Abstract
Homologous series of chiral (S) 4-(1-methylheptyloxycarbonyl)-phenyl and achiral 4-(4-heptyloxycarbonylphenyl 4-(perfluoroalkanoyloxyhexyloxy)biphenylates or 4-(alkanoyloxyhexyloxy)biphenylates, chiral (S) and racemic (R,S) 4′-(1-methyl heptyloxycarbonyl)biphenyl-4-yl 4-(perfluoroalkanoyloxyhexyloxy)benzoates or 4 (alkanoyloxyhexyloxy)benzoates have been prepared and their phase transitions have been investigated by DSC and polarizing thermomicroscopic methods. Moreover the temperature dependence of interlayer spacing by a small angle X-ray diffraction method has been studied. The chiral and achiral members exhibit a SmC anti. phase, while racemic members only exhibit SmC phase. Fluorinated compounds have lower melting points, lower melting enthalpy and broader range of the SmC anti. phase than earlier prepared series with shorter spacer group (CH 2 ) m , m < 6. They are very useful components for the formulation of orthoconic (interlayer tilt 90°) antiferroelectric mixtures with temperature range from (−20°C) to 100°C.
Acknowledgment
Financial support from the Polish Government (K.B.N.) grant No 4T09A 103 24 and European Network “SAMPA.”