Selective Ortho-π-Extension of Perylene Diimides for Rylene Dyes.

A range of ortho-π-extended PDI derivatives are straightforwardly synthesized in good yields through highly regioselective heteroannulations of ortho-alkynyl-substituted PDI derivatives with sulfur, selenium, or nitrogen nucleophiles. Successful synthesis of pyrrole-fused rylene dyes by using primary amines as nucleophiles indicates the great synthetic potential of this facile annulation route. Further opto-electrochemical study of these novel thiophene-, selenophene-, and pyrrole-fused PDIs suggests that effective π-conjugation enlargement combined with distortion of the perylene core renders these PDI derivatives tunable and desirable physical properties.