2,6,9,10-Tetra(p-dibutylaminostyryl)anthracene as a multifunctional fluorescent cruciform dye

Abstract

In this work, we have synthesized a tetradonor-capped anthracene-centered cruciform 2,6,9,10-tetra(p-dibutylaminostyryl)anthracene (TDC) and its optical properties are investigated. TDC is a light- and heat-stable dye and shows aggregation-enhanced emission (AEE), large and enhanced two-photon absorption cross sections (δ), fluorescence sensing selectively to transition metal ions such as Zn²⁺ and Cu²⁺, and appreciable piezofluorochromism (PFC), which is rarely found to exist simultaneously in cruciform or other configuration dyes. The AEE and PFC behaviours result from the existence of a strongly twisted 9,10-branch, and the large and enhanced δ is ascribed to the multiple conjugation pathways and introduction of donor end-groups. TDC possesses a non-centrosymmetric structure and a semi-disjoint Frontier molecular orbital, which could rationalize its fluorescence sensing selectively to Zn²⁺ and Cu²⁺. These findings indicate further that an anthracene ring is indeed a unique π-center that is different from other π-centers and can construct novel cruciforms with interesting optical properties.