Reduction of nitro compounds using 3d-non-noble metal catalysts

The reduction of nitro compounds to the corresponding amines is one of the most utilized catalytic processes in the fine and bulk chemical industry. The latest development of catalysts with cheap metals like Fe, Co, Ni, and Cu has led to their tremendous achievements over the last years prompting their greater application as "standard" catalysts. In this review, we will comprehensively discuss the use of homogeneous and heterogeneous catalysts based on non-noble 3d-metals for the reduction of nitro compounds using various reductants. The different systems will be revised considering both the catalytic performances and synthetic aspects highlighting also their advantages and disadvantages

Nitrogen-Enriched Graphene Iron Oxide Nanoparticles as Innovative Catalysts: First Application to Cyclopropanation Reactions

A new class of catalysts having a metal/metal oxide core surrounded by a few nitrogen-enriched graphene layers (NGR) has recently brought immense attention in research. Until now, NGR catalysts have mostly been employed for hydrogenation reactions. In this work, we expand the field of applicability of NGR catalysts to cyclopropanation reactions. The activity of Fe2O3/NGr@C has been studied by using ethyl diazoacetate and \u3b1-methylstyrene as substrates. Various parameters such as solvents, temperature and time were changed. Fe2O3/NGr@C-catalysts showed best activity in dimethoxyethane at 60 oC, affording high yields of the desired cyclopropanes (mixture of cis and trans isomers) and only 1-2 % of ethyl maleate and fumarate (Figure 1). The catalyst gradually deactivates after each recycle, but we were able to reactivate the recovered catalyst by treating it with dilute H2O2 (1:10 with distilled water). Like \u3b1-methylstyrene, several olefins such as 4-chloro-\u3b1-methyl styrene, 4-methylstyrene, 2- methylstyrene, 3-methylstyrene, 4-chlorostyrene, 4-t-butylstyrene, 1-octene etc. have been tested in order to explore the substrate scope. The corresponding cyclopropanes were obtained in high to excellent isolated yields (84-98%). In all cases trans diastereoselectivity was found, but even the minor cis isomer could be isolated in a pure form

Iron/N-doped graphene nano-structured catalysts for general cyclopropanation of olefins

The first examples of heterogeneous Fe-catalysed cyclopropanation reactions are presented. Pyrolysis of in situ-generated iron/phenanthroline complexes in the presence of a carbonaceous material leads to specific supported nanosized iron particles, which are effective catalysts for carbene transfer reactions. Using olefins as substrates, cyclopropanes are obtained in high yields and moderate diastereoselectivities. The developed protocol is scalable and the activity of the recycled catalyst after deactivation can be effectively restored using an oxidative reactivation protocol under mild conditions

Nonlocality, Bell's Ansatz and Probability

Quantum Mechanics lacks an intuitive interpretation, which is the cause of a generally formalistic approach to its use. This in turn has led to a certain insensitivity to the actual meaning of many words used in its description and interpretation. Herein, we analyze carefully the possible mathematical meanings of those terms used in analysis of EPR's contention, that Quantum Mechanics is incomplete, as well as Bell's work descendant therefrom. As a result, many inconsistencies and errors in contemporary discussions of nonlocality, as well as in Bell's Ansatz with respect to the laws of probability, are identified. Evading these errors precludes serious conflicts between Quantum Mechanics and both Special Relativity and Philosophy.Comment: 8&1/2 pages revtex; v2: many corrections, clairifications & extentions, all small; v3: editorial scru

Co-based heterogeneous catalysts from well-defined Α-diimine complexes : Discussing the role of nitrogen

Ar-BIANs and related \uce\ub1-diimine Co complexes were wet impregnated onto Vulcan\uc2\uae XC 72 R carbon black powder and used as precursors for the synthesis of heterogeneous supported nanoscale catalysts by pyrolysis under argon at 800\uc2\ua0\uc2\ub0C. The catalytic materials feature a core-shell structure composed of metallic Co and Co oxides decorated with nitrogen-doped graphitic layers (NGr). These catalysts display high activity in the liquid phase hydrogenation of aromatic nitro compounds (110\uc2\ua0\uc2\ub0C, 50 bar H2) to give chemoselectively substituted aryl amines. The catalytic activity is closely related to the amount and type of nitrogen atoms in the final catalytic material, which suggests a heterolytic activation of dihydrogen

Direct Observation of Long-Lived Isomers in 212 Bi

Long-lived isomers in Bi212 have been studied following U238 projectile fragmentation at 670 MeV per nucleon. The fragmentation products were injected as highly charged ions into a storage ring, giving access to masses and half-lives. While the excitation energy of the first isomer of Bi212 was confirmed, the second isomer was observed at 1478(30) keV, in contrast to the previously accepted value of >1910 keV. It was also found to have an extended Lorentz-corrected in-ring half-life >30 min, compared to 7.0(3) min for the neutral atom. Both the energy and half-life differences can be understood as being due a substantial, though previously unrecognized, internal decay branch for neutral atoms. Earlier shell-model calculations are now found to give good agreement with the isomer excitation energy. Furthermore, these and new calculations predict the existence of states at slightly higher energy that could facilitate isomer deexcitation studies. � 2013 American Physical Society

Being in front is good—but where is in front? Preferences for spatial referencing affect evaluation

Speakers of English frequently associate location in space with valence, as in moving up and down the “social ladder.” If such an association also holds for the sagittal axis, an object “in front of” another object would be evaluated more positively than the one “behind.” Yet how people conceptualize relative locations depends on which frame of reference (FoR) they adopt—and hence on cross‐linguistically diverging preferences. What is conceptualized as “in front” in one variant of the relative FoR (e.g., translation) is “behind” under another variant (reflection), and vice versa. Do such diverging conceptualizations of an object's location also lead to diverging evaluations? In two studies employing an implicit association test, we demonstrate, first, that speakers of German, Chinese, and Japanese indeed evaluate the object “in front of” another object more positively than the one “behind.” Second, and crucially, the reversal of which object is conceptualized as “in front” involves a corresponding reversal of valence, suggesting an impact of linguistically imparted FoR preferences on evaluative processes.publishedVersio

Present and Future Experiments with Stored Exotic Nuclei at Relativistic Energies

Recent progress is presented from experiments on masses and lifetimes of bare and few-electron exotic nuclei at GSI.Comment: Proceedings of International Conference on "Frontiers in Nuclear Structure, Astrophysics and Reactions", Kos, Greece, September 12-17, 200

Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}

Isotope shifts in dielectronic recombination spectra were studied for Li-like ^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV (stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of ^{142,150}\delta = -1.36(1)(3) fm^2. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review Letter