engleski

Bis(oxalato)chromium(III) salts with azabicyclic cations: structural and dielectric studies

Ferroelectric materials exhibit spontaneous electric polarization that can be reversibly switched under external applied electric field. In recent years, ferroelectrics have been extensively investigated, showing promising applications in memory devices, capacitors, microactuators, etc. [1] In attempt to design new molecular ferroelectric crystals, two metal-organic complex salts containing bicyclic amine cations, O-ABCO+ (1-azabicyclo[2.2.2]octan-3-one) and COOH-OH-ABCO+ (3-hydroxy-1-azabicyclo[2.2.2]octane-3-carboxylic acid), and bis(oxalato)chromium(III) anions, [Cr(bpy)(C2O4)2]– (bpy = 2, 2′-bipyridine), were prepared using mechanochemical synthesis. Single crystals of prepared complex salts were obtained by slow evaporation of their aqueous solutions, which allowed structure determination from single- crystal X-ray diffraction analysis. Thermal analysis showed that water molecules of crystallization are retained in the structure up to ~100 °C. Temperature dependent dielectric studies were performed in -90–100 °C temperature range. For compound (O-ABCO)[Cr(bpy)(C2O4)2]·H2O dielectric constant and loss increase while increasing the temperature and decrease toward higher frequencies, pointing to its semiconducting nature. Polarization–voltage measurements were conducted to further study the observed dielectric anomalies in this sample.

ferroelectric materials ; azabicyclic cation ; dielectric study

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