Toward new bay-substituted perylene derivatives: Synthetic approaches and mechanistic insights

JIMENEZ, LILIANA B.

Conferencia; 15 Conferencia Latinoamericana de Fisico-Química Orgánica; 2022

Rylenes constitute an important class of compounds with exceptional optoelectronic properties, fundamentals for applications in both OLEDs1 and OSCs devices. Among these, perylene bisimide (PBI) and perylene monoimide are two of the most studied compounds within rylene’s family due to its characteristic fluorescence with high quantum yield, which varies depending on both the nature of the substituents attached to the polycycle and their positions (e.g. the axial or equatorial regions). Different strategies have been developed for the synthesis of perylene, all of them focused on the formation of the perylene ring. Furthermore; most of the reported examples of substituted perylene in the different positions (bay, ortho or peri) discuss the incorporation of functional groups to an already formed perylene nucleus.We investigated the cyclodehydrogenation reactions to generate bay-substituted perylenes following three different mechanistically approaches: Scholl reaction (in which the arenium cation is involved), the oxidative aromatic coupling (radical cations as intermediates) and by anionic reductive conditions (radical anion and dianion as intermediates), Figure 1. DFT studies were carried out for the better understanding of these mechanisms and the experimental results obtained.We extended our bay-substitution mechanistic studies to Br-PBIs as substrates in aromatic substitution reactions with ambident nucleophiles as Ar-OH, Scheme 1. We observe the spontaneous formation of the radical anion of Br-PBI in presence of KOtBu/DMSO and, according to the experimental evidences; we propose a competition between SRN2 and SRN1 mechanisms.