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  • 1
    ISSN: 0947-6539
    Keywords: calixarenes ; cavitands ; molecular modeling ; resorcinarenes ; supramolecular chemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling reactions of calix[4]arenes and modified resorcin[4]arenes have been investigated. Reaction of mono(chloroacetamido)calix[4]arene 4 with tetrahydroxycavitand 9 gave the 1:1 coupled product 13 in 61% yield. Combination of upper-rim 1,3-difunctionalized calix[4]arene 5 with 9 afforded predominantly the 2:1 calix-resorcinarene 18 in 47% yield. Reaction of 1,2-difunctionalized calix[4]arene 6 with 9 gave five products, namely, endo 1:1 (19), exo 1:1 (20), endo-endo 2:1 (21), endo-exo 2:1 (22), and exo-exo 2:1 (23) in ratios that depend on the reaction conditions. The stereochemistry of the different products was determined with NOESY experiments. The structures of 21 a and 23 b were calculated by using molecular mechanics, which revealed that intramolecular hydrogen bonds are only present in the former. Reaction of 1,2-bis(chloroacetamido)calix[4]arene 26, which has two additional nitro groups at the remaining aromatic rings, with 9 yielded three different products, namely, endo 1:1 (28), endo-endo 2:1 (30), and endo-exo 2:1 (32) in ratios that depend on the reaction conditions. There is a preference for the endo orientation in the formation of the 1:1 coupled product, probably owing to an interaction of the nitro groups with the cavitand in the transition state. After conversion of the nitro groups in 28 into chloroacetamido moieties, reaction with Cs2CO3 in DMF under high-dilution conditions afforded holand 33 in 26% yield together with calix[4]arene-based carceplex 34 with an encapsulated DMF molecule (27% yield). Holand 33 was obtained in 33% yield by reaction of the tetrakis(chloroacetamide) endo-endo 2:1 isomer 31 with tetrahydroxycavitand 9. Holand 33 contains a cavity of nanosize dimensions. Molecular mechanics simulations indicate that holand 33 adopts a conformation with eight hydrogen bonds and a large, preorganized cavity with two entrances of smaller dimensions. Molecular dynamics simulations of holand 33 in both CHCl3 and THF showed that four solvent molecules can be accommodated in the cavity at well-defined positions.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2016-09-23
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Ecology 103 (2015): 202–218, doi:10.1111/1365-2745.12334.
    Description: Schedules of survival, growth and reproduction are key life-history traits. Data on how these traits vary among species and populations are fundamental to our understanding of the ecological conditions that have shaped plant evolution. Because these demographic schedules determine population growth or decline, such data help us understand how different biomes shape plant ecology, how plant populations and communities respond to global change and how to develop successful management tools for endangered or invasive species. Matrix population models summarize the life cycle components of survival, growth and reproduction, while explicitly acknowledging heterogeneity among classes of individuals in the population. Matrix models have comparable structures, and their emergent measures of population dynamics, such as population growth rate or mean life expectancy, have direct biological interpretations, facilitating comparisons among populations and species. Thousands of plant matrix population models have been parameterized from empirical data, but they are largely dispersed through peer-reviewed and grey literature, and thus remain inaccessible for synthetic analysis. Here, we introduce the compadre Plant Matrix Database version 3.0, an open-source online repository containing 468 studies from 598 species world-wide (672 species hits, when accounting for species studied in more than one source), with a total of 5621 matrices. compadre also contains relevant ancillary information (e.g. ecoregion, growth form, taxonomy, phylogeny) that facilitates interpretation of the numerous demographic metrics that can be derived from the matrices. Large collections of data allow broad questions to be addressed at the global scale, for example, in genetics (genbank), functional plant ecology (try, bien, d3) and grassland community ecology (nutnet). Here, we present compadre, a similarly data-rich and ecologically relevant resource for plant demography. Open access to this information, its frequent updates and its integration with other online resources will allow researchers to address timely and important ecological and evolutionary questions.
    Keywords: Big data ; Comparative approach ; Elasticity ; Matrix population model ; Open access ; Plant population and community dynamics ; Population growth rate ; Sensitivity ; Transient dynamics
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
    Format: application/msword
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  • 3
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