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A versatile, bottom-up approach allows the controlled fabrication of polydopamine (PD) nanostructures on DNA origami. PD is a biosynthetic polymer that has been investigated as an adhesive and promising surface coating material. However, the control of dopamine polymerization is challenged by the multistage-mediated reaction mechanism and diverse chemical structures in PD. DNA origami decorated with multiple horseradish peroxidase-mimicking DNAzyme motifs was used to control the shape and size of PD formation with nanometer resolution. These fabricated PD nanostructures can serve as “supramolecular glue” for controlling DNA origami conformations. Facile liberation of the PD nanostructures from the DNA origami templates has been achieved in acidic medium. This presented DNA origami-controlled polymerization of a highly crosslinked polymer provides a unique access towards anisotropic PD architectures with distinct shapes that were retained even in the absence of the DNA origami template.

Starring PD: Defined polydopamine (PD) nanostructures were created on DNA origami template. Multiple DNAzyme moieties precisely positioned on DNA origami oxidizes dopamine locally, which is crucial to control PD formation with nanoscale precision. The method provides a unique access towards the synthesis of anisotropic PD nanodevices coupled with precision spatial control.

By utilizing the oxygen bridge in dimeric μ-oxo-titanium-salen complexes as an efficient cross-linkage, a series of robust chiral titanium coordination assemblies has been successfully fabricated with the ditopic bridging ligands derived from BINOL and salen derivatives via coordination polymerization, which are fully characterized by IR, elemental analysis, XRD and microscopic studies. Because of their insolubility in most organic solvents and water, these metal-organic assemblies can successfully function as robust self-supported chiral catalysts, allowing an asymmetric ring opening (ARO) of meso-epoxides with aliphatic amines. Remarkably, owing to the linkage effects and the cooperation of two kinds of chiral titanium moieties in the metal-organic assemblies, the self-supported chiral catalysts demonstrate extremely high stability. They not only show high tolerance towards various meso-epoxides and nucleophilic aliphatic amines, but also can be reused in more than 20 runs without obvious metal leaching and loss in yields and enantioselectivities. Furthermore, the self-supported catalyst accomplished a one-pot tandem olefin epoxidation and ARO of an epoxide sequence starting from the olefin, 30% hydrogen peroxide and benzylamine. In marked contrast, the reaction failed to work when using the two corresponding homogeneous catalysts under identical reaction conditions. Good yields and enantioselectivities were obtained by the robust self-supported catalyst, which clearly indicates the cooperative effects between two chiral moieties within the metal-organic assemblies. The two catalytic centers can perform their own duties without interference and this further supports our strategy for the self-supported catalyst design.