Acceleration Effect of Bowl‐Shaped Structure in Aerobic Oxidation Reaction: Synthesis of Homosumanene ortho‐Quinone and Azaacene‐Fused Homosumanenes. Issue 10 (29th December 2022) - Nishimoto, Mikey
Abstract: An oxidation reaction of hydroxyhomosumanene on silica gel providing homosumanene ortho ‐quinone and its synthetic application for azaacene‐fused homosumanenes is described. Hydroxyhomosumanene is photochemically oxidized by air, when it is coated on silica gel; this aerobic oxidation proceeds faster than that of planar analogues. The difference of such reactivity was attributed to the unusual keto‐enol tautomerization due to structural difference between planar and curved π‐system. The homosumanene ortho ‐quinone was used in the synthesis of several azaacene‐fused homosumanenes, azaacenohomosumanenes. X‐ray diffraction analysis of the single crystals revealed their columnar stacking structures due to the interactions between each bowl. Azaacenohomosumanenes exhibited high electron affinity due to the combination of buckybowl and electron‐deficient azaacene moieties. Abstract : The intrinsic strain in the molecule considerably accelerates the oxidation rate of peripheral carbons in aromatic compounds. The aerobic oxidation of hydroxyhomosumanene proceeds much faster than for the planar analogue because of their unusual keto‐enol tautomerization caused by the curved structure. The homosumanene ortho ‐quinone was converted to several azaacene‐fused homosumanenes, and their crystal structures, photophysical properties, and charge transport properties were investigated.