Miscellaneous Type I Chiral Nematic Liquid Crystals

5 Miscellaneous Type I Chiral Nematic Liquid Crystals 

The former examples of type I materials are not the only examples of the class many other forms of novel side chains have also been investigated. These miscellaneous chiral nematic systems include the following types of material (R)- and (5 )-I-methylalk-oxy derivatives (102) [87, 88] derivatives of (5)-j3-citronellol (103) [89] (/ )-2-chlo-ropropanol and (5)-2-ethoxypropanol (104) [90, 91] (5)-2-chloropropyl derivatives (105) [29, 92] (5)-2-halogeno-4-methyl-pentyl derivatives (106) [29, 93] materials with (25, 3S)-3-propyloxirane groups (107) [29,94] and (/ )-4-(l-propoxyethyl)phenyl derivatives (108) [95]. These materials will not be covered in great detail, as many of them were synthesized as potential ferroelectric materials, nonetheless, they highlight the use of other novel chiral side chains. 

Some of these materials were readily available from commercial sources, others were not and have had to be synthesized from convenient precursors. This has often led to two distinct types of approach firstly, by employing mild synthetic methods which somehow preserve the optical activ- 

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