Application macrocyclic liquid crystals

Applications of this method include among others the preparation of unsym-metrical diaryldiynes [27] and of l,4-bis[2-(4 ,4"-dialkoxyphenyl)ethenyl]benzenes for polymer [28] and liquid-crystal synthesis [29]. Such one-pot acetylene double couplings are also possible between (substituted) 6-bromoazalenes and substituted bromobenzenes [30], and even macrocyclic polyenepolyynes have been made in this way ([31, 32], Scheme 3). 

From the standpoint of molecular complexity, the most intriguing applications of thiophene and its derivatives focus either on the occurrence of the thiophene moiety in naturally occurring molecules or in pharmacological agents. Transformation of thiophene into other moieties also produces some remarkable molecules. From a commercial view, the unique electronic and physical properties of thiophene make it ideal for applications in polymers, liquid crystals and dyes. Examples of thiophene-containing cyclophanes and other macrocycles as well as organometallic derivatives complete this chapter. 

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