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Synthetic amphiphiles have been found to self-assemble into a variety of structures such as micelles, vesicles, cylinders and lamellae in aqueous media over many length scales. We report herein cation-induced aggregation of hexaaza-cyclophanes in water. Pd(2+)- or proton-induced formation of submicro spherical aggregates was observed by several spectroscopic and microscopic methods.

Metal-mediated secondary structures of peptide-based foldamers were constructed using artificial backbone-coordinative oxime peptides. Complexation of the peptides with Pd(II) afforded several mononuclear and dinuclear secondary structures such as helices and hairpins as confirmed by single-crystal XRD and NMR analyses., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Upon complexation with Pd(II) ions, precisely designed strandlike ligands with two tris(3,5-pyridine) units at both terminals were assembled, with the aid of a linear template molecule, into a discrete tubular complex with a length of 3.5 nm. The high stability and the well-defined structure of the coordination nanotube were revealed by NMR spectroscopy, cold-spray ionization MS, and single-crystal X-ray analysis. Guest lengths were discriminated by the tube: When the association of strandlike guest molecules, in which two biphenylene units are linked with an (OCH2CH2)n linker, were compared, the tube selectively recognized an appropriate guest whose length was comparable to that of the tube. Tetrathiafulvalene (TTF)-terminated linear guests were directly oxidized to TTF2+ in the tube, but reduced stepwise via TTF+ outside the tube.

Porous crystals with well‐defined active metal centers on the pore surface have high potential as heterogeneous metal catalysts. We have recently demonstrated that a porous molecular crystal, metal‐macrocycle framework (MMF), catalyzes olefin migration reactions by photoactivation of its PdIICl2 moieties exposed on the crystalline channel surface. Herein we report a mechanistic study of the photoinduced olefin migration reactions at the PdII active centers of MMF. Several experiments, including a deuterium scrambling study, revealed that olefin migration is catalyzed via an alkyl mechanism by in situ generated Pd−H species on the channel surface during photoirradiation. This proposed mechanism was further supported by DFT and ONIOM calculations. [ABSTRACT FROM AUTHOR]

Porous crystals are excellent materials with potential spatial functions through molecular encapsulation within the pores. Co-encapsulation of multiple different molecules further expands their usability and designability. Herein we report the simultaneous arrangement of up to three different guest molecules, TTF (tetrathiafulvalene), ferrocene, and fluorene, on the pore surfaces of a porous crystalline metal-macrocycle framework (MMF). The position and orientation of adsorbed molecules arranged in the pore were determined by single-crystal X-ray diffraction analysis. The anchoring effect of hydrogen bonds between the hydroxy groups of the guest molecules and inter-guest cooperation and competition are significant factors in the adsorption behaviors of the guest molecules. This finding would serve as a design basis of multicomponent functionalized nanospaces for elaborate reactions that are realized in enzymes. [ABSTRACT FROM AUTHOR]

Synthetic amphiphiles have been found to self-assemble into a variety of structures such as micelles, vesicles, cylinders and lamellae in aqueous media over many length scales. We report herein cation-induced aggregation of hexaaza-cyclophanes in water. Pd2+- or proton-induced formation of submicro spherical aggregates was observed by several spectroscopic and microscopic methods. [ABSTRACT FROM AUTHOR]

Stacked rings: A diamond ‐ shaped macrocycle with two inward phenanthroline ligands and outward long alkyl chains, and its PdII complex form organic and organometallic fibrous aggregates, respectively, as revealed by NMR, UV/Vis, AFM, and TEM measurements. The most likely structures are face ‐ to ‐ face stacked macrocycles, generating nanotubes. [ABSTRACT FROM AUTHOR]

Keywords: mechanism; metallacycles; olefin migration; palladium; photoactivation EN mechanism metallacycles olefin migration palladium photoactivation 174 174 1 02/03/21 20210201 NES 210201 B One-dimensional crystalline channels b with well-defined active metal centers hold great potential as heterogeneous catalysts. Experimental and theoretical studies revealed that the olefin migration was catalyzed via an alkyl mechanism by in situ generated Pd-H species on the channel ceiling through photoirradiation. Mechanism, metallacycles, olefin migration, palladium, photoactivation. [Extracted from the article]

Stackable metallomacrocycles can form supramolecular micrometer ‐ long metallo ‐ fibers or ‐ tubes, thus providing novel structural motifs for supramolecular architectures. In their Communication on page 1368   ff., Mitsuhiko Shionoya et   al. report the formation of organic and organometallic fibrous aggregates by the assembly of diamond ‐ shaped macrocyclic ligands and their palladium complexes, respectively, as revealed by AFM, TEM, NMR, and UV/Vis measurements. In the Cover picture, the stacked structure of bis(cyclopalladated) macrocycles is expressed as a “supramolecular dragon” taking a moonlight swim. [ABSTRACT FROM AUTHOR]

Molekülanordnungen M. Shionoya et al. beschreiben in ihrer Zuschrift auf S. 8450 ff. die genau kontrollierte Aufnahme von bis zu drei verschiedenen Gastmolekülen in einer einzigen Pore eines Metall ‐ Makrocyclus ‐ Gerüsts. [ABSTRACT FROM AUTHOR]