Synthesis and mesomorphic properties of Cu-coordinating liquid crystallinepolysilsesquioxanes with heptyl side groups

In order to study the influence of the concentration of a flexible group on the liquid crystal behaviour of copper-containing complexes, series of Cu- coordinated, P-diketone-based liquid crystalline polysilsesquioxanes (abbr. H-DK-Cu) and random copolymethylsilsesquioxanes (abbr. Me-DK-Cu), have bee n synthesized by the hydrosilylation reaction of a vinyl-terminated beta-di ketone and 1-heptene with the polyhydrosilsesquioxane (H-T) and with the ra ndom copolymethylhydrosilsesquioxane (Me-T), followed by reaction with Cu(N H3)(4)Cl-2. Their mesomorphic properties were investigated by differential scanning calorimetry and optical polarizing microscopy. The H-DK-Cu and Me- DK-Cu complexes with M-w of approximate to 1 x 10(4) are thermotropic liqui d crystalline polymers and their clearing temperature and mesophase ranges are lower than those of the corresponding Cu-coordinated, P-diketone-based liquid crystalline polymethylsilsesquioxanes (Cu-FBDKLCP) without the n-hep tyl flexible group. However, their liquidity within the temperature range o f the liquid crystal state is better. The results are mainly attributed to the heptyl, flexible side group.