The even–odd effect in liquid crystals: A collective or intrinsic molecular property

We have made the first observation that nematogens and smectogens exhibit physical properties characterized by even–odd alternation with the number n of carbon atoms in their alkyl tails, even when molecules are isolated. For the cyano-biphenyl series, when n?5, the alkyl tail is found to be all in the trans configuration. When n≳5, gauche isomers appear and an important even–odd effect is experimentally evidenced and discussed.