Donor-Acceptor-Substituted Anthracene Centered Cruciforms: Synthesis, Enhanced Two-Photon Absorptions, And Piezallochr Omic Behaviour

The simultaneous absorption of two long wavelength photons by the same molecule was first analyzed theoretically in the 1930s by G?ppert-Mayer, and was first demonstrated experimentally in 1961 by Kaiser and Garret, soon after the invention of the laser. A new scientific field was opened up which mainly studied two-photon absorption and multi-photon absorption. Due to the important advantages of two-photon absorption over conventional one-photon absorption, two-photon absorption has potential applications in microscopy, microfabrication, three- dimensional data storage, optical power limiting, upconverted lasing, photodynamic therapy, for the localized release of bio-active species and so on. These potential applications have generated a demand for new dyes with high two-photon absorption cross-sections.In this work, using 2,6-Bis(diethylphosphorylmethyl)-9,10-dibromoanthracene for the key intermediate, we synthetized anthracene-centered cruciforms through Heck and Wittig-Horner reactions. Solvatochromic behaviors reveal that donor-acceptor- substituted anthracene-centered cruciforms show spatially separated HOMO and LUMO. The cruciforms with high two-photon absorption cross-section, AIE (aggregation-induced emission) can respond to different ions. The bandgap between LUMO and HOMO adjusts to the complexation properties with metal ions, which leads to the independent changes of colours. This property can also be used for metal ion of single photon and two-photon fluorescent sensors in water and organic medium.We also study the piezallochromic behaviour of the synthetized anthracene- centered cruciforms. Among the cruciforms, we discover the cruciforms with bisbutylamino group have obvious piezallochromic behaviour. Large redshifts are observed under natural light and 365nm UV light. Through analysis of DSC and XRD, piezallochromic behaviour of the synthetized anthracene-centered cruciforms are caused by destruction of crystalline. This change is reversible. The amorphous form returns to the crystalline state by heat and organic solvent fumigation.