Metallo-supramolecular complexes from mPEG/PDPA diblock copolymers and their self-assembled strip nanosheets

Abstract

Herein we designed and synthesized mPEG/PDPA copolymers containing two 4-([2,2′:6′,2′′-terpyridin]-4′-yl) phenyl (Tpyp) groups at the junction point of the two blocks (mPEG(-b-Tpyp)₂-b-PDPA_x, x = 23, 33, and 44). Interestingly, after a hierarchical pattern from the coordination of mPEG(-b-Tpyp)₂-b-PDPA_x with Ru(II) ions followed by the self-assembly in water, 2D strip nanosheets with a monomolecular layer were obtained. In contrast, mPEG(-b-Tpyp)₂-b-PDPA_x without coordination self-assembled into spherical micelles in the similar condition. The formation of the rigid and charged ⋯Tpyp-Ru(II)⋯ chain, the brush-shaped polymer architecture and the presence of the hexafluorophosphate (PF₆⁻) counterions should be responsible for the unique self-assembly behavior of the metallo-supramolecular complexes. It is expected that the hierarchical self-assembly pattern can provide a new strategy for preparation of self-assemblies with different morphologies.