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Described herein is the merging of allylic C(sp3)–H activation and directed C(sp2)–H activation into a single approach for discovering unprecedented chemical transformations. As a proof-of-concept, we disclose for the first time the rhodium-catalyzed regioselective oxidative annulation of anilines with allylbenzenes to deliver a variety of indoles. In this work, the C3 and C2 positions of the allylic segment are set to construct C–N and C–C bonds, respectively. [ABSTRACT FROM AUTHOR]

In this paper, an efficient method to fabricate Al-based metal organic framework (Al-MOF) MIL-96 crystals with controllable size and morphology, by mixing other forms of reactants to replace the coordination modulators or capping agents, is presented. The size and morphology of the MIL-96 crystals can be selectively varied by simply altering the ratio of dual reactants via their hydrolysis reaction. All the samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and nitrogen sorption. Then based on the BFDH theory, a mechanism for the impact of hydrolysis of reactants on the crystal size and morphology is presented and discussed. We also evaluated the performance of these MOFs as sorbents for capturing CO2, and they all show enhanced adsorption properties compared with the bulk material, displaying high adsorption capacities on CO2 at atmospheric pressure and ambient temperature. [ABSTRACT FROM AUTHOR]

Large-flake graphene membranes up to 300 μm2can be exfoliated from graphite by oleyl amine based on solvothermal conditions. The exfoliated graphene sheets are of high quality and have few defects. The graphene dispersion, predominantly composed of monolayer graphene, had a high concentration of 0.15 mg ml−1, and can be stabilized against re-aggregation. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskites exhibit superior optoelectrical properties and have been widely used in photodetectors. Perovskite photodetectors with excellent detectivity have great potential for developing artificial photonic synapses which can merge data transmission and storage. They are highly desired for next generation neuromorphic computing. The recent progress of perovskite photodetectors and their application in artificial photonic synapses are summarized in this review. Firstly, the key performance parameters of photodetectors are briefly introduced. Secondly, the recent research progress of photodetectors including photoconductors, photodiodes, and phototransistors is summarized. Finally, the applications of perovskite photodetectors in artificial photonic synapses in recent years are highlighted. All these demonstrate the great potential of perovskite photonic synapses for the development of artificial intelligence. [ABSTRACT FROM AUTHOR]

Two perylenediimide (PDI) regioisomers with the central core substituted at the ortho (Y-αPDI) and bay (Y-βPDI) areas of the PDIs were successfully prepared. The regioisomeric effects on the physicochemical and charge-transport properties were thoroughly investigated. The results unravel that Y-βPDI shows ambipolar transport with higher mobilities compared to its α-counterpart, which is due to its favourable molecular geometry, stronger intermolecular interaction and improved electron-withdrawing ability. [ABSTRACT FROM AUTHOR]

Stretchable electronics have received intense attention due to their broad application prospects in many areas, and can withstand large deformations and form close contact with curved surfaces. Stretchable conductors are vital components of stretchable electronic devices used in wearables, soft robots, and human–machine interactions. Recent advances in stretchable conductors have motivated basic scientific and technological research efforts. Here, we outline and analyse the development of stretchable conductors in transistors and circuits, and examine advances in materials, device engineering, and preparation technologies. We divide the existing approaches to constructing stretchable transistors with stretchable conductors into the following two types: geometric engineering and intrinsic stretchability engineering. Finally, we consider the challenges and outlook in this field for delivering stretchable electronics. [ABSTRACT FROM AUTHOR]

Graphene, an amazing two-dimensional material with excellent physical properties, has attracted great attention in various disciplines. Both fundamental studies and applications require graphene samples with controlled parameters including their quality, size, crystallinity, layer number and so on. While graphene can be prepared by direct exfoliation from mother materials or growth on transition metals, the uncontrolled production or the additional complex transfer process has been challenging for graphene applications. Direct preparation on a desired dielectric substrate is an important research direction that potentially addresses these problems. Many advances have been made in the past few years, and this tutorial review provides a brief summary of ways of preparing graphene on dielectric substrates. Various methods including the annealing method, direct chemical vapor deposition graphene synthesis on conventional dielectric substrates and hexagonal boron nitride layers are systematically reviewed and discussed. The main problems and further directions in this field are also presented. [ABSTRACT FROM AUTHOR]

Correction for 'Perovskite photodetectors and their application in artificial photonic synapses' by Xin Huang et al., Chem. Commun., 2021, DOI: 10.1039/d1cc04447h. [ABSTRACT FROM AUTHOR]

Determining the effect of crystal facets on reaction performance is essential for designing an efficient propane oxidation catalyst. Herein, α-MnO2 nanowires with exposed (110), (211), (310) and (200) facets were proposed, and their crystal facet-dependent reactivity to propane oxidation was investigated. The resultant α-MnO2 nanowires with predominantly exposed (110) facets showed the maximum propane oxidation activity (T90 = 262.1 °C), oxidation rate, and turnover frequency (at 230 °C), and high stability during the oxidation of propane. In situ diffuse reflectance infrared Fourier transform spectroscopy revealed that the oxidation to form carboxylates is the decisive step; therefore, the production of reactive oxygen species is very important. The results from density of states computations revealed that the lowest electron energy was present in the (110) facet, which helps in the generation of reactive oxygen species and the regulation of the surface valence of Mn. The characterization and calculation results indicated that the (110) facets are conducive to forming oxygen vacancies, which allowed the activation and adsorption of O2 and propane, resulting in significantly enhanced propane oxidation activity. Apart from offering new insights about the structure–activity relationship of α-MnO2 with different facets exposed for short-chain volatile oxidation reactions, this study proposes a technique that can be used for improving other manganese-based catalyst oxidation systems. [ABSTRACT FROM AUTHOR]

A series of novel bis-acenaphthoquinone diimides featuring a highly electron-deficient bis-acenaphthoquinone core are facilely synthesized via Knoevenagel condensation reaction. The diimides show high electron deficiency and good coplanar conformation, together with one of them having a maximum electron mobility up to 0.038 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

Direct and sensitive short-wavelength ultraviolet (UVC) dosimeters could provide a safer disinfection environment against viruses. We developed direct, quantitative, specific and highly sensitive UVC dosimeters based on DNA nanostructure-modified graphene field-effect transistors. Detectable doses of the dosimeters range from 0.005 to 6 kJ m−2 and such dosimeters have at least 5 times better sensitivity than the current direct UV dosimeters. [ABSTRACT FROM AUTHOR]

A heterocycloarene derivative (S-Octulene) possessing two sulfur atoms was conveniently synthesized through Bi(OTf)3-catalyzed cyclization from a macrocyclic tetramethoxyethenylated precursor. The physical properties of S-Octulene and its supramolecular host–guest interaction with C60 and C70 were investigated by fluorescence titration and 1H NMR. The solution-processed organic field-effect transistor (OFET) measurements demonstrated that S-Octulene behaved as a p-type semiconductor with a hole mobility exceeding 0.01 cm2 V−1 s−1. Our findings pave a new path to design novel heterocycloarenes for the development of host–guest chemistry and organic semiconductors. [ABSTRACT FROM AUTHOR]

In this paper, a facile route is reported for the synthesis of MIL-53(Al) particles with different sizes and morphologies via the addition of various ratios of an esterified ligand to realize the deferred release of the ligand. Detailed proof indicates that the hydrolysis and deferred release of the ligand play a crucial role in modulating the morphology and size of the obtained MIL-53 nanoparticles without disrupting the original structure and framework of MIL-53. A possible mechanism for the growth of MIL-53 crystals with different exposed facets is proposed based on the structure of MIL-53 and BFDH (Bravais, Friedel, Donnay and Harker) theory. In addition, the influence of the crystal morphologies or exposed surfaces on the breathing effect and gas adsorption performance was evaluated using N2 and CO2 adsorption, and the as-prepared MIL-53 particles showed different adsorption isotherms and adsorption behavior under the same conditions. The MIL-53 particles synthesized using an appropriate amount of an esterified ligand could present an enhanced surface area when compared to that of bulk MIL-53, and the breathing effect during CO2 adsorption was moderate, while excessive amounts of the esterified ligand resulted in a decrease in the porosity and the formation of boehmite. Based on the experiment, the discrepancy in the breathing effect is mainly attributed to the stability of the narrow pore form with different exposed facets, but not the decreased particle size. [ABSTRACT FROM AUTHOR]

Single-walled carbon nanotubes (SWNTs) possess unique electronic properties that make them very promising materials for use in both nano-electronics and thin film devices. However, SWNTs are always produced as a mixture of metallic and semiconducting nanotubes, which is a major roadblock to their widespread application. This tutorial reviewprovides a brief summary of ways of separating single-walled carbon nanotubes into metallic and semiconducting fractions. Various methods including selective growth, selective removal, selective adsorption and band structure modulation—all of which aim to produce pure SWNTs with well-defined electronic properties—are systematically discussed. The main problems in this field, the outlook for separation techniques and some views of future developments are presented. [ABSTRACT FROM AUTHOR]

Swift fabrication of a non-covalently modified reduced graphene oxide electronic sensor has been developed. An unparalleled detection limit is demonstrated for Hg2+, down to the picomolar range. [ABSTRACT FROM AUTHOR]

A diketopyrrolopyrrole–thiazolothiazole copolymer with a short π–π stacking distance (3.52 Å), due to the introduction of heteroaromatic rings, exhibits a high charge mobility above 3.40 cm2 V−1 s−1 at a relatively gentle annealing temperature. [ABSTRACT FROM AUTHOR]