Stacking Of Viologen Radical Cations Incorporated In Polymers Soluble In Water

Aromatic stacking has played a significant role in the design of discrete supramolecular systems.However, for many years, the stacking of conjugated radical cations has been considered only as a novelty due to its weakness. In recent years, it has been demonstrated that the stacking of conjugated radical cations, particularly those formed by bipyridinium or tetrathiafulvalene, can be enhanced remarkably when they are incorporated into rationally designed, preorganized frameworks or entrapped into a confined space. However, the development of this kind of supramolecular polymers in solution has been a challenge due to the lack of efficient building blocks or binding motifs.In the past decades, viologen dication has been widely used as an electron acceptor for studies in supramolecular and materials chemistry.In this paper, we herein synthesis a linear polymer and the new polymer have been characterized with 1H-NMR, UV-vis absorption and electron paramagnetic resonance can demonstrate that, by attaching viologen units, their corresponding radical cation units can undergo strong intermolecular dimerization and stabilization in water. By a series of fluorescent quenching test, the linear molecule can emerge strong donor acceptor interaction with electron rich molecules, the repeat units can performance a strong synergistic reaction that will enhance D-A interaction prominently.