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An efficient one-pot synthesis for Janus-type fullerenol derivatives and how to characterize them is reported. This synthesis provides access to asymmetrically substituted fullerenol with five substituents on one pole of the fullerene and polyhydroxylation moieties, mostly ether and hydroxy groups, on the rest of the fullerene core. As substituents a broad variety of primary amines can be used to obtain Janus-type amphiphilic fullerenols in good to excellent yield. These fullerenol amphiphiles can serve as suitable precursors for further reactions resulting in new applications for fullerenols.

Surfactants are ubiquitous in cellular membranes, detergents or as emulsification agents. Due to their amphiphilic properties, they cannot only mediate between two domains of very different solvent compatibility like water and organic but also show fascinating self-assembly features resulting in micelles, vesicles, or lyotropic liquid crystals. The current review article highlights some approaches towards the next generation surfactants, for example, those with catalytically active heads. Furthermore, it is shown that amphiphilic properties can be obtained beyond the classical hydrophobic-hydrophilic interplay, for instance with surfactants containing one molecular block with a special shape. Whereas, classical surfactants are static, researchers have become more interested in species that are able to change their properties depending on external triggers. The article discusses examples for surfactants sensitive to chemical (e.g., pH value) or physical triggers (temperature, electric and magnetic fields)., (© 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)

EuO is unique, because it belongs to the few solids combining semiconducting properties (E gap = 1.1 eV) with native ferromagnetism. For future applications of EuO, e.g. as spin-filters or for sensors, one has to learn how defined nanostructures can be prepared. Unlike other ceramic oxides, there are no established soft-chemistry routes (e.g. sol-gel) towards EuO nanomaterials e.g. porous materials. This is due to the labile nature of the oxidation state Eu(+ii). We present a particle-based method leading to a EuO aerogel. Instead of making the target material directly, we use nanoparticles of an organic-inorganic hybrid phase (Eu 2 O 3 -benzoate) and assemble those into an aerogel, followed by the transformation into phase-pure EuO. It is shown that organic aldehydes act as capping agents for controlling the morphogenesis of the hybrid particles. Depending on the steric demand of the aldehyde, one obtains plate-like particles or nanorods with increasing aspect ratio. The particles form a gel, when the aspect ratio is increased to >20. After supercritical drying, one receives a nanorod-based aerogel. Treatment of the latter with Eu-vapor leads to reduction of the Eu 2 O 3 domains to EuO while retaining the aerogel structure. Proof of ferromagnetism in the resulting EuO aerogel was delivered by SQUID measurements.

Surfactants are not only pivotal constituents in any biological organism in the form of phospholipids, they are also essential for numerous applications benefiting from a large, internal surface, such as in detergents, for emulsification purposes, phase transfer catalysis or even nanoparticle stabilization. A particularly interesting, green class of surfactants contains glycoside head groups. Considering the variability of glycosides, a large number of surfactant isomers become accessible. According to established models in surfactant science such as the packing parameter or the hydrophilic lipophilic balance (HLB), they do not differ from each other and should, thus, have similar properties. Here, we present the preparation of a systematic set of glycoside surfactants and in particular isomers. We investigate to which extent they differ in several key features such as critical aggregation concentration, thermodynamic parameters, etc. Analytical methods like isothermal titration calorimetry (ITC), tensiometry, dynamic light scattering (DLS), small angle-X-ray scattering (SAXS), transmission electron microscopy (TEM) and others were applied. It was found that glycosurfactant isomers vary in their emulsification properties by up to two orders of magnitude. Finally, we have investigated the role of the surfactants in a microemulsion-based technique for the generation of zinc oxide (ZnO) nanoparticles. We found that the choice of the carbohydrate head has a marked effect on the shape of the formed inorganic nanocrystals.

Surfactants are functional molecules comprising a water-compatible head group and a hydrophobic tail. One of their features is the formation of self-assembled structures in contact with water, for instance, micelles, vesicles, or lyotropic liquid crystals. One way to increase the functionality of surfactants is to implement moieties containing transition-metal species. Ferrocene-based surfactants represent an excellent example because of the distinguished redox features. In most existing ferrocene-based amphiphiles, an alkyl chain is classically used as the hydrophobic tail. We report the synthesis and properties of 1-triisopropylsilylethynyl-1'-trimethylammoniummethylferrocene (FcNMe 3 TIPS). In FcNMe 3 TIPS, ferrocene is part of the head group (Gemini design) but is also attached to a (protected) π-conjugated ethynyl group. Although this architecture differs from that of classical amphiphiles and those of other ferrocene-based amphiphiles, the compound shows marked surfactant properties comparable to those of lipids, exhibiting a very low value of critical aggregation concentration in water (cac = 0.03 mM). It forms classical micelles only in a very narrow concentration range, which then convert into monolayer vesicles. Unlike classical surfactants, aggregates already form at a very low concentration, far beneath that required for the formation of a monolayer at the air-water interface. At even higher concentration, FcNMe 3 TIPS forms lyotropic liquid crystals, not only in contact with water, but also in a variety of organic solvents. As an additional intriguing feature, FcNMe 3 TIPS is amenable to a range of further modification reactions. The TIPS group is easily cleaved, and the resulting ethynyl function can be used to construct heterobimetallic platinum-ferrocene conjugates with trans -Pt(PEt 3 ) 2 X (X = Cl, I) complex entities, leading to a heterobimetallic surfactant. We also found that the benzylic α-position of FcNMe 3 TIPS is rather reactive and that the attached ammonium group can be exchanged by other substituents (e.g., -CN), which offers additional opportunities for further functionalization. Although FcNMe 3 TIPS is reversibly oxidized in voltammetric and UV-vis spectroelectrochemical experiments, the high reactivity at the α-position is also responsible for the instability of the corresponding ferrocenium ion, leading to a polymerization reaction., Competing Interests: The authors declare no competing financial interest.

The importation of construction principles or even constituents from biology into materials science is a prevailing concept. Vice versa, the cellular level modification of living systems with nonnatural components is much more difficult to achieve. It has been done for analytical purposes, for example, imaging, to learn something about intracellular processes. Cases describing the improvement of a biological function by the integration of a nonnatural (nano)constituent are extremely rare. Because biological membranes contain some kind of a surfactant, for example, phospholipids, our idea is to modify cells with a newly synthesized surfactant. However, this surfactant is intended to possess an additional functionality, which is the reduction of oxidative stress. We report the synthesis of a surfactant with Janus-type head group architecture, a fullerene C 60 modified by five alkyl chains on one side and an average of 20 oxygen species on the other hemisphere. It is demonstrated that the amphiphilic properties of the fullerenol surfactant are similar to that of lipids. Not only quenching of reactive oxygen species (superoxide, hydroxyl radicals, peroxynitrite, and hydrogen peroxide) was successful, but also the fullerenol surfactant exceeds benchmark antioxidant agents such as quercetin. The surfactant was then brought into contact with different cell types, and the viability even of delicate cells such as human liver cells (HepG2) and human dopaminergic neurons (LUHMES) has proven to be extraordinarily high. We could show further that the cells take up the fullerenol surfactant, and as a consequence, they are protected much better against oxidative stress.

One efficient method to obtain disordered colloidal packing is to reduce the stability of colloidal particles by adding electrolytes to the colloidal dispersions. But the correct amount of additional electrolytes must be found empirically. Here, the effect of CaCl 2 on polystyrene colloidal dispersions is studied, and a link between the amount of CaCl 2 and the corresponding glassy colloidal structure is quantitatively built. A threshold concentration of CaCl 2 is found by dynamic light scattering. When exceeding this threshold, different nanoparticle oligomers are observed in the dispersions by analytical ultracentrifugation. The second objective is to achieve free-standing samples, which is required for many optical measurements. A universal method is established, using a centrifugal field to produce robust samples by polymerizing coassembled hydrophilic monomers to form a network, which traps the glassy colloidal structures. Photon time of flight measurements shows that the CaCl 2 concentration threshold should not be exceeded. Otherwise an optical shortcut may take place. Thus, the work provides a feasible universal route to prepare macroscopic free-standing photonic glasses from electrostatically stabilized nanoparticles, suitable for further optical investigation., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Heterogeneous catalysis can be understood as a phenomenon which strongly relies on the occurrence of thermodynamically less favorable surface motifs like defects or high-energy planes. Because it is very difficult to control such parameters, an interesting approach is to explore metastable polymorphs of the respective solids. The latter is not an easy task as well because the emergence of polymorphs is dictated by kinetic control and materials with high surface area are required. Further, an inherent problem is that high temperatures required for many catalytic reactions can also induce the transformation to the thermodynamically stable modification. Alumina (Al 2 O 3 ) was selected for the current study as it exists not only in the stable α-form but also as the metastable γ-polymorph. Kinetic control was realized by combining an aerosol-based synthesis approach and a highly reactive, volatile precursor (AlMe 3 ). Monolithic flakes of Al 2 O 3 with a highly porous, hierarchical structure (micro-, meso-, and macropores connected to each other) resemble so-called aerogels, which are normally known only from wet sol-gel routes. Monolothic aerogel flakes can be separated from the gas phase without supercritical drying, which in principle allows for a continuous preparation of the materials. Process parameters can be adjusted so the material is composed exclusively of the desired γ-modification. The γ-Al 2 O 3 aerogels were much more stable than they should be, and even after extended (80 h) high-temperature (1200 °C) treatment only an insignificant part has converted to the thermodynamically stable α-phase. The latter phenomenon was assigned to the extraordinary thermal insulation properties of aerogels. Finally, the material was tested concerning the catalytic dehydration of 1-hexanol. Comparison to other Al 2 O 3 materials with the same surface area demonstrates that the γ-Al 2 O 3 are superior in activity and selectivity regarding the formation of the desired product 1-hexene.

Single layer graphite, known as graphene, is an important material because of its unique two-dimensional structure, high conductivity, excellent electron mobility and high surface area. To explore the more prospective properties of graphene, graphene hybrids have been synthesised, where graphene has been integrated with other important nanoparticles (NPs). These graphene-NP hybrid structures are particularly interesting because after hybridisation they not only display the individual properties of graphene and the NPs, but also they exhibit further synergistic properties. Reduced graphene oxide (rGO), a graphene-like material, can be easily prepared by reduction of graphene oxide (GO) and therefore offers the possibility to fabricate a large variety of graphene-transition metal oxide (TMO) NP hybrids. These hybrid materials are promising alternatives to reduce the drawbacks of using only TMO NPs in various applications, such as anode materials in lithium ion batteries (LIBs), sensors, photocatalysts, removal of organic pollutants, etc. Recent studies have shown that a single graphene sheet (GS) has extraordinary electronic transport properties. One possible route to connecting those properties for application in electronics would be to prepare graphene-wrapped TMO NPs. In this critical review, we discuss the development of graphene-TMO hybrids with the detailed account of their synthesis. In addition, attention is given to the wide range of applications. This review covers the details of graphene-TMO hybrid materials and ends with a summary where an outlook on future perspectives to improve the properties of the hybrid materials in view of applications are outlined.

The solvent-mediated ability for molecularly encoded self-assembly into states of higher order (micelles, lyotropic liquid crystals) embodies the basis for many applications of surfactants in science and society. Surfactants are used frequently in recipes for nanoparticle synthesis. Because ordinary surfactants comprise insulating constituents (alkyl groups as side-chains and charged organic heads), such nanostructures are wrapped in an electrically inactive barrier, and this is a large disadvantage for future developments in nanotechnology. Implications of micelles with electrically conducting walls made from either "metallic" or "semiconducting" surfactants are huge, also in other areas such as nanoelectrocatalysis or micellar energy storage. We cross this frontier by replacing not only the hydrophilic chain but also the hydrophilic head by electronically conducting entities. We report the synthesis of surfactants with oligo para-phenylene-ethynylene as a π-conjugated side-chain attached to a redox-active, inorganic polyoxometalate cluster as charged head. It is proven that electronic communication between head and tail takes place. Hybridization on the molecular level leads to the emergence of advanced surfactant features such as semiconductor properties (E gap = 2.6 eV) in soft lyotropic systems (micelles, liquid crystals).

Significant progress in solar-cell research is currently made by the development of metal-organic perovskites (MOPs) owing to their superior properties, such as high absorption coefficients and effective transport of photogenerated charges. As for other semiconductors, it is expected that the properties of MOPs may be significantly improved by a defined nanostructure. However, their chemical sensitivity (e.g., towards hydrolysis) prohibits the application of methods already known for the synthesis of other nanomaterials. A new and general method for the synthesis of various (CH3NH3)PbI3 nanostructures from a novel single-source precursor is presented. Nanoporous MOP single crystals are obtained by a crystal-to-crystal transformation that is accompanied by spinodal demixing of the triethylene glycol containing precursor structure. Selective binding of a capping agent can be used to tune the particle shape of the MOP nanocrystals., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mesoporous materials are valuable supports for the immobilization of various molecular catalysts. Cases in which the performance of the catalyst improves after immobilization have seldom been reported, especially when it comes to enantioselective synthesis. Knowledge of how the presence of the support surface alters the properties of a bound catalyst is therefore very important. In the current article, a new periodically ordered mesoporous organosilica material (PMO) with walls exclusively made of a chiral building block is presented. The attachment of Al(III) as a Lewis acid center to the chiral group furnishes the material with catalytic activity, for instance, for the asymmetric carbonyl ene reaction. Thus, the presented materials are valuable model systems for studying the effect of the chiral surface and also neighboring groups attached to the silanol groups in the network. It is reported that surface-bound Al(III) exhibits significantly better performance (higher ee values) than an analogous molecular reference catalyst. Furthermore, it could be shown that the ee values increase even further when more bulky secondary groups are attached to the pore walls. Therefore, the main conclusion of the current report is that for cases in which steric conditions of a catalyst play a crucial role its immobilization inside a tailor-made mesoporous organosilica material is beneficial with respect to cooperative effects between the catalytic center and neighboring surface groups.

It has been recognized previously that inside nanosized cavities like in mesoporous materials a small ensemble situation can be realized. The limited number of reactants per confinement leads to unusual chemical behaviour whenever inter- vs. intramolecular pathways compete against each other. Therefore, the metathesis reaction might represent a chemical process for which the product distribution is influenced by a confining reaction field. In the current paper we report about the unusual reactivity of the Grubbs generation I catalyst inside mesoporous silica materials. It has been observed that due to a combination of confinement and surface effects the Grubbs catalyst is not stable inside small pores. It quickly rearranges to a variety of unexpected products. However, the undesired deactivation of the catalyst can be prohibited by surface modification of the silica surfaces.

The everyday routine of most chemists is dictated by large numbers. The chemical rules for ensembles of molar size (N approximately N(A)=6.022 x 10(23)) are well known and can be understood in most cases by using Boltzmann distribution. It is an interesting question how a small ensemble of a chemical system behaves and if it differs from the respective large-ensemble counterpart. The experimental approach presented in the current paper involves the division of a macroscopic volume into compartments that contain only a small number of reactants. The compartments represent the pores of tailor-made nanoporous materials.

Transition-metal-oxide materials possessing ordered mesoporosity have recently attracted significant research interest due to their numerous potential applications. Among them, ordered mesoporous zinc oxide (ZnO) is a very tempting material because of the importance of ZnO in heterogeneous catalysis. Here, first results of the preparation of ordered mesoporous ZnO materials by using different templates are reported. Porous materials with high surface area, different pore sizes, and nanocrystalline ZnO walls were obtained. Furthermore, we compare the two fundamental templating techniques, involving liquid crystals or ordered mesoporous carbon materials as templates. Regarding the formation of mesoporous ZnO, it was evident that the hard-matter carbon template is superior.

The sequential dissociations of the tetranuclear zinc cluster-ion [(CH3)3Zn4(O-i-C3H7)4]+ obtained by dissociative electron ionization of neutral [(CH3)Zn(O-i-C3H7)]4 are investigated by tandem mass spectrometry. After initial loss of a neutral (CH3)Zn(O-i-C3H7) unit to afford [(CH3)2Zn3(O-i-C3H7)3]+, hydrogen migration leads to the expulsion of neutral acetone concomitant with [(CH3)2Zn3(O-i-C3H7)2(H)]+ as ionic fragment. Unimolecular dissociation of the latter gives rise to [(CH3)2Zn2(O-i-C3H7)]+ and neutral HZn(O-i-C3H7). As demonstrated by collisional ionization of the neutral product, in the fragmentation of the dinuclear cluster [(CH3)2Zn2(O-i-C3H7)]+ neutral CH3ZnH is formed, rather than the more stable fragments Zn + CH4. From the resulting mononuclear species CH3Zn(OC(CH3)2)+ acetone is eliminated to afford CH3Zn+ as a quasi-terminal fragment ion.