Robust one-step catalytic machine for high fidelity anticloning and W-state generation in a multiqubit system

We propose a physically realizable machine which can either generate multiparticle W-like states, or implement high-fidelity 1-->M (M=1,2,...infinity) anticloning of an arbitrary qubit state, in a single step. This universal machine acts as a catalyst in that it is unchanged after either procedure, effectively resetting itself for its next operation. It possesses an inherent immunity to decoherence. Most importantly in terms of practical multiparty quantum communication, the machine's robustness in the presence of decoherence actually increases as the number of qubits M increases.     

Determination of 2,3-dinor-6-ketoprostaglandin F1 alpha in urine samples by liquid chromatography and radioimmunoassay

A method for 2,3-dinor-6-ketoprostaglandin F1 alpha quantification based on high-performance liquid chromatography-radioimmunoassay is described. Samples are acidified to pH 3 and processed through C18 disposable cartridges. The prostanoids are eluted with methyl formate and further separated on a reversed-phase column using acetonitrile-acetic acid-triethylamine buffer (32:68). Studies of the effect of eluent pH were performed in order to optimize resolution and separation of 2,3-dinor-6-keto-PGF1 alpha from other prostanoids. Eluates were collected and assayed by radioimmunoassay using a heterologous system, with 6-keto-PGF1 alpha as radioligand and an antiserum with high cross-reactivity for 2,3-dinor-6-keto-PGF1 alpha. Sensitivity, precision and accuracy of the assay procedure are reported together with the validation of its specificity. The proposed method has been applied to the determination of this prostacyclin metabolite in human urine.     

(9E)‐9‐Benzylidene‐3‐methyl‐2‐methylsulfanyl‐5‐phenyl‐5,6,7,8,9,10‐hexahydropyrimido[4,5‐b]quinolin‐4(3H)‐one: polarized molecules within hydrogen‐bonded bilayers

The molecules of the title compound, C₂₆H₂₅N₃OS, which was prepared by means of an acid‐catalysed cyclocondensation reaction between a 6‐aminopyrimidinone and 2,6‐dibenzylidenecyclohexanone, exhibit a polarized electronic structure, namely (9E)‐9‐benzylidene‐3‐methyl‐2‐methylsulfanyl‐5‐phenyl‐3,5,6,7,8,9‐hexahydropyrimido[4,5‐b]quinolin‐10‐ium‐4‐olate, involving charge separation in the vinylogous amide portion. Four hydrogen bonds, two each of the C—H...O and C—H...π(arene) types, link the molecules into bilayers comprising inversion‐related pairs of sheets, each containing a single type of R₄³(36) ring.     

9‐Benzoyl‐3,3,6,6‐tetramethyl‐1,2,3,4,5,6,7,8‐octahydroxanthene‐1,8‐dione: molecular conformation and supramolecular aggregation in xanthenediones

In the title compound, C₂₄H₂₆O₄, (I), the central ring of the fused tricyclic ring system adopts a shallow boat conformation, while the two outer rings adopt envelope conformations. The molecules are linked into C(9) chains by a single C—H...O hydrogen bond. The significance of this study lies in its comparison of the conformation and supramolecular aggregation of (I) with those of related compounds in the published literature.     

The electrochemistry of nanostructured Ni–W alloys

This work reports on the features that Ni–W nanostructured alloys, electrodeposited on carbon steel by different current pulse programs, may present depending on their surface morphology and surface composition. The Ni–W nanostructured coating, with a cauliflower structure, lack of fragility, and high WO₃/W surface composition ratio, is a stable electrode to catalyze hydrogen evolution reaction, exceeding bulk and electrodeposited Ni catalytic activity. Also, the nanostructured alloys must have a low WO₃/W surface composition ratio for Ni and its oxides to provide protection and improve corrosion resistance in sulfate media.     

Solvent‐Free Microwave‐Assisted Synthesis of Novel 4‐Hetarylpyrazolo[1,5‐a][1,3,5]triazines

A series of novel 4‐hetaryl substituted pyrazolo[1,5‐a][1,3,5]triazines were synthesized by microwave assisted reaction between O,S‐diethyl hetaroylimidothiocarbonates and 5‐amino‐3‐aryl‐1H‐pyrazoles under solvent‐free conditions. This procedure led to the formation of mixtures of two new pyrazolotriazine derivatives in a 1:4 ratio, which were separated by column chromatography being their corresponding structures unambiguously established by spectroscopic and analytical techniques. Comparison of the reactions mediated by microwave irradiation and by conventional heating in solution of DMF showed that both procedures afforded the same mixtures of products, but the first approach required shorter reaction times and gave higher yields than the second one.     

Natural sesquiterpenoids

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature is reviewed, and 435 references are cited.     

2‐Amino‐4‐chloro‐5‐formyl‐6‐[methyl(2‐methylphenyl)amino]pyrimidine and 2‐amino‐4‐chloro‐5‐formyl‐6‐[(2‐methoxyphenyl)methylamino]pyrimidine are isostructural and form hydrogen‐bonded sheets of R22(8) and R66(32) rings

2‐Amino‐4‐chloro‐5‐formyl‐6‐[methyl(2‐methylphenyl)amino]pyrimidine, C₁₃H₁₃ClN₄O, (I), and 2‐amino‐4‐chloro‐5‐formyl‐6‐[(2‐methoxyphenyl)methylamino]pyrimidine, C₁₃H₁₃ClN₄O₂, (II), are isostructural and essentially isomorphous. Although the pyrimidine rings in each compound are planar, the ring‐substituent atoms show significant displacements from this plane, and the bond distances provide evidence for polarization of the electronic structures. In each compound, a combination of N—H...N and N—H...O hydrogen bonds links the molecules into sheets built from centrosymmetric R₂²(8) and R₆⁶(32) rings. The significance of this study lies in its observation of the isostructural nature of (I) and (II), and in the comparison of their crystal and molecular structures with those of analogous compounds.     

Four 7‐aryl‐substituted pyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐diones: similar molecular structures but different crystal structures

Molecules of 1,3‐dimethyl‐7‐(4‐methylphenyl)pyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione, C₁₆H₁₅N₃O₂, (I), are linked by paired C—H...O hydrogen bonds to form centrosymmetric R₂²(10) dimers, which are linked into chains by a single π–π stacking interaction. A single C—H...O hydrogen bond links the molecules of 7‐(biphenyl‐4‐yl)‐1,3‐dimethylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione, C₂₁H₁₇N₃O₂, (II), into C(10) chains, which are weakly linked into sheets by a π–π stacking interaction. In 7‐(4‐fluorophenyl)‐3‐methylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione, C₁₄H₁₀FN₃O₂, (III), an N—H...O hydrogen bond links the molecules into C(6) chains, which are linked into sheets by a π–π stacking interaction. The molecules of 7‐(4‐methoxyphenyl)‐3‐methylpyrido[2,3‐d]pyrimidine‐2,4(1H,3H)‐dione, C₁₅H₁₃N₃O₃, (IV), are also linked into C(6) chains by an N—H...O hydrogen bond, but here the chains are linked into sheets by a combination of two independent C—H...π(arene) hydrogen bonds.     

(Z)‐5‐[(5‐Methyl‐1H‐imidazol‐4‐yl)methylidene]‐2‐sulfanylidene‐1,3‐thiazolidin‐4‐one monohydrate: a three‐dimensional hydrogen‐bonded framework structure

The non‐H atoms in the organic component of the title compound, C₈H₇N₃OS₂·H₂O, are almost coplanar, as the dihedral angle between the two ring planes is only 1.8 (2)°; there is a wide C—C—C angle of 127.8 (3)° at the methine C atom linking the two rings. The molecular components are linked into a three‐dimensional framework structure by two‐centre hydrogen bonds of N—H...O and O—H...N types, together with a three‐centre O—H...(N,S) system. Comparisons are made with some (Z)‐5‐arylmethylidene‐2‐sulfanylidene‐1,3‐thiazolidin‐4‐ones.