Core-modified phthalocyanine analogues with a seven-membered ring unit in place of a five-membered ring unit

A variety of phthalocyanine analogues with a seven-membered ring unit in place of a five-membered ring unit were synthesized from aromatic dicarbonitriles bearing cyano groups at 1,4-separate positions. Based on the spectroscopic analyses and theoretical calculations, tetraazachlorine-like electronic structures of these novel compounds stemming from severe twist of the conjugation system at the seven-membered ring unit have been revealed.