Structure-activity studies of ferroelectric and antiferroelectric imine ligands and their palladium(II) complexes. An antiferroelectric metallomesogen

The synthesis and characterization of the mesomorphic and dielectric properties of new imine-based liquid crystalline compounds that exhibit tilted SmC* phases is reported. The presence of an imino linkage within the mesogenic nucleus of these compounds is significant due to the ability of benzaldimines to coordinate to metals. Complexation to a divalent metal such as Pd(II) has been studied in order to assess the effects of antiparallel dimerization of organic ligands, through metal-coordination, on the appearance of antiferroelectric order in the mesophase. An organometallic palladium(II) complex has been prepared and this shows antiferroelectric behaviour over the whole range of the tilted smectic mesophase. Structure–activity studies have also been carried out by varying structural elements in the composition of the ligands. The changes include the disposition of the linking groups within the mesogenic core, and presence of a lateral hydroxy group.