Pentacoordinated Liquid Crystalline Zn(II) Complex Organized in Smectic Mesophase: Synthesis, Structural and Electrochemical Properties

The synthesis and structural characterization of a new liquid crystalline coordination
complex based on pentacoordinated Zn(II) metal centre with the coordination fulfilled by the tridentate
chelating NˆNˆN 2,20;60,20 0-terpyridine ligand and two monoanionic gallates decorated with
several long alkyl chains is described. The mesomorphic properties were accurately investigated by
small- and wide-angle X-ray scattering studies. Despite the bulky coordination around the metal
centre, the complex self-organizes into a smectic phase and, based on the structural and geometrical
parameters, a model for the supramolecular organization in the liquid crystalline phase is proposed.
Electrochemical investigations showed the importance of the molecular structure of the coordination
complex in enhancing its aqueous sensing capacities: the bulky organic ligands form an organic
shell separating the metal centres and favouring the redox system through their reduction followed
by stripping.