Facile synthesis of unsymmetrical benzotetrathiafulvalenes via cleavage of the corresponding hexathioorthooxalates

Unsymmetrical hexathioorthooxalates of types ($\text{1}$) and ($\text{2}$) undergo elimination of dialkyl disulfide on heating in an organic solvent; the reaction, which is catalyzed by acid, proceeds without fission of the central C:C bond and provides the first general, high yield synthesis of unsymmetrical benzotetrathiafulvalenes of types ($\text{3}$) and ($\text{4}$).     

Novel alkyl-modified anionic siloxanes as pseudostationary phases for electrokinetic chromatography. III. Performance in organic-modified buffers

Anionic water-soluble siloxanes modified with different amounts of alkyl chains have been used as pseudostationary phases in electrokinetic chromatography. Ionic siloxane polymers with attached alkyl chains of C8 and C12 and having different alkyl chain densities have been employed previously to achieve selective and efficient separations with a range of electrophoretic mobilities and methylene selectivities. In this study, the performance of three alkyl-modified siloxanes is examined in different organic-modified buffers and at differing amounts of organic modifier. The organic modifiers used are acetonitrile and methanol. The siloxanes are stable in these organic solvents and show good mobility and good methylene selectivities even at high concentration of organic solvent. Siloxanes have also been used to separate a mixture of 14 polynuclear aromatic hydrocarbons in an acetonitrile-modified buffer.     

Pentakis(methoxycarbonyl)cyclopentadiene,a strong organic acid: Crystal and molecular structures of HC5(CO)2Me)5 and Li[C5(CO2Me)5](H2O)

Contrary to some previously depicted structures, the proton in HC₅(CO₂Me)₅ is bonded to two oxygens rather than to carbon; the lithium ion in Li[C₅(CO₂Me)₅] (H₂O) is tetrahedrally coordinated by two carbonyl oxygens from one C₅ anion, one from a second anion, and a water molecule.     

Two-state curve crossing processes involving rotational coupling in the Na 2 + molecular ion

We examine the relative utility of the Landau-Zener, phase integral, and semiclassical Magnus approximations for processes involving a real crossing of two potential curves. As an example we consider rotational coupling in Na ₂ ⁺ . Numerical calculations for the ¦3p〉→¦3s〉 quenching process and for ¦3p〉→¦3d〉 excitation agree well with recent experiments in the energy range 20 eV≦E_K≦50 eV. Simple expressions forS-matrix elements, differential and total cross sections in these approximations depend only on accurate evaluation of a few JWKB phases. For the total cross section further simplification of the Magnus results yields a useful semiempirical formula.