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  • 1
    ISSN: 0044-2313
    Keywords: bimetallic Fe—Ni complexes ; CO2 fixation ; nickelalactones ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organometallic Chemistry of Binuclear 1-Azadiene-Nickel(0) Complexes: Bimetallic Compounds with a Ni—Fe Bond by Addition of Pentacarbonyl-iron(0) and Nickelalactons by Ring Opening Reaction of Cyclic AnhydridesThe binuclear nickel(0) complexes 1-3, which contain as well bridging 1-azadienes ligands as five or six-membered (N∩N)-chelate rings react at -30°C with Fe(CO)5 to form the bimetallic compounds 4-6, containing a Ni—Fe bond and two carbonyl groups as bridging ligands. The coordination of the [(bpy)Ni(0)] fragment to the olefin part of the 1-azadiene chain in 6 leads to the formation of the trinuclear complex 7, which can storage CO2 at the peripheral position. Succinic acid anhydride or glutaric acid anhydrid undergo a ring opening reaction by reacting with 3 yield nickelalactones upon elimination of CO.
    Notes: Die binuclearen Nickel(0)-Komplexe 1-3, die verbrückende 1-Azadieneinheiten und N∩N-Chelatfünf- oder Sechsringe enthalten, reagieren bei -30°C mit Fe(CO)5 zu den Bimetallcarbonylverbindungen 4-6, die eine Ni—Fe-Bindung und 2 CO-Brückencarbonylliganden aufweisen. Koordination des (bipy)Ni(0)-Fragments an den Olefinteil der 1-Azadienkette 6 liefert den Dreikernkomplex 7, der an der Peripherie CO2 speichert. Bernsteinsäureanhydrid oder Glutarsäureanhydrid reagieren mit 3 unter Ringöffnung und CO-Eliminierung zu Nickelalactonen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 620 (1994), S. 101-106 
    ISSN: 0044-2313
    Keywords: Sodium phenoxide ; CO2 transfer ; carboxylation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: CO2 Transfer by Metal Phenoxides: N-Methyl-ε-caprolactam/Sodium Phenoxide as a Selective Reagent for Carboxylation ReactionsCarboxylation reaction of aceton and other substrates with active C—H bonds can be carried out selectively by complexes of sodium phenoxide with N-methyl-ε-caprolactam („NMC“) and CO2. With aceton 3-keto-glutaric acid is formed in 85% yield upon hydrolysis. X-Ray structural analysis of the tetrameric [(NMC)Na(OPh)]4 shows that sodium- and oxygen ions of the phenoxide occupy the positions of a cubus. NMC acts as monodendate ligand, the oxygen atoms of the phenoxide are tridendate bridging ligands. The lithium compound has a similar structure. The complex solved in NMC takes up 0.5 mol CO2 per mol Natrium which at room temperature and normal pressure is transformed to aceton.
    Notes: Carboxylierungsreaktionen von Aceton und anderen Substraten mit aktiven C—H-Bindungen können selektiv mit Komplexen des Natriumphenolats mit N-Methyl-ε-caprolactam („NMC“) und CO2 durchgeführt werden. Mit Aceton entsteht in 85% Ausbeute nach Hydrolyse 3-Ketoglutarsäure. Die Röntgenstrukturanalyse des tetrameren Komplexes [(NMC)Na(OPh)]4 zeigt, daß Natrium- und Phenolatsauerstoffionen die Ecken eines Würfels besetzen.Na1 hat die Koordinationszahl 4. NMC fungiert als einzähliger Ligand, die Sauerstoffatome des Phenolats sind dreizählige Liganden. Die Lithiumverbindung hat eine vergleichbare Struktur. Der Komplex nimmt pro Mol Natriumion in NMC 0,5 Mol CO2 auf, das bei Raumtemperatur und Normaldruck auf Aceton übertragen wird.
    Additional Material: 2 Ill.
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  • 3
    Publication Date: 2016-12-28
    Description: Accurate predictions of net ecosystem productivity (NEP c ) of forest ecosystems are essential for climate change decisions and requirements in the context of national forest growth and greenhouse gas inventories. However, drivers and underlying mechanisms determining NEP c (e.g. climate, nutrients) are not entirely understood yet, particularly when considering the influence of past periods. Here we explored the explanatory power of the compensation day (cDOY) —defined as the day of year when winter net carbon losses are compensated by spring assimilation— for NEP c in 26 forests in Europe, North America, and Australia, using different NEP c integration methods. We found cDOY to be a particularly powerful predictor for NEP c of temperate evergreen needle-leaf forests (R 2  = 0.58) and deciduous broadleaf forests (R 2  = 0.68). In general, the latest cDOY correlated with the lowest NEP c . The explanatory power of cDOY depended on the integration method for NEP c , forest type, and whether the site had a distinct winter net respiratory carbon loss or not. The integration methods starting in autumn led to better predictions of NEP c from cDOY then the classical calendar method starting at January 1. Limited explanatory power of cDOY for NEP c was found for warmer sites with no distinct winter respiratory loss period. Our findings highlight the importance of the influence of winter processes and the delayed responses of previous seasons’ climatic conditions on current year's NEP c . Such carry-over effects may contain information from climatic conditions, carbon storage levels and hydraulic traits of several years back in time.
    Print ISSN: 0148-0227
    Topics: Biology , Geosciences
    Published by Wiley on behalf of American Geophysical Union (AGU).
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