LIQUID-CRYSTALLINE PHOSPHAZENES BEARING BIPHENYL MESOGENIC GROUPS

New thermotropic liquid crystalline phosphazene cyclic trimers and high polymers have been prepared by the incorporation of biphenyl derivative units connected to the skeleton by oligomeric ethyl- eneoxy spacer units. The cyclic trimer [NP|0(CH2CH2O)2C6H4C6H4CN}2]3 showed monotropic nematic schlieren texture between 102 and 59 °C. The phosphazene cyclic trimers and high polymers [NP{O-(CH2CH2O)3C6H4C6H4R}2]3 andn, where R = OMe, OEt, OPr-n, OPr-i, and OBu-n, have been synthesized. None of these cyclic trimers were liquid crystalline, but all the polymers showed enantiotropic liquid crystallinity. © 1990, American Chemical Society. All rights reserved.