Naphthoic acid derivatives as hydrogen bond donors in supramolecular materials

Abstract

The synthesis of a series of 6-hydroxy-2-naphthoic acid derivatives is described. These have been used to form supramolecular main-chain liquid crystalline polymers. These hydrogen bond donors are complexed with a series of bisfunctionalized rigid pyridine species. These associative chain structures were analyzed through differential scanning calorimetry and polarizing light thermal optical microscopy. The liquid crystalline phases formed displayed mainly enantiotropic nematic phases that display an increase in clearing temperature as the rigid portions of the supramolecular system increased in length. A decrease in the clearing temperature was observed as the length of the flexible spacer group increased. Both of these observations follow established trends in liquid crystalline behavior.