Synthesis and Properties of [2.2]cyclo(9,10)anthrylene-paraphenylene

A [4]cycloparaphenylene (CPP) derivative, [2.2]cyclo(9,10)anthrylene-paraphenylene ([2.2]CAPP), consisting of alternating 9,10-anthrylene and paraphenylene units, was synthesized through a six-step sequence without transition-metal-catalyzed coupling reactions. The structure was unambiguously confirmed by single-crystal X-ray diffraction analysis, which revealed a quinoidal character within the CPP core. This distortion originates from substantial ring strain, resulting in the loss of aromaticity in the anthrylene units. This molecular design strategy offers a promising route to constructing open-shell carbon nanorings composed exclusively of six-membered rings.