Ru–Se Coordination: A New Dynamic Bond for Visible-Light-Responsive Materials

Abstract

Photodynamic bonds are stable in the dark and can reversibly dissociate/form under light irradiation. Photodynamic bonds are promising building blocks for responsive or healable materials, photoactivated drugs, nanocarriers, extracellular matrices, etc. However, reactive intermediates from photodynamic bonds usually lead to side reactions, which limit the use of photodynamic bonds. Here, we report that the Ru–Se coordination bond is a new photodynamic bond that reversibly dissociates under mild visible-light-irradiation conditions. We observed that Ru–Se bonds form via the coordination of a selenoether ligand with [Ru­(tpy)­(biq)­(H2O)]­Cl2 (tpy = 2,2′:6′,2″-terpyridine, biq = 2,2′-biquinoline) in the dark, while the Ru–Se bond reversibly dissociates under visible-light irradiation. No side reaction is detected in the formation and dissociation of Ru–Se bonds. To demonstrate that the Ru–Se bond is applicable to different operating environments, we prepared photoresponsive amphiphiles, surfaces, and polymer gels using Ru–Se bonds. The amphiphiles with Ru–Se bonds showed reversible morphological transitions between spherical micelles and bowl-shaped assemblies for dark/light irradiation cycles. The surfaces modified with Ru–Se-bond-containing compounds showed photoswitchable wettability. Polymer gels with Ru–Se cross-links underwent photoinduced reversible sol–gel transitions, which can be used for reshaping and healing. Our work demonstrates that the Ru–Se bond is a new type of dynamic bond, which can be used for constructing responsive, reprocessable, switchable, and healable materials that work in a variety of environments.

Probing and Manipulating Noncovalent Interactions in Functional Polymeric Systems

“…Replacing Ag NPs with AuNPs and shifting AM monomers with NIPAM monomers also resulted in a hydrogel with a NIR-initiated self-healing property enabled by the dynamic RS–Au coordination interaction . In addition, the newly discovered photodynamic Ru–Se coordination bond has been exploited for the preparation of visible-light-responsive self-healing hydrogels, which could experience reversible sol–gel transitions without side reactions upon cyclic mild visible-light irradiation and storage in the dark …”

Transformation of Amorphous Nanobowls to Crystalline Ellipsoids Induced by Trans‐Cis Isomerization of Azobenzene

“…[21] Comparing with other stimuli, light is a non-interventional stimulus and widely used to trigger the morphology and structure transformation, while maintains the physicochemical environment unchanged. [22][23][24][25] For example, Lin and coworkers conducted systematic research in the self-assembly of azobenzene polymers and photo-responsive shape transformation of azobenzene containing nanostructures. [26][27][28][29] However, either triggered by temperature, pH and redox or by light, the previous studies mainly focus on the morphology transformation, while the transition between amorphous and crystalline of the nanostructures is rarely reported.…”

Complete Degradation of a High-Performance Epoxy Thermoset Enabled by γ-ray-Sensitive Motifs Based on the Cascaded Synergetic Strategy

“…As a high-energy stimulus derived from clean energy, γ-ray radiation is a viable candidate for disposal of waste CFRCs. Different from polymer materials that are degraded by UV radiation, pH, and heating, ,− γ-radiation technology does not need to add any initiator and can be processed at room temperature or low temperature; thus, the degradation conditions are more mild and simple. Moreover, high-energy ionizing γ-radiation penetrates deep in triggering simultaneous cleavage of internal and surface bonds for materials, which offer certain benefits in high efficiency over other degradation methods.…”