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 crystalline polysilsesquioxanes (Pd-FBI) including p-acetato-bridged Pd-FBI [Pd(mu -oAc>FBT] and mu-chloro-bridged Pd-FBI [Pd(mu-Cl)-FBT] has been synthesized first by a hydrosilylation reaction to form fishbone-like, imine-based liquid crystalline polysilsesquioxane (H-FBI and MH-FBI respectively,) and then by an ortho-palladation reaction with palladium acetates to obtain Pd(mu-oAc)-FBI. The latter was further subjected to ligand substitution reaction with NaCl to form Pd(mu-C1)-FBI. Their mesomorphic properties investigated by differential scanning calorimetry (DSC) and optical polarization microscopy (OPM). show that the Pd-FBI is a thermotropic liquid crystalline polymer and its clearing temperatures and mesophase range are much higher than those of the corresponding comb-like imine liquid crystalline polysiloxanes (IMLCP) by about 100 degrees C. In this paper the influence of the palladium content on mesogenic behavior is discussed.