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A novel redox-active quinone-based organic building block 1,4-dicyano-2,3,5,6-tetrahydroxybenzene (LH4) has been synthesized and used as a bridging ligand to form a new 1D copper-benzoquinoid coordination polymer [CuL(DMF)2]n. The compound is able to deliver an initial capacity as high as 268 mA h g−1 at 30 mA g−1 (∼C/2.5) when used as the cathode in Li batteries. Ex situ XPS and FT-IR reveal the involvement of both Cu and organic moieties in the multi-electron redox reaction. Cu K-edge XANES and EXAFS measurements confirm the change in the oxidation state and coordination environment of Cu during the discharge–charge process. In situ generated metallic nanoparticles have been observed by TEM. The obtained mechanistic understanding of the metal–organic electrode materials for Li-based batteries may pave the way for the design of next-generation energy-storage systems.

This study presents photoresponsive, dynamic pseudorotaxane crystals composed of axle molecules containing biferrocene or ferrocene groups threaded through a dibenzo[24]crown-8 ether ring. A biferr...

Directed assembly of loosely, Na+-bound, oxidovanadate-centered quartets of C4-symmetry from tailor-made chiral N-salicylidene-vanadyl(V) complexes, for the first time, allows for highly efficient Ba2+- or Hg2+-specific detection (by 51V NMR and VCD), transport (forming a unique helical capsule or a capped square planar complex, respectively), and green recovery from an aqueous phase containing 4 different alkaline earth ions or from at least 10 different metal ions of similar size and charge capacity into the CHCl3 layer without interference from oxa- or oxophilic ions like Mg2+, Ca2+, Cu2+, Cd2+, and Pb2+.

The highly enantioselective conjugate addition of a variety of arylboronic acids to β-nitroacrylates is reported to provide optically active α-aryl β-nitropropionates in up to 70% yields and >99.5% ee’s, which are useful building blocks for preparing chiral β2-amino acids. The applicability of this transformation is demonstrated by converting 3aa into the β2-amino acid 5 and transforming 3ap to β-amino ester 7 via reduction and reductive N-alkylation. The latter compound is a precursor for preparing ent-ipatasertib.

The authors analyze relevant public information provided by new media to predict the movement of the USD/TWD exchange rate and explore whether big data analytics with machine-learning modeling can exceed the random walk mechanism and the notion of market efficiency.

VO2(B) nanobelts were grown by a vapor transport and condensation method in a furnace and identified by standard electron microscopy methods. A phase transition process from VO2(B) to VO2(M1) was made possible under electron beam irradiation. To identify the phase transition, the variations of the phase and diffraction pattern were recorded for the VO2 nanobelts. A method to monitor the temperature of the samples in the transmission electron microscope under a certain electron beam convergence was proposed. A mesa made of the VO2 phase change material can be employed to monitor the elevated temperature in the area where the electron beam is converged.

As a new synthetic approach, a versatile building block of [(Re(CO)4)3(N3S3)] (1a) can be used to react with linear dipyridyl ligands (i.e., pyrazine (pz), 4,4'-bipyridine (bpy), 1,2-di(4-pyridyl)ethylene (dpe), bis(4-pyridyl)acetylene (bpa), and 1,4-bis(pyridyl-4-ylethynyl)benzene (bpb)) and a tripyridyl one (1,3,5-tris(4-pyridylethynyl)benzene (tpb)) to afford a series of molecular cages, [(Re(CO)3)6(L)3(N3S3)2] (L = pz 2; bpy 3; bpe 4; bpa 5; bpb 6) and [(Re(CO)3)9(tpb)3(N3S3)3] (7) by solvothermal methods. Interestingly, various structural dimensions and motifs can be systematically tuned and obtained depending on different dipyridyl and tripyridyl ligands used in the reaction condition. In this regard, molecular cages of hexanuclear complexes of 2-6 containing dipyridyl ligands feature interesting trigonal-prism structures with different dimensionalities. Furthermore, the nonanuclear complex of 7 shows a novel trianglular-star structure, and three benzene rings of tpb ligands form a triple-decker arrangement with significant pi...pi interactions of 3.490(1) and 3.528(1) A. In addition, molecular cages of 1-3 and 5-7 exhibit luminescence in the solid state, and their luminescent properties are also studied.

Here we report the preparation of an unprecedented Ge(I)-Ge(I) bonded digermylene [K2{Ge2(μ-κ2:η2:η4-2,6-(2,6-iPr2C6H3-N)2-4-CH3C5H2N)2}] (3) in an eclipsed conformation stabilized by two bridging diamidopyridyl ligands. Although 3 exhibits an eclipsed conformation, the Ge-Ge bond length is 2.5168(6) A, shorter than those in the trans-bent and gauche digermylenes. In combination with two pendant amido groups, the GeI2 motif of 3 is employed as a building block to assemble the first example of octagermylene [Ge4(μ-κ2:κ1-2,6-(2,6-iPr2C6H3-N)2-4-CH3C5H2N)2]2 (5) showing a cyclic configuration and containing three distinct types of Ge(I)-Ge(I) bonds.

An efficient palladium-catalyzed addition reaction of alkyl- and arylsulfonic acids to propiolate esters to yield alkenyl sulfonates is demonstrated. The formation of alkenyl sulfonates is highly regio- and stereoselective with favorable yields of up to 95%, and two of the alkenyl sulfonates are utilized for a Sonogashira cross-coupling reaction to produce (Z)-1,3-enynoates.

From yeast to humans, the cell cycle is tightly controlled by regulatory networks that regulate cell proliferation and can be monitored by dynamic visual markers in living cells. We have observed S phase progression by monitoring nuclear accumulation of the FHA-containing DNA binding protein Tos4, which is expressed in the G1/S phase transition. We use Tos4 localization to distinguish three classes of DNA replication mutants: those that arrest with an apparent 1C DNA content and accumulate Tos4 at the restrictive temperature; those that arrest with an apparent 2C DNA content, that do not accumulate Tos4; and those that proceed into mitosis despite a 1C DNA content, again without Tos4 accumulation. Our data indicate that Tos4 localization in these conditions is responsive to checkpoint kinases, with activation of the Cds1 checkpoint kinase promoting Tos4 retention in the nucleus, and activation of the Chk1 damage checkpoint promoting its turnover. Tos4 localization therefore allows us to monitor checkpoint-dependent activation that responds to replication failure in early versus late S phase.

An enantioselective RhI-catalyzed conjugate addition reaction of α-substituted β-nitroacrylates with various arylboronic acids by using chiral RhI diene catalysts is described for the first time. The addition reaction proceeds under mild conditions in a range of common organic solvents and additives, and it affords the corresponding quaternary-carbon-containing α,α-disubstituted β-nitropropionate products in up to 63 % yield and 99 % ee. Reaction of either (E)- or (Z)-β-nitroacrylates provided the same enantiomer of the product, and a range of esters and aryl groups were tolerated. To demonstrate the utility of the method, ethyl (R)-1,1-methyl-1-phenyl-3-nitropropionate, prepared herein, was converted to the non-proteinogenic β2,2-amino acid, (R)-2-(aminomethyl)-2-phenylpropanoic acid, and to the β2,2-lactam, (R)-3-methyl-3-phenylazetidin-2-one. In addition, a tripeptide, which comprised l-phenylalanine, l-alanine, and β2,2-amino acid 7, was also synthesized.

A boraamidinato ligand [PhB(N-2,6-(i) Pr2 C6 H3 )2 ](2-) was employed to stabilize a new family of multiply bonded dimolybdenum complexes [MoCl(μ-κ(2) -PhB(N-2,6-(i) Pr2 C6 H3 )2 )]2 (4) and [Mo(μ-κ(2) -PhB(N-2,6-(i) Pr2 C6 H3 )2 )]2 (n-) (n=0 (5), 1 (6), 2 (7)), with the respective formal Mo-Mo bond orders of 3, 4, 4.5, and 5. Each metal center in 5-7 is two-coordinate with respect to the ligands. Of particular interest is the quadruply bonded dimolybdenum complex 5, featuring an unprecedented angular conformation. The bent Mo2 N4 core of 5 distorts toward planarity upon reduction. As a result, compound 7 features a planar Mo2 N4 core, while that of 6 is still bent but less significantly than that of 5. Additionally, the Mo-Mo bond lengths of 4-7 systematically decrease as the valency of the central Mo2 units decreases. Complex 7 features the shortest Mo-Mo bond length (2.0106(5) Å) yet reported.

This paper considers forecast combination in a predictive regression. We construct the point forecast by combining predictions from all possible linear regression models given a set of potentially relevant predictors. We derive the asymptotic risk of least squares averaging estimators in a local asymptotic framework. We then develop a frequentist model averaging criterion, an asymptotically unbiased estimator of the asymptotic risk, to select forecast weights. Monte Carlo simulations show that our averaging estimator compares favorably with alternative methods such as weighted AIC, weighted BIC, Mallows model averaging, and jackknife model averaging. The proposed method is applied to stock return predictions.

Reaction of C63 NO2 (Ph)2 (Py) (1) with o-phenylenediamine and pyridine produces a mixture of C63 H4 NO2 (Ph)2 (Py)(N2 C6 H4 ) (2) and H2 O@2. Compound 2 is a new open-cage fullerene containing a 20-membered heterocyclic orifice, which has been fully characterized by NMR spectroscopy, high-resolution mass spectrometry, and X-ray crystallography. The elliptical orifice of 2 spans 7.45 Å along the major axis and 5.62 Å along the minor axis, which is large enough to trap water and small organic molecules. Thus, heating a mixture of 2 and H2 O@2 with hydrogen cyanide and formaldehyde in chlorobenzene affords HCN@2 and H2 CO@2, respectively. The (1) H NMR spectroscopy reveals substantial upfield shifts for the endohedral species (δ=-1.30 to -11.30 ppm), owing to the strong shielding effect of the fullerene cage.

Mediated by Lewis acids, a Friedel–Crafts type of addition of acyl chlorides to alkynes gives β-chloro α,β-unsaturated ketones, which are important precursors to the preparation of heterocycles. A similar principle had been applied to the quintuply bonded dimolybdenum amidinate [Mo2(μ-κ2-HC(N-2,6-iPr2C6H3)2)2] (1). Addition of acyl halides to 1 resulted in the formation of the β-halo α,β-quadruply bonded dimolybdenum acyl complexes anti-Mo2(X)(μ-κ2-OCR)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 (R = Me, X = Cl (3); R = C6H5, X = Cl (4), Br (5); R = 4-FC6H4, X = Cl (6); R = 2-MeC6H4, X = Cl (7)). DFT calculations on Mo2(Cl)(μ-κ2-OCMe)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 suggested that it equilibrates with the oxo alkylidyne Mo2(O)(μ-Cl)(μ-CMe)[μ-κ2-HC(N-2,6-iPr2C6H3)2]2 in a ratio of about 100:1. The nucleophilic Mo═O functionality turned out to be reactive toward various electrophiles. Complexes 3–7 were subsequently treated with acyl halides RC(O)X to undergo haloacylation and yield carbyne-bridged dimolybdenum species [Mo2(X)(...

CdTe/Mg0.46Cd0.54Te double heterostructures with n-type In doping concentrations, varied from 1 × 1016 to 7 × 1018 cm−3, have been grown on InSb substrates using molecular beam epitaxy. Secondary ion mass spectroscopy measurements show strong diffusion of In from the InSb substrate to the CdTe buffer layer, while the In concentration is constant in the CdTe layer between the two Mg 0.46Cd0.54Te barrier layers. Capacitance–voltage measurements show that the dopants are 100% ionized for the doping concentration range from 1 × 1016 to 1 × 1018 cm −3. The carrier lifetime decreases with increasing doping concentration (from 0.73 μs for an unintentionally doped sample to 0.74 ns for a 1 × 1018 cm−3 doped sample) due to the decrease of both radiative and nonradiative lifetimes. Decent carrier lifetimes are achieved (∼100 ns) between 1 × 1016 and 1 × 1017 cm−3 doping levels, which is beneficial for developing n-type monocrystalline CdTe solar cells, photodetectors, and other optoelectronic devices. The strongest photoluminescence intensity is observed when the doping concentration is 1 × 1017 cm −3, which corresponds to the highest internal quantum efficiency.

The highly enantioselective conjugate addition of a variety of arylboronic acids to β-nitroacrylates is reported to provide optically active α-aryl β-nitropropionates in up to 70% yields and99.5% ee's, which are useful building blocks for preparing chiral β

A one-pot, molecular sieve mediated sequential Knoevenagel condensation/decarboxylative Michael addition reaction has been developed. We discovered that the molecular sieves not only promoted the Knoevenagel condensation of isatins and malononitrile to generate isatylidene malononitriles, but also promoted the later decarboxylative Michael addition reactions of β-ketoacids and malonic acid half thioesters (MAHTs) with isatylidene malononitriles. This protocol provides a mild and efficient method for the preparation of 3,3-disubstituted oxindoles with an all carbon quaternary center in high yields.

Carbon dioxide is expected to be employed as an inexpensive and potential feedstock of C1 sources for the mass production of valuable chemicals and fuel. Versatile chemical transformations of CO2, i.e. insertion of CO2 producing bicarbonate/acetate/formate, cleavage of CO2 yielding μ-CO/μ-oxo transition-metal complexes, and electrocatalytic reduction of CO2 affording CO/HCOOH/CH3OH/CH4/C2H4/oxalate were well documented. Herein, we report a novel pathway for the reductive activation of CO2 by the [NiIII(OMe)(P(C6H3-3-SiMe3-2-S)3)]− complex, yielding the [NiIII(κ1-OCO˙−)(P(C6H3-3-SiMe3-2-S)3)]− complex. The formation of this unusual NiIII(κ1-OCO˙−) complex was characterized by single-crystal X-ray diffraction, EPR, IR, SQUID, Ni/S K-edge X-ray absorption spectroscopy, and Ni valence-to-core X-ray emission spectroscopy. The inertness of the analogous complexes [NiIII(SPh)], [NiII(CO)], and [NiII(N2H4)] toward CO2, in contrast, demonstrates that the ionic [NiIII(OMe)] core attracts the binding of weak σ-donor CO2 and triggers the subsequent reduction of CO2 by the nucleophilic [OMe]− in the immediate vicinity. This metal–ligand cooperative activation of CO2 may open a novel pathway promoting the subsequent incorporation of CO2 in the buildup of functionalized products.

An unprecedented infinite 3-D supramolecular assembly synergistically supported by mixed-valent AuI⋯AuIII aurophilicity and weak C–H⋯Cl hydrogen bonds was presented.

Two mononuclear nonheme Fe(III) complexes, [PPh4][Fe(III)(PS3″)(OCH3)] (1) and [PPh4][Fe(III)(PS3″)(Cl)] (2), supported by a tris(benzenethiolato)phosphine derivative PS3″ (PS3″ = P(C6H3-3-Me3Si-2-S)3(3-)) have been synthesized and characterized. The structures resolved from X-ray crystallography show that Fe(III) centers in both complexes adopt distorted trigonal-bipyramidal geometry with a methoxide or a chloride binding in the axial position. The magnetic data for both are consistent with intermediate-spin Fe(III) centers with a C3 symmetry (S = 3/2 ground state). The bound methoxide in 1 is labile and can be replaced by a CH3CN molecule. The forming Fe(III)-CH3CN species can be further reduced by cobaltcene quantitatively to a stable Fe(II)-CH3CN complex, [Fe(PS3″)(CH3CN)](-). One-electron oxidation of 2 by ferrocenium gave a Fe(IV) analogue, [Fe(IV)(PS3″)(Cl)]. Importantly, the Fe(III)-OCH3 moiety in complex 1 acts as a strong nucleophile that activates the C-Cl bond in CH2Cl2, leading to the formation of complex 2 quantitatively. Complex 1 also reacts with other electrophiles, benzyl chloride and benzyl bromide, to generate Fe(III)-X species (X = Cl or Br). The reactions were investigated and monitored by UV-vis-NIR, NMR, and ESI-MS spectroscopies.

The formation of RNA-DNA hybrids, referred to as R-loops, can promote genome instability and cancer development. Yet the mechanisms by which R-loops compromise genome instability are poorly understood. Here, we establish roles for the evolutionarily conserved Nrl1 protein in pre-mRNA splicing regulation, R-loop suppression and in maintaining genome stability. nrl1Δ mutants exhibit endogenous DNA damage, are sensitive to exogenous DNA damage, and have defects in homologous recombination (HR) repair. Concomitantly, nrl1Δ cells display significant changes in gene expression, similar to those induced by DNA damage in wild-type cells. Further, we find that nrl1Δ cells accumulate high levels of R-loops, which co-localize with HR repair factors and require Rad51 and Rad52 for their formation. Together, our findings support a model in which R-loop accumulation and subsequent DNA damage sequesters HR factors, thereby compromising HR repair at endogenously or exogenously induced DNA damage sites, leading to genome instability.

Herein, we report the employment of the Mo-Mo quintuple bonded amidinate complex to stabilize Group 10 metal fragments {(Et3P)2M} (M=Pd, Pt) and give rise to the isolation of the unprecedented δ complexes. X-ray analysis unambiguously revealed short contacts between Pd or Pt and two Mo atoms and a slight elongation of the Mo-Mo quintuple bond in these two compounds. Computational studies show donation of the Mo-Mo quintuple-bond δ electrons to an empty σ orbital on Pd or Pt, and back-donation from a filled Pd or Pt dπ orbital into the Mo-Mo δ* level (LUMO), consistent with the Dewar-Chatt-Duncanson model.