Anion‐π Interactions in Direct Amination of Core‐Unsubstituted Perylene Monoimides

OpenAlex İngilizce

ABSTRACT The incorporation of amino substituents at the peri ‐positions of perylene monoimides (PMIs) produces elusive push‐pull systems with absorption and emission properties in the UV–vis and Near‐IR regions. We describe a survey of different direct amination methods for the one‐step synthesis of a series of 9‐alkylamino and 9‐arylamino PMIs. The first method tested is direct amination in neat amines and succesfull only for pyrrolidine. The second method uses the PCC/AgNO 3 oxidant system, and high yields are obtained with pyrrolidine. The third method employs KMnO 4 /AgNO 3 as a stronger oxidant system. Pyrrolidine and piperidine are favorable amines for this method, and even diamino PMIs can be obtained. The fourth method uses a Cu(II) salt as a catalyst, and cyclic amines afford products in high yields. The final method is the anion‐mediated direct amination and provides the most suitable method for a variety of cyclic, alkyl, and aryl amines to give 9‐alkylamino and 9‐arylamino PMIs in high yields. In this method, TBAF or TBAOH is used as the anion source, and our detailed spectroscopic and synthetic studies reveal that, as a result of single‐electron transfer from the anion, PMIs can generate radical anions and participate in a radical mechanism in amination.