Review: 138 refs.
The syntheses and characterization of selenenate esters, thioselenenate ester and related derivatives are described. The reactions of n-butyl-4-tert-2,6-di(formyl)phenyl selenide (23) or bis(2,6-diformyl-4-tert-butylphenyl)diselenide (24) with bromine affords a new selenenate ester, 5-tert-butyl-7-(formyl)benzoxaselenol-3-one (25), stabilized by ortho-formyl group along with 3,3′-oxybis(5-tert-butyl-3H-benzo[c][1,2]oxoselenole-7-carbaldehyde) (16). Oxidation of (25) with H2O2 gives 5-tert-butyl-7-(carboxylic)benzoxaselenol-3-one-Se-oxide (26). However, the direct oxidation of (23) with H2O2 affords 5-tert-butyl-7-(butylcarboxylate)benzoxaselenol-3-one (27). The synthesis of 5-tert-butyl-7-(methylcarboxylate) benzothiaselenol-3-one (28) has been accomplished by the reaction of (26) with thionyl chloride (SOCl2) with a catalytic amount of N, N-dimethylformamide. Attempted thionation of 7-nitro-1,2-benzisoselenole(3H)-Se-oxide (20) leads to the isolation of bis(2-chloromethyl-6-nitrophenyl)diselenide (29). The presence of intramolecular secondary Se···O interactions in all the esters is confirmed by single crystal X-ray diffraction studies and computational studies. Glutathione peroxidase-like activity of (16), (25)-(29) has been determined by the coupled reductase assay.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Allocation and management of agricultural water resources is an emerging concern due to diminishing water supplies and increasing water demands. To achieve economic, social, and environmental goals in a specific irrigation district, decisions should be made subject to the changing water supply and water demand—the two critical random parameters in agricultural water resources management. This paper presents the foundations of a systematic framework for agricultural water resources management, including determination of distribution functions, joint probability of water supply and water demand, optimal allocation of agricultural water resources, and evaluation of various schemes according to agricultural water resources carrying capacity. The maximum entropy method is used to estimate parameters of probability distributions of water supply and demand, which is the basic for the other parts of the framework. The entropy-weight-based TOPSIS method is applied to evaluate agricultural water resources allocation schemes, because it avoids the subjectivity of weight determination and reflects the dynamic changing trend of agricultural water resources carrying capacity. A case study using an irrigation district in Northeast China is used to demonstrate the feasibility and applicability of the framework. It is found that the framework works effectively to balance multiple objectives and provides alternative schemes, considering the combinatorial variety of water supply and water demand, which are conducive to agricultural water resources planning.
The reaction of selenides (I) with bromine and subsequent treatment of the brominated intermediate with Et 3 N leads to novel photoluminescent selenospirocycles (II).
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
A better understanding of the effects of climate change and land use/cover change (LUCC) on streamflow promotes the long-term water planning and management in the arid regions of northwestern China. In this paper, the Soil and Water Assessment Tool (SWAT) and a separation approach were used to evaluate and separate the effects of climate change and LUCC on streamflow in the Xiying River basin. The SWAT model was calibrated by the hydro-meteorological data from 1980–1989 to obtain the optimum parameters, which were validated by the subsequent application to the period between 1990–2008. Moreover, streamflow under several scenarios with different climate change and land use conditions in 1990–2008 and 2010–2069 were further investigated. Results indicate that, in the period of 1990–2008, the streamflow was dominated by climate change (i.e., changes in precipitation and temperature), which led to a 102.8% increase in the mean annual streamflow, whereas LUCC produced a decrease of 2.8%. Furthermore, in the future period of 2010–2039, the mean annual streamflow will decrease by 5.4% and 4.5% compared with the data of 1961–1990 under scenarios A2 and B2, respectively, while it will decrease by 21.2% and 16.9% in the period of 2040–2069, respectively.
No abstract is provided for this article.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
No abstract is provided for this article.
We report a new excited‐state intramolecular proton transfer (ESIPT)‐inspired hydroxyl (OH)‐substituted pyrene‐imidazole that promote unprecedented intramolecular proton transfer in the ground state (GSIPT). The enol and keto isomers are in equilibrium, with a high keto‐isomer component in the solid state. In conjunction with DFT calculations, the photophysical studies and crystal structure analysis shred substantial evidence for the ground state transformation. The ESIPT‐active compounds also show the rare feature of high dual solution (φ f =70 %) and solid state (φ f =41 %) emission characteristics and counter‐intuitive stronger intermolecular interactions in the solid state versus the ESIPT‐inactive counterparts.
An attempt has been made for agricultural resources planning of the village Jalondar (District Junagadh, Gujarat) using Remote Sensing and GIS Techniques. Out of five micro-watersheds in the village area, a micro-watershed having an area of 602.83 ha was selected for preparing the action plan. Maps on various themes such as land use/land cover, soil texture, slope and drainage pattern were prepared using remote sensing image (IRS P6 LISS IV image) and Arc View and ENVI softwares. Arc View software was used for preparation of thematic maps while the Environment for Visualizing Images (ENVI) software was used for registration and superimposition of cadastral map with thematic maps. Rational method was used to estimate the peak runoff rate while curve number method was used to estimate the runoff volume. Information available from various thematic maps was used for designing various soil and water conservation measures such as contour bunding, staggered contour trenches, continuous contour trenches, loose rock dams and water harvesting structures. Annual water storage capacities of suggested structures were estimated at 69.89, 14.10, 9.45, 1.48 and 6.78 ha-m, respectively. The suggested conservation measures fulfill the existing water resource gap (167.76 mm) of watershed at 60% probability of rainfall.
