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To gain insight into the host functions of a nanocavity encircled by both polyaromatic panels and heteroatoms, nitrogen‐doped polyaromatic capsules were successfully synthesized from metal ions and pyridine‐embedded, bent anthracene‐based ligands. The new capsules display unique host–guest interactions in the isolated cavities, which are distinct from those of the undoped analogues. Besides the inclusion of Ag+ ions, the large absorption change of fullerene C60 and altered emission of a BODIPY dimer are observed upon encapsulation by the present hosts. Moreover, the N‐doped capsule exhibits specific binding ability toward progesterone and methyltestosterone, known as a natural female and synthetic male hormone, respectively, in water. [ABSTRACT FROM AUTHOR]

A gemini‐type amphiphilic molecule, constituted of two V‐shaped polyaromatic amphiphiles linked by a linear acetylene spacer, was synthesized. The gemini amphiphile assembles into a well‐defined aromatic micelle (ca. 2 nm in core diameter), providing higher stability in water even at low concentration (0.09 mm) and high temperature (>130 °C). Unlike common gemini amphiphiles with aliphatic chains, the present amphiphile and its micellar assembly emit green and orange fluorescence (ΦF=33 and 9 %), respectively. Despite strong and multiple π‐stacks of the polyaromatic panels of the amphiphiles, the water‐soluble gemini aromatic micelle incorporates medium‐size to large hydrophobic compounds into the frameworks. Interestingly, the guest binding capability toward large planar molecules was enhanced by more than two times through the pre‐encapsulation of spherical molecules in the cavity. [ABSTRACT FROM AUTHOR]

Host functions of polyaromatic nanocavities were revealed by using an M2L4 molecular cage and capsule. On the basis of the previously reported M2L4 capsule with a closed polyaromatic cavity, a new M2L4 cage (as a mixture of the isomers) was prepared by the quantitative assembly of two metal ions and four desymmetrized bispyridine ligands with a single polyaromatic panel. The obtained, open nanocavity of the cage exhibited enhanced binding abilities toward large dyes and pigments in water. For example, two molecules of coumarin dyes were bound in the nanocavity and showed strong whitish emission (up to ΦF=34 %). Furthermore, metallopigments, the sizes of which are larger than the inner cavities of the cage and capsule, were bound only in the open polyaromatic nanocavity of the cage to give water‐soluble 1:1 host–guest complexes. A new M2L4 polyaromatic cage was quantitatively formed from metal ions and desymmetrized bispyridine ligands with a single polyaromatic panel. The obtained, open nanocavity of the cage exhibited enhanced binding abilities toward large organic dyes in water. Furthermore, metallopigments, the sizes of which are larger than the inner cavities of the cage and an M2L4 polyaromatic capsule, were bound only in the open polyaromatic nanocavity of the cage to give water‐soluble 1:1 host–guest complexes. [ABSTRACT FROM AUTHOR]

Abstract: A polyaromatic tube with a subnanometer‐sized cavity was efficiently prepared on a gram‐scale through the stereo‐controlled cyclotrimerization of a diphenylanthracene derivative as a key step. The facile exterior alkylation of the polyaromatic framework leads to a moderately fluorescent tube (R=‐OC10H21; ΦF=20 %) in the solid state. The emission intensity of the solid‐state alkyl‐substituted tube is remarkably enhanced upon heating (up to 1.6 times, ΦF=31 %) as well as doping with fluorescent dyes (up to 4.2 times, ΦF=83 %) through efficient energy transfer. [ABSTRACT FROM AUTHOR]

A V-shaped bisanthracene derivative with three butyl groups formed two types of emissive solids that display bluish green and blue fluorescence (ΦF=72 and 32 %, respectively), depending on the preparation conditions. The crystal and powder X-ray analyses reveal that the highly emissive solid adopts a head-to-head arrangement with discrete stacks of the anthracene moieties, whereas the moderately emissive solid adopts a head-to-tail arrangement without the stacks. The obtained molecular arrangements are transformed by thermal stimuli accompanying the change in fluorescence. Furthermore, large enhancements of dye emissions (12-45-fold) through highly efficient host-guest energy transfer were achieved in the solid state by adding minute amounts of various fluorescent dyes (e.g. rubrene and Nile red) to the V-shaped compound. [ABSTRACT FROM AUTHOR]

Functionalization of the polyaromatic shell of a micelle-like molecular capsule was accomplished by simple functionalization of the amphiphilic subunits composed of a bent bis-anthracene framework and two trimethylammonium groups. In aqueous solutions, functionalized subunits assemble spontaneously and quantitatively into spherical capsules providing anthracene shells with external diameters of 2-3 nm through hydrophobic and aromatic-aromatic interactions. The shape and size of the functionalized capsules remain similar to the original, but the emissive intensities increase significantly (up to 5-fold) by attaching cyano or phenylethynyl groups. Furthermore, the shell-functionalization drastically enhances the host-guest photophysical properties (up to 8-fold) in the cavities of the capsules, as estimated by emission intensities from the encapsulated fluorescent dyes. [ABSTRACT FROM AUTHOR]

A fluorescent macrocycle containing four anthracene panels linked by meta-phenylene spacers and amino hinges was synthesized. The macrocycle adopts a twisted, compressed conformation that places embedded anthracene fluorophores in close contact. Emission from the convoluted macrocycle is highly solvatochromic and significantly enhanced as compared with that of the partial structures. [ABSTRACT FROM AUTHOR]

Aromatic micelles: Hydrophobic and aromatic–aromatic interactions promoted the spontaneous formation of micelle‐inspired molecular capsules with large aromatic shells from bent bisanthracene amphiphiles (see picture). The micellar capsules could accommodate fluorescent‐dye guests in water, and the resultant nanocomposites exhibited strong fluorescence through efficient energy transfer from the host shells to the encapsulated guests. [ABSTRACT FROM AUTHOR]

Combining meta-triphenylamine or triphenylphosphine with three anthracene fluorophores gives rise to fluorescent non-planar triskelions 1 and 2. The emissive properties of 1 are highly solvatochromic, yielding blue to pale green and even pale yellow fluorescence, whereas the blue emission of 2 is solvent-insensitive. Anthracene trimers 1 and 2 are both emissive in the solid state, displaying yellow and pale green fluorescence, respectively, with moderate quantum yields. [ABSTRACT FROM AUTHOR]

An isostructural series of M2L4 molecular capsules quantitatively self-assembled from two MII ions (M=Zn, Cu, Pt, Pd, Ni, Co, and Mn) and four bent ligands with embedded anthracene fluorophores. X-ray crystallographic analysis (for M=Zn, Cu, Ni, and Pd) confirmed the formation of closed-shell structures in which the large interior cavities inside the molecular capsules (about 1 nm) were shielded by eight anthracene panels. Analysis of the ZnII and CuII structures showed the inclusion of an unusual triad guest cluster; four MeCN molecules, one water molecule, and one CF3SO3− ion were located inside the cavities. Full characterization by NMR spectroscopy and MS (ESI-TOF) demonstrated that the molecular capsules were quite stable and persist in solution. The fluorescence properties of the isostructural capsules were strongly dependent on the identity of the metal species: the ZnII capsule emitted strong blue fluorescence with a high quantum yield ( Φ=0.8), in sharp contrast to the weakly emissive NiII and MnII capsules and the completely non-emissive PdII, PtII, and CoII capsules. On the other hand, the CuII capsule exhibited solvatochromism and solvent-dependent emission behavior; blue emission of the capsule was 'on' in DMSO but 'off' in MeCN. [ABSTRACT FROM AUTHOR]

M2L4molecular capsules self-assembled from M(ii) ions (where M = Zn, Ni, and Pd) and bent bidentate ligands constructed from anthracene fluorophores. The Ni(ii) and Zn(ii) capsules exhibited weak to strong blue emission unlike traditional Pd(ii) cages and capsules. [ABSTRACT FROM AUTHOR]