SYNTHESIS AND MESOMORPHIC PROPERTIES OF FISBBONE-LIKE, LIQUID-CRYSTALLINE POLYSILSESQUIOXANES .4. PD-COORDINATING, FISHBONE-LIKE IMINE-BASED LIQUID-CRYSTALLINE POLYSILSESQUIOXANE

A new type of Pd-coordinating, imine-based, fishbone-like liquid cryst alline polysilsesquioxanes (Pd-FBI) including p-acetato-bridged Pd-FBI [Pd(mu -oAc>FBT] and mu-chloro-bridged Pd-FBI [Pd(mu-Cl)-FBT] has bee n synthesized first by a hydrosilylation reaction to form fishbone-lik e, imine-based liquid crystalline polysilsesquioxane (H-FBI and MH-FBI respectively,) and then by an ortho-palladation reaction with palladi um acetates to obtain Pd(mu-oAc)-FBI. The latter was further subjected to ligand substitution reaction with NaCl to form Pd(mu-C1)-FBI. Thei r mesomorphic properties investigated by differential scanning calorim etry (DSC) and optical polarization microscopy (OPM). show that the Pd -FBI is a thermotropic liquid crystalline polymer and its clearing tem peratures and mesophase range are much higher than those of the corres ponding comb-like imine liquid crystalline polysiloxanes (IMLCP) by ab out 100 degrees C. In this paper the influence of the palladium conten t on mesogenic behavior is discussed.