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Atomically thin two-dimensional (2D) materials have received considerable research interest due to their extraordinary properties and promising applications. Here we predict the monolayered indium triphosphide (InP3) as a new semiconducting 2D material with a range of favorable functional properties by means of ab initio calculations. The 2D InP3 crystal shows high stability and promise of experimental synthesis. It possesses an indirect band gap of 1.14 eV and a high electron mobility of 1919 cm[sup 2] V-1 s-1, which can be strongly manipulated with applied strain. Remarkably, the InP3 monolayer suggests tunable magnetism and half-metallicity under hole doping or defect engineering, which is attributed to the novel Mexican-hat-like bands and van Hove singularities in its electronic structure. A semiconductor-metal transition is also revealed by doping 2D InP3 with electrons. Furthermore, monolayered InP3 exhibits extraordinary optical absorption with significant excitonic effects in the entire range of the visible light spectrum. All these desired properties render 2D InP3 a promising candidate for future applications in a wide variety of technologies, in particular for electronic, spintronic, and photovoltaic devices. [ABSTRACT FROM AUTHOR]

Thetreatment of 2-(ArNCH)C6H4-HNC9H6N ([NQNANIMe]H, Ar = 2,6-Me2C6H3; [NQNANIEt]H, Ar = 2,6-Et2C6H3; [NQNANIiPr]H, Ar = 2,6-iPr2C6H3) with nBuLi and CrCl3(THF)3achieves the hetero-dinuclearcomplexes [NQNANIR]CrCl(μ-Cl)2Li(THF)2(1a, R = Me; 1b, R = Et; 1c, R = iPr) or bisligated complex κ5-[NQNANIiPr]2CrCl (2c)depending on the reactant ratios used. Reactions of these ligandswith nBuLi and CrCl2(THF)2couldachieve the square-pyramidal complexes [NQNANIR]CrCl(THF) (3b, R = Et; 3c, R = iPr). Complex 3ccan be oxidized by alkyl chloride to dimeric complex {[NQNANIiPr]CrCl}2(μ-Cl)2(4) through a single-electron-transfer mechanism. Similar reactionof 2-(C9H6N)NCHC6H4-HNAr ([NQNINAMe]H, Ar = 2,6-Me2C6H3; [NQNINAEt]H, Ar = 2,6-Et2C6H3; [NQNINAiPr]H, Ar = 2,6-iPr2C6H3) with nBuLi andCrCl3(THF)3furnishes [NQNINAR]CrCl(μ-Cl)2Li(THF)2(5a, R = Me; 5b, R = Et; 5c, R = iPr) in high yields. However,a chromium complex with a butyl-substituted ligand, [NQBuNINAiPr]CrCl2(6), is obtained when 2 equiv of nBuLi is used. The molecularstructures of 1c, 2c, 3c, 4, 5c, and 6are confirmed by X-raycrystallography. Upon activation with MAO, the Cr(III) complexes (1a–1c, 4, and 5a–5c) show moderate catalytic activities (50 to218 kg of PE·mol(Cr)−1·h–1) in ethylene polymerization, whereas the Cr(II) complexes 2c, 3b, and 3care inert under thesame conditions. [ABSTRACT FROM AUTHOR]

Four heterobimetallic lanthanide–potassium complexes stabilized by the carbon-bridged bis(phenolate) ligand MBMP2–(MBMP = 2,2′-methylene bis(6-tert-butyl-4-methylphenolate)), [{(MBMP)2La(THF)2}2K][K(THF)6] (1), [(MBMP)Nd(μ-MBMP)K(THF)]2(2), [(THF)2Sm(MBMP)2K(THF)2] (3), and [(THF)2Yb(MBMP)2K(THF)3] (4), were synthesized, and their structural features were provided. It was found that the ionic radii of lanthanide metals have a profound effect on the structures of the heterobimetallic complexes. Complexes 1to 4are efficient catalysts for amidation reactions of aldehydes with amines to produce amides in good to excellent yields under mild conditions. [ABSTRACT FROM AUTHOR]

An efficient FeCl3-catalyzed substitution reaction of propargylic acetates with enoxysilanes under mild conditions to afford corresponding γ-alkynyl ketones has been developed. The substitution reaction is followed by a TsOH-catalyzed cyclization without purification of the γ-alkynyl ketone intermediates, offering a straightforward synthetic route to tri- or tetrasubstituted furans. [ABSTRACT FROM AUTHOR]

cis,cis-1,2,3,4-Tetraphenylbutadiene (TPBD) exhibits aggregation-induced emission (AIE) in the UV-blue band: the photoluminescence (PL) quantum yield of TPBD aggregates can differ from that of molecularly dissolved species by 2 orders of magnitude (>200). When the isolated molecules in solutions are cooled to extremely low temperature, they also emit intense light comparable to that in the solid state. TPBD thin layer shows on−off fluorescence switching behavior that can be utilized for the sensing of organic vapors. The phenyl substituents in TPBD are twisted in the solid state, and excimer formation is greatly prohibited. The cooling-enhanced emission of the TPBD solution and the fluorescence switching behavior suggest that the aggregation-induced emission is caused by restricted intramolecular rotation of the phenyl groups. The intramolecular phenyl rotations of TPBD can be regarded as rotational relaxations around their equilibrium positions, from which mean relaxation time is defined based on an Arrhenius equation. All the PL behaviors of TPBD can be well explained qualitatively by the magnitude of the relaxation time. [ABSTRACT FROM AUTHOR]

How insulin binds to and activates the insulin receptor has long been the subject of speculation. Of particular interest are invariant phenylalanine residues at consecutive positions in the B chain (residues B24 and B25). Sites of mutation causing diabetes mellitus, these residues occupy opposite structural environments: PheB25 projects from the surface of insulin, whereas PheB24 packs against the core. Despite these differences, site-specific cross-linking suggests that each contacts the insulin receptor. Photoactivatable derivatives of insulin containing respective p-azidophenylalanine substitutions at positions B24 and B25 were synthesized in an engineered monomer (DKP-insulin). On ultraviolet irradiation each derivative cross-links efficiently to the receptor. Packing of PheB24 at the receptor interface (rather than against the core of the hormone) may require a conformational change in the B chain. Sites of cross-linking in the receptor were mapped to domains by Western blot. Remarkably, whereas B25 cross-links to the C-terminal domain of the α subunit in accord with previous studies (Kurose, T., et al. (1994) J. Biol. Chem. 269, 29190-29197), the probe at B24 cross-links to its N-terminal domain (the L1 β-helix). Our results demonstrate that consecutive residues in insulin contact widely separated sequences in the receptor and in turn suggest a revised interpretation of electron-microscopic images of the complex. By tethering the N- and C-terminal domains of the extracellular a subunit, insulin is proposed to stabilize an active conformation of the disulfide-linked transmembrane tyrosine kinase. [ABSTRACT FROM AUTHOR]

Studies the reactions of triphenylphosphine N-(perfluoroalkyl) sulfonyl)immune and triphenylarsine N-perfluoroalky)sulfonyl)immune. Experimental procedure used; Results of the study.

Proposes a strategy for the efficient synthesis of bicyclic compounds, in which the two rings are expected to be formed in one step. Advantage of this protocol.

An efficient rhodium-catalyzed tandem C–H bond olefination and annulation approach was developed to afford 1,2-dihydrophthalazines in good to excellent yields from easily accessible sulfonylhydrazones and alkenes. [ABSTRACT FROM AUTHOR]

Naturally occurring mutations in insulin associated with diabetes mellitus identify critical determinants of its biological activity. Here, we describe the crystal structure of insulin Wakayama, a clinical variant in which a conserved valine in the A chain (residue A3) is substituted by leucine. The substitution occurs within a crevice adjoining the classical receptor-binding surface and impairs receptor binding by 500-fold, an unusually severe decrement among mutant insulins. To resolve whether such decreased activity is directly or indirectly mediated by the variant side chain, we have determined the crystal structure of LeuA3-insulin and investigated the photo-cross-linking properties of an A3 analogue containing p-azidophenylalanine. The structure, characterized in a novel crystal form as an R6 zinc hexamer at 2.3 Å resolution, is essentially identical to that of the wild-type R6 hexamer. The variant side chain remains buried in a nativelike crevice with small adjustments in surrounding side chains. The corresponding photoactivatable analogue, although of low affinity, exhibits efficient cross-linking to the insulin receptor. The site of photo-cross-linking lies within a 14 kDa C-terminal domain of the α-subunit. This domain, unrelated in sequence to the major insulin-binding region in the N-terminal L1 β-helix, is also contacted by photoactivatable probes at positions A8 and B25. Packing of ValA3 at this interface may require a conformational change in the B chain to expose the A3-related crevice. The structure of insulin Wakayama thus evokes the reasoning of Sherlock Holmes in "the curious incident of the dog in the night": the apparent absence of structural perturbations (like the dog that did not bark) provides a critical clue to the function of a hidden receptor-binding surface. [ABSTRACT FROM AUTHOR]

Aromatic iodinated disinfection byproducts (DBPs) are a newly identified category of highly toxic DBPs. Among the identified aromatic iodinated DBPs, 2,4,6-triiodophenol and 2,6-diiodo-4-nitrophenol have shown relatively widespread occurrence and high toxicity. In this study, we found that 4-iodophenol underwent transformation to form 2,4,6-triiodophenol and 2,6-diiodo-4-nitrophenol in the presence of monochloramine. The transformation pathways were investigated, the decomposition kinetics of 4-iodophenol and the formation of 2,4,6-triiodophenol and 2,6-diiodo-4-nitrophenol were studied, the factors affecting the transformation were examined, the toxicity change during the transformation was evaluated, and the occurrence of the proposed transformation pathways during chloramination of source water was verified. The results revealed that 2,4,6-triiodophenol and 2,6-diiodo-4-nitrophenol, which could account for 71.0% of iodine in the transformed 4-iodophenol, were important iodinated transformation products of 4-iodophenol in the presence of monochloramine. The transformation pathways of 4-iodophenol in the presence of monochloramine were proposed and verified. The decomposition of 4-iodophenol in the presence of monochloramine followed a pseudo-second-order decay. Various factors including monochloramine dose, pH, temperature, nitrite concentration, and free chlorine contact time (before chloramination) affected the transformation. The cytotoxicity of the chloraminated 4-iodophenol samples increased continuously with contact time. The proposed transformation pathways occurred during chloramination of source water. [ABSTRACT FROM AUTHOR]

A facile gold-catalyzed oxidation terminal alkynes to synthesize substituted dihydronaphthalen-2(1H)-ones 3 and phenanthrenols 5 was realized. Various useful structures and drug precursors were generated in up to 99% yield under mild condition and low catalyst loading. [ABSTRACT FROM AUTHOR]

The protein toxin ricin obtained from castor bean plant (Ricinus communis) seeds is a potent biological warfare agent due to its ease of availability and acute toxicity. In this study, we demonstrated a rapid and simple method to detect ricin in serum in vitro. The ricin was mixed with serum and digested by trypsin, then all the peptides were efficiently extracted using Cu-chelated magnetic beads and were detected with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The specific ricin peptides were identified by Nanoscale Ultra Performance liquid chromatography coupled to tandem mass spectrometry according to their sequences. The assay required 2.5 hours, and a characteristic peptide could be detected down to 4 ng/μl and used as a biomarker to detect ricin in serum. The high sensitivity and simplicity of the procedure makes it valuable in clinical practice. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

An unexpected rhodium-catalyzedregioselective C–H chlorinationof 7-azaindoles was developed using 1,2-dichloroethane (DCE) as achlorinating agent and 7-azaindole as the directing group. This protocolprovides an efficient access to ortho-chlorinatedazaindoles with operational simplicity, good functional group tolerance,and a wide substrate scope. [ABSTRACT FROM AUTHOR]

An efficient palladium-catalyzedoxidative annulation reactionwas developed through sequential isocyanide insertions into N–Hand O–H bonds of hydrazides, which provides an efficient accessto valuable 2-amino-1,3,4-oxadiazoles and their derivatives. [ABSTRACT FROM AUTHOR]

Thecatalytic mechanism offers an efficient tool to produce crystallinesemiconductor nanowires, in which the choice, state, and structureof catalysts are active research issues of much interest. Here wereport a novel solution–solid–solid (SSS) mechanismfor nanowire growth catalyzed by solid-phase superionic conductornanocrystals in low-temperature solution. The preparation of Ag2Se-catalyzed ZnSe nanowires at 100–210 °C is exampledto elucidate the SSS model, which can be extendable to grow otherII–VI semiconductor (e.g., CdSe, ZnS, and CdS) nanowires bythe catalysis of nanoscale superionic-phase silver or copper(I) chalcogenides(Ag2Se, Ag2S, and Cu2S). The exceptionalcatalytic ability of these superionic conductors originates from theirstructure characteristics, known for high-density vacancies and fastmobility of silver or copper(I) cations in the rigid sublattice ofSe2–or S2–ions. Insights intothe SSS mechanism are provided based on the formation of solid solutionand the solid-state ion diffusion/transport at solid–solidinterface between catalyst and nanowire. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed regioselective C–H cyanation of heteroarenes was achieved using tert-butyl isocyanide as “CN” source, which provides a new and unique strategy for the preparation of (hetero)aryl nitriles. Indoles, pyrroles, and aromatic rings could be efficiently cyanated through C–H bond activation with high regioselectivity. [ABSTRACT FROM AUTHOR]

An efficient palladium-catalyzed synthesis of N-functionalized multisubstituted indoles from easily accessible ortho-haloarylallenes and primary amines has been developed. A wide range of electronically and structurally varied nitrogen fragments could be introduced through this tandem C–N bond-forming process by tuning the reaction conditions. [ABSTRACT FROM AUTHOR]