In situ real time single atom resolution observations of dynamic water gas shift catalysts in CO + water (WGS) environments.

N-Carboxy-(F-benzyloxycarbony1)-L-lysine anhydride (Z-L-lysine NCA) was polymerized in dimethylformamide with triethylamine, diethylamine or hexylamine as initiator, at varying molar ratios of NCA to initiator (MII ratio). After removal of the protecting Z-group the resulting poly-L-lysine was characterized with 'H NMR and MALDI TOF MS. Both diethylamine-and hexylamine-initiated polymerization yielded poly-Llysine in which the initiators were incorporated at the carboxylic end of the polymer. This indicates that the NCA polymerization occurred exclusively via nucleophilic attack of the initiator on the monomer. On the other hand, when triethylamine was used as the initiator, poly-L-lysine was obtained in which no triethylamine-derived end group could be detected by MS. These polymer chains are most likely end-capped with an N-acyl-2,5dioxopiperazine group at the carboxylic end of the polymer. Incorporation of diethylamine and hexylamine allowed determination of the degree of polymerization (DP) of the obtained polymers by 'H NMR. The DP depended linearly on the MII ratio, for both diethylamine and hexylamine, with higher DPs for the diethylamine-initiated poly-Llysine at equal MA ratio.

The potentially C,N,N′-chelating anionic aryldiamine ligand [C 6 H 4 (CH 2 N(Me)CH 2 CH 2-NMe 2)-2]-(CNN) has been employed in the preparation of six-coordinate Ta(V) alkylidene complexes. The new dichloro alkylidene complex [TaCl 2 (dCH-t-Bu)(CNN)], 2, prepared from [TaCl 3 (dCH-t-Bu)(THF) 2 ] and [Li(CNN)] 2 , 1, has been obtained as a mixture of three diastereoisomers (2a-c) in 51% yield. The molecular structure of the major isomer 2a, determined by X-ray methods, shows this to be a tetragonal bipyramidal complex in which the metal coordination sphere is comprised of the C,N,N′ facially bonded CNN, two cispositioned chlorides in the equatorial plane, and a neopentylidene group and the NMe 2 nitrogen donor mutually trans-positioned at the apices. The dialkoxide complexes [Ta-(dCHR)(CNN)(O-t-Bu) 2 ] (R) t-Bu (3a), CMe 2 Ph (3b)) have been obtained by transmetallation of [TaCl(dCHR)(O-t-Bu) 2 (PMe 3)] with 1. The neopentylidene complex 3a was isolated as an analytically pure orange solid in 47% yield, whereas the neophylidene complex 3b was isolated as an orange oil of (90% purity. Complex 3b reacts in pentane with ethene at room temperature to afford the tantalacyclobutane complex [Ta{(CH 2) 3-1,3}(CNN)(O-t-Bu) 2 ], 4, which was isolated as a white solid in 81% yield. An X-ray diffraction study of 4 shows it to be a heptacoordinate pentagonal bipyramidal tantalum species in which two mutually trans alkoxide groups are in the apical positions; the meridional ligation is comprised of the C,N,N′-coordination of CNN and the σ-bonded carbon atoms of the metallacyle. Reaction of 3b in hexane at 69°C with ethene gives a mixture of the new tantalum alkene complex [Ta(CNN)(O-t-Bu) 2 (H 2 CdCH 2)], 5, and 4 in a 5:2 ratio. Complex 5 can be isolated from this mixture as a yellow solid by recrystallization from diethyl ether at-30°C. The X-ray molecular structure of 5 shows it to be a pentagonal bipyramidal complex in which the array of atoms directly bonded to tantalum is like that in 4. However, in 5, the meridional ligation is comprised of the C,N,N′-coordination of CNN and the two C atoms of the ethene molecule. Complexes 3b and 4 initiate ring-opening metathesis polymerization with strained cyclic olefins; dicyclopentadiene produces cross-linked polymers, whereas norbornene produces polycyclopentamers with approximately 90% trans-vinylene bonds. In contrast, none of the isomers of alkylidene complex 2 show any reactivity toward either ethene or norbornene.

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From the reactions of the unsubstituted tantalacyclobutane complex [Ta{(CH 2 ) 3 -1,3}(CNN)-(O-t-Bu) 2 ] (CNN ) [C 6 H 4 (CH 2 N(Me)CH 2 CH 2 NMe 2 )-2] -) (1) with propene and styrene have been isolated in good yields the substituted tantalacyclobutane complexes [Ta{CH 2 CH(Me)-CH 2 -1,3}(CNN)(O-t-Bu) 2 ] (2) and [Ta{CH 2 CH(Ph)CH 2 -1,3}(CNN)(O-t-Bu) 2 ] (3), respectively. The X-ray molecular structures of 2 and 3 show them to be seven-coordinate pentagonal bipyramidal species in which the meridional ligation comprises C,N,N′-bonding of the aryldiamine ligand CNN and σ-bonding of two carbons of the metallacycle; the two alkoxide groups occupy the apical positions. The organyl substituent of the metallacycle is positioned on the -carbon. Complexes 2 and 3 can both be converted back into 1 by reacting them in Et 2 O with ethene. The reaction of 1 with carbon monoxide yields the oxytantalacyclopropane complex [Ta{C(O)((CH 2 ) 3 -1,3)}(CNN)(O-t-Bu) 2 ] (4), which has been isolated as an air-stable white solid in 59% yield. The X-ray molecular structure of 4 reveals that the carbon and oxygen atoms of the CdO function are ligated in the meridional plane with further η 3 -C,N,N′-ligation of CNN and the two alkoxides as found in 2 and 3. Reaction of the tantalacyclobutane complexes 2-4 with 1 equiv of t-BuNC affords the 1:1 insertion products [Ta{C(dN-t-Bu)-CH 2 CH(R)CH 2 -1,4}(CNN)(O-t-Bu) 2 ] (R ) H (5), Me (6), and Ph (7), respectively). Complexes 5 and 7 have been isolated as yellow solids (yields: 5, 62%; 7, 50%), while 6 has been prepared and characterized in situ. 1 H and 13 C NMR spectroscopy of 6 and 7 indicate for each complex the presence of two isomers in solution. The X-ray molecular structure of 7 shows η 2 -C,Nbonding of the CNN ligand through the aryl C ipso atom and the N(Me) donor atom and, most importantly, the presence of two tantalacyclic rings of different sizes that have a common Ta-C bond. The smaller three-membered ring comprises the metal center with the nitrogen and the R-carbon atom of the η 2 -bonded iminoacyl fragment, while the larger five-membered ring is a metallacylopentane system comprising the metal center and four carbon atoms.

Copper containing oxides are widely used in a range of catalytic applications. Here, we report the use of Cu K-edge high resolution XANES to determine the local site symmetry of...

Industrial processes contribute significantly to global carbon dioxide emissions, with iron and steel manufacturing alone responsible for 6% of the total figure. The STEPWISE project, funded through the European Horizon 2020 (H2020) Low Carbon Energy (LCE) programme under grant agreement number 640769, is looking at reducing CO2 emissions in the iron and steel making industries. At the heart of this project is the ECN technology called sorption-enhanced water-gas shift (SEWGS), which is a solid sorption technology for CO2 capture from fuel gases such as blast furnace gas (BFG). This technology combines water-gas shift (WGS) in the WGS section with CO2/H2 separation steps in the SEWGS section. Scaling up of the SEWGS technology for CO2 capture from BFG and demonstrating it in an industrially relevant environment are the key objectives of the STEPWISE project, which are achieved by international collaboration between the project partners towards design, construction and operation of a pilot plant at Swerea Mefos, Luleå, Sweden, next to the SSAB steel manufacturing site.

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