Spiro-Fused Perylene Diimide Arrays

The
straightforward palladium-catalyzed synthesis protocol toward
spiro-fused perylene diimides is developed. The reaction involves
two palladium-catalyzed C–H activations and 4-fold C–C
bond formation sequence from readily available precursors. This facile
and step-economic approach also provides another convenient access
to ethylene-bridged dimer (NDP) and further π-extended
spiro system (SNTP). In addition, the molecular structure
of spirodiperylenetetraimide (SDP) is illustrated to
show a three-dimensional (3D) cruciform configuration, and its absorbance
is distinctly red-shifted due to the significant spiroconjugation
effect. With combined properties of broadened and intensive absorption,
aligned LUMO levels, and unique molecular geometry, the spiro-fused
PDI system represents a new kind of high-performance semiconducting
framework as the electron acceptor in high-efficiency organic solar
cells.