Multi-Maleimides Bearing Electron-Donating Chromophores: Reversible Fluorescence and Aggregation Behavior

A(=)−D, [A(=)]2−D and [A (=)]3−D multi-maleimides and multi-itaconimides bearing electron-donating chromophores display a strong fluorescence quenching due to an intramolecular charge-transfer interaction. The electron-accepting CC bond plays a key role in the intramolecular quenching. For the isomerization of these multi-itaconimides and Michael additions of these multi-maleimides, their emission behavior is irreversible. For the Diels−Alder additions of these multi-maleimides, their emission behavior is reversible due to the reversible opening and closing of intramolecular charge-transfer pathway. Tris-maleimide TMPA peripherally modified with furfural alcohol displays not only reversible fluorescence behavior but also reversible aggregation behavior.