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Metal Organic Frameworks (MOFs) are organic-inorganic hybrid materials with exceptionally customizable composition and properties. MOFs intrinsically possess open metal sites, tunable pore size/shape and an ultra-large specific surface area, and have obtained significant attention over the past 30 years. Furthermore, through the integration of functional moieties such as, molecules, functional groups, noble metal clusters and nanocrystals or nanoparticles into MOFs, the resulting composites have greatly enriched the physical and chemical properties of pure MOFs, enabling their application in a wider range of fields. Triethylamine (TEA) as an organic base has consistently played a fundamental role in the development of MOFs. In this Concept, the versatility of triethylamine when involved in the synthesis of MOFs is discussed. Four sections are used to elaborate on the role of TEA including: (1) Single crystal synthesis; (2) Size and morphology control; (3) Counterion of MOFs; (4) MOFs composites synthesis. In the last part, we highlight the potential of TEA for further developments., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Fluorine-containing polyanionic compounds have attracted much attention in the last few years as potential positive electrode materials for rechargeable batteries. With their formula A a M b X c O 4 Y d (A=Li, Na…; M=Ti, V, Mn, Fe, Co, Ni…; X=P or S, and Y=F, OH, O), they offer a very rich chemistry and their electrochemical properties can be tuned by carefully choosing the different constituting elements. However, synthesis approaches that allow these materials to be obtained at low temperature are almost nonexistent. In this paper, the use of a nonaqueous fluorolytic sol-gel approach is reported to synthesize a tavorite-type LiFePO 4 F material and its electrochemical characterization was performed. The obtained material displays an electrochemical performance that positively compares with the literature with an excellent cycling stability (115 mA h -1  g -1 after 100 cycles at C/2 rate). A slight change in the synthesis parameters allowed Li 2 CoPO 4 F to be successfully obtained, demonstrating the versatility of the reported route, which can be adapted to synthesize other fluorine-containing polyanionic compounds, which are of great interest for energy storage applications., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The atomically precise bimetallic nanocluster (NC), Au 24 Ag 20 (PhCC) 20 (SPy) 4 Cl 2 (1) (Py=pyridine), was employed for the first time as a stable photosensitizer for photoelectrochemical applications. The sensitization of TiO 2 nanotube arrays (TNA) with 1 greatly enhances the light-harvesting ability of the composite because 1 shows a high molar extinction coefficient (ϵ) in the UV/Vis region. Compared to a more standard Au 25 (SG) 18 -TNA (2-TNA; SG=glutathione) composite, 1-TNA shows a much better stability under illumination in both neutral and basic conditions. The precise composition of the photosensitizers enables a direct comparison of the sensitization ability between 1 and 2. With the same cluster loading, the photocurrent produced by 1-TNA is 15 times larger than that of 2-TNA. The superior performance of 1-TNA over 2-TNA is attributed not only to the higher light absorption ability of 1 but also to the higher charge-separation efficiency. Besides, a ligand effect on the stability of the photoelectrode and charge-transfer between the NCs and the semiconductor is revealed. This work paves the way to study the role of metal nanoclusters as photosensitizers at the atomic level, which is essential for the design of better material for light energy conversion., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

MoS 2 , a typical layered transition-metal dichalcogenide, is promising as an electrode material in supercapacitors. However, its low electrical conductivity could lead to limited capacitance if applied in electrochemical devices. Herein, a new nanostructure composed of hollow carbon-MoS 2 -carbon was successfully synthesized through an l-cysteine-assisted hydrothermal method by using gibbsite as a template and polydopamine as a carbon precursor. After calcination and etching of the gibbsite template, uniform hollow platelets, which were made of a sandwich-like assembly of partial graphitic carbon and two-dimensional layered MoS 2 flakes, were obtained. The platelets showed excellent dispersibility and stability in water, and good electrical conductivity due to carbon provided by the calcination of polydopamine coatings. The hollow nanoplate morphology of the material provided a high specific surface area of 543 m 2  g -1 , a total pore volume of 0.677 cm 3  g -1 , and fairly small mesopores (≈5.3 nm). The material was applied in a symmetric supercapacitor and exhibited a specific capacitance of 248 F g -1 (0.12 F cm -2 ) at a constant current density of 0.1 A g -1 ; thus suggesting that hollow carbon-MoS 2 -carbon nanoplates are promising candidate materials for supercapacitors., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Anhydrous nanoscopic CuF 2 is synthesized from alkoxides Cu(OR) 2 (R=Me, tBu) by their reaction either in pure liquid HF at -70 °C, or under solvothermal conditions at 150 °C using excess HF and THF as solvent. Depending on the synthesis method, nanoparticles of sizes between 10 and 100 nm are obtained. The compound is highly hygroscopic and forms different hydrolysis products under moist air, namely CuF 2 ⋅2 H 2 O, Cu 2 (OH)F 3 , and Cu(OH)F, of which only the latter is stable at room temperature. CuF 2 exhibits an electrochemical plateau at a potential of ≈2.7 V when cycled versus Li in half cell Li-ion batteries, which is attributed to a non-reversible conversion mechanism. The cell capacity in the first cycle depends on the particle size, being 468 mAh g -1 for ≈8 nm crystallite diameter, and 353 mAh g -1 for ≈12 nm crystallite diameter, referred to CuF 2 . However, such a high capacity cannot be sustained for several cycles and the capacity rapidly fades out. The cell voltage decreases to ≈2.0 V for CuF 2 ⋅2 H 2 O, Cu 2 (OH)F 3 , and Cu(OH)F. As all the compounds studied in this work show irreversible conversion reactions, it can be concluded that copper-based fluorides are unsuitable for Li-ion battery applications., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

TiO2 is frequently combined with carbon materials, such as reduced graphene oxide (RGO), to produce composites with improved properties, for example for photocatalytic applications. It is shown that heating conditions significantly affect the interface and photocatalytic properties of TiO2 @C, and that microwave irradiation can be advantageous for the synthesis of carbon-based materials. Composites of TiO2 with RGO or amorphous carbon were prepared from reaction of titanium isopropoxide with benzyl alcohol. During the synthesis of the TiO2 nanoparticles, the carbon is involved in reactions that lead to the covalent attachment of the oxide, the extent of which depends on the carbon characteristics, heating rate, and mechanism. TiO2 is more efficiently stabilized at the surface of RGO than amorphous carbon. Rapid heating of the reaction mixture results in a stronger coupling between the nanoparticles and carbon, more uniform coatings, and smaller particles with narrower size distributions. The more efficient attachment of the oxide leads to better photocatalytic performance., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

4-Carboxyphenyl groups are covalently grafted onto graphene oxide via diazonium chemistry for studying their role on the adsorption of iron oxide nanoparticles. The nanoparticles are deposited via a novel phase-transfer approach involving specific interactions at the interface between two immiscible solvents. The increased density and the homogeneous distribution of surface carboxyl moieties enable the preparation of a nanocomposite with improved iron oxide distribution and loading. Structure-properties relationships are investigated by analysing the electrochemical properties of the nanocomposites, which are regarded as promising active materials for application in supercapacitors. It is demonstrated that the nature of the interactions between the components similarly affects the overall electrochemical performances of the nanocomposites and the structure of the materials., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nanoparticle powders composed of surface-functionalized anatase crystals with diameters of about 3 nm self-organize into different structures upon redispersion in water. The assembly is directed by a small amount of a low-molecular-weight functional ligand (the "assembler") adsorbed on the surface of the nanoparticles. The ligand functionality determines the anisotropy of the resulting structures. Multidentate ligands, such as trizma ((HOCH(2))(3)CNH(2)) and serinol ((HOCH(2))(2)CNH(2)), with a chargeable terminal group preferentially induce the formation of anisotropic nanostructures several hundreds of nanometers in total length, whereas all the other investigated ligands (ethanolamine H(2)N(CH(2))(2)OH, glycine hydroxamate H(2)NCH(2)CONHOH, dopamine (OH)(2)C(6)H(3)(CH(2))(2)NH(3)Cl, tris (HOCH(2))(3)CCH(3)) mainly lead to uncontrolled agglomeration. Experimental data suggests that the anisotropic assembly is a consequence of the water-promoted desorption of the organic ligands from the {001} faces of the crystalline building blocks together with the dissociative adsorption of water on these crystal faces. Both processes induce the preferred attachment of the titania nanoparticles along the [001] direction. The use of polydentate and charged ligands to functionalize the surface of nanoparticles thus provides a versatile tool to control their arrangement on the nanoscale.

Crystallization of DL-alanine by cooling of a supersaturated solution in the presence of a chiral double-hydrophilic block copolymer poly(ethylene glycol)-block-poly(ethylene imine)-S-isobutyric acid (PEG4700-PEI1200-S-iBAc) yields crystal superstructures with an astonishing morphology. Although analysis by light microscopy reveals these crystals to be apparently well facetted, electron microscopy shows that they consist of three-dimensionally, well-aligned nanocrystals that are scaffolded to a so-called mesocrystal. This mesocrystal is formed by polymer-mediated structuration, and provides evidence for the importance of mesoscopic events in a typical crystallization process.