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  • 1
    Electronic Resource
    Electronic Resource
    Rotationsbehinderung um die Arsen- und Antimon-Stickstoff-Bindung (1970)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 103 (1970), S. 2784-2793 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hindered Rotation about the Arsenic and Antimony Nitrogen BondProton n. m. r. of aminoarsines and aminostibines of the type [(CH3)3C]2El-N[M(CH3)3]2 (El = As, Sb; M = Si, Ge) has been measured as a function of temperature. At 35° 4a, 4d, and 6c possess gauche-configuration with hindered rotation about the El—N bond. The corresponding ΔG≠ -values are 〉 23.2 kcal/Mol for 4a, 22.8 kcal/Mol for 4d and 19.6 kcal/ Mol for 6c. Comparison of 4a, 4d, and 6c with 6a, 6b, 7, and 8 supports the hypothesis that steric interactions and not (p→d)π-bonds between the El-N bond cause this hindered rotation. The proton n. m. r. spectra of 4b, 4c, 4e, and 5 give evidence that in the case of 4b, 4c, and 4e rotamers with different population are formed at 35°, whereas in the case of 5 only one rotamer is formed at 35°.
    Notes: Temperaturabhängige 1 H-NMR-Untersuchungen an Aminoarsinen und Aminostibinen des Typs [(CH3)3C]2El-N[M(CH3)3]2(El = As, Sb; M = Si, Ge) zeigen, daß 4a, 4d und 6c bei 35° in der gauche-Form mit rotationsgehinderter El-N-Bindung vorliegen. Die entsprechenden ΔG≠-Werte betragen für 4a 〉 23.2 kcal/Mol, für 4d 22.8 kcal/Mol und für 6c 19.6 kcal/Mol. Die Hypothese, daß diese Rotationsbehinderung auf sterische und nicht auf (p→d)π-Wechselwirkung zurückzuführen ist, wird durch die Vergleichssubstanzen 6a, 6b, 7 und 8 erhärtet. Für 4b, 4c, 4e und 5 geben die 1H-NMR-Spektren einen Hinweis darauf, daß 4b, 4c und 4e bei 35° Rotamere unterschiedlicher Population, 5 ausschließlich ein Rotameres bildet.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19701030911
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    Paper (German National Licenses)
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  • 2
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    Trade‐offs between carbon stocks and biodiversity in European temperate forests (2019)
    Wiley
    Details
    Publication Date: 2019
    Description: Can managing forests for storing carbon jointly achieve biodiversity conservation and climate change mitigation goals? Global and regional environmental policies often assume co‐benefits between carbon and biodiversity, but it is unclear whether this assumption holds at fine scales relevant for management. By modelling the carbon–biodiversity relationship for a broad range of taxa in temperate forests, we found that biodiversity and carbon stocks are not well‐aligned spatially at stand‐scale, and their relationship varied substantially across taxa. This suggests that forest management aimed at storing carbon may benefit some taxa but harm others, highlighting that broad‐scale co‐benefits may break down at fine scales. Abstract Policies to mitigate climate change and biodiversity loss often assume that protecting carbon‐rich forests provides co‐benefits in terms of biodiversity, due to the spatial congruence of carbon stocks and biodiversity at biogeographic scales. However, it remains unclear whether this holds at the scales relevant for management, and particularly large knowledge gaps exist for temperate forests and for taxa other than trees. We built a comprehensive dataset of Central European temperate forest structure and multi‐taxonomic diversity (beetles, birds, bryophytes, fungi, lichens, and plants) across 352 plots. We used Boosted Regression Trees (BRTs) to assess the relationship between above‐ground live carbon stocks and (a) taxon‐specific richness, (b) a unified multidiversity index. We used Threshold Indicator Taxa ANalysis to explore individual species’ responses to changing above‐ground carbon stocks and to detect change‐points in species composition along the carbon‐stock gradient. Our results reveal an overall weak and highly variable relationship between richness and carbon stock at the stand scale, both for individual taxonomic groups and for multidiversity. Similarly, the proportion of win‐win and trade‐off species (i.e., species favored or disadvantaged by increasing carbon stock, respectively) varied substantially across taxa. Win‐win species gradually replaced trade‐off species with increasing carbon, without clear thresholds along the above‐ground carbon gradient, suggesting that community‐level surrogates (e.g., richness) might fail to detect critical changes in biodiversity. Collectively, our analyses highlight that leveraging co‐benefits between carbon and biodiversity in temperate forest may require stand‐scale management that prioritizes either biodiversity or carbon in order to maximize co‐benefits at broader scales. Importantly, this contrasts with tropical forests, where climate and biodiversity objectives can be integrated at the stand scale, thus highlighting the need for context‐specificity when managing for multiple objectives. Accounting for critical change‐points of target taxa can help to deal with this specificity, by defining a safe operating space to manipulate carbon while avoiding biodiversity losses.
    Print ISSN: 1354-1013
    Electronic ISSN: 1365-2486
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Published by Wiley
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