STUDIES ON STRUCTURE CHANGES OF DISCOTIC LIQUID-CRYSTALS OF TRANSITION-METAL COMPLEXES

Disklike liquid crystals of bis(beta-diketonato)palladium(II) complex and copper(II) complex with different flexible chain lengths (number of carbons = 12 and 14) have been studied by means of DSC, X-ray diffraction, polarizing microscopy and infrared spectroscopy. Analysis revealed that all have the mesophase structure called ''discotic lamellar phase'', but with different types of lamellas. With the same flexible chain lengths for Pd(II) and Cu(II) discotics, different layer thicknesses of the mesophase have been observed. Various conformational distortions of the merogenic cores of the molecules were found in their crystalline states. Considerable conformational alterations of these cores that occurred during the crystal-mesophase transition were detected.