Cyclo[4]naphthobipyrroles: Naphthobipyrrole-derived cyclo[8]pyrroles with strong near-infrared absorptions

Abstract

Expanded porphyrins: Strong NIR absorption between 1273 to 1339 nm was observed for cyclo[4]naphthobipyrroles, obtained through acid-catalysed oxidative coupling methods from β-dialkylnaphthobipyrroles (see figure). These molecules display a large redshift (161-228 nm) in their lowest energy bands relative to the reported alkylated cyclo[8]pyrrole, owing to the induced structural rigidification and extended π conjugation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.