The role of the linker heteroatom and the position of the substituents on the mesogenic properties of nickel (II) phthalocyanines

Novel nickel (II) phthalocyanines carrying four branched thia- and oxy-oligo(ethyleneoxy) groups on peripheral and non-peripheral positions have been synthesized from the corresponding phthalonitrile derivatives. The new compounds have been characterized by elemental analysis, mass spectrometry, infrared, nuclear magnetic resonance, and ultraviolet–visible spectroscopy. The spectroscopic properties and aggregation behaviors of these phthalocyanine complexes have been studied in different solvents and concentrations. The mesogenic properties of these new materials have been determined by differential scanning calorimetry, optical polarized microscopy and X-ray diffraction investigations. The effects of the substituents’ position (α or β) and the nature of the linker heteroatom (O or S) on the mesogenic properties of the synthesized nickel (II) phthalocyanines have also been explained.