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Chiral hybrid metal halides with high photoluminescence quantum yield (PLQY) and superior dissymmetry factor (glum) are promising candidates for circularly polarized luminescence (CPL) emitting sources. However, it is a great challenge to achieve both high glum and large PLQY. Here, we report a new supramolecular strategy to fabricate chiral hybrid Cu(I)-halides with near-unity quantum yields and intense CPL emissions. The dissymmetry factor can be dramatically modulated by tuning the host-guest complexations. Attributing to the chirality and variable conformations of the host-guest complexes, a series of chiral [G@LR/S]2Cu4I6 have been prepared. The incorporation of different cations within the chiral LR/S hosts leads to variations of packing modes along the c-axis and different extent of distortions in the [Cu4I6]2−polyhedra. Among them, [H3O@LR/S]+ cations are stacked based on Van der Waals interactions and hierarchically self-assemble into a right/left-handed helix in [H3O@LR/S]2Cu4I6, which results in a high glum of −7×10−3 and a large PLQY of 96.92%. Notably, [G@LR/S]2Cu4I6 shows promising applications in single-component white light emitting diodes (WLEDs), exhibiting a maximum dissymmetry factor of −1.2×10−3. The effective host-guest complexation and oriented hierarchical self-assembly provide an effective strategy for the development of high-performance CPL materials. [ABSTRACT FROM AUTHOR]

Developing efficient adsorbents to capture radioactive iodine produced from nuclear wastes is highly desired. Here we report the facial synthesis of a hexacationic imidazolium organic cage and its iodine adsorption properties. Crucial role of counteranions has been disclosed for iodine capture with this cage, where distinct iodine capture behaviors were observed when different counteranions were used. Mechanistic investigations, especially with the X-ray crystallographic analysis of the iodine-loaded sample, allowed the direct visualization of the iodine binding modes at the molecular level. A network of multiple non-covalent interactions including hydrogen bonds, halogen bonds, anion···π interactions, electrostatic interaction between polyiodides and the hexacationic skeleton of the cage are found responsible for the observed high iodine capture performance. Our results may provide an alternative strategy to design efficient iodine adsorbents. The development of efficient adsorbents to capture iodine originating from radioactive wastes is of importance. Here, the authors synthesize hexacationic imidazolium organic cages and study the crucial role of the counter anions for iodine capture and the iodine binding modes at the molecular level on the solid state. [ABSTRACT FROM AUTHOR]

By introduction of a new Fe(L1)2 spin-crossover (SCO) unit into the polynuclear system, a nano-scale Fe4(L2)4 molecular square architecture is designed through coordination-directed self-assembly strategy. Both the mononuclear Fe(L1)2 and tetranuclear Fe4(L2)4 complexes have been structurally confirmed by 1H nuclear magnetic resonance (NMR), electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and temperature-dependent single crystal X-ray diffraction studies. Variable-temperature magnetic susceptibility measurements reveal the presence of an abrupt SCO behavior with a thermal hysteresis width of 4 K for Fe(L1)2. By clear contrast, Fe4(L2)4 undergoes a gradual spin transition behavior with enlarged thermal hysteresis width and higher spin transition temperature. [ABSTRACT FROM AUTHOR]

By introduction of a new Fe(L1)2 spin-crossover (SCO) unit into the polynuclear system, a nano-scale Fe4(L2)4 molecular square architecture is designed through coordination-directed self-assembly strategy. Both the mononuclear Fe(L1)2 and tetranuclear Fe4(L2)4 complexes have been structurally confirmed by 1H nuclear magnetic resonance (NMR), electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and temperature-dependent single crystal X-ray diffraction studies. Variable-temperature magnetic susceptibility measurements reveal the presence of an abrupt SCO behavior with a thermal hysteresis width of 4 K for Fe(L1)2. By clear contrast, Fe4(L2)4 undergoes a gradual spin transition behavior with enlarged thermal hysteresis width and higher spin transition temperature. [ABSTRACT FROM AUTHOR]

A self-assembled Pd4L2 cage is employed as a water-soluble molecular flask for the synthesis of functionalized coumarins from a series of salicylaldehyde derivatives and cyanoacetates/malononitrile. The catalytic reaction features mild aqueous conditions and broad substrate scope. Crystal structures of the host-guest complexes for two substrates and one analogous intermediate have been obtained, shedding light on the supramolecular reaction mechanism. Michaelis-Menten kinetic studies were performed in one typical case, revealing that the rate of product formation has been enhanced by over 23-fold in contrast to the background reaction without cage. Moreover, the same reaction catalyzed by a smaller Pd6L4 cage gives a mixture of products and much lower yields, suggesting that fine-tuning on the size and symmetry of the cages' cavity is crucial for their applications in supramolecular catalysis. [ABSTRACT FROM AUTHOR]

Platonic and Archimedean polyhedra, well-known to mathematicians, have been recently constructed by chemists at a molecular scale by defining the vertices and the edges with metal ions (M) and organic ligands (L), respectively. Here, we report the first synthesis of a concave-surface 'stellated polyhedron', constructed by extending the faces of its precursor polyhedron until they intersect, forming additional nodes. Our approach involves the formation of an M12L24 cuboctahedron core, the linkers of which each bear a pendant ligand site that is subsequently able to bind an additional metal centre to form the stellated M18L24 cuboctahedron. During this post-stellation process, the square faces of the M12L24 core are closed by coordination of the pendant moieties to the additional metal centres, but they are re-opened on removing these metals ions from the vertices. This behaviour is reminiscent of the analogous metal-triggered gate opening-closing switches found in spherical virus capsids. [ABSTRACT FROM AUTHOR]

Container-molecules are attractive to chemists due to their unique structural characteristics comparable to enzymes and receptors in nature. We report here a family of artificial self-assembled macrocyclic containers that feature induced-fit transformations in response to different anionic guests. Five metal-organic macrocycles with empirical formula of MnL2n (M=Metal; L=Ligand; n=3, 4, 5, 6, 7) are selectively obtained starting from one simple benzimidazole-based ligand and square-planar palladium(II) ions, either by direct anion-adaptive self-assembly or induced-fit transformations. Hydrogen-bonding interactions between the inner surface of the macrocycles and the anionic guests dictate the shape and size of the product. A comprehensive induced-fit transformation map across all the MnL2n species is drawn, with a representative reconstitution process from Pd7L14 to Pd3L6 traced in detail, revealing a gradual ring-shrinking mechanism. We envisage that these macrocyclic molecules with adjustable well-defined hydrogen-bonding pockets will find wide applications in molecular sensing or catalysis. [ABSTRACT FROM AUTHOR]