conformation obtained in the solid state. Unlike the Perchlorate anion, the thiocyanate anion seemed to have a definite role in stabilising the various complexes. While the conformation of the 1:1 complex indicated a mechanism of ion capture at the membrane interface, the sandwich complexes might explain the transport process by a relay mechanism.

Reactive state selectivity in photodimerization through micellar counter-ion effects: photodimerization of acenaphthylenes

Photodimerization of acenaphthylene and 5,6-dichloroacenaphthylene solubilized in sodium dodecylsulphate (SDS), cetyltrimethylammonium chloride (CTAC), dodecyltrimethylammonium chloride (DTAC), cetyltrimethylammonium bromide (CTAB) and Triton X-100 micelles gives a mixture of cis and trans dimers. The magnitude of the cis:trans ratio is sensitive to the type of micelle used. In CTAB micelles the heavy atom effect of the bromide counter-ions leads to an increased triplet-derived trans dimer yield, whereas in micelles with light atom counter-ions (CTAC, DTAC and SDS) the singlet-derived cis dimer predominates.

Study of switching characteristics and thermal noise in ferroelectric crystals both in the pure and radiation damaged state

The phase transition in gamma-irradiated triglycine sulphate (TGS) has been investigated by using a method based on the measurement of thermal noise. The results of a study of the polarization switching characteristics of gamma irradiated TGS and sodium nitrite (NaNO2) have also been presented. The effect of irradiation on the phase transition and the switching processes has been discussed.

Multi-state-choice automata model for expedient learning in random environment

A new automata model Mr,k, with a conceptually significant innovation in the form of multi-state alternatives at each instance, is proposed in this study. Computer simulations of the Mr,k, model in the context of feature selection in an unsupervised environment has demonstrated the superiority of the model over similar models without this multi-state-choice innovation.

Thermal Decomposition of hydrazinium monoperchlorate in the solid state

Hydrazinium monoperchlorate (HP-1) has been shown to decompose thermally in the solid state according to the chemical equation: 5N2H5CIO4 = 4NH4CIO4+1HCI+3N2+4H2O The activation energy for the evolution of HCl as determined mass spectrometrically is 8.05 kcal mol−1 in the temperature range of 80 to 120°C. The rate of decomposition is seen to be altered by doping HP-1 with small concentrations of SO2−4, Ca2+ and Al3+.

Investigations on the preparation, oxidation and reduction reactions of thiophosphoryl fluoride

Pure thiophosphoryl fluoride has been prepared by the fluorination of thiophosphoryl chloride by sodium fluoride in acetonitrile medium. Oxidation of this phosphoryl fluoride by acidified chloramine-T ruptures the phosphorus-sulphur bond and oxidises the sulphur present to the hexavalent state. Anhydrous hydrogen iodide reduces the sulphur to hydrogen sulphide and phosphorus to the trivalent state.

An analytical approach to the study of a class of bi-state social interaction processes

Sufficient conditions for obtaining an equivalent linear model to classes of non-linear, bi-state, social interaction processes are derived. These parametric constraints, when satisfied, permit analytical determination of the dynamics of the non-linear process of social interaction.