Versatile access to nitrogen-rich π-extended indolocarbazoles via a Pictet–Spengler approach. Issue 1 (27th October 2022)

• Record Type: Journal Article
• Authors: Heckershoff, Robin; Eberle, Lukas; Richert, Nick; Delavier, Christian; Bruckschlegel, Michael; Schäfer, Moritz R.; Krämer, Petra; Rominger, Frank; Rudolph, Matthias; Hashmi, A. Stephen K.
• Is Part Of: Organic chemistry frontiers. Volume 10:Issue 1(2023)
• Page Start: 12
• Page End: 21
• Publication Date: 2022-10-27
• Subjects: Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1039/d2qo01459a
• Languages: English
• ISSNs: 2052-4110

Abstract

Abstract : A bidirectional Pictet-Spengler Reaction allows easy access to nitrogen-rich aromatics with seven fused rings. Photophysical measurements and computational methods show significant differences to parent N-heteropolycycles with fewer nitrogen atoms. Abstract : The Pictet–Spengler reaction was applied to synthesize benzobispyrrolo[3, 2- c ]quinolines as new scaffolds for organic electronics. The addressed compounds are nitrogen-enriched analogues of π-extended indolocarbazoles formally accessed by the isosteric replacement of CH moieties by nitrogen atoms. The straightforward and robust methodology allows easy access to these heptacycles with the possibility of late-stage functionalization. 17 new compounds were synthesized, fully characterized and their properties were investigated by X-ray crystallography, photophysical measurements and computational methods. The study evaluated the effect of different substituents on the observed photophysical and electronical properties. Comparison with π-extended indolocarbazoles showed that the introduction of two nitrogens to the molecule core results in a significant decrease of the HOMO and LUMO energies and an increase of the optical and HOMO–LUMO gaps.