Synthesis and mesomorphic properties of novel fishbone-like liquid crystalline polysilsesquioxanes VI. Fishbone-like, ester-based liquid crystalline polysilsesquioxanes

Two novel kinds of fishbone-like, ester-based, liquid crystalline, random c opolysilsesquioxanes, LC1-CH3-P and LC2-CH3-P, have been synthesized for th e first time by stepwise coupling polymerization (SCP) from trichlorosilane monomers (RSiCl3) containing mesogenic ester groups, using three main step s including preaminolysis, hydrolysis and polycondensation. Two new monomer s 4-(11-trichlorosilylundecloyloxy)phenyl 4-methoxybenzoate (M-1) and 4-(3- trichlorosilylpropoxy)phenyl 4-methoxybenzoate (M-2) have been synthesized by hydrosilylation reaction of trichlorosilane and the mesogens 4-n-undecen oyloxyphenyl 4-methoxybenzoate and 4-allyloxyphenyl 4-methoxy-benzoate, res pectively, in the presence of dicyclo-pentadienylplatinum(II) chloride (Cp( 2)Ptcl(2)) catalyst. The structures and mesomorphic properties of LC1-CH3-P and LC2-CH3-P were investigated by FTIR,H-1 NMR, C-13 NMR, Si-29 NMR, gel permeation chromatography, polarizing optical microscopy, differential scan ning calorimetry and X-ray diffraction. It is proposed from the characteriz ation data that these two polymers not only have an ordered ladder-like, do uble main chain, but also show thermotropic smectic behaviour with high cle aring points and wide mesophase ranges (Delta T), which may bold promise fo r potential applications as highly stable gas chromatographic stationary ph ases.