An electron-poor C64 nanographene by palladium-catalyzed cascade C-C bond formation: One-pot synthesis and single-crystal structure analysis

Abstract

Herein, we report the one-pot synthesis of an electron-poor nanographene containing dicarboximide groups at the corners. We efficiently combined palladium-catalyzed Suzuki-Miyaura cross-coupling and dehydrohalogenation to synthesize an extended two-dimensional π-scaffold of defined size in a single chemical operation starting from N-(2,6-diisopropylphenyl)-4,5-dibromo-1,8-naphthalimide and a tetrasubstituted pyrene boronic acid ester as readily accessible starting materials. The reaction of these precursors under the conditions commonly used for Suzuki-Miyaura cross-coupling afforded a C64 nanographene through the formation of ten C-C bonds in a one-pot process. Single-crystal X-ray analysis unequivocally confirmed the structure of this unique extended aromatic molecule with a planar geometry. The optical and electrochemical properties of this largest ever synthesized planar electron-poor nanographene skeleton were also analyzed. Ten bonds in a single operation: The synthesis of an electron-poor nanographene with dicarboximide corners was accomplished by a palladium-catalyzed cascade process, with ten C-C bonds formed in a single chemical operation. The planar geometry of this novel C64 nanographene was revealed by single-crystal X-ray analysis.