Multi-responsive rotaxane with tunable fluorescence under azobenzene-based benzoxazine structure

Abstract

Rotaxanes are known for the mechanically interlocked molecules for decades. The present work demonstrates a method to prepare multi-responsive rotaxane by conjugating with a multi-responsive supramolecule. Benzoxazine dimers, N, N’-bis(3,5-dimethyl-2-hydroxybenzyl) methylamine derivatives, are good models because their simple chemistry. An azobenzene containing benzoxazine with remaining hydroxyl group for further conjugation with rotaxane was designed. The ring opening of rotaxane using fluorescent phenol provides benzoxazine dimer with metal ion responsive and fluorescent properties. Based on this concept, light responsive benzoxazine conjugated with rotaxane system shows light, metal ion and rotaxane shuttling responsiveness which can be followed by fluorescent signals. The present work shows simple way to develop rotaxanes with multi-responsive functions using supramolecular chemistry of benzoxazine dimer prepared from light responsive phenol.