A Simple Nickel Catalyst Enabling an E‐Selective Alkyne Semihydrogenation

Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom economic reducing agent dihydrogen (H 2 ), only few catalysts for the challenging E ‐selective alkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates the E ‐selective alkyne semihydrogenation of a wide variety of substituted internal alkynes. This results in a simple and broadly applicable overall protocol to stereoselectively access E ‐alkenes employing H 2 which could serve as a general method for synthesis.DFG, 352364740, Diwasserstoff-vermittelte nachhaltige BindungsknüpfungsreaktionenTU Berlin, Open-Access-Mittel - 201

Stereoselective alkyne semihydrogenations with an air-stable copper(I) catalyst

An air-stable and preactivated copper(I) hydroxide/N-heteroyclic carbene (NHC) complex for alkyne semihydrogenations is reported. Next to an enhanced practicability of the process, the resulting alkenes are obtained with high Z-selectivities and no overreduction to the corresponding alkanes

Room-Temperature Activation of Hydrogen by Semi-immobilized Frustrated Lewis Pairs in Microporous Polymer Networks

Porous polymer networks based on sterically encumbered triphenylphosphine motifs, mimicking the basic sites employed in frustrated Lewis pair (FLP) chemistry, were synthesized via Yamamoto polymerization and their interactions with the strong Lewis acid B(C6F5)3 probed. The combinations yield semi-immobilized FLPs, which are able to cleave dihydrogen heterolytically at ambient temperature and low hydrogen pressure.DFG, 53182490, EXC 314: Unifying Concepts in CatalysisEC/FP7/278593/EU/Organic Zeolites/ORGZE

Catalytic Hydrogenations with Cationic Heteroleptic Copper(I)/N-Heterocyclic Carbene Complexes

A new heteroleptic cationic copper(I) complex bearing two N-heterocyclic carbene (NHC) ligands has been prepared. In situ, a Cu-O bond can be generated which enables the complex to catalytically activate H (2) . The resulting complex shows activity in catalytic chemo- and stereoselective alkyne semihydrogenations as well as conjugate reductions of enones

Catalytic hydrogenation of α,β-unsaturated carboxylic acid derivatives using copper(i)/N-heterocyclic carbene complexes

A simple and air-stable copper(I)/N-heterocyclic carbene complex enables the catalytic hydrogenation of enoates and enamides, hitherto unreactive substrates employing homogeneous copper catalysis and H2 as a terminal reducing agent. This atom economic transformation replaces commonly employed hydrosilanes and can also be carried out in an asymmetric fashion.TU Berlin, Open-Access-Mittel - 201

Treatise on Invertebrate Paleontology, Part W, conodonts, conoidal shells, worms, trace fossils: comments and additions

18 p., 21 fig.http://paleo.ku.edu/contributions.htm

Synthetic Approaches to Highly Functional beta-Carboline Building Blocks via Allylic Amidation

A new, straightforward synthesis of highly functional beta-carboline building blocks is presented that makes use of allylic amidation methodology. The products obtained carry a terminal double bond as well as an easy-to-deprotect amide, which make them perfectly suitable for further functionalization. The use of the trifluoroacetamide group is exploited in a dual fashion; it acts as a protecting group and functions as the nucleophile for the allylic amidation reaction

Using alcohols as simple H2-equivalents for copper-catalysed transfer semihydrogenations of alkynes

Copper(I)/N-heterocyclic carbene complexes enable a transfer semihydrogenation of alkynes employing simple and readily available alcohols such as isopropanol. The practical overall protocol circumvents the use of commonly employed high pressure equipment when using dihydrogen (H2) on the one hand, and avoids the generation of stoichiometric silicon-based waste on the other hand, when hydrosilanes are used as terminal reductants.DFG, 352364740, Diwasserstoff-vermittelte nachhaltige BindungsknüpfungsreaktionenDFG, 53182490, EXC 314: Unifying Concepts in CatalysisTU Berlin, Open-Access-Mittel - 201

Intergovernmental cooperation for hydrometry – what, why and how?

Two thirds of hydrological observation networks in developing countries are reported to be in poor or declining condition. At the same time innovation in sensor technologies and data processing are presenting opportunities for enhancing observation networks that are not being realized. The World Meteorological Organization’s Global Hydrometry Support Facility, or WMO HydroHub, was launched in 2016 to transform assistance to operational water monitoring agencies around the world. If successful, the initiative will increase the amount of hydrometric data available to researchers, catchment managers and water policy makers. To those unfamiliar with UN organizations, however, the nature of such initiatives, the reasoning behind the decisions taken to establish them and the mechanisms by which they try to deliver benefits for society, can be opaque. This paper adopts a novel dialogue-style format to explore the set-up of the WMO HydroHub and build awareness amongst those who ultimately may benefit from its approaches

Is keV ion induced pattern formation on Si(001) caused by metal impurities?

We present ion beam erosion experiments performed in ultra high vacuum using a differentially pumped ion source and taking care that the ion beam hits the Si(001) sample only. Under these conditions no ion beam patterns form on Si for angles below 45 degrees with respect to the global surface normal using 2 keV Kr ions and fluences of 2 x 10^22 ions/m^2. In fact, the ion beam induces a smoothening of preformed patterns. Simultaneous sputter deposition of stainless steel in this angular range creates a variety of patterns, similar to those previously ascribed to clean ion beam induced destabilization of the surface profile. Only for grazing incidence with incident angles between 60 degrees and 83 degrees pronounced ion beam patterns form. It appears that the angular dependent stability of Si(001) against pattern formation under clean ion beam erosion conditions is related to the angular dependence of the sputtering yield, and not primarily to a curvature dependent yield as invoked frequently in continuum theory models.Comment: 15 pages, 7 figures. This is an author-created, un-copyedited version of an article published in Nanotechnology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i