Self-Healing Heterometallic Supramolecular Polymers Constructed by Hierarchical Assembly of Triply Orthogonal Interactions with Tunable Photophysical Properties

Abstract

Here, we present a method for the building of new bicyclic heterometallic cross-linked supramolecular polymers by hierarchical unification of three types of orthogonal noncovalent interactions, including platinum(II)−pyridine coordination-driven self-assembly, zinc−terpyridine complex, and host−guest interactions. The platinum−pyridine coordination provides the primary driving force to form discrete rhomboidal metallacycles. The assembly does not interfere with the zinc−terpyridine complexes, which link the discrete metallacycles into linear supramolecular polymers, and the conjugation length is extended upon the formation of the zinc−terpyridine complexes, which red-shifts the absorption and emission spectra. Finally, host−guest interactions via bis-ammonium salt binding to the benzo-21-crown-7 (B21C7) groups on the platinum acceptors afford the cross-linked supramolecular polymers. By continuous increase of the concentration of the supramolecular polymer to a relatively high level, supramolecular polymer gel is obtained, which exhibits self-healing properties and reversible gel−sol transitions stimulated by various external stimuli, including temperature, K + , and cyclen. Moreover, the photophysical properties of the supramolecular polymers could be effectively tuned by varying the substituents of the precursor ligands.

Fluorescent Supramolecular Polymers Formed by Crown Ether-Based Host-Guest Interaction

“…(C) Cartoon representation of the construction of supramolecular metallacycles, linear supramolecular polymers, and cross-linked supramolecular polymeric networks. Adapted with permission from Zhang et al ( 2019b ); copyright 2019, American Chemical Society.…”

“…However, the preparation of organometallic materials with precise structural control via hierarchical self-assembly remains a challenge, in particular in the case of systems containing heterometals. For example, Zhang et al ( 2019b ) reported the construction of four rhomboidal metallacycles 50a−50d bearing a P21C7 group and a conjugately-linked tripyridine moiety by platinum(II)-ligand coordination-driven self-assembly ( Figure 14C ). A linear bimetallic supramolecular polymer was then formed through metal-coordination between Zn and the tripyridine moiety.…”

Fluorescent Platinum(II) Metallacycle-cored Polymers

“…Recently, Yin, Stang and coworkers reported a type of heterometallic fluorescent polymer gels prepared by hierarchical assembly of triply orthogonal interactions. 18 A rhomboidal metallacycle was first prepared by Pt(II)-pyridine coordination interactions and then linked by Zn-terpyridine coordination interactions to form linear supramolecular polymers. Because the formation of supramolecular polymers increased the conjugated length of the metallacycles, bathochromic shifts were observed for the absorption and emission.…”

An antibacterial and biocompatible multilayer biomedical coating capable of healing damages

“…Recently, there have been several reports on various types of polyelectrolyte stent coatings; 6,7 however, their further application in clinical environments is greatly limited by the deterioration and accumulation of damages of the coatings during applications. 8,9 Therefore, the designation and preparation of durable functional polyelectrolyte stent coatings are crucial. 10 One of the most efficient strategies for the inhibition of damages of the polyelectrolyte stent coatings primarily involves on chemical polymerization and crosslinking.…”