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To develop new hybrid micelles with alkyl/polyaromatic core–shell structures, we synthesized umbrella‐shaped amphiphiles bearing a bent anthracene dimer with a linear alkyl chain (i.e. octyl and hexadecyl groups). The amphiphiles quantitatively assemble into spherical micelles (~2–3 nm in core diameter), possessing an alkylated cavity surrounded by a polyaromatic framework, in water. The alkylation significantly enhances the stability of the micellar structures against dilution (up to 9 μM) and heat (up to >120 °C). The highly condensed hexadecyl core of the hybrid micelle, as indicated by solvatochromic guest probes, displays increased uptake ability toward large alkylated metallodyes. Interestingly, efficient uptake of aromatic macrocycles (i.e. [n]cycloparaphenylenes) by the present micelle provides pseudorotaxane‐shaped host–guest composites with high emissivity (ΦF=up to 35 %). Internal multi‐alkylation of an aromatic micelle can thus successfully enhance its assembly stability/guest uptake functions. [ABSTRACT FROM AUTHOR]

A ferrocene‐based capsule is spontaneously and quantitatively formed in water by the assembly of bent amphiphiles carrying two ferrocene units. The disassembly and assembly of the new organometallic capsule, with a well‐defined and highly condensed ferrocene core, are demonstrated by chemical redox stimuli in a fully reversible fashion under ambient conditions. In contrast to previously reported multiferrocene assemblies, only the present capsule efficiently encapsulates typical organic/inorganic dyes as well as electron‐accepting molecules in water. As a result, unusual host‐guest charge‐transfer (CT) interactions, displaying relatively wide absorption bands in the visible to near‐infrared region (λ=650–1350 nm), are observed upon the encapsulation of acceptors (i.e. chloranil and TCNQ). The resultant encapsulation‐induced CT interactions can be released by a redox stimulus through the disassembly of the capsule. [ABSTRACT FROM AUTHOR]

π‐Conjugated aromatic polymers (πCAPs) are central components of functional materials yet suffer from insolubility without multiple covalent substituents on their backbones. We herein disclose a new strategy for the facile processing of unsubstituted heterocyclic πCAPs (i.e. poly(para‐phenylene‐2,6‐benzobisoxazole) and poly(benzimidazobenzo‐phenanthroline)), independent of the polymer length, via non‐covalent encircling with aromatic micelles, composed of bent aromatic amphiphiles, in water. The UV/Visible studies reveal that the efficiencies of the present encircling method are ≈10 to 50‐fold higher than those using conventional amphiphiles under the same conditions. The AFM and SEM analyses of the resultant aqueous polymer composites show that otherwise insoluble πCAPs form fine bundles (e.g. ≈1 nm in thickness) in the tubular aromatic micelles, through efficient π‐stacking interactions. In the same way, pristine poly(para‐phenylene) can be dissolved in water, displaying enhanced fluorescence (10‐fold), relative to the polymer solid. Two types of unsubstituted πCAPs are likewise co‐encircled in water, indicated by UV/Visible analysis. Importantly, aqueous processing of the encircled πCAPs into free‐standing single‐ or multicomponent films with submicrometer thickness is demonstrated through a simple filtration‐annealing protocol. [ABSTRACT FROM AUTHOR]

Development of porous materials capable of capturing volatile organic compounds (VOCs), such as benzene and its derivatives, with high efficiency, selectivity, and reusability is highly demanded. Here we report unusual vapor adsorption behavior toward VOCs by a new porous solid, composed of a polyaromatic capsule bearing a spherical nanocavity with subnano‐sized windows. Without prior crystallization and high‐temperature vacuum drying, the porous polyaromatic solid exhibits the following five features: vapor adsorption of benzene over cyclohexane with 90 % selectivity, high affinity toward o‐xylene over benzene and toluene with >80 % selectivity, ortho‐selective adsorption ability (>50 %) from mixed xylene isomers, tight VOCs storage even under high temperature and vacuum conditions, and at least 5 times reusability for xylene adsorption. The observed adsorption abilities are accomplished at ambient temperature and pressure within 1 h, which has not been demonstrated by organic/inorganic porous materials reported previously. [ABSTRACT FROM AUTHOR]

π‐π Interactions are established as a powerful supramolecular tool, whereas the usability of CH‐π interactions has been rather limited so far. Here we present (i) selective binding of planar polyaromatics and (ii) effective isolation of planar metal complexes by a polyaromatic capsule, utilizing multiple CH‐π interactions. In the spheroidal cavity, one molecule of large and medium‐sized polyaromatic molecules (i. e. coronene and pyrene) is exclusively bound from mixtures bearing the same number of aromatic CH groups. Theoretical studies reveal that multiple host‐guest CH‐π interactions (up to 32 interactions) are the predominant driving force for the observed selectivity. In addition, one molecule of planar metal complexes (i. e. porphine and bis(acetylacetonato) Cu(II) complexes) is quantitatively bound by the capsule through aromatic and aliphatic CH‐π multi‐interactions, respectively. The ESR and theoretical studies demonstrate the isolation capability of the capsular framework and an unusual polar environment in the polyaromatic cavity. [ABSTRACT FROM AUTHOR]

To explore new cavity functions, we herein employed cis‐trans stereoisomers with a N=N, C=C, or C=N unit as guest indicators for a polyaromatic capsule. Thanks to the rigid, spherical cavity with a diameter of ∼1 nm, azobenzene and stilbene derivatives are quantitatively encapsulated by the capsule with 100 % cis‐selectivity in water. The isomerization of the cis‐azo compound is suppressed against heat and light in the cavity, due to the confinement effect. Furthermore, C,N‐diphenyl imine derivatives are quantitatively encapsulated by the capsule in water and adopt an otherwise unstable cis‐form. The polyaromatic cavity suppresses the hydrolysis of the imines in water, even at elevated temperature, due to the shielding effect. Accordingly, the properties of the cis‐trans isomers could be largely altered through supramolecular manipulation. [ABSTRACT FROM AUTHOR]

Catalyst‐ and reagent‐free reactions are powerful tools creating various functional molecules and materials. However, such chemical bonds are usually hydrolysable or require specific functional groups, which limits their use in aqueous media. Herein, we report the development of new amphiphiles through the Staudinger reaction. Simple mixing of chlorinated aryl azide with a hydrophilic moiety and various triarylphosphines (PAr3) gave rise to azaylide‐based amphiphiles NPAr3, rapidly and quantitatively. The obtained NPAr3 formed ca. 2 nm‐sized spherical aggregates (NPAr3)n in water. The hydrolysis of NPAr3 was significantly suppressed as compared with those of non‐chlorinated amphiphiles nNPAr3. Computational studies revealed that the stability is mainly governed by the decrease in LUMO around the phosphorus atom owing to the o‐substituted halogen groups. Furthermore, hydrophobic dyes such as Nile red and BODIPY were encapsulated by the spherical aggregates (NPAr3)n in water. [ABSTRACT FROM AUTHOR]

To develop a new type of synthetic saccharide clusters with changeable fluorescent colors, we herein designed a multisaccharide‐coated aromatic micelle. The new cluster forms in water through the quantitative assembly of bent polyaromatic amphiphiles bearing three mannose groups. The spherical assembly, with a 2 nm‐sized polyaromatic core and ca. 18 saccharide pendants, is stable even under high dilution conditions (up to 0.02 mM). The emission intensity and color of the saccharide cluster can be altered from moderate blue (ΦF=19 %) to strong red, orange, and green (ΦF up to 67 %) upon encapsulation of hydrophobic fluorescent dyes in water. Moreover, the present fluorescent clusters, both with and without the dyes, display selective interactions with mannose‐binding proteins in vitro. [ABSTRACT FROM AUTHOR]

An aromatic oligomer micelle, featuring both high stability and high uptake ability, was quantitatively formed in water from amphiphilic oligomers, composed of three bent polyaromatic amphiphiles connected alternately by two hydrophilic chains. The well‐defined micelle, with a diameter of ca. 2 nm, remains intact even under highly diluted conditions (ca. 3 μM) and at elevated temperature (>130 °C), due to the polyaromatic chelate effect. The thermodynamic studies reveal that large enthalpic gain (ΔH=−110 kJ mol−1) is the key for the micelle formation. The oligomer micelle selectively encapsulates unsubstituted oligothiophenes (≥4‐mer) to a high degree and the resultant, aqueous host‐guest complexes display unusual emission derived from the multiply stacked oligomers. Furthermore, facile uptake and release of unsubstituted polythiophenes can be achieved using the oligomer micelle. [ABSTRACT FROM AUTHOR]

A nanocapsule composed of multiple carbazole panels (ca. 12 panels) was quantitatively generated from bent carbazole‐based amphiphiles in water. Unlike previously reported macrocycles and coordination cages bearing several carbazole panels, the resultant nanocapsule displays enhanced emissivity and improved electrochemical stability as compared with the monomeric amphiphile. The spectroscopic properties of substituted coumarin and boron‐dipyrromethene dyes can be modulated upon encapsulation by the nanocapsule in water. In the cavity, a highly blue‐shifted absorption band is observed from largely twisted coumarin dyes and two absorption bands are found from boron‐dipyrromethene dimers stacked in an unusual L‐shaped fashion. Moreover, the encapsulated dimers exhibit unique excimer‐like emission. [ABSTRACT FROM AUTHOR]

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]

Selective recognition of natural fatty acids is intrinsically difficult owing to the long, flexible, and poorly interactive hydrocarbon chains. Inspired by biological recognition systems, we herein demonstrate the exclusive binding of a monounsaturated fatty acid by an artificial polyaromatic receptor from a mixture of the unsaturated and corresponding saturated substrates (i.e. oleic and stearic acids) in water. The selectivity stems from multiple CH–π/π–π interactions between the host framework and the guest in its roughly coiled conformation. Moreover, competitive binding experiments elucidate higher binding affinities of the receptor for oligo‐ and polyunsaturated fatty acids (e.g. α‐linolenic acid and EPA). Within the receptor, the biosubstrates are remarkably stabilized against air, light, and heat owing to the polyaromatic shielding effect. [ABSTRACT FROM AUTHOR]

Synthesis of molecular containers capable of incorporating multiple fullerenes remains challenging. Reported here is that room‐temperature mixing of metal ions with W‐shaped bispyridine ligands featuring polyaromatic panels results in the quantitative formation of a peanut‐shaped M2L4 capsule. The capsule reversibly converts into two molecules of an ML2 double tube in response to changes in the solvent. Notably, the capsule allows the incorporation of two fullerene molecules into the connected two spherical cavities at room temperature. The close proximity yet non‐contact of the encapsulated C60 molecules, with a separation of 6.4 Å, was revealed by X‐ray crystallographic analysis. The resultant, unusual fullerene dimer undergoes sequential reduction within the capsule to generate (C60.−)2, C60.−⋅C602−, and (C602−)2 species. Furthermore, temperature‐controlled stepwise incorporation of two C60 molecules into the capsule is demonstrated. [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]

Unlike previously well‐studied, acyclic pentacene oligomers, the first synthesis of a cyclic pentacene trimer with a fixed tubular conformation is reported. A short‐step synthesis starting from common pentacenequinone yielded the target molecule with a 1.5 nanometer length and a subnanometer pore. Steady‐state spectroscopic analyses revealed that the close proximity of the non‐conjugated, three pentacene chromophores allows the nanotube to display stepwise electrochemical/chemical oxidation characteristics. Furthermore, time‐resolved transient absorption measurements elucidated the generation of an excited triplet state of the nanotube, with high quantum yield reaching about 180 % through intramolecular singlet fission and a very long triplet lifetime. A pentacene‐based nanotube was synthesized for the first time. The close proximity of the three non‐conjugated pentacene chromophores allows the nanotube to display stepwise electrochemical/chemical oxidation characteristics. Time‐resolved transient absorption measurements show the generation of an excited triplet state, with a high quantum yield (ca. 180 %) and very long triplet lifetime, through intramolecular singlet fission. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are excellent building blocks for the creation of two‐dimensional (2D) nanosheets. However, large PAHs tend to exhibit poor or no solubility in organic solvents and water. To overcome this issue, we employed water‐soluble micellar capsules consisting of V‐shaped amphiphilic molecules. Characteristic electrochemical behavior was observed in 0.1 m H2SO4 in the presence of the water‐soluble capsules containing PAHs, such as ovalene, circobiphenyl, and dicoronylene. Furthermore, under these conditions, PAHs were released from the capsules, resulting in the formation of a 2D adlayer of PAHs at the electrochemical interface. Finally, using electrochemical scanning tunneling microscopy, we demonstrate that our molecular containers based on water‐soluble molecular capsules allow the facile preparation of 2D PAH adlayers in addition to structurally controlling nanostructure formation on Au surfaces. Packaged and delivered: Water‐soluble molecular capsules consisting of V‐shaped amphiphiles were designed for the uptake of polycyclic aromatic hydrocarbons (PAHs). The PAHs were released from the molecular containers in 0.1 m H2SO4 at an electrochemical interface, thus enabling the facile preparation of 2D PAH adlayers on an Au surface with controlled nanostructure formation (see picture). [ABSTRACT FROM AUTHOR]

Abstract: Biologically relevant hydrophilic molecules rarely interact with hydrophobic compounds and surfaces in water owing to effective hydration. Nevertheless, herein we report that the hydrophobic cavity of a polyaromatic capsule, formed through coordination‐driven self‐assembly, can encapsulate hydrophilic oligo(lactic acid)s in water with relatively high binding constants (up to Ka=3×105  m−1). X‐ray crystallographic and ITC analyses revealed that the unusual host–guest behavior is caused by enthalpic stabilization through multiple CH–π and hydrogen‐bonding interactions. The polyaromatic cavity stabilizes hydrolyzable cyclic di(lactic acid) and captures tetra(lactic acid) preferentially from a mixture of oligo(lactic acid)s even in water. [ABSTRACT FROM AUTHOR]

Abstract: The effect of molecular interactions between the components on the self‐assembly process of Pd2L4 structures was investigated by a 1H NMR‐based quantitative approach (QASAP: quantitative analysis of self‐assembly process). Although the self‐assembly of the Pd2L4 cage without interactions between the bent ligands took place, mainly producing small intermediates, the self‐assembly of the Pd2L4 capsule composed of bent ligands with anthracene panels tends to produce large intermediates containing more components than the capsule. This is ascribed to steric interactions between the panels. [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]

Micelles are a versatile class of molecular assemblies typically composed of aliphatic molecules with hydrophilic groups. Polyaromatic molecules with hydrophilic groups, on the other hand, usually do not assemble into micellar structures in water but rather form columnar, π-stacked architectures. This Minireview article focuses on the recent development of aqueous micellar nanostructures with multiple oligoarylene rods or polyaromatic panels. The new micelles with spherical polyaromatic shells, which we name 'aromatic micelles', serve as functional molecular flasks with superior binding abilities for medium to very large molecules in water. [ABSTRACT FROM AUTHOR]

Bulk molybdenum disulfide (MoS2) itself is virtually insoluble in common organic solvents because of the tight stacks of multiple MoS2 nanosheets. Here we report that V-shaped polyaromatic compounds with non-ionic side chains can efficiently exfoliate and disperse the inorganic nanosheets. Simple grinding and sonication (less than total 1 h) of MoS2 powder with the V-shaped compounds gave rise to large MoS2 nanosheets highly dispersed in NMP through efficient host-guest S-π interactions. DLS and AFM analyses revealed that the lateral sizes (ca. 150-270 nm) and thicknesses (ca. 2-8 nm) of the products depend on the identity of the non-ionic side chains on the V-shaped dispersant. [ABSTRACT FROM AUTHOR]

In spite of wide-ranging previous studies on synthetic macrocycles, the installation of open-close functions into the frameworks remains a challenge. We present a new polyaromatic macrocycle capable of switching between open and closed forms in response to external stimuli, namely, base and acid. The macrocycle, which is prepared in three steps, has a well-defined hydrophobic cavity with a length of around 1 nm, surrounded by four pH-responsive acridinium panels. The open and closed structures were confirmed by single-crystal X-ray analysis. The cylindrical cavity can bind long hydrophilic molecules up to 2.7 nm in length in neutral water and then release the bound guests through a reversible open-to-closed structural change upon simple addition of base. [ABSTRACT FROM AUTHOR]

A pentanuclear coordination complex assembled from any palladium(II) component and non-chelating ligands is hitherto unreported. The pentanuclear complex [Pd5( L1)5( L2)5](BF4)10, 1 reported here was prepared by the spontaneous complexation of [Pd(DMSO)4](BF4)2 with the non-chelating bidentate ligands 1,4-phenylenebis(methylene) diisonicotinate, L1 and 4,4′-bipyridine, L2 in a one-pot method at room temperature. The planar polycyclic complex 1 with outer diameters of ≈3 nm is termed as a 'molecular star' owing to its resemblance with a pentagram shape. Interim paths leading to the star were also probed to decipher related dynamics of the system. [ABSTRACT FROM AUTHOR]

By the covalent linkage of two bent bisanthracene amphiphiles with a biphenyl spacer bearing hydrophilic pendants, we synthesized a new molecular clip with a C-shaped conformation. The molecular clip provides an acyclic, open cavity surrounded by four anthracene panels in water. In contrast to previous clip- and tweezers-like compounds as well as cage-shaped compounds, the C-shaped polyaromatic cavity displays unusual wide-ranging capturing abilities toward not only planar perylene-based pigments and cylindrical single-walled carbon nanotubes but also highly branched macromolecules (carbazole dendrimers). [ABSTRACT FROM AUTHOR]

For the development of novel nanospace with unique electrostatic character, we prepared new capsular and tubular nanostructures by the quantitative assembly of metal ions and bent bisacridinium ligands. The capsule and tube have closed spherical and open cylindrical cavities, respectively, with diameters of around 1 nm surrounded by cationic polyaromatic panels. Thanks to the facile synthetic protocol (three steps), another polycationic capsule with an elliptical nanocavity was also prepared by using an elongated ligand. In spite of the absence of pendant hydrophilic groups, the spherical polyaromatic capsule shows sufficient water solubility due to the polycationic shell. Moreover, the highly cationic cavity (12+) can selectively encapsulate anionic organic compounds in water. [ABSTRACT FROM AUTHOR]

Preparation of molecular nanostructures with polyradical frameworks remains a significant challenge because of the limited synthetic accessibility which is entirely different from that of neutral and ionic ones. Herein we report the quantitative formation of a new M2L4 molecular capsule from metal ions and dihydrophenazine-based ligands. The capsule has a spherical nanocavity (ca. 1 nm in diameter) enclosed by eight redox-active, dihydrophenazine panels. Electrochemical oxidation of the capsule leads to the generation of multiple radical cations on the shell framework. Moreover, a stable tetra(radical cation) capsule can be reversibly obtained by chemical as well as electrochemical oxidation. [ABSTRACT FROM AUTHOR]

The methyl group is a small substituent, usually showing relatively weak or no interactions with other functional groups and metal ions. Herein, we present the recognition of the number of methyl groups on synthetic and natural aromatic compounds (i.e., benzene and xanthine derivatives, respectively) by the 1 nm-sized polyaromatic cavity of a coordination capsule in water. Detailed competitive encapsulation experiments as well as X-ray crystallographic analysis revealed that multiple guest-host CH3-polyaromatic interactions in the confined nanospace are key driving forces for the high selectivity. [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]

PtII- and PdII-linked M2L4 coordination capsules, providing a confined cavity encircled by polyaromatic frameworks, exhibit anticancer activities superior to cisplatin against two types of leukemic cells (HL-60 and SKW-3) and pronounced toxicity against cisplatin-resistant cells (HL-60/CDDP). Notably, the cytotoxic selectivities of the PtII and PdII capsules toward cancerous cells are up to 5.3-fold higher than that of cisplatin, as estimated through the non-malignant/malignant-cells toxicity ratio employing normal kidney cells (HEK-293). In addition, the anticancer activity of the coordination capsules can be easily altered upon encapsulation of organic guest molecules. [ABSTRACT FROM AUTHOR]

Metallophthalocyanines (MPcs) are very useful pigments but scarcely soluble without appropriate functional groups in common solvents. Herein, we report that bent polyaromatic amphiphiles act as excellent solubilizing reagents for nonfunctionalized MPcs and larger MPc derivatives (e.g., CuPc, perhalogenated CuPcs, Cu-naphthalocyanine, CuPc polymers, and double-decker MPcs) in neutral water upon encapsulation. The resultant MPc nanocomposites display high stability towards heat and pH change. More importantly, the encapsulated MPcs can be released by simple protocols under mild conditions both into a bulk solvent and onto glass or polymer plates. [ABSTRACT FROM AUTHOR]

Nanocarbons are synthetic carbon-rich compounds with polyaromatic frameworks that have lately attracted attention as emerging functional materials. However, their extreme hydrophobicity and aggregation peculiarity, besides their shape and size diversities, precluded their study in solution, especially in 'green' water. More convenient and general solubilizing methods of nanocarbon frameworks are required by using non-covalent supramolecular interactions. Here we report a protocol for solubilizing a wide range of nanocarbons, that is, fullerenes (C60, C70, C84, and C120), polyarenes (tetracene, pentacene, perylene, coronene, and hexabenzocoronene), and carbon nanotubes (single-walled and multi-walled CNTs), in water through manual grinding with V-shaped polyaromatic amphiphiles. The obtained aqueous nanocomposites are composed of nanocarbons encircled by the polyaromatic frameworks of the amphiphiles through multiple aromatic-aromatic interactions. Notably, the encapsulated photosensitive nanocarbons, such as tetracene, pentacene, and fullerene dimer, exhibit unusual stability toward UV/Vis light. [ABSTRACT FROM AUTHOR]

Anisotropic expansion of a spherical M2L4 coordination capsule through the elongation of the ligand led to a new M2L'4 capsule. The expanded capsule provides an elliptical cavity encircled by polyaromatic frameworks with large openings and thereby can encapsulate elliptical fullerene C70 and monofunctionalized fullerene C60 in high yields. In addition, selective formation of a new M2L2L'2 capsule occurs by mixing the original M2L4 and expanded M2L'4 capsules in a 1:1 ratio upon addition of C60 or monofunctionalized C60 as a template molecule. [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]

An M2L4 coordination capsule or an M2L2 coordination tube was selectively formed by the combination of HgII hinges and bent bispyridine ligands. The two structures reversibly interconvert at room temperature in response to modulation of the metal-to-ligand ratio and exhibit different host-guest interaction behavior. The capsule alone encapsulates large spherical molecules, fullerenes C60 and C70, and the bound guests are released upon capsule-to-tube transformation by the simple addition of metal ions. [ABSTRACT FROM AUTHOR]

Atroposelective formation: Selective formation of a molecular capsule was demonstrated from an amphiphilic cis‐atropisomer bearing three anthracene rings and four sulfonate groups through hydrophobic and aromatic–aromatic interactions. The dimeric capsule binds small guest molecules; the resultant host–guest complexes exhibit ground‐state charge‐transfer interactions accompanied by changes in host emission. [ABSTRACT FROM AUTHOR]

This article reports that an M2L4 molecular capsule is capable of encapsulating various neutral molecules in quantitative yields. The capsule was obtained as a single product by mixing a small number of components; two PdII ions and four bent bispyridine ligands containing two anthracene panels. Detailed studies of the host capability of the PdII-linked capsule revealed that spherical (e.g., paracyclophane, adamantanes, and fullerene C60), planar (e.g., pyrenes and triphenylene), and bowl-shaped molecules (e.g., corannulene) were encapsulated in the large spherical cavity, giving rise to 1:1 and 1:2 host-guest complexes, respectively. The volume of the encapsulated guest molecules ranged from 190 to 490 Å3. Within the capsule, the planar guests adopt a stacked-dimer structure and the bowl-shaped guests formed an unprecedented concave-to-concave capsular structure, which are fully shielded by the anthracene shell. Competitive binding experiments of the capsule with a set of the planar guests established a preferential binding series for pyrenes≈phenanthrene>triphenylene. Furthermore, the capsule showed the selective formation of an unusual ternary complex in the case of triphenylene and corannulene. [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]

Micelles are one of the oldest classes of supramolecules and typically composed of amphiphilic molecules with aliphatic subunits. This article focuses on the recent development of micellar nanostructures formed from amphiphile compounds with polyaromatic or oligoarylene frameworks. The new aromatic micelles providing polyaromatic shells display superior binding capabilities toward medium to large molecules (for example, Nile red, pentacene, fullerenes, metallo ‐ phthalocyanines, and carbon nanotubes) in water. For more details, see the Minireview by M. Yoshizawa et al. on page 16710 ff. [ABSTRACT FROM AUTHOR]

A pentanuclear palladium(II) complex has been prepared by incorporating non ‐ chelating ligands in a supramolecular framework by using a self ‐ assembly method. The unprecedented title complex is heteroleptic, planar, and polycyclic and resembles the shape of a pentagram. Interim paths leading to the star were probed to decipher related dynamics of the system. The molecular shape resembles a starfish as shown in the cover artwork. More information can be found in the Communication by D. K. Chand et al. on page 12456. [ABSTRACT FROM AUTHOR]