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In this paper, we report a new synthetic procedure to immobilize a transfer hydrogenation catalyst on the surface of colloidal polystyrene particles. Using supports of colloidal dimensions allows for combining a relatively high surface area for catalyst binding, mobility of the catalyst, and facile recovery by centrifugation or sedimentation. The immobilization procedure relies on the covalent attachment of terpyridine moieties on the particle surface. These immobilized terpyridines are subsequently employed as colloidal ligands, which participate in the formation of an active ruthenium-based transfer hydrogenation catalyst. The resulting functional colloidal particles successfully catalyze the transfer hydrogenation of acetophenone with 2-propanol as the hydrogen donor. Thorough analysis of the chemical composition of the colloidal surface led to the determination of the catalyst loading per particle. This enabled us to conduct reference hydrogenations with equal concentrations of the homogeneous transfer hydrogenation catalyst to probe the effect of the immobilization procedure on the catalytic activity. Despite a decrease in transfer hydrogenation activity, full acetophenone conversion is still achievable within 24 h. Preliminary experiments show that the catalytic colloids are recyclable without significant loss of transfer hydrogenation activity. [ABSTRACT FROM AUTHOR]

Anisotropic and binary colloids self-assemble into a variety of novel supracolloidal structures within the thermo-switchable confinement of molecular microtubes, achieving structuring at multiple length scales and dimensionalities. The multistage self-assembly strategy involving hard colloidal particles and a soft supramolecular template is generic for colloids with different geometries and materials as well as their binary mixtures. The colloidal architectures can be controlled by colloid shape, size, and concentration. Colloidal cubes align in chains with face-to-face arrangement, whereas rod-like colloids predominantly self-organize in end-to-end configurations with their long axis parallel with the long axis of the microtubes. The 1D microconfinement imposed on binary mixtures of anisotropic and isotropic colloids further increases the diversity of colloid-in-tube structures. In cube-sphere mixtures, cubes may act as additional confiners, locking in colloidal sphere chains, while a 'colloidal Morse code' is generated where rods and spheres alternate in the case of rod-sphere mixtures. The versatile confined colloidal superstructures including their thermoresponsive assembly and disassembly are relevant for the development of stimulus-responsive materials where controlled release and encapsulation are desired. [ABSTRACT FROM AUTHOR]

The crystalline structure assembled out of charge-stabilized asymmetric dumbbell-like colloidal particles in ethyl alcohol by sedimentation has been probed using small-angle X-ray scattering with microradian resolution. The existence of plastic face-centered cubic crystals was inferred from the observed Bragg peaks. The presence of stacking faults and the mosaic structure of the sample lead to the appearance of diffuse scattering, forming Bragg scattering cylinders in the three-dimensional reciprocal space. The quality of the crystalline structure, as ascertained from a detailed analysis of the diffuse scattering intensity distribution, indicates the presence of only 1.5% of stacking faults between the hexagonal close-packed layers. [ABSTRACT FROM AUTHOR]

Manipulation of the self-assembly of magnetic colloidal particles by an externally applied magnetic field paves a way toward developing novel stimuli responsive photonic structures. Using microradian X-ray scattering technique we have investigated the different crystal structures exhibited by self-assembly of core-shell magnetite/silica nanoparticles. An external magnetic field was employed to tune the colloidal crystallization. We find that the equilibrium structure in absence of the field is random hexagonal close-packed (RHCP) one. External field drives the self-assembly toward a body-centered tetragonal (BCT) structure. Our findings are in good agreement with simulation results on the assembly of these particles. [ABSTRACT FROM AUTHOR]

The co‐assembly of spherical colloids and surfactant–cyclodextrin microtubes yields a library of dynamic colloid‐in‐tube structures, including helices. In situ observations of these structures, including their thermo‐reversible assembly and disassembly, demonstrate the potential of the interplay between molecular and colloidal self‐assembly, thereby providing a novel route to temperature‐sensitive particle alignment and release. [ABSTRACT FROM AUTHOR]

Hierarchical, bottom‐up, self‐organization processes of nano‐ and microscale building blocks constitute an important design route for stimulus‐responsive materials. On page 313, Andrei V. Petukhov and co‐workers demonstrate that a rich variety of novel supracolloidal structures emerge from the self‐organization of various shape‐anisotropic colloids and binary mixtures of isotropic and anisotropic colloids in 1D microconfinement. [ABSTRACT FROM AUTHOR]

Hierarchical self‐assembly is often exploited by nature to build complex functional entities. A similar approach yielded a library of dynamic colloid‐in‐tube structures, such as colloidal zigzags, double‐ and triple‐helices, by utilizing the thermo‐reversible co‐assembly of colloidal spheres and molecular microtubes, as reported by J. Huang, A. V. Petukhov, et al. in their Communication on page 3364 ff. The assembly and disassembly of these structures near human body temperature was explored in situ and in real time. [ABSTRACT FROM AUTHOR]

Hierarchische Selbstorganisation führt oft in der Natur zum Aufbau komplexer funktioneller Einheiten. Ein ähnlicher Ansatz, der die thermoreversible Coassemblierung sphärischer Kolloidpartikel und molekularer Mikroröhren nutzt, ergab dynamische Kolloid ‐ in ‐ Röhre ‐ Strukturen, wie kolloidale Zickzack ‐ Ketten, Doppel ‐ und Tripelhelices. Der Auf ‐ und Abbau dieser Strukturen nahe Körpertemperatur wurde in situ und in Echtzeit untersucht, wie J. Huang, A. V. Petukhov et al. in der Zuschrift auf S. 3448 ff. berichten. [ABSTRACT FROM AUTHOR]