Structure and phase transitions of azomethine biligand complexes of iron(III) based on 3,4,5-tri(tetradecyloxy)benzoyloxy-4-salicylidene-N′-ethyl-N-ethylenediamine

Abstract

New biligand complexes of iron(III) are synthesized based on 3,4,5-tri(tetradecyloxy)benzoyloxy-4-salicylidene-N′-ethyl-N-ethylenediamine azomethine with the outer sphere NO₃⁻, PF₆⁻, Cl⁻, BF₄⁻, ClO₄⁻, and CNS^– anions. All the target compounds are characterized by gel exclusion chromatography, elemental analysis, and electron, IR, and NMR spectroscopy. The presence of complex-forming ions is confirmed by FT-IR spectra in the far region. The formation of biligand polychelate complexes with an octahedral packing of the iron ion is observed. Phase transitions in the resulting coordination compounds are studied by differential scanning calorimetry and optical polarizing thermomicroscopy. The presence of several polymorphic crystalline modifications, as well as mesophases, is established. Mesomorphic properties are found for complexes with chloride and tetrafluoroborate anions.