Synthesis and Characterization of New Liquid Crystals containing a Non-Activated Indolinobenzospiropyranyl Group. Part 4*[1]
摘要:
A series of new liquid crystalline compounds, 1', 3', 3'-Trimetylspiro [2H-1-benzopyran-2,2'-indolin]-6-yl 4-(4'-alkoxyphenylazo)benzoate, SP-APAB 1a similar to 1f, has been synthesized. Their liquid crystallines were subjected to thermal analysis on a differential scanning calorimeter (DSC), to texture of phases on a polarizing microscope and to phase transition on an X-ray diffraction and electro-optical measurement. Most of compounds examined exhibit monotropic nematic and SmA liquid crystal phases on cooling from isotropic liquid. Suprisingly, SP-APAB 1c is shown to exhibit monotropic SmC phase in addition. X-ray diffraction study of the layer spacing confirmed that there was a layer spacing in the range of two theta from 2.25 to 2.45 Angstrom on the temperature near the phase transition from SmA to SmC.