Abstract: The search for high active, stable, and cost-efficient hydrogen evolution reaction (HER) electrocatalysts for water electrolysis has attracted great interest. The coordinated water molecules in the hydronium ions will obviously reduce the positive charge density of H+ and hamper the ability of H+ to receive electrons from the cathode, leading to large overpotential of HER on nonprecious metal catalysts. Here we realize Pt-like hydrogen evolution electrocatalysis on polyaniline (PANI) nanodots (NDs)-decorated CoP hybrid nanowires (HNWs) supported on carbon fibers (CFs) (PANI/CoP HNWs-CFs) as PANI can effectively capture H+ from hydronium ions to form protonated amine groups that have higher positive charge density than those of hydronium ions and can be electro-reduced easily. The PANI/CoP HNWs-CFs as low-cost electrocatalysts show excellent catalytic performance toward HER in acidic solution, such as super high catalytic activity, small Tafel slope, and superior stability.

Abstract: Despite the widespread success of transition-metal-catalysed cross-coupling methodologies, considerable limitations still exist in reactions at sp3-hybridized carbon atoms, with most approaches relying on prefunctionalized alkylmetal or bromide coupling partners1,2. Although the use of native functional groups (for example, carboxylic acids, alkenes and alcohols) has improved the overall efficiency of such transformations by expanding the range of potential feedstocks3–5, the direct functionalization of carbon–hydrogen (C–H) bonds—the most abundant moiety in organic molecules—represents a more ideal approach to molecular construction. In recent years, an impressive range of reactions that form C(sp3)–heteroatom bonds from strong C–H bonds has been reported6,7. Additionally, valuable technologies have been developed for the formation of carbon–carbon bonds from the corresponding C(sp3)–H bonds via substrate-directed transition-metal C–H insertion8, undirected C–H insertion by captodative rhodium carbenoid complexes9, or hydrogen atom transfer from weak, hydridic C–H bonds by electrophilic open-shell species10–14. Despite these advances, a mild and general platform for the coupling of strong, neutral C(sp3)–H bonds with aryl electrophiles has not been realized. Here we describe a protocol for the direct C(sp3) arylation of a diverse set of aliphatic, C–H bond-containing organic frameworks through the combination of light-driven, polyoxometalate-facilitated hydrogen atom transfer and nickel catalysis. This dual-catalytic manifold enables the generation of carbon-centred radicals from strong, neutral C–H bonds, which thereafter act as nucleophiles in nickel-mediated cross-coupling with aryl bromides to afford C(sp3)–C(sp2) cross-coupled products. This technology enables unprecedented, single-step access to a broad array of complex, medicinally relevant molecules directly from natural products and chemical feedstocks through functionalization at sites that are unreactive under traditional methods. Direct coupling of aliphatic C–H nucleophiles to aryl electrophiles is described, through the combination of light-driven polyoxometalate hydrogen atom transfer and nickel catalysis.

Abstract: Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF-8 layer is coated onto a self-assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor-specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS-active GSPs substrates through a ZIF-8 channel. Through a Schiff base reaction with 4-aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.

Abstract: ConspectusThe field of supramolecular chemistry has its foundation in molecular recognition and selective binding of guest molecules, often with remarkably strong binding affinities. The field evolved to leverage these favorable interactions between the host and its guest to catalyze simple, often biomimetic transformations. Drawing inspiration from these early studies, self-assembled supramolecular hosts continue to capture a significant amount of interest toward their development as catalysts for increasingly complex transformations. Nature often relies on microenvironments, derived from complex tertiary structures and a well-defined active site, to promote reactions with remarkable rate acceleration, substrate specificity, and product selectivity. Similarly, supramolecular chemists have become increasingly intrigued by the prospect that self-assembly of molecular components might generate defined and spatially segregated microenvironments that can catalyze complex transformations.Among the growing pale...

Abstract: Plasmon-induced chemical reactions of molecules adsorbed on metal nanostructures are attracting increased attention for photocatalytic reactions. However, the mechanism remains controversial because of the difficulty of direct observation of the chemical reactions in the plasmonic field, which is strongly localized near the metal surface. We used a scanning tunneling microscope (STM) to achieve real-space and real-time observation of a plasmon-induced chemical reaction at the single-molecule level. A single dimethyl disulfide molecule on silver and copper surfaces was dissociated by the optically excited plasmon at the STM junction. The STM study combined with theoretical calculations shows that this plasmon-induced chemical reaction occurred by a direct intramolecular excitation mechanism.

Abstract: Sulfurized polyacrylonitrile (SPAN) is the most promising cathode for next-generation lithium–sulfur (Li–S) batteries due to the much improved stability. However, the molecular structure and reaction mechanism have not yet been fully understood. Herein, we present a new take on the structure and mechanism to interpret the electrochemical behaviors. We find that the thiyl radical is generated after the cleavage of the S–S bond in molecules in the first cycle, and then a conjugative structure can be formed due to electron delocalization of the thiyl radical on the pyridine backbone. The conjugative structure can react with lithium ions through a lithium coupled electron transfer process and form an ion-coordination bond reversibly. This could be the real reason for the superior lithium storage capability, in which the lithium polysulfide may not be formed. This study refreshes current knowledge of SPAN in Li–S batteries. In addition, the structural analysis is applicable to analyze the current organic catho...

Abstract: ConspectusCross-coupling reactions have been established as potential tools for manufacture of complex molecular frameworks of diversified interests by connecting two simple molecules through the formation of a carbon–carbon (C–C) or a carbon–heteroatom (C–X) bond. Conventional cross-couplings are transition metal-catalyzed reactions between electrophiles and nucleophiles. Generally, the electrophilic partner is an aryl or alkenyl halide, the nucleophile is an organometallic reagent, and both are obtained from prefunctionalization of their corresponding hydrocarbons. During the past decade, transition metal-catalyzed dehydrogenative cross-couplings between two carbon–hydrogen (C–H) bonds and between one C–H bond and one heteroatom–hydrogen (X–H) bond, which build a C–C and a C–X linkage respectively, have emerged as an attractive strategy in synthetic chemistry. Such straightforward couplings allow use of less functionalized reagents, thus reducing the number of steps to the target molecule and minimizing...

Abstract: Side-chain-type polymer architectures have been extensively studied for development of highly conductive fuel cell membranes. However, the commonly used rigid, hydrophobic spacers (between the ionic end-group and polymer backbone) limit self-assembly of ionic side-chains and, therefore, ion transport. Herein, we report a flexible, hydrophilic side-chain-type anion exchange membrane (AEM), where ethylene oxide spacers are incorporated into imidazolium-containing cationic side-chains. AFM and SAXS analysis confirm that the flexible spacers facilitate self-assembly of the ionic side-chains to form continuous conducting channels. Most importantly, both in situ FTIR spectroscopy and molecular dynamic theory simulations indicate that the ethylene oxide spacers are capable of hydrogen bonding to both H2O molecules and hydrated OH− ions. This unique auxiliary function facilitates both ion and H2O transport during fuel cell operation. The resultant AEM exhibits a peak power density of 437 mW cm−2 at 65 °C when tested in a H2/O2 single-cell anion-exchange membrane fuel cell, which is among the highest reported for comparable side-chain-type AEMs.

Abstract: Boron-graphdiyne (BGDY), which has a unique π-conjugated structure comprising an sp-hybridized carbon skeleton and evenlydistributed boron heteroatoms in a well-organized 2D molecular plane, is prepared through a bottom-up synthetic strategy. Excellent conductivity, a relatively low band gap and a packing mode of the planar BGDY are observed. Notably, the unusual bonding environment of the all sp-carbon framework and the electron-deficient boron centers generates affinity to metal atoms, and thus provides extra binding sites. Furthermore, the expanded molecule pores of the BGDY molecular plane can also facilitate the transfer of metal ions in the perpendicular direction. The practical effect of the all sp-carbon structure and boron heteroatoms on the properties of BGDY are demonstrated in its performance as the anode in sodium-ion batteries.

Abstract: The chemical composition of an exoplanet is a key ingredient in constraining its formation history. Iron is the most abundant transition metal, but has never been directly detected in an exoplanet due to its highly refractory nature. KELT-9b (HD 195689b) is the archetype of the class of ultra-hot Jupiters that straddle the transition between stars and gas-giant exoplanets and serve as distinctive laboratories for studying atmospheric chemistry, because of its high equilibrium temperature of 4050 +/- 180 K. These properties imply that its atmosphere is a tightly constrained chemical system that is expected to be nearly in chemical equilibrium and cloud-free. It was previously predicted that the spectral lines of iron will be detectable in the visible range of wavelengths. At these high temperatures, iron and several other transition metals are not sequestered in molecules or cloud particles and exist solely in their atomic forms. Here, we report the direct detection of atomic neutral and singly-ionized iron (Fe and Fe+), and singly-ionized titanium (Ti+) in KELT-9b via the cross-correlation technique applied to high-resolution spectra obtained during the primary transit of the exoplanet.

Abstract: Single-protein molecules are identified in parallel through fluorescence monitoring of Edman degradation. The identification and quantification of proteins lags behind DNA-sequencing methods in scale, sensitivity, and dynamic range. Here, we show that sparse amino acid–sequence information can be obtained for individual protein molecules for thousands to millions of molecules in parallel. We demonstrate selective fluorescence labeling of cysteine and lysine residues in peptide samples, immobilization of labeled peptides on a glass surface, and imaging by total internal reflection microscopy to monitor decreases in each molecule's fluorescence after consecutive rounds of Edman degradation. The obtained sparse fluorescent sequence of each molecule was then assigned to its parent protein in a reference database. We tested the method on synthetic and naturally derived peptide molecules in zeptomole-scale quantities. We also fluorescently labeled phosphoserines and achieved single-molecule positional readout of the phosphorylated sites. We measured >93% efficiencies for dye labeling, survival, and cleavage; further improvements should enable studies of increasingly complex proteomic mixtures, with the high sensitivity and digital quantification offered by single-molecule sequencing.

Abstract: We present a hybrid metageneralized-gradient-approximation functional, revM06, which is based on adding Hartree–Fock exchange to the revM06-L functional form Compared with the original M06 suite of density functionals, the resulting revM06 functional has significantly improved across-the-board accuracy for both main-group and transition-metal chemistry The revM06 functional improves on the M06-2X functional for main-group and transition-metal bond energies, atomic excitation energies, isomerization energies of large molecules, molecular structures, and both weakly and strongly correlated atomic and molecular data, and it shows a clear improvement over M06 and M06-2X for noncovalent interactions, including smoother potential curves for rare-gas dimers The revM06 functional also predicts more accurate results than M06 and M06-2X for most of the outside-the-training-set test sets examined in this study Therefore, the revM06 functional is well-suited for a broad range of chemical applications for both main-group and transition-metal elements

Abstract: We report high-performance aqueous Zn-ion batteries consisting of a zinc anode, a poly(benzoquinonyl sulfide) (PBQS) cathode, and a 3 M Zn(CF3SO3)2 aqueous electrolyte. The PBQS cathode displays an initial discharge capacity of 203 mA h g−1 at 0.1C and a good capacity retention of 86% after 50 cycles at 0.2C. The PBQS cathode can deliver a high reversible capacity of 126 mA h g−1 at a high rate of 5.0C. Meanwhile, we also studied the redox mechanism during discharge/charge processes by ex situ infrared spectra and theoretical calculations, revealing that reversible bonding of Zn2+ ions with carbonyl oxygen atoms in PBQS occurs in the redox reactions of PBQS molecules. The redox reactions of PBQS molecules can be regarded as the reversible bonding of Zn2+ ions with carbonyl oxygen atoms in PBQS.

Abstract: In this protocol, we report an allylic defluorinative reductive cross-coupling reaction for C–C bond formation Under the Ni-catalysis the challenging C(sp3)–F bond cleavage of trifluoromethyl-substituted alkenes was achieved with easily accessible primary, secondary and tertiary alkyl halides as the coupling partners and Zn-powder as reducing agent This process provides an efficient and convenient entry to gem-difluoroalkenes bearing various sensitive functional groups under mild reaction conditions Moreover, this method proves to be suitable for late-stage functionalization of multifunctional complex molecules

Abstract: The selective detection and separation of target ions or molecules is an intriguing issue. Herein, a novel supramolecular organic framework (SOF-THBP) was constructed by bis-thioacetylhydrazine functionalized pillar[5]arenes. The SOF-THBP shows a fluorescent response for Fe3+ , Cr3+ , Hg2+ and Cu2+ ions. The xerogel of SOF-THBP shows excellent recyclable separation properties for these metal ions and the absorption rates were up to 99.29 %. More interestingly, by rationally introducing these metal ions into the SOF-THBP, a series of metal-ion-coordinated SOFs (MSOFs) such as MSOF-Fe, MSOF-Hg and MSOF-Cu were constructed. These metal ions coordinated MSOFs could selectively sense F- , Br- , and l-Cys, respectively. The detection limits of these MSOFs for F- , Br- and l-Cys were about 10-8 m.

Abstract: The work is an evolution of research already begin and in development. Therefore, we can observe a part that has already been commented that presents the whole development of the research from its beginning. Preliminary bibliographic studies did not reveal any works with characteristics studied here. With this arrangement of atoms and employees with such goals. Going beyond with imagination using quantum chemistry in calculations to obtain probable one new bio-inorganic molecule, to the Genesis of a bioinorganic membrane with a combination of the elements Be, Li, Se, Si, C and H. After calculation a bio-inorganic seed molecule from the previous combination, it led to the search for a molecule that could carry the structure of a membrane. From simple molecular dynamics, through classical calculations, the structure of the molecule was stabilized. An advanced study of quantum chemistry using ab initio, HF (Hartree-Fock) method in various basis is applied and the expectation of the stabilization of the Genesis of this bio-inorganic was promising. The calculations made so far admit a seed molecule at this stage of the quantum calculations of the arrangement of the elements we have chosen, obtaining a highly reactive molecule with the shape polar-apolar-polar. Calculations obtained in the ab initio RHF method, on the set of bases used, indicate that the simulated molecule, C13H20BeLi2 SeSi, is acceptable by quantum chemistry. Its structure has polarity at its ends, having the characteristic polar-apolar-polar. Even using a simple base set the polar-apolar-polar characteristic is predominant. The set of bases used that have the best compatible, more precise results are CC-pVTZ and 6-311G (3df, 3pd). In the CC-pVTZ base set, the charge density in relation to 6-311G (3df, 3pd) is 50% lower. The structure of the bio-inorganic seed molecule for a bio-membrane genesis that challenge the current concepts of a protective mantle structure of a cell such as bio-membrane to date is promising, challenging. Leaving to the biochemists their experimental synthesis.

Abstract: ConspectusOver hundreds of new organic semiconductor molecules have been synthesized as hole transport materials (HTMs) for perovskite solar cells. However, to date, the well-known N2,N2,N2′,N2′,N7,N7,N7′, octakis-(4-methoxyphenyl)-9,9-spirobi-[9,9′-spirobi[9H-fluorene]-2,2′,7,7′-tetramine (spiro-OMeTAD) is still the best choice for the best perovskite device performance. Nevertheless, there is a consensus that spiro-OMeTAD by itself is not stable enough for long-term stable devices, and its market price makes its use in large-scale production costly.Novel synthetic routes for new HTMs have to be sought that can be carried out in fewer synthetic steps and can be easily scaled up for commercial purposes. On the one hand, synthetic chemists have taken, as a first approach, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the spiro-OMeTAD molecule as a reference to synthesize molecules with similar energy levels, although these HOMO and LUMO energy...

Abstract: Radical hydrofunctionalization occurs with ease using metal-hydride hydrogen atom transfer (MHAT) catalysis to couple alkenes and competent radicalophilic electrophiles. Traditional two-electron electrophiles have remained unreactive. Herein we report the reductive coupling of electronically unbiased olefins with imines and aldehydes. Iron catalysis allows addition of alkyl-substituted olefins into imines through the intermediacy of free radicals, whereas a combination of catalytic Co(Salt-Bu,t-Bu) and chromium salts enables a branch-selective coupling of olefins and aldehydes through the formation of a putative alkyl chromium intermediate.

Abstract: The use of MoS2 nanosheets as oil additives has been proved effective to reduce friction and wear. Furthermore, it has been suggested that the synthesis of MoS2 nanosheets with an ultrathin structure could benefit the friction and wear reduction, as they would penetrate into the contact area easily. In this paper, two-dimensional MoS2 nanosheets were successfully fabricated by a solvothermal method with the aid of oleylamine. Meanwhile, the synthesized MoS2 nanosheets exhibited perfect dispersing stability in paraffin oil, due to the surface modification by oleylamine molecules. The friction and wear properties of the synthesized MoS2 nanosheets as oil additives were investigated using a ball-on-disk tribotester. The results showed that the two-dimensional MoS2 nanosheets exhibited enhanced friction-reducing and antiwear behaviors as compared to the multilayered MoS2 nanosheets. The prominent tribological performance of the two-dimensional MoS2 nanosheets was attributed to the formation of a thick tribofilm inside the wear tracks, which was confirmed by XPS analyses of the rubbing interfaces.

Abstract: A novel porphyrin-based two-dimensional metal–organic framework (MOF) nanodisk with small size and few layers was prepared by coordination chelation between meso-tetra(4-carboxyphenyl)porphine ligand and Zn(II) paddlewheel metal nodes. With 4,4′-biphenyldicarboxylic acid (BPDC) as nucleation modulator, the anisotropic growth of MOF was impeded by the increased steric hindrance, yielding small Zn–TCPP(BP) MOF crystals. The as-prepared MOF nanodisk exhibited good electrocatalytic activity and selectivity towards nitrite due to the independent distribution of the porphyrin molecules in the framework and the sandwich structure of the prepared Zn–TCPP(BP) nanodisk, which increased the accessible active sites.

Abstract: Porous molecular crystals are an emerging class of porous materials that is unique in being built from discrete molecules rather than being polymeric in nature. In this study, we examined the effects of molecular structure of the precursors on the formation of porous solid-state structures with a series of 16 rigid aromatics. The majority of these precursors possess pyrazole groups capable of hydrogen bonding, as well as electron-rich aromatics and electron-poor tetrafluorobenzene rings. These precursors were prepared using a combination of Pd- and Cu-catalyzed cross-couplings, careful manipulations of protecting groups on the nitrogen atoms, and solvothermal syntheses. Our study varied the geometry and dimensions of precursors, as well as the presence of groups capable of hydrogen bonding and [π···π] stacking. Thirteen derivatives were crystallographically characterized, and four of them were found to be porous with surface areas between 283 and 1821 m2 g–1. Common to these four porous structures were (a...

Abstract: Proton conducting nanoporous materials attract substantial attention with respect to applications in fuel cells, supercapacitors, chemical sensors, and information processing devices inspired by biological systems. Here, a crystalline, nanoporous material which offers dynamic remote-control over the proton conduction is presented. This is realized by using surface-mounted metal-organic frameworks (SURMOFs) with azobenzene side groups that can undergo light-induced reversible isomerization between the stable trans and cis states. The trans-cis photoisomerization results in the modulation of the interaction between MOF and guest molecules, 1,4-butanediol and 1,2,3-triazole; enabling the switching between the states with significantly increased (trans) and reduced (cis) conductivity. Quantum chemical calculations show that the trans-to-cis isomerization results in the formation of stronger hydrogen bridges of the guest molecules with the azo groups, causing stronger bonding of the guest molecules and, as a result, smaller proton conductivity. It is foreseen that photoswitchable proton-conducting materials may find its application in advanced, remote-controllable chemical sensors, and a variety of devices based on the conductivity of protons or other charged molecules, which can be interfaced with biological systems.

Abstract: We explored the adsorption of SO2, SOF2, and SO2F2 on Pt- or Au-doped MoS2 monolayer based on density functional theory. The adsorption energy, adsorption distance, charge transfer as well as density of states were discussed. SO2 and SOF2 exhibit strong chemical interactions with Pt-doped MoS2 based on large adsorption energy, charge transfer, and changes of electron orbitals in gas molecule. SO2 also shows obvious chemisorption on Au-doped MoS2 with apparent magnetism transfer from Au to gas molecules. The adsorption of SO2F2 on Pt–MoS2 and SOF2 on Au–MoS2 exhibits weaker chemical interactions and SO2F2 losses electrons when adsorbed on Pt-MoS2 which is different from other gas adsorption. The adsorption of SO2F2 on Au–MoS2 represents no obvious chemical interaction but physisorption. The gas-sensing properties are also evaluated based on DFT results. This work could provide prospects and application value for typical noble metal-doped MoS2 as gas-sensing materials.