169171-37-3Relevant articles and documents
Improving FLC properties. Simplicity, planarity, and rigidity in new chiral oxazoline derivatives
Serrano, José Luis,Sierra, Teresa,González, Yolanda,Bolm, Carsten,Weickhardt, Konrad,Magnus, Angelika,Moll, Guido
, p. 8312 - 8321 (2007/10/03)
In an attempt to develop new dopants for improved ferroelectric properties in liquid crystals, aryloxazolines have been chosen as chiral moieties. They were prepared in optically active form from (S)-β-amino alcohols via a short stereospecific synthesis and incorporated into mesogenic systems. Mesogenic and ferroelectric properties of 11 compounds in five series of chiral oxazoline derivatives [I(OH), I(H), II(OH), II(H), and III(OH)] have been studied. In order to establish the relationship between the molecular structure and ferroelectric properties, an indepth structural investigation of both H-bonded and non-H-bonded phenyloxazoline moieties was carried out (by means of semiempirical calculations - AMI - and spectroscopic studies - IR, UV and 1H NMR). These studies have proved a planar structure for both types of structures, which should have a strong influence on ferroelectric properties. These properties have been evaluated in 10 mol % binary mixtures. The highest Ps values were measured for compounds of series I(OH) [P5 maxI(OH)a = 16.7 nC/cm2, Ps maxI(OH)b = 13.2 nC/cm2] containing a hydrogen bond, which makes the chiral part of the molecule more rigid. Compound III(OH)a shows a wide SmC* phase range which supercools well below room temperature, and it has been studied as a ferroelectric liquid crystal in the pure state. The Ps max measured is appreciably high: 225 nC/cm2. Its special thermal behavior (showing a glass transition at -28 °C) makes this compound very interesting from the point of view of practical applications and will be the target of further studies.
