A growing attachment: Porous coordination polymer (PCP) nanorods are synthesized by modulation of the coordination equilibria between framework components, which regulates the rate of framework extension and crystal growth. Investigation of the crystal growth mechanism by TEM indicates that face-selective modulation on the surfaces of PCP crystals enhances the anisotropic crystal growth of nanorods by an oriented attachment mechanism.

A new sugar-based gelator 1 was synthesized, and its gelation ability was evaluated in organic solvents and water. Very surprisingly, 1 was found to gelate organic solvents as well as water, indicating that 1 can act as an amphiphilic gelator. We characterized on superstructures of an aqueous gel from 1 using SEM, TEM, NMR, IR, and XRD. The aqueous gel 1 formed a three-dimensional network with 20-500 nm diameter puckered fibrils. In addition, the chiral aggregate was found to be largely twisted helical ribbons with ca. 85 nm width, ca. 315 nm pitch, and up to several micrometer length, whose helicity was exclusively left-handed. XRD diagrams indicate that an aqueous gel 1 maintains a bilayered structure with 2.90 nm long-range spacing. This gives the first example of the formation of well ordered bilayer-based aqueous gel. The XRD, FT-NMR, and FT-IR results suggested that the aqueous gel 1 is stabilized by a combination of the hydrogen bonding, π-π interactions, and hydrophobic forces.

In various cultures, the Lotus plant has been considered to be a symbol of purity for a very long time because the leaves have a natural cleaning mechanism. Instead of wetting the surface, water droplets roll off the leaves' surfaces taking with them dirt and contamination.[1] This so-called Lotus effect is based on the superhydrophobic nature of the surface, realized by the fractal morphology of the two-tier roughness on both micro-and nanometer length scales. In order to artificially mimic water-repellent surfaces, it is necessary to prepare a surface composed of hydrophobic molecular or polymeric building blocks that exhibits a low surface energy and a rough fractal interfacial morphology. [2][3][4][5][6] However, when applying these principles to manufacturing of self-cleaning surfaces, the resulting biomimetic structures additionally have to be durable and stable, which is generally a difficult issue for self-organized supramolecular systems based on weak intermolecular forces. [7][8][9][10] Previously, superhydrophobic surfaces have been prepared using several techniques, such as sol-gel processing, [11,12] fabrication of structures from carbon nanotubes [13,14] and fluorinated polymers, [15] chemical vapor deposition, [16] and so forth. [17,18] To our knowledge fullerenes have not been employed as molecular components for superhydrophobic surfaces so far, even though they are at present one of the most fascinating carbon nanomaterials, [19] and are inexpensive compared to carbon nanotubes. To date, superhydrophobic materials have not been prepared by molecular self-organization in a convincing way. Here, we show for the first time that molecular self-organization of a fullerene derivative leads to macroscopic globular objects with a two-tier roughness on the micro-and nanoscopic length scale. Surfaces resulting from simple casting of these objects are superhydrophobic and surprisingly durable. The fullerene used in the present study is based on C 60 functionalized with three eicosyloxy aliphatic chains (1). Both parts of the molecule are hydrophobic and exhibit low free surface energies, which is one key requirement for the construction of superhydrophobic materials, with high surface roughness being the other criterion. Notably, the strength of the interactions between C 60 moieties and aliphatic chains depends on the environment and, therefore, allows us to control the self-assembly and aggregation behavior through the choice of the solvent. This gives us two independent parameters to manipulate the self-assembly of this class of fullerenes: [20][21][22][23][24][25] i) the design of the derivative, e.g., the number and length of aliphatic chains; and ii) the experimental conditions for self-assembly. Recently, we reported on the hierarchical self-assembly of a fullerene derivative bearing three hexadecyloxy groups furnishing various polymorphs depending on the experimental conditions such as solvent and temperature.[20]The fullerene derivative 1 (Fig. 1a) was prepared by refluxing the corresponding benza...

A novel strategy for constructing a vertical arrangement of bicontinuous donor-acceptor arrays on a semiconducting electrode has been developed. The relationship between the film structure and the photoelectrochemical properties has been elucidated as a function of the number of donor layers for the first time. The maximum incident photon-to-current efficiency value (21%) is comparable to the highest value (20%) reported for vertical arrangements of bicontinuous donor-acceptor arrays on electrodes.

Well-designed metal-organic hybrid porous materials-socalled porous coordination polymers (PCPs) or metalorganic frameworks (MOFs)-can be made from an assembly of organic linkers with metal ions. [1][2][3][4][5][6] This class of materials was recently recognized as an intriguing class of crystalline nanoporous materials for gas sorption, separation, and catalysis because their framework topologies and pore sizes can be designed for selective guest accommodation, and the functionality of the pore surfaces directly influences the interaction with guest molecules. Miniaturizing the size of PCP crystals to the nanometer scale [7][8][9][10] by functionalizing the crystal interfaces will provide further opportunities to integrate novel functions into the materials without changing the characteristic features of the PCP crystal itself, and will allow the correlation between the porous properties and interfacial structures of nanocrystals to be investigated. Despite the advantages of nanosized PCPs, growth processes that are most important in establishing a universal methodology for the creation of nanosized PCPs are still unclear because there is no suitable defining protocol. [7,[10][11][12][13] Understanding the crystal growth of framework materials, moreover, promises to determine the fundamental requirements of bottom-up selfassembly processes. Herein, we show that a simple but straightforward method using capping reagents that perturb the framework extension of PCPs can be applied to determine their crystal features. We describe the tetragonal framework system of PCP nanorods defined by selectively modulating the coordination interaction in the framework, which enhances the one-dimensional anisotropic fusion of the cubic nanocrystals, indicating an oriented attachment mechanism. [14,15] Moreover, the correlation between the sorption properties and crystallinity of the nanorods shows that the coordination modulation method can produce highly crystalline nanorods with high porosity comparable to that of bulk crystals synthesized by using the conventional solvothermal method.The relatively weak interactions of the coordination bonds dominate the hierarchical self-assembly process involved in constructing the sparse three-dimensional porous frameworks of PCPs with nanometer lattice constants, leading to the formation of crystals. This feature distinguishes this class of molecular-based materials from dense inorganic materials, such as metal [16] and semiconductor crystals, [17] and from conventional porous materials such as zeolites [18,19] and mesoporous silica. [20,21] Controlling the interactions between metal ions and organic linkers, so-called "coordination equilibria", is important when varying the crystal features of PCPs, such as their size, morphology, and crystallinity. Although several approaches have been developed to fabricate PCP nanoparticles, such as reversed micelles [22] and microwave-assisted methods, [23,24] the crystal-growth mechanism has rarely been discussed because it is difficult to control th...

Nucleotide-appended bolaamphiphiles 1−7, in which two 3‘-phosphorylated thymidine moieties are connected to both ends of a long oligomethylene spacer, have been first synthesized. Their self-assembling behavior in aqueous solutions was investigated in terms of gelling ability of water molecules. The longer homologues 6 and 7 with the C18 and C20 oligomethylene spacers, respectively, proved to be capable of gelling water very effectively (>25 000 water molecules per molecule) through spontaneous formation of a fibrous network. Gelation behavior of both bolaamphiphiles strongly depended on the pH and temperature of the aqueous solutions used. The gel-to-sol transition temperature (TGS) of 7 was determined to be approximately 85 °C. XRD measurement of a freeze-dried hydrogel from 7 suggested the presence of lamellar organization consisting of monolayer sheets. Hydrogen bonds involving the 5‘-hydroxyl group of the deoxyribose moiety, hydrophobic interaction between the long oligomethylene chains, and π−π stacking of the thymine residues are responsible for the effective hydrogel formation.

Four long-chain phenyl glucoside amphiphiles possessing a saturated or unsaturated long alkyl chain group as the self-assembling unit of a highly organized molecular architecture were synthesized. Their self-assembling properties were investigated by EF-TEM, SEM, CD, FT-IR, and XRD. Compound 2 possessing one double bond in the lipophilic portion showed twisted helical fibers, which formed a bilayered structure with a 3.59 nm period, while compound 3 showed the helical ribbons and left-handed nanotubular structures with 150-200 nm inner diameters and ca. 20 nm of wall. Very interestingly, compound 4 possessing three double bonds showed a nanotubular structure with ca. 70 nm of inner diameter through a helical ribbon, which formed a loose bilayered structure with 4.62 nm. These results indicate that self-assembling properties strongly depend on the number of cis double bonds.

Hierarchical supramolecular assemblies of micrometer‐sized flower‐shaped objects (see image) are constructed by transformation of an interdigitated bilayer precursor composed of a fullerene derivative bearing three long aliphatic chains. Intermediate transforming structures provide evidence for the formation mechanism of the flower‐shaped objects.