Research on two-dimensional (2D) materials is one of the most active fields in materials science and nanotechnology. Among the members of the 2D family, layered hydroxides (LHs) represent an ...exceptional case of study due to their unparalleled chemical versatility which allows the modulation of their physicochemical properties at will. Nowadays, LHs based on earth-abundant metals are key materials in the areas of energy storage and conversion, hybrid materials or magnetism. ɑ-Co hydroxides (Simonkolleite-like structures) are promising phases with tuneable electronic and magnetic properties by ligand modification. However, even in the simple case of ɑ-CoII hydroxychlorides, the preparation of well-defined large 2D crystals is not straightforward, hindering the development of fundamental studies. Herein, we present the synthesis of 2D hexagonal crystals with outstanding size-thickness relationship (diameter > 5 μm and thickness of 20 ± 7 nm) by a simple homogeneous synthesis taking place at room temperature. In structural terms, no differences are observed between our layered materials and those obtained hydrothermally. However, dynamic susceptibility measurements alert about different arrangements of the magnetic sublattices, which have been rationalized with structural DFT calculations. This work provides an extremely easy bottom-up method to obtain high-quality 2D crystals based on ɑ-CoII hydroxides, paving the way for the development of fundamental studies and applications.
Two‐dimensional (2D) black phosphorus (BP) represents one of the most appealing 2D materials due to its electronic, optical, and chemical properties. Many strategies have been pursued to face its ...environmental instability, covalent functionalization being one of the most promising. However, the extremely low functionalization degrees and the limitations in proving the nature of the covalent functionalization still represent challenges in many of these sheet architectures reported to date. Here we shine light on the structural evolution of 2D‐BP upon the addition of electrophilic diazonium salts. We demonstrated the absence of covalent functionalization in both the neutral and the reductive routes, observing in the latter case an unexpected interface conversion of BP to red phosphorus (RP), as characterized by Raman, 31P‐MAS NMR, and X‐ray photoelectron spectroscopies (XPS). Furthermore, thermogravimetric analysis coupled to gas chromatography and mass spectrometry (TG‐GC‐MS), as well as electron paramagnetic resonance (EPR) gave insights into the potential underlying radical mechanism, suggesting a Sandmeyer‐like reaction.
The addition of diazonium salts to black phosphorus intercalation compounds does not lead to covalent functionalization, instead it causes a drastic structural evolution in the interface of few‐layer BP leading to amorphous red phosphorus.
The chemical bulk reductive covalent functionalization of thin‐layer black phosphorus (BP) using BP intercalation compounds has been developed. Through effective reductive activation, covalent ...functionalization of the charged BP by reaction with organic alkyl halides is achieved. Functionalization was extensively demonstrated by means of several spectroscopic techniques and DFT calculations; the products showed higher functionalization degrees than those obtained by neutral routes.
The reductive covalent functionalization of thin‐layer black phosphorus (BP) proceeds via BP intercalation compounds. Following the reductive activation of BP, the resulting charged BP reacts with alkyl halides and undergoes covalent functionalization. The BP lattice shows unprecedented opening and a higher degree of functionalization than that obtained by neutral routes.
Ruddlesden‐Popper lead halide perovskite (RP‐LHP) nano‐nanostructures can be regarded as self‐assembled quantum wells or superlattices of 3D perovskites with an intrinsic quantum well thickness of a ...single or a few (n=2‐4) lead halide layers; the quantum wells are separated by organic layers. They can be scaled down to a single quantum well dimension. Here, the preparation of highly (photo)chemical and colloidal stable hybrid LHP nanosheets (NSs) of ca. 7.4 μm lateral size and 2.5 nm quantum well height (thereby presenting a deep blue emission at ca. 440 nm), is reported for the first time. The NSs are close‐lying and they even interconnect when deposited on a substrate. Their synthesis is based on the use of the p‐toluenesulfonic acid/dodecylamine (pTS/DDA) ligand pair and their (photo)chemical stability and photoluminescence is enhanced by adding EuBr2 nanodots (EuNDs). Strikingly, they can be preserved as a solid and stored for at least one year. The blue emissive colloid can be recovered from the solid as needed by simply dispersing the powder in toluene and then using it to prepare solid films, making them very promising candidates for manufacturing devices.
Quantum confined nanosheets (NSs) of 3D perovskites with a thickness of two lead halide layers can be prepared by using the dodecylammonium/tosylate ligand pair. The addition of Eu‐nanodots to the colloid prevented the NSs from a structural rearrangement and/or coalescence. Deep blue‐emissive colloids were recovered by simply dispersing it in toluene.
2D materials show outstanding properties that can bring many applications in different technological fields. However, their uses are still limited by production methods. In this context, antimonene ...is recently suggested as a new 2D material to fabricate different (opto)electronic devices, among other potential applications. This work focuses on optimizing the synthetic parameters to produce high‐quality antimonene hexagons and their implementation in a large‐scale manufacturing procedure. By means of a continuous‐flow synthesis, few‐layer antimonene hexagons with ultra‐large lateral dimensions (up to several microns) and a few nanometers thick are isolated. The suitable chemical post‐treatment of these nanolayers with chloroform gives rise to antimonene surfaces showing low oxidation that can be easily contacted with microelectrodes. Therefore, the reported procedure offers a way to solve two critical problems for using antimonene in many applications: large‐scale preparation of high‐quality antimonene and the ability to set electrical contacts useful for device fabrication.
A continuous‐flow synthesis approach offers large‐scale preparation of high‐quality few‐layer antimonene (FLA) hexagons. This procedure is based on colloidal synthesis followed by a post‐treatment with chloroform to isolate FLA hexagons which present ultra‐large lateral dimensions and a few nanometers thickness. Mechanical and electrical analyses reveal their high‐quality and low surface oxidation, opening the door for applications in electronics and beyond.
Antimonene, a monolayer of β-antimony, is increasingly attracting considerable attention, more than that of other monoelemental two-dimensional materials, due to its intriguing physical and chemical ...properties. Under ambient conditions, antimonene exhibits a high thermodynamic stability and good structural integrity. Some theoretical calculations predicted that antimonene would have a high oxidation tendency. However, it remains poorly investigated from the experimental point of view. In this work, we study the oxidation behavior of antimonene nanosheets (ANS) prepared by ultrasonication-assisted liquid-phase exfoliation. Using a set of forefront analytical techniques, a clear effect of sonication time on the surface chemistry of prepared ANS is found. A dynamic oxidation behavior has been observed, which upon annealing at moderate temperature (210 °C) resulted in a semiconducting behavior with a bandgap of approximately 1 eV measured by ultraviolet photoelectron spectroscopy. This study yields valuable information for future applications of antimonene and paves the way towards novel modification approaches in order to tailor its properties and complement its limitations.
AIM: To study the interleukin-1（IL-1） pathway as a therapeutic target for liver fibrosis in vitro and in vivo using the ATP-binding cassette transporter b4-/-(Abcb4-/-) mouse model.METHODS: Female ...and male Abcb4-/- mice from 6 to 13 mo of age were analysed for the degree of cholestasis（liver serum tests）, extent of liver fibrosis（hydroxyproline content and Sirius red staining） and tissue-specific activation of signalling pathways such as the IL-1 pathway quantitative polymerase chain reaction（q PCR）. For in vivo experiments, murine hepatic stellate cells（HSCs） were isolated via pronasecollagenase perfusion followed by density gradient centrifugation using female mice. Murine HSCs were stimulated with up to 1 ng/m L IL-1β with or without 2.5 μg/m L Anakinra, an IL-1 receptor antagonist, respectively. The proliferation of murine HSCs was assessed via the Brd U assay. The toxicity of Anakinra was evaluated via the fluorescein diacetate hydrolysis（FDH） assay. In vivo 8-wk-old Abcb4-/- mice with an already fully established hepatic phenotype were treated with Anakinra（1 mg/kg body-weight daily intraperitoneally） or vehicle and liver injury and liver fibrosis were evaluated via serum tests, q PCR, hydroxyproline content and Sirius red staining. RESULTS: Liver fibrosis was less pronounced in males than in female Abcb4-/- animals as defined by a lower hydroxyproline content（274 ± 64 μg/g vs 436 ± 80 μg/g liver, respectively; n = 13-15; P < 0.001; MannWhitney U-test） and lower m RNA expression of the profibrogenic tissue inhibitor of metalloproteinase-1（TIMP）（1 ± 0.41 vs 0.66 ± 0.33 fold, respectively; n = 13-15; P < 0.05; Mann-Whitney U-test）. Reduced liver fibrosis was associated with significantly lower levels of F4/80 m RNA expression（1 ± 0.28 vs 0.71 ± 0.41 fold, respectively; n = 12-15; P < 0.05; Mann-Whitney U-test） and significantly lower IL-1β m RNA expression levels（1 ± 0.38 vs 0.44 ± 0.26 fold, respectively; n = 13-15; P < 0.001; Mann-Whitney U-test）. No gender differences in the serum liver parameters bilirubin; alanine aminotransferase（ALT）; aspartate aminotransferase and alkaline phosphatase（AP） were found. In vitro, the administration of IL-1β resulted in a significant increase in HSC proliferation 0.94 ± 0.72 arbitrary units（A.U.） in untreated controls, 1.12 ± 0.80 A.U. at an IL-1β concentration of 0.1 ng/m L and 1.18 ± 0.73 A.U. at an IL-1β concentration of 1 ng/m L in samples from n = 6 donor animals; P < 0.001; analyses of variance（ANOVA）. Proliferation was reduced significantly by the addition of 2.5 μg/m L Anakinra（0.81 ± 0.60 A.U. in untreated controls, 0.92 ± 0.68 A.U. at an IL-1β concentration of 0.1 ng/m L, and 0.91 ± 0.69 A.U. at an IL-1β concentration of 1 ng/m L; in samples from n = 6 donor animals; P < 0.001; ANOVA） suggesting an anti-proliferative effect of this clinically approved IL-1 receptor antagonist. The FDH assay showed this dose to be non-toxic in HSCs. In vivo, Anakinra had no effect on the hepatic hydroxyprolinecontent, liver serum tests（ALT and AP） and profibrotic（collagen 1α1, collagen 1α2, transforming growth factor-β, and TIMP-1） and anti-fibrotic matrix metalloproteinase 2（MMP2）, MMP9 and MMP13 gene expression after 4 wk of treatment. Furthermore, the hepatic IL-1β and F4/80 m RNA expression levels were unaffected by Anakinra treatment.CONCLUSION: IL-1β expression is associated with the degree of liver fibrosis in Abcb4-/- mice and promotes HSC proliferation. IL-1 antagonism shows antifibrotic effects in vitro but not in Abcb4-/- mice.
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