Controlling Lewis basicity in polythioarsenate fluxes: stabilization of KSnAsS(5) and K(2)SnAs(2)S(6). Extended chains and slabs based on pyramidal beta-[AsS(4)](3-) and [AsS(3)](3-) units

Two low-dimensional compounds, KSnAsS(5) and K(2)SnAs(2)S(6), were prepared using liquid polythioarsenate salts, and the results differ from those obtained with the well studied thiophosphate flux. KSnAsS(5) crystallizes in the orthorhombic space group Pbam with cell parameters of a = 8.136(2) A, b = 13.784(4) A, c = 7.428(2) A. KSnAsS(5) features the unusual pyramidal species [AsS(2)(S(2))](3-). K(2)SnAs(2)S(6) crystallizes in the trigonal space group P3 macro with cell parameters a = 6.717(5) A, b = 7.204(8) A, gamma = 120 degrees. The compounds were obtained by controlling the Lewis basicity of the K(2)S/As(2)S(3)/S flux. The optical, thermal, and spectroscopic properties of the compounds are reported.     

Phase transitions in thallous nitrate. A reinvestigation

A detailed reinvestigation of the phase transitions in thallous nitrate using DSC, X-ray, IR and optical microscopy has been undertaken. The DSC measurements on anhydrous samples show that the orthorhombic [OR] → hexagonal [HEX] transition sets in at 349 ± 1 K and peaks around 353 K. However, its intensity depends upon several factors such as particle size, moisture content and thermal history of the sample. The HEX→cubic [C] transition sets in around 405 K and shows two peaks at ～409 K and 413 K. Their relative intensities depend on the moisture content and thermal history of the sample. On cooling, the peaks show hysteresis and, by selective thermal cycling, the pairs of transitions, which correspond to the same process during heating and cooling, have been identified. IR spectra recorded in the OR and HEX phases at room temperature show that the symmetric stretching frequency (～1040 cm^?1) of the nitrate ion gets damped in the HEX phase. X-ray and optical microscopy data are in good agreement with the DSC observations.     

Recovery of plutonium and americium from laboratory acidic waste solutions using tri-n-octylamine and octylphenyl-N-N- diisobutylcarbamoylmethylphosphine oxide

Plutonium from acidic waste solutions has been recovered quantitatively using tri-n-octylamine (TnOA) in xylene and americium using a mixture of octylphenyl-N-N- diisobutylcarbamoylmethylphosphine oxide (CMPO) and TBP in dodecane by extraction and extraction chromatographic methods. The Pu ( IV ) TnOA species extracted into the organic phase from higher nitric acid concentrations has been confirmed as (R(3)NH)(2)Pu(NO(3))(6) (where R(3)N = TnOA by employing slope analysis as well as spectrophotometric studies.     

Spectrophotometric determination of ziram (dithiocarbamate fungicide) by thiocyanate and rhodamine 6G method

A sensitive spectrophotometric method has been developed for the determination of ziram in water, vegetables and grains. The method is based on the dissociation of dithiocarbamate complex of zinc with thiocyanate and rhodamine 6G at pH 4 to form a pink coloured complex that is stabilized by gelatin. The method is simple and Beer's law is obeyed over the concentration range of 0.05-1 ppm of ziram. The method is free from interference of similar dithiocarbamate fungicides containing Mn(2+) and Fe(3+) ions.     

Synthesis of erythrinin A,a naturally occurring pyranoisoflavone

Erythrinin A ($\text{10}$) has been synthesised by the oxidative rearrangement of dihydropyranochalcone $\text{1}$ with thallium(III) nitrate (TTN) in trimethyl orthoformate (TMOF) to the dimethyl acetal $\text{2}$, followed by cyclisation to $\text{3}$, demethylation to $\text{6}$ and dehydrogenation. Compound $\text{10}$ could also be obtained from chalcone $\text{4}$ on similar rearrangement followed by cyclisation, demethoxymethylation and dehydrogenation. In another route, chalcone $\text{7}$ was oxidatively rearranged with TTN in TMOF, to $\text{8}$ which on treatment with HCl yielded $\text{10}$.     

A representation theorem for weak automorphisms of a universal algebra

Given a group G and a descending chainG ₀,G ₁,...,G _n, of normal subgroups ofG, we prove that there exists a universal algebra , such that the chain ...W_n( )...W₁( }) W₀( )W( ) is isomorphic to the chain ...G _n ...G ₁G ₀G, where W( ) is the group of weak automorphisms of , and W_n( ) is the group of weak automorphisms of that leaves alln-ary operations fixed.We also prove that there are an infinite number of non-isomorphic algebras that satisfy the above.These results are a generalization of those proved by J. Sichler, in the special case when G=G₀, and G₁=G₂=...=G_n=....Presented by J. Mycielski.This paper comprises part of the author's doctoral dissertation at the University of Notre Dame in 1983. The author wishes to express her deep gratitude to Professor Abraham Goetz for suggesting this problem, for being extremely generous with his time and experience, and for giving her his constant encouragement. The author also thanks the reviewer for his helpful comments.     

Enantioselective catalytic epoxidation of nonfunctionalized prochiral olefins by dissymmetric chiral Schiff base complexes of Mn(III) and Ru(III) metal ions II

A series of new dissymmetric chiral Schiff base complexes has been obtained by a systematic condensation of (1S,2S)(+)-diaminocyclohexane and 3-acetyl-4-hydroxy-6-methyl-2-pyrone with salicylaldehyde, 5-chloro-, 5-methoxy-and 5-nitrosalicylaldehyde and by subsequent metallation with manganese and ruthenium. The characterization of the complexes 1–8 was accomplished by physico chemical studies viz. microanalysis, IR-, UV/VIS-, and CD spectral studies, optical rotation, molar conductance measurements and cyclic voltammetry. Enantioselective epoxidation of non functionalised olefins, viz. cis-stilbene, trans-3-nonene and trans-4-octene with iodosyl benzene as oxidant was demonstrated in the presence of catalytic amounts of chiral Mn(III) and Ru(III) dissymmetric Schiff base complexes. Good optical yields of epoxides were obtained for the catalyst 4 with the substrates trans-3-nonene and cis-stilbene.     

Energy expressions for atomic configurations in the L–S coupling scheme

The matrix elements of the spin-free Hamiltonian between two atomic configuration state functions (CSF 'S ) in the L–S coupling scheme are expressed in terms of the atomic integrals F^k's and G^k's. Using these general expressions, the matrix elements have been obtained for all the atomic configurations with three valence electrons that have not been solved so far by earlier methods. The scope for applying this new approach to obtain the Auger line energies and the promotion energies of metals that involve more than two partially filled shells is indicated. The energy expressions for some of the relevant configurations are tabulated.