Near-Infrared-Absorbing B–N Lewis Pair-Functionalized Anthracenes: Electronic Structure Tuning, Conformational Isomerism, and Applications in Photothermal Cancer Therapy

B–N-fused dianthracenylpyrazine derivatives are synthesized to generate new low gap chromophores. Photophysical and electrochemical, crystal packing, and theoretical studies have been performed. Two energetically similar conformers are identified by density functional theory calculations, showing that the core unit adopts a curved saddle-like shape (x-isomer) or a zig-zag conformation (z-isomer). In the solid state, the z-isomer is prevalent according to an X-ray crystal structure of a C6F5-substituted derivative (4-Pf), but variable-temperature nuclear magnetic resonance studies suggest a dynamic behavior in solution. B–N fusion results in a large decrease of the HOMO–LUMO gap and dramatically lowers the LUMO…

• NN
  National Natural Science Foundation of China

  Awards: 22101025, 32101153
• DO
  Division of Chemistry

  Awards: CHE-1954122, CHE-1664975