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1.
农作物不仅需要吸收C、H、O、N、P、K、Ca、Mg等营养元素,而且还需要吸收B、Mn、Zn等营养元素,以维持它们正常生长的需要.尿素是一种含氮量很高(46.60%)、性能很好的氮肥,而硼化合物又是一种很重要的微量元素肥料.因此,研究尿素与硼化合物间的相互作用,以得到既含氮又含硼的一种化合物,是一种很有意义的工作。目前,国外已开展了尿素与硼酸间相互作用的研究工作.研究结果表明,在一定条  相似文献   

2.
In this study we report about the aromaticity of the prototypical [(H(t)Ac)(3)(μ(2)-H)(6)], [(H(t)Th)(3)(μ(2)-H)(6)](+), and [(H(t)Pa)(3)(μ(2)-H)(6)] clusters via two magnetic criteria: nucleus-independent chemical shifts (NICS) and the magnetically induced current density. All-electron density functional theory calculations were carried out using the two-component zeroth-order regular approach and the four-component Dirac-Coulomb Hamiltonian, including scalar and spin-orbit relativistic effects. Four-component current density maps and the integration of induced ring-current susceptibilities clearly show that the clusters [(H(t)Ac)(3)(μ(2)-H)(6)] and [(H(t)Th)(3)(μ(2)-H)(6)](+) are non-aromatic whereas [(H(t)Pa)(3)(μ(2)-H)(6)] is anti-aromatic. However, for the thorium cluster we find a discrepancy between the current density plots and the classification through the NICS index. Our results also demonstrate the increasing influence of f orbitals, on bonding and magnetic properties, with increasing atomic number in these clusters. We think that the enhanced electron mobility in [(H(t)Pa)(3)(μ(2)-H)(6)] is due the significant 5f character of its valence shell. Also the participation of f orbitals in bonding is the reason why the protactinium cluster has the shortest bond lengths of the three clusters. This study provides another example showing that the magnetically induced current density approach can give more reliable results than the NICS index.  相似文献   

3.
三元体系LiCl-CS(NH2)2-H2O及LiCl-CH3CONHCONH2-H2O的研究   总被引:1,自引:0,他引:1  
关于钾盐-有机物-水体系的研究至今报导甚少,B·Begaliev[1]等对体系LiCl·CO(NH2)2-H2O进行了研究,发现有两个复合物:LiCl·CO(NH2)2,LiCl·3CO(NH3)2生成.为了进一步探讨这类体系中锂盐与有机物的相互作用,本文对LiCl·CS(NH2)2-H2O(Ⅰ)(0°,25℃)和LiCl-CH3CONHCONH2-H2O(Ⅱ)(0°,35℃)两个体系进行了研究.  相似文献   

4.
The lanthanum trichloroacetate-lanthanum perchlorate-water ternary system was studied by the isothermal solubility method at 25°C. The compositions of solid phases were studied by the Schreinemakers method. The refraction indices, specific volumes, and viscosities of liquid phases were determined. The crystallization of the initial components and, the formation of a closed area of solid solutions were established in the system.  相似文献   

5.
安替比林及其4位取代衍生物是较强的配位剂,可与不同的稀土盐作用生成组成各不相同的配合物,为了进一步探讨安替比林的衍生物对稀土离子的配位作用,我们研究了以4-一氯乙酰基安替比林(4-ClCH2COAP)为配体与硝酸镧或氧化镧的三元水盐体系。  相似文献   

6.
测定了三元体系DyCl3-CdCl2-H2O和四元体系DyCl3-CdCl2-HCl(~8%)-H2O(25℃)的相平衡溶度数据,绘制了相应的溶度图.三元体系和四元体系均为复杂体系且均有新化合物9CdCl2·2DyCl3·29H2O生成.对化合物9CdCl2·2DyCl3·29H2O进行了XRD、TG-DTG和荧光光谱研究,并对X-射线粉末衍射数据进行了指标化.该化合物属单斜晶系,具有一定的荧光强度,在50~242℃分3步失去结晶水.  相似文献   

7.
用H^+和NO3^-离子选择电极组成的电池用电势法测定了HNO3-UO2(NO3)2-H2O系统在25°C时的HNO3的平均活度系数, 求得了同时含有^E0和 ^S0-I关系式的Pitzer方程中的两粒子和三粒子作用参数(^s0(0), ^s(1),Ψ)。用Pitzer方程计算了该系统中水的活度, 并用Pitzer方程、Mckay-Perring方法和Harned方程分别计算了系统中HNO3和UO2(NO3)2的平均活度系数。  相似文献   

8.
Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 (1) with azulene under thermal activation afforded the novel clusters RuOs3(μ-H)(CO)93522-C10H9) (3) and Ru2Os3(μ-H)2(CO)13(μ-CO)(μ352-C10H8) (5a), with 4,6,8-trimethylazulene to give RuOs3(μ-H)(CO)8(μ-CO)(μ,η54-C10H6Me3) (4) and Ru2Os3(μ-H)2(CO)13(μ-CO)(μ352-C10H5Me3) (5b), and with guaiazulene to give Ru2Os3(CO)113533-C10H5Me2iPr) (6), respectively. In 35, cluster-to-ligand hydrogen transfer appears to have taken place, with the organic moiety capping a trimetallic face in 3, bridging a metal–metal bond in 4 and via a μ352 bonding mode in 5a and 5b. Cluster 6 contains a trigonal bipyramidal metal framework with the guaiazulene ligand over a triangular metal face. All five clusters have been completely characterised, including by single-crystal X-ray diffraction analysis.  相似文献   

9.
Pyrolysis a the cluster Os3(µ-H h (CO)10 (SnMe2 H) produced an as yet unidentified purple duster, which upon reaction with PEt2Ph at room temperature, gave essentially a quantitative yield of the cluster Os3(µ-H)3(CO)93-Sn) Os3(µ-H)(CO)10(PEt2Ph), 4. The X-ray structure of 4 (as the toluene solvate) shows that it consists Or two Os, triangles linked through a µ4-Sn unit, such that one of the Os3 triangle is µ3-bonded to the Sn atom (Os-Sn range 2.689(2)–2.707(2) Å) and the other is bonded via a single covalent bond (Os-Sn = 2.643(2) Å). The phosphine ligand occupies the equatorial site on a second osmium atom a be latter Os3 moiety that is syn to the Sn atom; the unique bridging hydride ligarid is believed to occupy a site that Acis to both the P and Sn atoms. Crystallographic data for compound4. 0.5C7H8: space group,P ; ca= 11862(4) Å,b = 12.940(4) Å,c = 16.513(5) Å, =68.96(3),=80.60(3)°,=62.49(2).R=0.029, 4118 observed reflections.  相似文献   

10.
The reaction of [Os3(CO)10(μ-dppm)] (1) with tBu2PH in refluxing diglyme results in the electron-deficient metal cluster complex [Os3(CO)5(μ3-H)(μ-PtBu2)2(μ-dppm)] (2) (dppm = Ph2PCH2PPh2) in good yields. The molecular structure of 2 has been established by a single crystal X-ray structure analysis. In contrast to the known homologue [Ru3(μ-CO)(CO)4(μ3-H)(μ-H)(μ-PtBu2)2(μ-dppm)] (3), no bridging carbonyl ligand was found in 2. The electronically unsaturated cluster 2 does not react with carbon monoxide under elevated pressure, therefore 2 seems to be coordinatively saturated by reason of the high steric demands of the phosphido ligands.  相似文献   

11.
采用等温溶解法测定了偏钒酸铵(NH4VO3)在NH4H2PO4-H2O和(NH4)3PO4-H2O体系中T = 298.15-328.15 K时的溶解度以及溶液的密度和pH值。结果表明, NH4VO3的溶解度随着(NH4)3PO4或NH4H2PO4溶液浓度的增大,先降低后升高,这是由于同离子效应、化学反应平衡及离子活度的共同作用。比较T = 298.15K时, NH4VO3分别在NH4H2PO4-H2O、(NH4)2HPO4-H2O和(NH4)3PO4-H2O体系中溶解度,发现在相同的磷酸盐浓度下, NH4VO3的溶解度在NH4H2PO4-H2O体系中最大,在(NH4)3PO4-H2O体系中居中,在(NH4)2HPO4-H2O体系中最小。进一步地,在T = 298.15 K和磷酸盐浓度C = 0.5 mol·kg-1时,结合pH值和反应溶度积常数KSP等计算三个体系中的平均离子活度系数(γ±),发现γ±值在(NH4)2HPO4-H2O体系中最大,在(NH4)3PO4-H2O体系中居中,在NH4H2PO4-H2O体系中最小,与溶解度规律一致。  相似文献   

12.
The reaction of (μ-H)Os3μ-O2CC5H4Mn(CO)3(CO)10 with PPh3 in the presence of Me3NO gave mono- and disubstituted heterometallic complexes (μ-H)Os3μ-O2CC5H4Mn(CO)3(PPh3)(CO)9 and (μ-H)Os3μ-O2CC5H4Mn(CO)3 (PPh3)2(CO)8. Crystal structure determination was performed for three isomeric cluster complexes (μ-H)Os3μ-O2CC5H4Mn(CO)3(PPh3)2(CO)8, which are both geometrical and conformational isomers differing in color. The geometrical isomerism is due to the attachment of the PPh3 group at different vertices of the Os3 triangle relative to the O2CC5H4Mn(CO)3 bridging ligand. The conform ational isomerism implies that the molecules have the same arrangement of ligands and differ only in the values of bond angles between the planar fragments of the clusters.  相似文献   

13.
Electrochemical and photochemical properties of the tetrahedral cluster [Ru3Ir( 3-H)(CO)13] were studied in order to prove whether the previously established thermal conversion of this cluster into the hydrogenated derivative [Ru3Ir(-H)3(CO)12] also occurs by means of redox or photochemical activation. Two-electron reduction of [Ru3Ir( 3-H)(CO)13] results in the loss of CO and concomitant formation of the dianion [Ru3Ir( 3-H)(CO)12]2–. The latter reduction product is stable in CH2Cl2 at low temperatures but becomes partly protonated above 283K into the anion [Ru3Ir(-H)2(CO)12] by traces of water. The dianion [Ru3Ir( 3-H)(CO)12]2– is also the product of the electrochemical reduction of [Ru3Ir(-H)3(CO)12] accompanied by the loss of H2. Stepwise deprotonation of [Ru3Ir(-H)3(CO)12] with Et4NOH yields [Ru3Ir(-H)2(CO)12] and [Ru3Ir( 3-H)(CO)12]2–. Reverse protonation of the anionic clusters can be achieved, e.g., with trifluoromethylsulfonic acid. Thus, the electrochemical conversion of [Ru3Ir( 3-H)(CO)13] into [Ru3Ir(-H)3(CO)12] is feasible, demanding separate two-electron reduction and protonation steps. Irradiation into the visible absorption band of [Ru3Ir( 3-H)(CO)13] in hexane does not induce any significant photochemical conversion. Irradiation of this cluster in the presence of CO with irr>340nm, however, triggers its efficient photofragmentation into reactive unsaturated ruthenium and iridium carbonyl fragments. These fragments are either stabilised by dissolved CO or undergo reclusterification to give homonuclear clusters. Most importantly, in H2-saturated hexane, [Ru3Ir( 3-H)(CO)13] converts selectively into the [Ru3Ir(-H)3(CO)12] photoproduct. This conversion is particularly efficient at irr >340nm.  相似文献   

14.
The complexes Pt(nb)3-n(P-iPr3)n (n=1, 2, nb=bicyclo[2.2.1]hept-2-ene), prepared in situ from Pt(nb)3, are useful reagents for addition of Pt(P-iPr3)n fragments to saturated triruthenium clusters. The complexes Ru3Pt(CO)11(P-iPr3)2 (1), Ru3Pt(-H)(3-3-MeCCHCMe)(CO)9(P-iPr3) (2), Ru3Pt(3-2-PhCCPh)(CO)10(P-iPr3) (3), Ru3Pt(-H)(4-N)(CO)10(P-iPr3) (4) and Ru3Pt(-H)(4-2-NO)(CO)10(P-iPr3) (5) have been prepared in this fashion. All complexes have been characterized spectroscopically and by single crystal X-ray determinations. Clusters 1–3 all have 60 cluster valence electrons (CVE) but exhibit differing metal skeletal geometries. Cluster 1 exhibits a planar-rhomboidal metal skeleton with 5 metal–metal bonds and with minor disorder in the metal atoms. Cluster 2 has a distorted tetrahedral metal arrangement, while cluster 3 has a butterfly framework (butterfly angle=118.93(2)°). Clusters 4 and 5 posseses 62 CVE and spiked triangular metal frameworks. Cluster 4 contains a 4-nitrido ligand, while cluster 5 has a highly unusual 4-2-nitrosyl ligand with a very long nitrosyl N–O distance of 1.366(5) Å.  相似文献   

15.
体系Mg(NO3)2-MgCl2-H2O作为相变储能材料的相图预测   总被引:1,自引:0,他引:1  
周权宝  尹霞  汪琼  王成 《化学学报》2011,69(15):1725-1730
应用修正的BET热力学模型对Mg(NO3)2-MgCl2-H2O体系在273~373 K的相图进行预测, 发现两个共晶点, 并通过实验对共晶点组成材料的吸热和放热行为进行测定, 发现三元共晶点Mg(NO3)2•6H2O(45.6%)-Mg(NO3)2•2H2O (29.6%)-MgCl2•6H2O(24.8%)储能效果较差, 而二元共晶点Mg(NO3)2•6H2O(61.6%)-MgCl2•6H2O(38.4%)在熔点附近具有很好的储放热能力, 其相变热焓经差热分析为136.8 J•g-1, 说明该材料可用作潜在的相变储能材料.  相似文献   

16.
研究发现稀土卤化物与一些金属卤化物所形成的化合物具有特殊的光学性质[1,2]。为了寻找这类新化合物及其它们的形成机理,文献研究了稀土卤化物与碱金属卤化物在盐酸介质中的相化学关系,且发现了新物相化合物Cs5EuCl8·14H2O和Cs2EuCl5·4H2O具有上转换发光性能[3~5]。为比较过  相似文献   

17.
本文首次报道须在两种金属离子同时作用下的振荡反应——KBrO_3-CH_3CH(NH_2)CO_2H-MnSO_4-[Fe(phen)_3]SO_2-H_2SO_4体系的振荡反应,对反应产物作了分析,研究了两种金属离子在振荡反应中的不同作用,Mn~(2+)起催化氧化丙氨酸以产生丙酮酸的作用,而[Fe(phen)_3]~(2+)则是丙酮酸-BZ型反应的催化剂.研究了温度变化对振荡反应的影响,从而得出振荡反应各阶段的表观活化能.考察了Cl~-、自由基抑制剂及反应物浓度对振荡反应的影响.实验证明,振荡反应同时受Br~-及Br_2的控制,振荡机理与Br_2-水解控制模型相同.  相似文献   

18.
本文首次报道须在两种金属离子同时作用下的振荡反应─KBrO3-CH3CH(NH2)CO2H-MnSO4-[F3(phen)3]SO4-H2SO4体系的振荡反应, 对反应产物作了分析, 研究了两种金属离子在振荡反应中的不同作用, Mn^2^+起催化氧化丙氨酸以产生丙酮酸的作用, 而[Fe(phen)3]^2^+则是丙酮酸-BZ型反应的催化剂。研究了温度变化对振荡反应的影响, 从而得出振荡反应各阶段的有观活化能。考察了Cl^-、自由基抑制剂及反应物浓度对振荡反应的影响。实验证明, 振荡反应同时受Br^-及Br2的控制, 振荡机理与Br2^-水解控制模型相同。  相似文献   

19.
氧化钇;苯丙胺酸;三元体系;配合物;YCl3-β-Phenylalanine(Phe)-H2O体系的相化学行为  相似文献   

20.
YCl3-β-Phenylalanine(Phe)-H2O体系的相化学行为   总被引:2,自引:0,他引:2  
任非  高胜利 《应用化学》2000,17(2):203-205
  相似文献   

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