Pyrene Derivatives Containing Triphenylacrylonitrile as Aggregation Induced Emissive Mechanochromic Materials

Organic materials possessing multiple functional properties such as aggregation induced emission, mechanochromism and acidochromism are rare. In this paper we demonstrate the design of polyfunctional materials using the aggregation quenching chromophore, pyrene. The pyrene derivatives possessing 2,3,3-triphenylacrylonitrile as aggregation induced emission chromophore and phenanthroimidazole or N-phenylcarbazole as auxiliary electron-rich chromophore are designed, synthesized by Suzuki coupling reactions and characterized as aggregation induced emissive mechanochromic materials. Though all the dyes exhibit aggregation induced emission, the dyes containing para-linked 2,3,3-triphenylacrylonitrile and auxiliary chromophore such as phenanthroimidazole or N-phenylcarbazole display mechanochromism. Additionally, the phenanthroimidazole containing dyes show acidochromism attributable to the protonation of phenanthroimidazole moiety. Pyrene derivatives exhibiting mechanochromism and acidochromism are developed by incorporating 2,3,3-triphenylacrylonitrile and phenanthroimidazole units. image