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1.
Ultra-dense deuterium D(−1) can be formed by a catalytic process from Rydberg Matter (RM) of deuterium as reported previously. Laser-induced inertial confinement fusion (ICF) has recently been observed in this material. The formation of D(−1) is now studied through experiments observing the deuterium RM clusters D N in excitation levels n B  = 1, 3 and 4. These levels are intermediate in the formation process of D(−1). Laser-induced fragmentation is used, with neutral time-of-flight (TOF) and TOF–MS measurements of the kinetic energy release (KER) from the quantized Coulomb explosions (CE). Several types of pure D N clusters, mixed clusters containing both D and H atoms, and clusters containing both D and K atoms are identified. The large planar RM clusters which are common for H and K are less common for D. The neutral D N clusters are small and have high kinetic temperature, typically at 100 K instead of 10 K for K N and H N . Large D N + clusters are only observed when an electric field is applied, probably stabilized by increased cooling. A strong coupling of the D(1) laser fragmentation signal to the ultra-dense D(−1) signal is observed, and the materials D(1) and D(−1) are two rapidly interchangeable forms of quantum fluids.  相似文献   

2.
Down to the wire: Pentacene exhibits crystal-plane-dependent photoluminescence (PL) activity, as demonstrated in highly crystalline 1D?wires and 2D?disks, which were selectively synthesized using the vaporization-condensation-recrystallization (VCR) process. Although pentacene 1D?wires and 2D?disks have identical triclinic crystal structures, PL?activity is observed only from pentacene 1D?wires owing to the presence of "PL-active" (010) planes.  相似文献   

3.
4.
Divalent metal coordination polymers containing terephthalate (tere) and bis(4-pyridylformyl)piperazine (bpfp) show diverse and interesting two-dimensional (2D) interpenetrated, three-dimensional (3D) self-penetrated, or one-dimensional (1D) polyrotaxane topological features. Isostructural {[M(tere)(bpfp)(H(2)O)(2)]?4H(2)O}(n) phases (1, Zn; 2, Co) exhibit mutually inclined 2D + 2D → 3D interpenetration of gridlike layers. {[Cd(4)(tere)(4)(bpfp)(3)(H(2)O)(2)]·8H(2)O}(n) (3) possesses a novel 3,4,8-connected trinodal self-penetrated network with (4.6(2))(2)(4(2)6(16)8(7)10(3))(4(2)6(4))(2) topology. [Zn(2)Cl(2)(tere)(bpfp)(2)](n) (4) is the first example of a 1D + 1D → 1D polyrotaxane coordination polymer, to the best of our knowledge. Metal coordination geometry plays a crucial role in dictating the overall dimensionality in this system. Thermal decomposition behavior and luminescent properties of the d(10) configuration metal derivatives are also presented herein.  相似文献   

5.
Adiabatic (1A' or 1A' state) and non-adiabatic (2A'/1A' states) quantum dynamics calculations have been carried out for the title reaction (O((1)D) + D(2) → OD + D) to obtain the initial state-specified (v(i) = 0, j(i) = 0) integral cross section and rate constant using the potential energy surfaces of Dobbyn and Knowles. A total of 50 partial wave contributions have been calculated using the Chebyshev wave packet method with full Coriolis coupling to achieve convergence up to the collision energy of 0.28 eV. The total integral cross section and rate constant are in excellent agreement with experimental as well as quasi-classical trajectory results. Contributions from the adiabatic pathway of the 1A' state and the non-adiabatic pathway of the 2A'/1A' states, increase significantly with the collision energy. Compared to the O((1)D) + H(2) system, the kinetic isotope effect (k(D)/k(H)) is found to be nearly temperature independent above 100 K and its value of 0.77 ± 0.01 shows excellent agreement with the experimental result of 0.81.  相似文献   

6.
Gold 3D cylindrical nanoelectrode ensembles (NEEs), 100 nm in diameter and 500 nm in length were prepared by electroless template synthesis in polycarbonate filter membranes, followed by selective controlled chemical etching. The morphology of the nanowires and cylindrical NEEs was imaged by scanning electron microscopy. The protruding nanoelectrodes were in good parallel order. EDX study showed that the nanoelectrode elements consisted of pure gold. The electrochemical evaluation of the 3D electrodes was conducted using the well known [Fe(CN)6]^3-/[Fe(CN)6]^4- couple. Cyclic voltammgrams (CV) show a very low double layer charging current and a higher ratio of signal to background current than 2D disc NEEs. Electrochemical impedance spectroscopy (EIS) indicates that the 3D cylindrical NEEs effectively accelerate the charge transfer process, which is in consistent with the results of CV. The linear relationship with a slope of 0.5 between lg Ipc and lg v shows that linear diffusion is dominant on the 3D cylindrical NEEs at conventional scan rates.  相似文献   

7.
The first total synthesis of (±)-pallambins C and D has been accomplished in a linear 38 step reaction from (±)-Wieland-Miescher ketone. The key conversions are featured as follows: a Grob fragmentation-intramolecular aldol cyclization and a thiourea/palladium-catalyzed carbonylative annulation.  相似文献   

8.
The total synthesis of the 2-pyrone natural products nectriapyrone, aplysiopsenes A–C, ent-aplysiopsene D, phomapyrones A and D, and of 8,9-dehydroxylarone were achieved by Wittig olefination starting with vermopyrone. Infectopyrone was synthesized by Horner–Wadsworth–Emmons reaction starting with phomapyrone D. Racemic phomapyrone C methyl ether was obtained by hydrogenation of nectriapyrone. The total syntheses were achieved starting from commercially available 3,5-heptanedione and led to the desired natural products in 18–46% over 5–6 steps, whereupon all five-step syntheses were carried out with a single chromatographic workup. The total synthesis of infectopyrone, aplysiopsenes A–D, of phomapyrones A and D, and of 8,9-dehydroxylarone were achieved for the first time, giving unambiguous proof for the proposed structures of these natural products.  相似文献   

9.

Starting from 1,2‐isopropylidene‐d‐xylose (1), 3‐methoxyoxetane δ‐amino acids with dlyxo, dribo, and darabino configurations were synthesized. The early introduction of an azide function at C‐5 of 1 shortened the synthetic pathway. Ring contraction of the intermediate d‐xylono‐1,4‐lactone 6 via triflation and treatment with base led to the corresponding 3‐methoxyoxetane δ‐amino ester with dlyxo configuration 7. The analogous procedure for d‐ribono‐1,4‐lactone 16 furnished a mixture of dribo and darabino esters 17 and 18. Hydrolysis of the methyl esters 7, 17, and 18 to their corresponding δ‐amino acids was successful with LiOH in THF, in contrast to that of their 3‐hydroxy analog 11.   相似文献   

10.
1 INTRODUCTION There is continuing interest in the assembly of molecular capsules based on concomitant formation of multiple hydrogen bonds between smaller mole- cular components[1]. A particularly attractive buil- ding block is calix[4]resorcinarenes with eight pen- dant hydroxyl functional groups[2]. In a crystal engi- neering design strategy for molecular self-assembly, cocrystallization of C-methylcalix[4]resorcinarenes with nitrogen-donor molecules such as pyridines in the presence …  相似文献   

11.
In a program of investigating the chemical constituents of the potentially α-amylase- inhibiting complex, WC670, extracted from the culture filtrate of Streptomyces luteogriseus, we found it contains the known aminooligosaccharides, isovalertatins M03, M…  相似文献   

12.
In this paper, 238 Rayleigh wave path data are selected and processed by the matched-filtering frequency-time analysis technique and the grid dispersion inversion method to obtain the 3D S-wave velocity structure of China mainland and its adjacent sea regions. The results show that the velocity structure relates to geotectonic division, Bouguer gravity anomaly is basically controlled by the relief of Moho discontinuity, the buried depth of LVL in upper mantle concerns the surface heat flow deeply. In this paper, authors indicate the main characteristics of the velocity structure in tectonic active and stable regions.  相似文献   

13.

Microwave‐assisted organic synthesis (MAOS) of D‐gluconic acid can be efficiently done by oxidation of D‐glucose with bromine water, upon irradiation with microwave (MW). It was also used for the conversion of D‐gluconic acid to ethyl D‐gluconate, D‐glucono‐1,4‐ and 1,5‐lactones, gluconyl hydrazide, and gluconyl phenylhydrazide in yields comparable to those obtained by conventional methods, but in much shorter times. A convenient microwave‐mediated condensation of D‐gluconic acid with o‐phenylenediamines provided the respective acyclonucleoside benzimidazole in short time and good yield.   相似文献   

14.
The double cyclopalladated complex with azobenzene, μ-[(E)-1,2-diphenyldiazene-C2,8, N1,2]-di-[chloro(dimethylsulfoxide)palladium(II)]; (DMSO)PdCl(μ-C6H4NNC6H4)(DMSO)PdCl (1) and its analogous complex with DMF as ancillary ligand, (DMF)PdCl(μ-C6H4NNC6H4)(DMF)PdCl; μ-[(E)-1,2-diphenyldiazene-C2,8,N1,2]-di-[chloro(dimethylformamide)palladium(II)] (2a) were synthesized and the function of cyclopalladated moiety in molecular assembling in the solid state is illustrated by their crystal packings. The polymorphism of 2a and 2b is discussed. The crystal structures reveal assemblies with molecular components self-organized by C-H?Cl-Pd hydrogen bonds, π?π, and C-H?π interactions. The double cyclopalladated complexes of azobenzene, with two Pd-Cl moieties participating in the hydrogen bond formation and π-conjugated system involved in the π?π or C-H?π interactions, represent a new class of building blocks for construction of solid state supramolecular assemblies.  相似文献   

15.
An unprecedented 2D → 3D metal-organic polyrotaxane framework, based on a new star-like tri(4-imidazolylphenyl)amine ligand, has been synthesized and characterized, which represents the first example of 2D → 3D polyrotaxane entangled in a parallel fashion.  相似文献   

16.
The properties of noncovalent complexes of the enzyme exo-1,4-β-D-glycanase (“Cex”) with three aza-sugar inhibitors, deoxynojirimycin (X2DNJ), isofagomine lactam (X2IL), and isofagomine (X2IF), have been studied with solution and gas-phase hydrogen deuterium exchange (H/Dx) and measurements of collision cross sections of gas-phase ions. In solution, complexes have lower H/Dx levels than free Cex because binding the inhibitors blocks some sites from H/Dx and reduces fluctuations of the protein. In mass spectra of complexes, abundant Cex ions are seen, which mostly are formed by dissociation of complexes in the ion sampling interface. Both complex ions and Cex ions formed from a solution containing complexes have lower cross sections than Cex ions from a solution of Cex alone. This suggests the Cex ions formed by dissociation “remember” their solution conformations. For a given charge, ions of the complexes have greater gas-phase H/Dx levels than ions of Cex. Unlike cross sections, H/Dx levels of the complexes do not correlate with the relative gas-phase binding strengths measured by MS/MS. Cex ions from solutions with or without inhibitors, which have different cross sections, show the same H/Dx level after 15 s, indicating the ions may fold or unfold on the seconds time scale of the H/Dx experiment. Thus, cross sections show that complexes have more compact conformations than free protein ions on the time scale of ca. 1 ms. The gas-phase H/Dx measurements show that at least some complexes retain different conformations from the Cex ions on a time scale of seconds.  相似文献   

17.
Building on the MOF approach to prepare porous materials, herein we report the engineering of porous BN-doped materials using tricarboxylic hexaarylborazine ligands, which are laterally decorated with functional groups at the full-carbon ‘inner shell’. Whilst an open porous 3D entangled structure could be obtained from the double interpenetration of two identical metal frameworks derived from the methyl substituted borazine, the chlorine-functionalised linker undergoes formation of a porous layered 2D honeycomb structure, as shown by single-crystal X-ray diffraction analysis. In this architecture, the borazine cores are rotated by 60° in alternating layers, thus generating large rhombohedral channels running perpendicular to the planes of the networks. An analogous unsubstituted full-carbon metal framework was synthesised for comparison. The resulting MOF revealed a crystalline 3D entangled porous structure, composed by three mutually interpenetrating networks, hence denser than those obtained from the borazine linkers. Their microporosity and CO2 uptake were investigated, with the porous 3D BN-MOF entangled structure exhibiting a large apparent BET specific surface area (1091 m2 g−1) and significant CO2 reversible adsorption (3.31 mmol g−1) at 1 bar and 273 K.  相似文献   

18.
A new 2D Ca(Ⅱ) coordination polymer, [Ca(H2btc)(H2O)2]n(1, H4 btc = biphenyl-3,3',5,5'-tetracarboxylic acid), has been synthesized using the hydrothermal method and characterized by single-crystal X-ray diffraction, elemental analysis, IR, thermogravimetric analysis, and photoluminescent analysis. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 17.5676(15), b = 11.4496(8), c = 7.6197(8)A, β = 102.787(2)o, V = 1494.6(2) A3, Z = 4, D3 c = 1.797 Mg·m-, μ = 0.483 mm-1, F(000) = 832, the final R = 0.0348 and wR = 0.0915 for 1521 observed reflections with I 2σ(I). Complex 1 has a 2D network containing 1D calcium-oxygen chains. These 2D networks are further connected by O–H···O hydrogen bonding interactions to generate a 3D supramolecular structure.  相似文献   

19.
Two unusual metal-organic frameworks {[Ag(2)(Hbtc)(bpy)(2)]·(H(2)O)(2)}(n) (1), {[Ag(3)(btc)(bpy)(3)(H(2)O)]·(H(2)O)(7)}(n) (2) (H(3)btc = 1,2,3-benzenetricarboxylic acid, bpy = 4,4'-bipyridine) have been synthesized and characterized by single crystal X-ray diffraction. Complex 1 features an infinite 1D→1D tubular intertwinement network, while complex 2 exhibits a double ladder structure which contains rare winding water chains. Both infinite 1D→1D tubular chains in complex 1 and double ladder in 2 are mutually interconnected by hydrogen bonding and π···π stacking interactions into three-dimensional (3D) supramolecular networks. In addition, thermogravimetric analysis, powder X-ray diffraction (XRD), and photoluminescent behavior of the complexes have also been investigated.  相似文献   

20.
Gibbilimbols (1) were isolated from the leaves of Piper gibbilimbum in Papua New Guinea, which showed cyto toxicity toward KB nasopharyngal cancer cells (EDs0 2~ 8 μg/mL) and antibacterial activity against Staphylococcus epidermidis and Bacillus cereus (MIC 2 ~4 μg/mL). [1] Only two methods were reported for the synthesis of them,one is a coupling of phenolic part with alkyne, followed by reduction of triple bond by Mori. [2]  相似文献   

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