Synthesis and low dimensional conductive behaviour of columnar bis(beta-diketonato)copper(II) complexes with oligo(ethylene oxide) groups

Several kinds of beta-diketone with oligo(ethylene oxide) groups and their Cu-complexes were synthesized and characterized by H-1 NMR, IR, MS, and ele mental analysis. The columnar mesomorphism of the bis[1-(p-ethoxy-di(ethyle neoxy)phenyl)-3-(p-n-hexyloxylphenyl)propane-1,3-dionato] copper(II) comple x (abbreviated as C6EDK-Cu) was studied by differential scanning calorimetr y, polarizing optical microscopy and temperature variable X-ray diffraction . In comparison with the conductivity value of c. 10(-8) S cm(-1) of the pu re columnar liquid crystal (C6EDK-Cu), that of C6EDK-Cu doped with LiClO4 o r iodine is increased by about three orders of magnitude and reaches 10(-5) S cm(-1) when heated to the columnar mesophase. It is noteworthy that the conductivity of C6EDK-Cu doped with iodine is maintained when the sample is cooled from the mesophase to room temperature, while that of C6EDK-Cu dope d with LiClO4 is decreased. The two kinds of conductive mechanism of C6EDK- Cu doped with LiClO4 or iodine are discussed.