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791.
792.
Xiaojia Tang Lin Guo Quan Liu Yeye Li Tie Li Yimin Zhu 《Crystal Research and Technology》2015,50(3):203-209
In order to investigate the microstructure of magnesium oxide hydration product within seawater, two reaction conditions (liquid‐solid and gas‐liquid‐solid) and two solutions (seawater and deionized water) were adopted for magnesium oxide hydration. The characterization of the hydration product using X‐Ray diffraction and scanning electron microscope was performed. Experimental results indicate that cations and anions in seawater promote the hydration. Most of the hydration products within seawater system display flower‐like morphology, but the agglomeration phenomenon is not obvious within deionized water system, especially for the supernatant layer products within deionized water system under gas‐liquid‐solid reaction condition. There was no stratification phenomenon occurred when MgO hydrated with seawater under three‐phase reaction condition. 相似文献
793.
Marimuthu Sangavi Narayanasamy Kumaraguru Colin D. McMillen Ray J. Butcher 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(10):435-442
Four salts, namely, 2,4,6-triaminopyrimidinium 6-chloronicotinate dihydrate, C4H8N5+·C6H3ClNO2−·2H2O, (I), 2,4,6-triaminopyrimidinediium pyridine-2,6-dicarboxylate dihydrate, C4H9N52+·C7H3NO42−·2H2O, (II), 2,4,6-triaminopyrimidinediium sulfate monohydrate, C4H9N52+·SO42−·H2O, (III), and 2,4,6-triaminopyrimidinium 3,5-dinitrobenzoate dihydrate, C4H8N5+·C7H3N2O6−·2H2O, (IV), were synthesized and characterized by X-ray diffraction techniques. Proton transfer from the corresponding acid to the pyrimidine base has occurred in all four crystal structures. Of the four salts, two [(I) and (IV)] exist as monoprotonated bases and two [(II) and (III)] exist as diprotonated bases. In all four crystal structures, the acid interacts with the pyrimidine base through N—H…O hydrogen bonds, generating an R22(8) ring motif. The sulfate group mimics the role of the carboxylate anions. The water molecules present in compounds (I)–(IV) form water-mediated large ring motifs. The formation of water-mediated interactions in these crystal structures can be used as a model in the study of the hydration of nucleobases. Water molecules play an important role in building supramolecular structures. In addition to these strong hydrogen-bonding interactions, some of the crystal structures are further enriched by aromatic π–π stacking interactions [(I) and (II)]. 相似文献
794.
795.
Prof. Ran Friedman 《Chemphyschem》2023,24(2):e202200516
The use of actinides for medical, scientific and technological purposes has gained momentum in the recent years. This creates a need to understand their interactions with biomolecules, both at the interface and as they become complexed. Calculation of the Gibbs binding energies of the ions to biomolecules, i. e., the Gibbs energy change associated with a transfer of an ion from the water phase to its binding site, could help to understand the actinides’ toxicities and to design agents that bind them with high affinities. To this end, there is a need to obtain accurate reference values for actinide hydration, that for most actinides are not available from experiment. In this study, a set of ionic radii is developed that enables future calculations of binding energies for Pu3+ and five actinides with renewed scientific and technological interest: Ac3+, Am3+, Cm3+, Bk3+ and Cf3+. Reference hydration energies were calculated using quantum chemistry and ion solvation theory and agree well for all ions except Ac3+, where ion solvation theory seems to underestimate the magnitude of the Gibbs hydration energy. The set of radii and reference energies that are presented here provide means to calculate binding energies for actinides and biomolecules. 相似文献