Synthesis and crystal structure of (S)-pindolol

Racemic 3-(4-indolyloxy)-1,2-propanediol 2 has been effectively resolved into (S)- and (R)-enantiomers by a preferential crystallization procedure. Non-racemic (S)-2 was converted into (S)-4-(2,3-epoxypropoxy)-1H-indole (S)-4 via a Mitsunobu reaction and then into (S)-pindolol (S)-1. The crystalline (S)-1 was studied by single crystal X-ray diffraction. A large number of symmetry independent molecules (Z′ = 6) led to a weakening of the system of strong intermolecular hydrogen bonds, which combined with a loose packing (PI = 64.6%), may be the cause of the abnormally low melting point of (S)-1 as compared with rac-1.     

Zinc-Bromine Alkali-Salt Membrane Chemical Power Cell

Zinc-bromine alkali-salt membrane-type chemical power cell was assembled and studied. The open-circuit voltage (OCV) of the zinc-bromine alkali-salt membrane chemical power cell (CPC) was experimentally obtained (2.30 V). This value is close to the theoretically calculated value of the electromotive force (EMF) of the cell (2.27 V) and exceeds the EMF and OCV of many known power cells using a single homogeneous-composition aqueous electrolyte and having no ion-exchange membrane. The maximum theoretical specific energy of the zinc-bromine alkali-salt membrane CPC is 317.3 W h kg^–1, which is lower that the corresponding values for the zinc-silver and zinc-nickel power cells and exceeds that of nickel-iron, nickel-cadmium, and lead sulfuric acid CPCs. It is shown that the cell under study can be used as an electric battery.     

Estimation of ion scattering by atomic chains on single crystal surfaces

Estimation of ion movement close to atomic chains taking into account the elastic and inelastic energy losses and vacancy type imperfections was performed on the basis of a model of binary interactions of ions with the atoms of a crystal.

An analysis of results shows that at scattering by atomic chains a phenomenon which makes a substantial contribution to scattering by the single crystal surface the inelastic energy losses exceed the single scattering ones by a factor of 5–6.     

Regioselective alkylation of the lower rim of p-tert-butylthiacalix[4]arene with N-(p-nitrophenyl)-α-bromoacetamide

The preparation of partially substituted thiacalix[4]arenes 2–6 has been accomplished by conducting the reaction of the thiacalixarene 1 with N-(p-nitrophenyl)-α-bromoacetamide in acetone or acetonitrile in the presence of M₂CO₃ (M = Na, K and Cs). The influence of the reaction conditions (temperature, time, solvent, ratio of the reagents and the nature of the alkali metal carbonate) on regio- and stereoselectivity of this reaction is described.