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- Yang, Dong, et al.
(author)
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Encapsulation of Halocarbons in a Tetrahedral Anion Cage
- 2015
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In: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 54:30, s. 8658-8661
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Journal article (peer-reviewed)abstract
- Caged supramolecular systems are promising hosts for guest inclusion, separation, and stabilization. Well-studied examples are mainly metal-coordination-based or covalent architectures. An anion-coordination-based cage that is capable of encapsulating halocarbon guests is reported for the first time. This A(4)L(4)-type (A=anion) tetrahedral cage, [(PO4)(4)L-4](12-), assembled from a C-3-symmetric tris(bisurea) ligand (L) and phosphate ion (PO43-), readily accommodates a series of quasi-tetrahedral halocarbons, such as the Freon components CFCl3, CF2Cl2, CHFCl2, and C(CH3)F-3, and chlorocarbons CH2Cl2, CHCl3, CCl4, C(CH3)Cl-3, C(CH3)(2)Cl-2, and C(CH3)(3)Cl. The guest encapsulation in the solid state is confirmed by crystal structures, while the host-guest interactions in solution were demonstrated by NMR techniques.
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| 2. |
- Li, Yiyin, et al.
(author)
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Pollen production estimates (PPEs) and fall speeds for major tree taxa and relevant source areas of pollen (RSAP) in Changbai Mountain, northeastern China
- 2015
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In: Review of Palaeobotany and Palynology. - 0034-6667. ; 216, s. 92-100
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Journal article (peer-reviewed)abstract
- For model-based quantitative reconstructions of past vegetation cover on the scale of landscapes, pollen productivity estimates (PPEs) are key input parameters. In this study, we employed a random sampling strategy to collect moss polsters at 20 sites in Changbai Mountain, northeastern China. A detailed vegetation survey within 1000-m radius around each sampling point was carried out and digitized vegetation maps were used for, vegetation data compilation. A forest map at the scale of 1:25,000 was used to extract information about vegetation for the area between 1000 and 5000 m from each sampling point. Using the ERV (Extended R-Value) model, pollen productivity was estimated for Larix, Pinus, Juglans, Ulmus, Tilia, Betula and Fraxinus relative to Quercus. Estimates of pollen fall speeds for the eight taxa as well as the relevant source area of pollen (RSAP) were also obtained. Three different ERV sub-models were tested against the data. The sub-model 3 produced the best goodness of fit and the PPE values calculated with this sub-model show that BMA (5.04), Pinus (3.11), Juglans (1.94) and Ulmus (1.40) are high pollen producers with higher PPEs than Quercus while Fraxinus (0.76), Larix (0.30), Tilia (0.16) are low pollen producers compared to Quercus. The high pollen producers are all anemophilous species, while low pollen producing plants include both entomophilous, such as Fraxinus, Tilia and anemophilous species such as Larix. The estimated RSAP for the eight tree pollen taxa is about 2000-2500 m. (C) 2015 Elsevier B.V. All rights reserved.
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