LIQUID-CRYSTALLINE OYLOXY)-PHENYL]-5-(4-N-HEXYLOXYPHENYL)-PYRIMIDINES- NEW FERROELECTRIC COMPOUNDS EXHIBITING INTERESTING POLYMORPHISM

Seven chiral oyloxy)-phenyl]-5-(4-n-hexyloxyphenyl)-pyrimidines were s ynthesized and their liquid crystalline as well as their ferroelectric properties investigated. The new compounds possess a rich variety of polymorphism including six different smectic phase types. On the basis of X-ray investigations and miscibility studies these smectic modific ations were classified as SmA, SmC, SmJ*, SmG*, SmH* and SmM'* whereb y SmM' denotes a smectic phase which presumably is identical to the r ecently discovered SmM phase. In the second part of this paper the fe rroelectric properties of the oyloxy)-phenyl]-5-(4-n-hexyloxyphenyl)-p yrimidines were investigated. High values of spontaneous polarization (up to about 400 nC/cm(2)) were established for the SmC and SmM'* pha ses of these compounds as well as in one case also for the SmJ phase.