Corrole–imide dyads — Synthesis and optical properties

Two rarely seen building blocks have been incorporated into light absorbing arrays: corroles and 2,3-naphthalimides. General synthetic strategy consisting in direct condensation of formyl substituted aromatic imides with dipyrranes led to diverse range of trans-A2B-corroles in acceptable yields. Spectroscopic properties of all five dyads studied suggest that regardless the imide's structure, components are weakly electronically coupled. Positioning 2,3-naphthalimide unit partially above the corrole core leads to slight alteration of their optical properties. Dyads bearing blue-absorbing imide components display different behavior depending on their structure. In corrole linked with naphthalenyl-naphthalene-1,8-carboximide a 100% effective energy transfer reaction from the imide component to the corrole component occurred. On the contrary, in small, strongly polarized amino-cyano-phthalimide neither efficient energy-nor electron-transfer could be detected and excitation leads to fluorescence from both components.