Structure Switching and Modulation of the Magnetic Properties in Diarylethene‐Bridged Metallosupramolecular Compounds by Controlled Coordination‐Driven Self‐Assembly

We report three self‐assembled iron complexes that comprised an anti‐parallel open form (o‐ L _anti), a parallel open form (o‐ L _syn), and a closed form (c‐ L ) of diarylethene conformers. Under kinetic control, Fe^II₂(o‐ L _anti)₃ was isolated, which exhibited a dinuclear structure with diamagnetic properties. Under light‐irradiation control, Fe^II₂(c‐ L )₃ was prepared and exhibited paramagnetism and spin‐crossover behaviour. Under thermodynamic control and in the presence of indispensable [Fe^III(Tp*)(CN)₃]^?, Fe^II₂(o‐ L _anti)₃ and Fe^II₂(c‐ L )₃ transformed into tetranuclear Fe^III₂Fe^II₂(o‐ L _syn)₂, which exhibited complete spin‐crossover behaviour at T_1/2=353 K.     

Cation‐Driven Self‐Assembly of a Gold(I)‐Based Metallo‐Tweezer

A combination of self‐complementary π–π‐stacking interactions and metallophilic interactions triggered the self‐assembly of a new digold(I) metallo‐tweezer in the presence of several types of M⁺ ions. Titrations by fluorescence spectroscopy enabled the determination of the association constants of the resulting inclusion duplex complexes.     

Biocatalytic Self‐Assembly Cascades

The properties of supramolecular materials are dictated by both kinetic and thermodynamic aspects, providing opportunities to dynamically regulate morphology and function. Herein, we demonstrate time‐dependent regulation of supramolecular self‐assembly by connected, kinetically competing enzymatic reactions. Starting from Fmoc‐tyrosine phosphate and phenylalanine amide in the presence of an amidase and phosphatase, four distinct self‐assembling molecules may be formed which each give rise to distinct morphologies (spheres, fibers, tubes/tapes and sheets). By varying the sequence or ratio in which the enzymes are added to mixtures of precursors, these structures can be (transiently) accessed and interconverted. The approach provides insights into dynamic self‐assembly using competing pathways that may aid the design of soft nanostructures with tunable dynamic properties and life times.