Azepiphthalocyanine—an unprecedented large twist of a π-conjugation system upon core-modification with a seven-membered ring unit

Aromatic dicarbonitrile bearing cyano groups in a 1,4-relationship was utilized for a phthalocyanine synthesis to give azepiphthalocyanine having a seven-membered ring unit instead of a five-membered ring unit. This molecule exhibits a significantly twisted structure and large splitting of the Q band absorption, indicative of its azachlorin-like conjugation system.