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Employing cheap halogen salts as both mediators and electrolytes, transition metal-free electrochemical approaches for NaCl-mediated hydrolysis of hydrosilanes have been well established to prepare silanols in moderate to good yields with good functional group tolerance under ambient conditions. Furthermore, electrochemical NaBr-promoted alcoholysis of hydrosilanes with a series of alcohols was successfully achieved under metal-free conditions. The synthetic application of eco-friendly and low-cost protocols has been highlighted through scale-up experiments in a galvanostatic mode. Preliminary mechanistic investigations have confirmed that NaCl played an important role in the functionalization of hydrosilanes and indicated that the transformation might proceed via a free radical process under electrochemical conditions. [ABSTRACT FROM AUTHOR]

Reported herein is a photochemical strategy for C(sp3)–H azolation of ethers via a hydrogen-atom transfer and radical-polar crossover process, offering efficient access to valuable N-alkylated azoles under visible-light irradiation. The protocol is metal-free and photocatalyst-free, and exhibits good to excellent yields and broad substrate scope with regard to azoles. EPR experiments provide evidence for the formation of intermediates formed in situ. [ABSTRACT FROM AUTHOR]

A novel solid-state second harmonic generation (SHG) organic–inorganic hybrid switch [Me3NCH2CH2F]FeBr4 (1) exhibits genuine three-step "on–off–on–off" SHG-switching above-room temperature, which has potential applications in multi-step optical devices. [ABSTRACT FROM AUTHOR]

Transition-metal sulfides (TMSs) have indeed drawn dramatic interest as a potential species of electrocatalysts by virtue of their unique structural features. However, their poor stability and inherent activity have impeded their use in electrocatalytic water splitting. Here, we provide a rational design of a hierarchical nanostructured electrocatalyst containing CeOx-decorated NiCo-layered double hydroxide (LDH) coupled with Ni3S2 protrusions formed on a Ni foam (NF). Specifically, the as-prepared electrocatalyst, denoted as Ni2Co1 LDH-CeOx/Ni3S2@NF, presents only 250 and 300 mV overpotential at ±100 mA cm−2, respectively, along with the Tafel slope values of 92 and 52 mV dec−1, as well remarkable long-term life for water splitting in an alkaline electrolyte. Based on systematic experiments and theoretical analysis, the superior electrocatalytic property in terms of Ni2Co1 LDH-CeOx/Ni3S2@NF can be imputed to the following reasons: the porous framework of Ni3S2@NF provides a largely surface area and high conductivity; the NiCo LDH nanosheets provide enriched active sites and favorable adsorption ability; the oxygen-vacancy-rich CeOx optimizes the electronic configuration. Overall, these factors work synergistically to expedite the catalytic kinetics of splitting water. Our work concentrates on a rational interface to devise efficient, multifunctional, and serviceable electrocatalysts for future applications. [ABSTRACT FROM AUTHOR]

Herein we demonstrate the application of continuous flow technology to the synthesis of hydrazine derivatives by deoxygenation of free alcohols with di-tert-butylazodicarboxylate. This operationally simple protocol has excellent functional group tolerance and enables large-scale synthesis and late-stage functionalization. It also provides access to three families of pharmacological compounds. [ABSTRACT FROM AUTHOR]

Herein, we describe an efficient method involving the synthesis of diverse quinoxalines using the DMSO/tBuONa/O2 system as a single-electron oxidant to form α-imino radicals and nitrogen radicals for the direct construction of C–N bonds. This methodology provides a novel approach to form α-imino radicals with good reactivity. [ABSTRACT FROM AUTHOR]

The construction of efficient and bifunctional electrocatalysts for overall water splitting is necessary but still remains a tremendous challenge owing to their low surface area and sluggish reaction kinetics. Herein, we demonstrate an electrocatalyst with a rough and porous surface morphology, where copper sulfides and oxides could be grown directly on the copper wire (CW) via an in situ corrosion method. Benefitting from its unique lamellar structure and fast charge transfer kinetics, the as-fabricated electrocatalyst presented a low overpotential of 160 mV for the OER at 10 mA cm−2 and overpotential of 230 mV for the HER at 100 mA cm−2. Besides, this electrocatalyst as an electrode exhibited remarkable durability after 1000 cyclic voltammetry (CV) cycles. In short, this work presents a Cu-based electrocatalyst for efficient water splitting, which has seldom been reported to the best of our knowledge, for exploring high-activity non-noble metal catalysts. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) hybrid organic–inorganic perovskites (HOIPs) have attracted tremendous research interest due to their unique structure and promising applications. However, research on the design, synthesis and properties of this kind of metal-free crystalline material is still in the exploratory stage. Herein, two 3D perovskite molecules [1,4-3.2.2-dabcn]NH4Br3 (1) and [1,4-3.2.2-dabcn]NH4I3·0.5H2O (2) were obtained by reacting 1,4-diazabicyclo[3.2.2]nonane (1,4-3.2.2-dabcn) with NH4X (X = Br and I) in the corresponding concentrated halogen acids. The single X-ray diffraction results demonstrated that the inorganic framework structures in compounds 1 and 2 constructed with NH4Br and NH4I are completely different, caused by the radius of the bromide ion being smaller than that of the iodide ion. The 3D framework of compound 1 is constructed with a coplanar dimer [(NH4)2Br6]2− as the basic building unit, leading to the expanded 3D perovskite framework structure with a larger cavity to accommodate the 1,4-3.2.2-dabcn molecule. Nevertheless, compound 2 adopts a familiar 3D crystal framework structure with corner-sharing [(NH4)I6] octahedra, where the [1,4-3.2.2-dabcn] cations and water solvent molecule are confined in the cavities enclosed by the octahedra. Notably, both compounds exhibit reversible phase transition, dielectric anomaly and the second harmonic generation (SHG) effect. From the perspective of molecular design, this work is of great significance to guide the construction of new 3D metal-free perovskite molecular materials with reversible properties. [ABSTRACT FROM AUTHOR]

Radical/radical cross-coupling remains challenging due to diffusion control issues. Herein, we report a visible-light-induced radical/radical cross-coupling reaction of quaternary ammonium salts and Hantzschs via C–N and C–C bond cleavage. The current synthetic approach furnishes 1,2-diphenylethanes in moderate to good yields and provides a method for the construction of the C(sp3)–C(sp3) bond. [ABSTRACT FROM AUTHOR]

The excellent properties of host–guest crown ether inclusions in phase transition, dielectric and second-order nonlinear optical properties have attracted much attention. In this paper, we successfully designed and prepared two novel host–guest crown ether supramolecules [(DFBA)(15-crown-5)]X (X = ClO4−, 1; ReO4−, 2) by reactions of 2,6-difluorobenzylamine (DFBA) with 1,4,10,13-pentaoxacyclopentadecane (15-crown-5) in HClO4, or HReO4 aqueous solution. By the introduction of difluoro-substituted benzylamine as a guest cation, the phase transition temperatures are greatly increased to 377 K for 1 and 391 K for 2. More importantly, the space group of 1 has changed from centrosymmetric (CS) P2/c to the non-centrosymmetric (NCS) Pca21 in 2 when substituting perchlorate (ClO4−) with the larger and heavier perrhenate (ReO4−), which leads to 2 showing a switchable and stable second-harmonic generation (SHG) effect. According to the principle of momentum matching between a cation and anion, the perrhenate group increases the energy barrier of the molecular thermal motion, which not only significantly increases the phase transition temperature of 2 but also causes it to be frozen and crystallized in a NCS space group at room temperature. This research demonstrates that a polar molecule can adjust the suitability of anions and cations inside the crystal by practical chemical means. [ABSTRACT FROM AUTHOR]

Compared with the spherical molecule 1,4-diazoniabicyclo[2.2.2]-octane (2.2.2-dabco), 1,5-diazabicyclo[3.2.2]nonane (3.2.2-dabcn) bears a lower symmetry and larger size. As expected, reactions of 3.2.2-dabcn with rubidium halides gave two 3D molecular ferroelectrics [3.2.2-H2dabcn]RbX3 (X = Br for 1; X = I for 2) with Tc at 342 K (1) and 293 K (2). [ABSTRACT FROM AUTHOR]

A one-dimensional organic–inorganic hybrid perovskite material [3.3.0-dabco]PbBr3 (1) was synthesized by the reaction of 1,5-diazabicyclo[3.3.0]octane (3.3.0-dabco) with PbBr2 in concentrated HBr aqueous solution. Differential scanning calorimetry, dielectric measurements, and variable-temperature structural analyses revealed that compound 1 exhibits two successive structural phase transitions from P212121 to Pbcm at 387 K (T1) and then to P6/mmc at 436 K (T2), accompanied by two pairs of dielectric anomalies with a clear one at T1 and an unobvious one at T2. In addition, compound 1 shows a robust second harmonic generation (SHG) effect between SHG-OFF and SHG-ON states during its centrosymmetric to non-centrosymmetric symmetry breaking phase transition at T1. [ABSTRACT FROM AUTHOR]

An efficient protocol to synthesize aryl selenoethers through deborylative selenylation of widely available arylboronic acids has been established under electrochemical conditions in the absence of metal catalyst and external oxidant. The synthesis of bioactive molecules and gram-scale transformation have been performed to highlight the synthetic utility of the protocol. CV (cyclic voltammetry) experiment indicates that anodic oxidation of diselenide occurs prior to that of the arylboronic acid substrate under the standard conditions. [ABSTRACT FROM AUTHOR]

Transition metal-free electrochemical approaches for the N-cyanation of secondary amines and the α C-cyanation of tertiary amines have been well established, with products being obtained in moderate to good yields and with good functional group tolerance under ambient conditions. The synthetic application of the protocols has been highlighted through scale-up experiments in a galvanostatic mode. Preliminary mechanistic investigation has confirmed that TBAB played a critical role in N-cyanation transformation and has indicated that the transformation might proceed via a free radical process. [ABSTRACT FROM AUTHOR]

Recently, the development of multifunctional thermochromic materials that exhibit switching characteristics in phase transition and dielectric properties has attracted widespread attention due to their potential application in signal processing and smart devices. But most traditional thermochromic materials tend to be rather than reversible phase change materials. Here, a square-pyramidal coordinated copper complex [Me3NNH2CuCl3]2 (1) (Me3NNH2 = trimethyl hydrazine) showing switchable properties in phase transition, dielectricity and thermochromic properties has been prepared by reaction of Me3NNH2I with CuCl2 in concentrated HCl aqueous solution. Compound 1 has a reversible phase transition temperature of 45 °C. When the temperature exceeds the phase transition temperature, the green color of 1 gradually changed into dark red. Compared with traditional thermochromic materials, the reversible phase transition and dielectric properties within the thermochromic materials will bring additional spectral encryption possibilities for future information processing. [ABSTRACT FROM AUTHOR]

Herein, copper-catalyzed direct C–C bond cleavage of amides fused to 8-aminoquinoline as a directing group to form urea in the presence of amines and dioxygen is reported. Compared to the previous C–H aminations of amides via C–H activation, this reaction presents a catalyst and oxidant controlled C–C bond cleavage strategy that enables amidation through a radical process. CuBr/Ag2CO3/O2 shows the best catalytic result at 150 °C. A series of aryl and alkyl amides were compatible with this transformation. Notably, this method provided access to cyclohexanone, one of the most important industrial materials. The pathway of this reaction was investigated. [ABSTRACT FROM AUTHOR]

A versatile and environmentally friendly synthetic method for the formation of acyl phosphates is reported. By employing electrochemical oxidative dehydrogenative coupling, this transformation features a broad range of substrates, as well as metal-free, oxidant-free and mild conditions. One-pot synthesis of amides from acyl phosphates with amines was accomplished with high efficiency and regioselectivity, without using any additional catalysts and additives, within 2 hours under room temperature. The mechanism is proposed according to the control experiments. [ABSTRACT FROM AUTHOR]

An electrochemical deborylative seleno/thiocyanation of arylboronic acids has been well established to synthesize the corresponding aryl seleno/thiocyanates with good functional group tolerance under ambient conditions. A gram-scale reaction has been performed to highlight the advantages of the protocol. Preliminary mechanistic studies indicate that the oxidation of the seleno/thiocyanate anion occurs prior to that of the arylboronic acid substrate in galvanostatic mode, and that free radicals are involved in the process. [ABSTRACT FROM AUTHOR]

An organic–inorganic hybrid molecule [(PyCH2NH3)6][Pb5I22]·3H2O (1) with a 2D inorganic layer was produced by reaction of 2-aminomethyl-pyridine with PbI2 in a concentrated HI aqueous solution. Compound 1 exhibited solid thermochromism showing a reversible color change from orange at room temperature to red at 80 °C, which was caused by the structural changes. [ABSTRACT FROM AUTHOR]

Reactions of two free N-heterocyclic carbenes (NHCs) 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-dimesitylimidazol-2-yliden (IMes) with group VB transition metals MCl5 at low temperature gave a mono-NHC complex [(IPr)TaCl5] (1) and two bis-NHCs [(IMes)2MCl4][MCl6] (M = Ta, 2; =Nb, 3). Crystallographic studies revealed that the substitution effect plays an important role in the construction of these two different types of NHC complexes. Although mono-NHC complex 1 has been theoretically analyzed by F. Marchetti, complexes 2 and 3 represented the first examples of the structurally characterized bis-NHCs Ta(v) and Nb(v) complexes. In addition, complexes 1–3 showed catalytic efficiency in the cycloaddition between CO2 and propylene oxide to synthesize cyclic carbonates under mild conditions. [ABSTRACT FROM AUTHOR]

A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials. [ABSTRACT FROM AUTHOR]