Organoboron compounds

Conclusions Condensation of triallylborane with vinyl- and isopropenylacetylene yields, depending on the temperature, the corresponding substituted derivatives of 2-borinene (20–80C) or 3-borabicyclo[3.3.1]non-6-ene (120–140C) with a system of conjugated double bonds. These compounds were used for the preparation of different derivatives of 1,3-butadiene, isoprene or vinylcyclohexene (hydrocarbons, alcohols or diols).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2114–2119, September, 1981.     

Effect of the chiral chain length on structural and phase properties of ferroelectric liquid crystals

Studies of structural and phase properties obtained on several ferroelectric liquid crystalline materials with 2-alkoxypropionate group used as a chiral centre and without any lateral substitution are presented. In dependence on the chiral chain length these compounds exhibit the cholesteric N* phase, the ferroelectric smectic C* and a low-temperature SmX phase. Values of the spontaneous polarization and spontaneous tilt angle have been determined within the whole range of the SmC* phase. A low-temperature SmX phase has been identified as the orthogonal hexatic SmB* phase. The molecular parameters, namely the layer spacing in the SmC* and SmB* phases and the average intermolecular distances (D) between neighbouring parallel molecules in all investigated phases have been determined using the results of the X-ray diffraction obtained on non-oriented samples. The effect of the chiral chain length on mesomorphic, structural and physical properties of the studied ferroelectric liquid crystalline materials is discussed.     

Boron-chelate assisted synthesis of new bipyrazole derivatives

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