Convenient synthetic route of versatile 21-monothiatetraphenylporphyrins of the A4 and AB3 type

A novel convenient synthetic route for poly-functional 21-monothiatetraphenylporphyrins of the type A₄ und AB₃ having base labile substituents in meso position was developed. Using this method a series of symmetric and asymmetric 21-thiaporphyrins containing different functional groups at the meso position is reported. The new products were characterized by NMR, UV-Vis and mass spectroscopy.     

Cu12As3VS16, eine neue Verbindung im System Sulvanit-Enargit

Cu₁₂As₃VS₁₆, a New Compound in the Sulvanite-Enargite System The compound Cu₁₂As₃VS₁₆ is formed by solid state reaction between Cu₃AsS₄ (enargite) and Cu₃VS₄ (sulvanite). The X-ray powder diagram shows a cubic pattern (a = 10.528 Å) but the compound exhibits a slight optical anisotropy. The specific resistivity of Cu₁₂As₃VS₁₆ is 10⁷ Ωcm, the Seebeck coefficient +390 μV/K. The i.r. spectrum has been measured. Mixed crystals and other compounds in the system enargite-sulvanite have not been observed.     

Heterotrimeric liquid crystalline thiadiazole derivatives

Various trimeric co-oligomers combining 2-phenyl-1,3,4-thiadiazole mesogenic moieties with a biphenyl mesogenic moiety were synthesized and their mesomorphic behaviour investigated by polarizing microscopy, calorimetry and X-ray scattering. Such co-oligomeric structures provide an opportunity to combine different mesogenic units. Thus readily accessible homochiral biphenyl mesogenic units were connected with thiadiazole mesogenic units leading to an oligomeric liquid crystal material with ferroelectric properties.