Fluorescent Donor–Acceptor Psoralen Cruciforms by Consecutive Suzuki–Suzuki and Sonogashira–Sonogashira One-Pot Syntheses
Sarah R. Geenen, Torben Schumann, Thomas J. J. Müller
Abstract
Two novel donor–acceptor cruciform topologies are efficiently synthesized by site-selective Suzuki–Suzuki and Sonogashira–Sonogashira multicomponent reactions starting from a bromo-triflato-functionalized psoralen scaffold. In addition to tunability of photophysical properties, such as absorption and emission, many derivatives possess partially high relative fluorescence quantum yields in solution and fluoresce strongly in the solid state. Additionally, the promising compounds show solvatochromism and acidochromic effects. In addition, 8-p-anisyl-5-p-cyanophenyl-substituted psoralen exhibits aggregation-induced emission properties. Experimentally (applying the Lippert-Mataga model) and computationally (TD-DFT calculations), the pronounced charge transfer character of the longest wavelength absorption band was confirmed.