Liquid-crystalline complexes of palladium(II) and platinum(II) with di- and tri-alkoxystilbazoles: ligand control of mesomorphism

Liquid-crystalline complexes of palladium and platinum are formed when the metals are complexed to stilbazoles (4-styrylpyridines) bearing either two or three alkoxy chains. The complexes, termed polycatenar, show smectic C mesophases for most 3,4-disubstituted ligands, while the use of trisubstituted ligands leads to complexes showing columnar organisation, demonstrating that the spatial organisation of the metals in the liquid-crystal mesophase can be rather readily controlled. Complexes of these di-and tri -substituted stilbazoles with a cis-dicarbonylchloroiridium(I) fragment were not liquid crystalline.