Fusion growth from each nanocluster applying the random coil–globule transition of a thermoresponsive polymer was explored for alloy nanoparticle (NP) formation for the first time. The fusion growth of bimetallic Au–Pt alloy NPs was examined at 100, 150, and 200 °C via the structural collapse caused by the transition of a thermoresponsive polymer, poly(N-isopropylacrylamide). A significant temperature dependence was revealed in the formation path, even in the narrow range of reaction temperatures studied here. Structural investigations for the products were performed using transmission electron microscopy, energy-dispersive X-ray spectrometry, elemental mapping, X-ray absorption fine structure, and X-ray diffraction. At 100 °C, Au NPs slightly alloyed with Pt atoms rather than form neat Au NPs. The element ratio was determined to be Au:Pt = 12:1 or less of Pt atoms. Small Pt particles coated the surface of the central NPs. A nonmetallic component of Pt atoms was mainly detected in the product solution on ...

The enantiopure macrocyclic tetraimines containing adamantane moieties (1, 2) were synthesized from (R,R)- or (S,S)-1,2-cyclohexanediamine and a disubstituted adamantane derivative having salicylaldehyde in moderate yield. Single crystals (1a) were obtained from a methanol/ chloroform mixture and 1. X-ray crystallographic analysis revealed that the macrocycles had a rhomboidal structure and were arranged into a molecular network bearing layer structures through CH center dot center dot center dot O and CH center dot center dot center dot pi interactions. Racemic crystals (1.2-a) were formed from crystallization of 1 and 2 in a 1:1 stoichiometry. The macrocycles had a rhomboidal framework with a longer axis, and 1 and 2 were alternatively aligned into the molecular network composed of columnar structures by CH center dot center dot center dot pi and CH center dot center dot center dot O interactions. Macrocycle 1 self-assembled into spheres, and their fused fibrous and network aggregates, and eventually were translated into crystals. Meanwhile, the mixing of both enantiomers 1 and 2 at a ratio of 1:1 afforded racemic crystals by way of similar self-assembled structures under identical conditions; however, the rate of crystal formation was faster than that of 1.

An adamantane-based macrocycle possessing eight hydroxyl groups (1) was synthesized, in which the macrocyclic framework comprises two disubstituted adamantane molecules bearing phenyl derivatives connected to two biphenylene spacers by oxygen atoms. Furthermore, functionalized macrocycles containing methyl (2) and methoxycarbonylmethyl (3) groups were prepared. From the X-ray crystallographic analysis, the backbone of the macrocycles in all crystals had a nearly hexagonal shape with a cavity and these macrocycles could be arranged into different tubular structures dependent on the substituents. In acetone, macrocycle (1) formed stable hollow spherical aggregates with multilayer membranes. In contrast, macrocycle (3) exhibited no production of self-assembled materials in chloroform. The addition of hexane into the solution caused the generation of solid spheres and their fused network aggregates, which were finally transformed into crystals owing to the solvent effects.

Three tetrapodal tetraaryladamantanes bearing imidazole derivatives exhibit unique self-assembly and crystallization behaviors, including hollow spherical aggregation, a morphological change by fus...

A naphthalenediimide-based macrocycle with adamantane parts was synthesized from naphthalenetetracarboxylic dianhydride and 1,3-adamantanedimethanamine. The addition of methanol to a chloroform solution of the macrocycle led to formation of spherical species and their fused network aggregates, which were transformed into crystals. X-ray analysis showed a crescent-shaped molecular structure. In the presence of perylene, charge-transfer co-crystals of sandwich-type complexes were generated via self-assembly of nanostructures.

The morphology and stability of amorphous nanoparticles of glibenclamide (GLB) prepared by the antisolvent method using different methods of adding hypromellose (HPMC) were evaluated. Nano-A was prepared by the injection of a dimethyl sulfoxide (DMSO) solution of GLB into the HPMC solution, whereas nano-B was obtained by the injection of a DMSO solution of GLB and HPMC into water. Cryogenic transmission electron microscopy, field-emission scanning electron microscopy, and field-emission transmission electron microscopy, including energy dispersive X-ray spectrometry, revealed that the particles of the nano-A and nano-B samples are hollow spheres and nonspherical nanoparticles, respectively. Powder X-ray diffraction and solid-state NMR measurements showed that GLB is present in an amorphous state in both nano-A and nano-B. The weight ratios of HPMC in the GLB/HPMC nanoparticles were 11 and 16% for nano-A and nano-B, respectively, as determined by solution-state NMR. The glass transition temperatures ( Tg) of nano-A and nano-B evaluated using differential scanning calorimetry were lower by about 10 °C compared to that of amorphous GLB, presumably because of a Tg confinement effect and the surface coverage and mixing of HPMC, as suggested by the inverse gas chromatography experiment. GLB crystallization during storage was suppressed more strongly in nano-B than nano-A, owing to the higher amount of HPMC and the higher miscibility between GLB and HPMC. It is suggested that the diffusion rate of the solvent during nanoprecipitation determined the nanoparticle properties. In nano-A, the precipitation of GLB first occurred at the outer interface because of the rapid diffusion of the solvent. Thus, hollow spherical particles with HPMC preferentially located near the surface were formed. On the other hand, the diffusion of the solvent in nano-B was suppressed because of the presence of HPMC, yielding small nonspherical nanoparticles with a high miscibility of GLB and HPMC.

The mixing of a tripodal ligand bearing pyridyl groups with AgOTf affords crystals with a coordination cage from a mixture of acetonitrile and toluene. In the complex, two ligands are linked with three metal centers, where counter anions are coordinated to the silver atoms. The crystals are formed through the spherical particles and their fused network aggregates consisting of the complexes.

A salen-based macrocycle possessing adamantane units was constructed from two ethylenediamine and two disubstituted adamantane-bearing salicylaldehyde components. The addition of methanol to a tetrahydrofuran solution of the macrocycle afforded the crystals via hollow spherical and fused aggregates, and X-ray crystallographic analysis showed that the macrocycle had a rhomboidal structure. The use of chloroform instead of methanol gave the crystals of a square-shaped macrocycle without the formation of self-assembled materials.

An adamantane-derived azacyclophane containing triazine rings was synthesized by the SNAr reaction of a disubstituted adamantane with amino groups and cyanuric chloride. X-ray analysis of the macrocycle reveals a nearly rectangular structure. The macrocycles self-assembled into hollow spherical aggregates bearing a multilayer membrane in aqueous solution, which fused into disordered aggregates and eventually formed single crystals.

The reaction of 1,3,5-triphenyladamantane-bridged trisbenzimidazolium or trisimidazolium salts bearing long alkyl chains with silver oxide affords trinuclear silver(1) hexacarbene complexes with a three-dimensional organometallic framework in moderate yield, where two tricarbene ligands are linked with three metal centers. The complex self-assembles into hollow spherical aggregates in a polar organic solution.

On the basis of the structure of the unimolecular Zn3(OAc)4–3,3′‐bis(aminoimino)binaphthoxide complex, a poly‐Zn3(OAc)4–3,3′‐bis(aminoimino)binaphthoxide (poly‐Zn) complex was prepared from 3,3′‐diformylbinaphthol, tetramine, and Zn(OAc)2. The first‐generation poly‐Zn catalyst (poly‐Zn1) was prepared from poly(aminoiminobinaphthol) and Zn(OAc)2. Although poly‐Zn1 showed high catalytic activity for iodolactonization, the catalyst could not be reused. The second‐generation poly‐Zn catalyst (poly‐Zn2) was prepared by the self‐organization of 3,3′‐diformylbinaphthol, tetramine, and Zn(OAc)2. This produced a stable and active poly‐Zn2 catalyst for asymmetric iodolactonization that was reused over five cycles.

Two adamantane-based oxacyclophanes were synthesized by the SNAr reaction of bis-phenol derivatives based on adamantane with 2,6-dichloropyrazine. Their crystal structures had distorted or twisted 1,3-alternate conformations. The oxacyclophanes indicated no formation of spherical aggregates in acetone. However, addition of water into the solution caused the generation of hollow spherical aggregates with a multilayer membrane. Over time, the hollow spheres were induced into fibrous and network assemblies, which were eventually transformed into single crystals.

Nanosilicas can disperse single-wall carbon nanotube (SWCNT) in aqueous solution efficiently; SWCNTs are stably dispersed in aqueous media for more than 6 months. The SWCNT dispersing solution with nanosilica can produce highly conductive transparent films which satisfy the requirements for application to touch panels. Even multiwall carbon nanotube can be dispersed easily in aqueous solution. The highly stable dispersion of SWCNTs in the presence of nanosilica is associated with charge transfer interaction which generates effective charges on the SWCNT particles, giving rise to electrostatic repulsion between the SWCNTs in the aqueous solution. Adhesion of charged nanosilicas on SWCNTs in the aqueous solution and a marked depression of the S11 peak of optical absorption spectrum of the SWCNT with nanosilicas suggest charge transfer interaction of nanosilicas with SWCNT. Thus-formed isolated SWCNTs are fixed on the flexible three-dimensional silica jelly structure in the aqueous solution, leading to the uniform and stable dispersion of SWCNTs.

Single-walled carbon nanotubes (SWCNTs) have been recognized as promising nanocarriers by many researchers from around the world through hundreds of articles published in the last decade pertaining to SWCNTs-based drug delivery applications. In line with this issue, systematic studies of non-covalent interaction between camptothecin (CPT) and the oxidized SWCNTs (Ox-SWCNTs) have been done in this work. Through the developed process of purification and acid oxidation, we obtained the Ox-SWCNTs that were essentially free of metals and well dispersed in aqueous solutions. A quenching phenomenon, which is indicative of the interactions between CPT and the Ox-SWCNTs, was observed and used as the basis of analysis for monitoring the adsorption of CPT. A comparison of the kinetic models and the overall adsorption capacity was best described by the pseudo second-order kinetic model and Weber-Morris kinetic model. Langmuir and Freundlich models were introduced to fit the adsorption isotherms data. The adsorption of CPT was found to be dependent on concentration and adsorption temperature. The thermodynamic analysis exhibited that the adsorption of CPT on the Ox-SWCNTs was exothermic and spontaneous. (C) 2015 Elsevier B.V. All rights reserved.

Graphical Abstract The Cover shows an image of a polymer catalyst for iodolactonization (two kinds of “gingerbread men” represent the spacers 3,3’-diformyl binaphthol and the tetramine). In their Communication, T. Arai et al. reported a Zn3(OAc)4-3,3’-bis(aminoimino)binaphthoxide (tri-Zn) catalyst for the asymmetric iodolactonization. Based on the structure of unimolecular tri-Zn catalyst, a poly-Zn complex was also prepared by the self-organization of 3,3’-diformyl binaphthol, tetramine, and Zn(OAc)2. More details can be found in the Communication by T. Arai et al. on page 3234 in Issue 20, 2015 (DOI: 10.1002/cctc.201500842).

A hydrophobic tetrapodal molecule is composed of carbazole units at the periphery linked by a phenyl spacer on an adamantane core. Tetrapodal adamantane self-assembles into hollow spherical aggregates with a multilayer membrane in organic media. The spherical assembly size is dependent on the organic solvent used. Hollow spheres can entrap guest molecules within their internal spaces. By increasing the concentrations of tetrapodal molecules, hollow spheres fused into necklace-shaped nanostructures and two-dimensional networks were obtained.

A new non-porous carbon material from granular olive stones has been prepared to be used as a reference material for the characterization of the pore structure of activated carbons. The high precision adsorption isotherms of nitrogen at 77.4K and argon at 87.3K on the newly developed sample have been measured, providing the standard data for a more accurate comparative analysis to characterize disordered porous carbons using comparative methods such as t- and αS-methods.