SYNTHESIS AND MESOMORPHIC PROPERTIES OF PALLADIUM CHELATES OF LIQUID CRYSTAL POLYSILOXANE WITH β-DIKETONE-BASED SIDE CHAINS

A new type of palladium chelate of β-diketone-based side chain liquid crystal polysiloxane （Pd-DKLCP） has been synthesized by chelation reaction of palladium dichloride with polymeric ligand, β-diketone polysiloxane （DKLCP）, using THF as solvent at R.T.. The Pd-chelation results in greatly increasing the phase transition temperature T;and the enthalpy change △H;from crystal to liquid crystal state and making the temperature range of LC state △T(△T=T;-T;) widened. All these chelates Pd-DKLCP’s do not show T;until decomposition at 205℃. It is noteworthy that the Pd-chelation can exert more positive effect on the mesomorphic behaviour of the polymer ligand than the counterpart Cu-DKLCP does. It is probable due to the bigger size of disc-like mesogen formed from β-diketone and Pd;ion with 4d orbital.