New designs for functional metallomesogens: Demonstration of ferroelectric behavior in achiral systems

The underlying theme of the work presented in this thesis is to determine the structure function properties of metallomesogens which are designed to exhibit specific physical properties. The goal is to design molecules which will self align into polar assemblies which are ferroelectric. Our approach utilizes liquid crystalline vanadyl Schiff-bases complexes which form head-to-tail polymers due to metal-oxygen dative interactions. The polymers are incorporated into columnar mesophases by attaching alkoxy sidechains about the Schiff-base unit. Hexagonal assemblies are utilized because their triangular symmetry should force frustrated polar assemblies and thus eliminate antiferroelectric superstructures.;The result is that bis(trialkoxybenzoate)Vanadyl Schiff-Base materials have a propensity to exhibit weak and strong polymeric (-V=O-V=O-);Ferroelectric behavior was observed by triangle wave analysis, which shows a spontaneous polarization current for more ordered liquid crystalline polymeric mesophases. Frequency response analysis was used to probe molecular relaxation processes within the mesophases. We have found changes in the dielectric constant which correlate with the spontaneous polarization. Due to the novel nature of the liquid crystalline systems, assignment of the molecular relaxation processes is difficult.;Synthesis and characterization of novel tetra-2,3-thiophenophorphyrazines were developed for application in conducting, photoconducting, and sensory materials. Metal-free and metallated derivatives of the parent and octa-alkoxymethyl complexes were synthesized. The liquid crystalline derivatives were found to have lower transition temperatures when compared to phthalocyanine derivatives due to the existence of isomeric mixtures. The parent compounds were synthesized specifically for electrochemical polymerization of the thiophenes on the phorphyrazine macrocycle. Due to their insolubility in appropriate solvents for electrochemical polymerization, routes into more soluble derivatives were explored.