Structure and electronic properties of quinone dimers connected with acetylene and diacetylene linkages

Quinone dimers connected with acetylene (QAQ) and diacetylene linkages (QAAQ) have been synthesized and their structure and electronic properties studied. X-ray analysis, DFT calculations, and UV–vis measurements showed that, unlike directly connected quinone dimers (QQ), they had planar and thus efficiently extended π conjugation systems. The respective reduction potentials of QAQ and QAAQ were considerably raised, and QAQ thereby behaved as a mild oxidizing agent.