Design and synthesis of extended pyrene based discotic liquid crystalline dyes

Abstract

The past few years have witnessed tremendous progress towards the design of new liquid crystalline (LC) materials comprised of rigid π-conjugated molecules, particularly disc shape molecules with appropriate substitution as an active component for the electronic device applications. Herein we report a new class of polycyclic aromatic hydrocarbons (PAHs) derived from pyrene core. These molecules are synthesized with 1, 6 dibromo pyrene and di-substituted arylethynylene via palladium-catalyzed cyclopentannulation followed by Scholl reaction. LC properties of these compounds were studied using a polarizing optical microscope, differential scanning calorimetry and X-ray diffractometry. Synthesized molecules show the hexagonal columnar mesophase over a wide range of temperatures. Pyrene derivatives have been extensively explored as novel dyes and widely used in various device applications. Therefore, these novel self-assembling supramolecular materials may find application in several optoelectronic devices.