Novel macro metallomesogens derived from simple dihydroxy benzenes

A series of tetradentate Schiff base metallomesogenic diols and their model compounds were synthesized from two simple dihydroxy benzenes. The metallomesogenic diol was constructed from three ring containing mesogen linked through ester and azomethine with terminal hydroxy group. This upon complexation with copper(II) formed metallomesogenic diol with varing terminal chain length. The related model metallomesogenic compounds were also synthesized with varying chain length with terminal methyl group and compared the properties with metallomesogenic diols. Extensive characterization of all metallomesogenic compounds and intermediates were carried out by FT-IR, 1H & 13C NMR, EPR, VSM, Mass (EI and FAB) and UV–Vis spectroscopy. Hot stage polarizing microscope, Differential scanning calorimetry was used to ensure the phase characteristics such as nature of phase, melting and clearing temperatures and phase range. The appearance of enantiotropic smectic A phases indicated high molecular polarizability of the core due to the metal ion. The role of copper(II) ion on mesogens were discussed.

A series of metallomesogenic diols and their model compounds were synthesized from two simple dihydroxy benzenes. Mesomorphic properties of compounds were studied using HOPM and DSC. The appearance of enantiotropic smectic A phases indicated high molecular polarizability of the core due to the metal ion. The role of copper(II) ion on mesogens were discussed.Figure optionsDownload as PowerPoint slideHighlights
► Design and synthesis of metallomesogenic diols.
► The model methyl terminated metallomesogenic compounds were also synthesized with varying chain length.
► A square pyramidal structure for the copper(II) complexes have been proposed.
► Copper(II) complexes exhibited enantiotropic smectic A and smectic C phases.