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91.
HAN Qiu-xia ;WANG Chun-zhang ;Institute of Molecular Crystal Engineering School of Chemistry Chemical Engineering Henan University Kaifeng P R. China ;NIU Jing-yang ;WANG Jing-ping 《高等学校化学研究》2008,24(3):255-259
The reaction of α-H3[PW12O40] with Y(NO3)3 in the presence of DMF or DMSO leads to two complexes with the formulae {Y(DMSO)7}·PW12O40(1) and {[Y(DMF)7]2PW12O40}·PW12O40(2). The crystal structures indicate that complex 1 consists of discrete [YLn]3+ cations and α-Keggin heteropolyanions [PW12O40]3-, whereas, in complex 2, donor-acceptor interaction results in a cation-anion-cation triplet. In addition, the electrochemical behavior of the two complexes indicates the usual successive reduction processes of the W atoms in the anions. 相似文献
92.
Slejkovec Z Falnoga I Goessler W van Elteren JT Raml R Podgornik H Cernelc P 《Analytica chimica acta》2008,607(1):83-91
Urine and blood samples of cancer patients, treated with high doses of arsenic trioxide were analysed for arsenic species using HPLC-HGAFS and, in some cases, HPLC-ICPMS. Total arsenic was determined with either flow injection-HGAFS in urine or radiochemical neutron activation analysis in blood fractions (in serum/plasma, blood cells). The total arsenic concentrations (during prolonged, daily/weekly arsenic trioxide therapy) were in the μg mL−1 range for urine and in the ng g−1 range for blood fractions. The main arsenic species found in urine were As(III), MA and DMA and in blood As(V), MA and DMA.With proper sample preparation and storage of urine (no preservation agents/storage in liquid nitrogen) no analytical artefacts were observed and absence of significant amounts of alleged trivalent metabolites was proven. On the contrary, in blood samples a certain amount of arsenic can get lost in the speciation procedure what was especially noticeable for the blood cells although also plasma/serum gave rise to some disappearance of arsenic. The latter losses may be attributed to precipitation of As(III)-containing proteins/peptides during the methanol/water extraction procedure whereas the former losses were due to loss of specific As(III)-complexing proteins/peptides (e.g. cysteine, metallothionein, reduced GSH, ferritin) on the column (Hamilton PRP-X100) during the separation procedure. Contemporary analytical protocols are not able to completely avoid artefacts due to losses from the sampling to the detection stage so that it is recommended to be careful with the explanation of results, particularly regarding metabolic and pharmacokinetic interpretations, and always aim to compare the sum of species with the total arsenic concentration determined independently. 相似文献
93.
94.
用跳浓驰豫法测定不同温度下的驰豫时间τ.根据拟定的机理导出了1/τ的函数表达式为1/τ=k[H6R]0/[H3+O]-(6k/ε[H3+O]0)A∞,获得表观速率常数k及摩尔吸光系数ε,表观活化能为52.82KJ/mol,活化焓为50.34kJ/mol,活化熵在278K~298K范围内为负值,配合物稳定常数lgK'.为13.84。与孤立变量法、比尔法、平衡移动法获得的结果吻合. 相似文献
95.
96.
Two Chloride Silicates of Yttrium: Y3Cl[SiO4]2 and Y6Cl10[Si4O12] The chloride‐poor yttrium(III) chloride silicate Y3Cl[SiO4]2 crystallizes orthorhombically (a = 685.84(4), b = 1775.23(14), c = 618.65(4) pm; Z = 4) in space group Pnma. Single crystals are obtained by the reaction of Y2O3, YCl3 and SiO2 in the stoichiometric ratio 4 : 1 : 6 with ten times the molar amount of YCl3 as flux in evacuated silica tubes (7 d, 1000 °C) as colorless, strongly light‐reflecting platelets, insensitive to air and water. The crystal structure contains isolated orthosilicate units [SiO4]4– and comprises cationic layers {(Y2)Cl}2+ which are alternatingly piled parallel (010) with anionic double layers {(Y1)2[SiO4]2}2–. Both crystallographic different Y3+ cations exhibit coordination numbers of eight. Y1 is surrounded by one Cl– and 7 O2– anions as a distorted trigonal dodecahedron, whereas the coordination polyhedra around Y2 show the shape of bicapped trigonal prisms consisting of 2 Cl– and 6 O2– anions. The chloride‐rich chloride silicate Y6Cl10[Si4O12] crystallizes monoclinically (a = 1061,46(8), b = 1030,91(6), c = 1156,15(9) pm, β = 103,279(8)°; Z = 2) in space group C2/m. By the reaction of Y2O3, YCl3 and SiO2 in 2 : 5 : 6‐molar ratio with the double amount of YCl3 as flux in evacuated silica tubes (7 d, 850 °C), colorless, air‐ and water‐resistant, brittle single crystals emerge as pseudo‐octagonal columns. Here also a layered structure parallel (001) with distinguished cationic double‐layers {(Y2)5Cl9}6+ and anionic layers {(Y1)Cl[Si4O12]}6– is present. The latter ones contain discrete cyclo‐tetrasilicate units [Si4O12]8– of four cyclically corner‐linked [SiO4] tetrahedra in all‐ecliptical arrangement. The coordination sphere around (Y1)3+ (CN = 8) has the shape of a slightly distorted hexagonal bipyramid comprising 2 Cl– and 6 O2– anions. The 5 Cl– and 2 O2– anions building the coordination polyhedra around (Y2)3+ (CN = 7) form a strongly distorted pentagonal bipyramid. 相似文献
97.
Herbert Schumann Frank Erbstein Dirk F. Karasiak Igor L. Fedushkin Jrg Demtschuk Frank Girgsdies 《无机化学与普通化学杂志》1999,625(5):781-788
The stepwise reaction of Me2SiCl2 with K[C5H3 tBuMe‐3] or Li[C9H7] and then with K[C9H6CH2CH2‐ NMe2‐1] followed by double deprotonation with NaH or LiBu, yields the two dimethylsilicon bridged cyclopentadienyl‐indenyl and indenyl‐indenyl donor‐functionalized ligand systems K2[(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)] ( 1 ), and Li2[(1‐C9H6)SiMe2(1‐C9H5CH2CH2NMe2‐3)] ( 2 ), respectively. Treatment of 1 with YCl3(THF)3, SmCl3(THF)1.77, TmI3(DME)3, and LuCl3(THF)3 gives the mixed ansa‐metallocenes [(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)]LnX (X = Cl, Ln = Y ( 3 ), Sm ( 4 ), Lu ( 5 ); X = I, Ln = Tm ( 6 )), respectively. The reaction of 2 with LuCl3(THF)3 yields [(1‐C9H6)SiMe2(1‐C9H5CH2CH2NMe2‐3)]LuCl ( 7 ). Compound 4 reacts with LiMe to give the corresponding alkyl derivative [(C5H2 tBu‐3‐Me‐5)SiMe2(1‐C9H5CH2CH2NMe2‐3)]Sm(CH3) ( 8 ). The new complexes were characterized by elemental analyses, MS spectrometry, and NMR spectroscopy. The molecular structures of 5 and 6 were determined by single crystal X‐ray diffraction. 相似文献
98.
Mathias S. Wickleder 《无机化学与普通化学杂志》1999,625(10):1707-1711
Syntheses and Crystal Structures of Y(HSO4)3-I and Y(HSO4)3 · H2O Lath shaped crystals of Y(HSO4)-I are obtained by treatment of Y2O3 with conc. sulfuric acid at 200 °C. Y(HSO4)3-I crystallizes orthorhombic (Pbca, Z = 8, a = 1201.5(1), b = 953.76(8), c = 1650.4(1) pm, Rall = 0.0388). In the crystal structure Y3+ is coordinated by eight monodentate HSO4– groups. Colorless, plate like single crystals of Y(HSO4)3 · H2O grew from a solution of Y2O3 in 85% sulfuric acid upon cooling. In the crystal structure of the triclinic compound (P1, Z = 2, a = 679.8(1), b = 802.8(2), c = 965.9(2) pm, α = 79.99(2)°, β = 77.32(2)°, γ = 77.50(2)°, Rall = 0.0264) Y3+ is surrounded by seven HSO4– groups and one molecule of water. 相似文献
99.
本文介绍了一种简便的方法制备n-十二烷基三甲氧基硅烷@三氧化钨包覆的超亲油超疏水的铜网.所制备的铜网显示了较为突出的超亲油和超疏水性能,该铜网的水接触角大约有154.39°,而油接触角接近于0°.实验利用了各种有机溶剂和水的混合物对所制备网膜进行分离性能测试,结果表明所得涂覆铜网的油水分离效率高达99.3V,并且水的通量大约为9962.3 L·h~(-1)·m~(-2).所制备的铜网具有良好的稳定性,经过10次分离循环后分离效率仍然保持在90%以上.由于三氧化钨优异的光催化降解性能,所制备铜网具有自清洁能力.因此,被润滑油污染的网膜可以恢复超疏水性,而这种自清洁性使所制网膜可以反复用于油水分离. 相似文献
100.
本文采用基于密度泛函理论(DFT)的第一性原理方法,分别计算了120 GPa的压力范围内钇铝石榴石理想晶体和含氧空位点缺陷晶体的光学性质.计算数据表明:(1)在120 GPa的压力范围内其理想晶体和含2+价氧离子空位(形成能最低)的缺陷晶体在可见光区不存在光吸收(是透明的).(2)压力加载将导致其反射谱峰值强度降低,且空位缺陷的存在使其峰值强度进一步减弱.这些结果对进一步实验有重要的参考价值. 相似文献