首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Two new wheel-shaped tungstophosphates based on 3d-transition metals (Co(II), Ni(II)) ions decorated [P8W49O187]40− anion (TM-{P8W49}), K4Na22{[Co(H2O)2Cl][Co(H2O)3]2[Co(H2O)5]1.5 [Co(H2O)3H4P8W49O187(H2O)]}·2NaCl·41·5H2O 1 and Na30{[Ni(H2O)3]2[{Ni(H2O)3}1.5H3P8W49O187 (H2O)]}·41.5H2O 2 have been synthesized by routine synthetic reaction of hexavacant Dawson polyoxonanion [P2W12O48]14− with divalent 3d transition-metal ions in aqueous solution. The two compounds are characterized by elemental analysis, IR spectroscopy, TG analysis, electrochemical analysis, and single-crystal X-ray diffraction. Both compounds contain a 2D layer-like structure constructed from 1D chains of wheel-type [P8W49O187]40− anions bridged via CoO6 or NiO6 units. Cyclic voltammograms and 31P NMR analysis suggest that the polyanion [P8W49O187]40− of both compounds are stable in aqueous solution (pH = 4).  相似文献   

2.
The reactions of the oxalate complexes [M3Q7(C2O4)3]2− (M = Mo or W; Q = S or Se) with MnII, CoII, NiII, and CuII aqua and ethylenediamine complexes in aqueous and aqueous ethanolic solutions were studied. The previously unknown heterometallic complexes [Mo3Se7(C2O4)3Ni(H2O)5]·3.5H2O (1) and K3{[Cu(en)2H2O]([Mo3S7(ox)3]2Br)}·5.5H2O (2) were synthesized. In these complexes, the oxalate clusters serve as monodentate ligands. The K(H2en)2[W3S7(C2O4)3]2Br·4H2O salt (3) was isolated from solutions containing CoII, NiII, or CuII aqua complexes and ethylenediamine. The reaction of [Mo3Se7(C2O4)3]2− with HBr produced the bromide complex [Mo3Se7Br6]2−, which was isolated as (Bu4N)2[Mo3Se7Br6] (4). Complexes 1–3 were characterized by X-ray diffraction, IR spectra, and elemental analysis. The formation of 4 was detected by electrospray mass spectrometry. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1645–1649, September, 2007.  相似文献   

3.
The reactions of the [Mo3(μ3-Q)(μ2-Q)3(H2O)3(C2O4)3]2− complex (Q = S or Se) with CuX salts (X = Cl, Br, I, or SCN) in water produce the cuboidal heterometallic clusters [Mo3(CuX)(μ3-Q)4(H2O)3(C2O4)3]2−, which were isolated as the potassium and tetraphenylphosphonium salts. Two new compounds, K2[Mo3(CuI)(μ3-S)4(H2O)3(C2O4)3]·6H2O and (PPh4)2[Mo3(CuBr)(μ3-S)4(H2O)3(C2O4)3]·7H2O, were structurally characterized. All compounds were characterized by elemental analysis and IR spectroscopy. The K2[Mo3(CuI)(μ3-Se)4(H2O)3(C2O4)3] compound was characterized by the 77Se NMR spectrum; the (PPh4)2[Mo3(CuI)(μ3-S)4(H2O)3(C2O4)3], (PPh4)2[Mo3(CuI)(μ3-Se)4(H2O)3(C2O4)3] and K2[Mo3(CuSCN)(μ3-S)4(H2O)3(C2O4)3]·7H2O compounds, by electrospray mass spectra. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1639–1644, September, 2007.  相似文献   

4.
The heteropolytungstate (NH4)21{La(H2O)5[Ni(H2O)]2As4W40O140}·53H2O is obtained by the reaction of Na27[NaAs4W40O140]· 60H2O with NiCl2·6H2O, La(NO3)3·6H2O and NH4Cl at pH‐4.5. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are a = 1.9551(3) nm, b = 2.4156(4) nm, c= 3.7068(6) nm, β = 91.505(3)°, V = 17.500 (5) nm3, monoclinic crystal system with space group P21/n, Z = 4, R1 = 0.0573, wR2 = 0.0717 [I >2<s?(I)], R1, = 0.2463 and wR2 = 0.1199 (all data). [La(H2O)5] {Ni(H2O)}2AS4W40O140 has C2, symmetry. IR spectra of the ligand [NaAs4W40O140]27‐ and its three complexes were discussed.  相似文献   

5.
A new molybdophosphate (NH4)8{Mo2VO4[(Mo2VIO6)CH3C(O)(PO3)2]2}·14H2O (1), has been synthesized by the reaction of {Mo2VO4(H2O)6}2+ fragments with 1-hydroxyethylidenediphosphonate (hedp HOC(CH3)(PO3H2)2), and it is characterized by 31P NMR, IR, UV, element analysis, TG and single-crystal X-ray analysis. The structure analysis reveals that the polyoxoanion can be described as two {(Mo2VIO6)(CH3C(O)(PO3)2} units connected by a {Mo2VO4}2+ moiety. In the structure, the six Mo atoms are arranged into a new “W-shaped” structure, which represents a new kind of molybdophosphate.  相似文献   

6.
Heteropoly acid (HPA) H8(PW11TiO39)2O·xH2O (I) is synthesized by three different ways and studied by chemical analysis, potentiometric titration, mass-spectrometry, IR, 31P, 183W, and 17O NMR spectroscopy, thermogravimetry, and transmission electron microscopy. Anion I consists of two subparticles of the Keggin structure bridged by Ti-O-Ti. The dimeric anion exists in HPA aqueous solutions at [I] > 0.02 M. At pH > 0.6 it splits to a [PW11TiO40]5− monomer stable up to pH ∼ 6. When heated (150–400)°C, I splits into H3PW12O40 and, apparently, H3PW10Ti2O38 without phase separation. Thermolysis products are soluble and when dissolved in water turn again into I. Complete decomposition of I to oxides occurs at ∼450°C.  相似文献   

7.
Gas-phase infrared photodissociation spectroscopy is reported for the microsolvated [Mn(ClO4)(H2O) n ]+ and [Mn2(ClO4)3(H2O) n ]+ complexes from n = 2 to 5. Electrosprayed ions are isolated in an ion-trap where they are photodissociated. The 2600–3800 cm−1 spectral region associated with the OH stretching mode is scanned with a relatively low-power infrared table-top laser, which is used in combination with a CO2 laser to enhance the photofragmentation yield of these strongly bound ions. Hydrogen bonding is evidenced by a relatively broad band red-shifted from the free OH region. Band assignment based on quantum chemical calculations suggest that there is formation of water—perchlorate hydrogen bond within the first coordination shell of high-spin Mn(II). Although the observed spectral features are also compatible with the formation of structures with double-acceptor water in the second shell, these structures are found relatively high in energy compared with structures with all water directly bound to manganese. Using the highly intense IR beam of the free electron laser CLIO in the 800–1700 cm−1, we were also able to characterize the coordination mode (η2) of perchlorate for two clusters. The comparison of experimental and calculated spectra suggests that the perchlorate Cl—O stretches are unexpectedly underestimated at the B3LYP level, while they are correctly described at the MP2 level allowing for spectral assignment.  相似文献   

8.
Joint thermolysis of the dinuclear pivalate complexes M2(μ-H2O)(μ-Piv)2(Piv)2(HPiv)4 (M = Co (1) and Ni (2), Piv- is the pivalate anion), in decane at 174 °C at the reactant ratio 1: 1 followed by treatment of the dry thermolysis product with methanol afforded crystals of a new cocrystallization product of the molecules containing the heterometallic cubane-like core M4(Co,Ni)O4. According to the X-ray diffraction data and the results of magnetic measurements, inductively coupled plasma atomic emission spectrometry (ICP-AES), and investigations of the solid-state thermal decomposition products, the isolated cocrystallization product has the general formula [Co1.6Ni2.4(μ3-OMe)4(μ2-Piv)2(pg2 -Piv)2(MeOH)4] ·4MeOH (3·4MeOH). Thermolysis of the crystals of the solvate 3·4MeOH is a destructive process accompanied by the intramolecular redox reaction. A mixture of metallic Ni and cobalt oxide (CoO) are the final solid decomposition products of 3 · 4MeOH in an argon atmosphere, whereas a mixture of the phases NiO, Co3O4, and NiCo2O4 is formed in air.  相似文献   

9.
The reactions of the tetranuclear hydroxo complexes [M4(μ2-OH)8(H2O)16]8+ (M = Zr or Hf) with the lacunary Keggin-type ([α-PW11O39]7−) and Dawson-type ([α 2-P2W17O61]10−) phosphotungstates in aqueous solutions produce the sandwich polyoxometalate complexes [M(α-PW11O39)2]10− (M = Zr (1) or Hf (2)) and [M(α 2-P2W17O61)2]16− (M = Zr (3) and Hf (4)). The complexes were isolated and structurally characterized as salts with potassium and dimethylammonium cations. The zirconium and hafnium atoms have a square antiprismatic coordination environment (coordination number is 8). In all complexes, the mutual arrangement of the ligands corresponds to the syn isomer. Hafnium complexes 2 and 4 are the first structurally characterized polyoxometalate complexes of this metal. The structures of the resulting compounds were confirmed also by 31P NMR spectroscopy in solution. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 214–218, February, 2007.  相似文献   

10.
In this paper, we investigated three ligand systems, symmetric and asymmetric pyridyl-containing tridentate ligands (L1NH2 = (bis(2-pyridylmethyl)-amino)-ethylamine, L2H = (bis(2-pyridylmethyl)-amino)-acetic acid, L3NH2 = [(6-amino-hexyl)-pyridyl-2-methyl-amino]-acetic acid) as bifunctional chelating agents for labeling biomolecules. These ligands reacted with the precursor fac-[188Re(CO)3(H2O)3]+ and yielded the radioactive complexes fac-[188Re(CO)3L] (L = three ligands), which were identified by RP-HPLC. The corresponding stable rhenium tricarbonyl complexes (1–3) were allowed for macroscopic identification of the radiochemical compounds. 188Re tricarbonyl complexes, with log P o/w values ranging from −1.36 to −0.32, were obtained with yields of ≥90% using ligand concentrations within the 10−6−10−4M range. Challenge studies with cysteine and histidine revealed the high stability properties of these radioactive complexes, and biodistribution studies in normal mice indicated a fast rate of blood clearance and high rate of total radioactivity excretion, primarily through the renal-urinary pathway. In summary, these asymmetric and symmetric pyridyl-containing tridentate ligands are potent bifunctional chelators for the future biomolecules labeling of fac-[188Re(CO)3(H2O)3]+.  相似文献   

11.
The A1, O, AlO, A12O, Al2O2, WO2, and WO3, partial pressures in the vapor over Al2O3 in a tungsten Knudsen effusion cell between 2300 and 2600 K were derived from A1+, O+, AlO+, A12O+, Al2O2+, WO2+, and WO3+, ion intensities. The mass spectrometer was calibrated against the equilibrium constant of the WO3(g) = WO2(g) + O(g) reaction. Refined values of the ionization cross sections of AlO and A12O2 were used in the partial pressure calculations. The enthalpies of atomization of aluminum suboxides were determined to be Δat H o(AlO, g, 0) = 510.7 ± 3.3 kJ mol−1, Δat H o(Al2O, g, 0) = 1067.2 ± 6.9 kJ mol−1, and Δat H o(Al2O2, g, 0) = 1556.7 ± 9.9 kJ mol−1.  相似文献   

12.
The reaction of a sulfur and oxygen-bridged 8-quinolinolato trinuclear molybdenum cluster [Mo3OS3(qn)3(H2O)3]+ (3; Hqn = 8-quinolinol) with equimolar amounts of acetylene carboxylic acid, 4-pentynoic acid, 5-hexynoic acid, acetic acid, and pimelic acid gave clusters having μ-carboxylato groups, [Mo3OS3(qn)3(H2O)(μ-HC≡CCOO)] (6), [Mo3OS3(qn)3(H2O)(μ-HC≡C(CH2)2COO)] (7), [Mo3OS3(qn)3(H2O)(μ-HC≡C(CH2)3COO)] (8), [Mo3OS3(qn)3(H2O)(μ-CH3COO)] (4), and [{Mo3OS3(qn)3(C2H5OH)}2(μ-C7H10O4)] (5), respectively. X-ray structural analyses, 1H NMR, and electronic spectra of these clusters made clear that each of the COO− groups of the reagents bridges two Mo atoms in each cluster and that no adduct formation occurred at the sulfurs in the clusters. The reaction of 3 with a large excess-molar amount (50 times) of acetylene carboxylic acid gave [Mo3OS(μ3-SCH=C(COOH)S)(qn)3(H2O)(μ-HC≡CCOO)] (9) with two molecules of acetylene carboxylic acid, one acting as a carboxylato bridge and the other in adduct formation, as supported by the electronic and 1H NMR spectra. The corresponding aqua cluster [Mo3OS3(H2O)9]4+ (1), on the contrary, reacts with acetylene carboxylic acid to give adduct [Mo3OS(μ3-SCH=C(COOH)S)(H2O)9]4+ (2). Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

13.
Perovskite phases Ba3In2ZrO8 and Ba4In2Zr2O11 with the nominal concentration of structural oxygen vacancies 1/9 and 1/12, respectively, were synthesized by solid-phase and solution methods. X-ray diffraction showed cubic symmetry of both phases with the unit cell parameter a = 0.4193(2) and 0.4204(3) nm, respectively. The absence of superstructural lines resulted in the conclusion on statistical arrangement of oxygen vacancies. Thermogravimetry and mass spectrometry proved that both phases can reversibly absorb water from gas phase (pH2O = 2 × 10−2 atm) with observed correlation between the concentration of oxygen vacancies and amount of absorbed water. The total water amount was up to 0.9 mol per formula unit or, if recalculated for perovskite unit ABO3, 0.3 and 0.23 mol H2O, respectively. The temperature curves of coductivity in the atmosphere with various partial water vapor pressures (pH2O = 3 × 10−5 and 2 × 10−2 atm) showed significantly higher conductivity and lower activation energy (0.52 eV) in humid atmosphere due to proton transfer. The proton conductivity is up to 5 × 10−4 Ohm−1 cm−1 at 300°C for Ba3In2ZrO8 specimen. IR spectrometry showed that protons in the structure exist primarily in OH-groups.  相似文献   

14.
The two complexes, [RE(Gly)4(Im)(H2O)](ClO4)3(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl3·6H2O(s)+4Gly(s)+Im(s)+3NaClO4(s) = =[RE(Gly)4(Im)(H2O)](ClO4)3(s)+3NaCl(s)+5H2O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δf H mΘ {Eu(Gly)4(Im)(H2O)}(ClO4)3(s)} = = −(3396.6±2.3) kJ mol−1 and Δf H mΘ {Sm(Gly)4(Im)(H2O)}(ClO4)3(s)} = −(3472.7±2.3) kJ mol−1, respectively.  相似文献   

15.
Solubility product (Lu(OH)3(s)⇆Lu3++3OH−) and first hydrolysis (Lu3++H2O⇆Lu(OH)2++H+) constants were determined for an initial lutetium concentration range from 3.72·10−5 mol·dm−3 to 2.09·10−3 mol·dm−3. Measurements were made in 2 mol·dm−3 NaClO4 ionic strength, under CO2-free conditions and temperature was controlled at 303 K. Solubility diagrams (pLuaq vs. pC H) were determined by means of a radiochemical method using 177Lu. The pC H for the beginning of precipitation and solubility product constant were determined from these diagrams and both the first hydrolysis and solubility product constants were calculated by fitting the diagrams to the solubility equation. The pC H values of precipitation increases inversely to [Lu3+]initial and the values for the first hydrolysis and solubility product constants were log10 β* Lu,H = −7.92±0.07 and log10 K*sp,Lu(OH)3 = −23.37±0.14. Individual solubility values for pC H range between the beginning of precipitation and 8.5 were S Lu3+ = 3.5·10−7 mol·dm−3, S Lu(OH)2+ = 6.2·10−7 mol·dm−3, and then total solubility was 9.7·10−7 mol·dm−3.  相似文献   

16.
Spherical Li[Ni1/3Co1/3Mn1/3]O2 cathode materials with different microstructure have been prepared by a continuous carbonate co-precipitation method using LiOH⋅H2O, Li2CO3, CH3COOLi⋅2H2O and LiNO3 as lithium source. The effects of Li source on the physical and electrochemical properties of Li[Ni1/3Co1/3Mn1/3]O2 are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results show that the morphology, tap density and high rate cycling performance of Li[Ni1/3Co1/3Mn1/3]O2 spherical particles are strongly affected by Li source. Among the four Li sources used in this study, LiOH⋅H2O is beneficial to enhance the tap density of Li[Ni1/3Co1/3Mn1/3]O2, and the tap density of as-prepared sample reaches 2.32 g cm−3. Meanwhile, Li2CO3 is preferable when preparing the Li[Ni1/3Co1/3Mn1/3]O2 with high rate cycling performance, upon extended cycling at 1 and 5C rates, 97.5% and 92% of the initial discharge capacity can be maintained after 100 cycles.  相似文献   

17.
The reactions of the tetranuclear hydroxo complexes [M4(fu2-OH)8(H20)16]8+ (M = Zr or Hf) with monolacunar Keggin-type [α-PW11O39]7- and Dawson-type [α2-P2W17O61] phosphotungstates afford the polyoxoanions [(H2O)HT(fu2-OH)(PW11O39)2]8- and [(H2O)M(fu2-OH)(P2W17O61)2]14- (M = Zr or Hf), respectively, in which the 1: 1 heterometal lacunary polyoxotungstate complexes are linked into dimers through two hydroxo bridges coordinated to the heterometal atoms. The structures of these compounds were established by single-crystal X-ray diffraction and confirmed by 31P NMR spectroscopy in solution.  相似文献   

18.
The visible light irradiation of the [(η5-C6H7)Fe(η-C6H6)]+ cation (1) in acetonitrile resulted in the substitution of the benzene ligand to form the labile acetonitrile species [(η5-C6H7)Fe(MeCN)3]+ (2). The reaction of 1 with ButNC in MeCN produced the stable isonitrile complex [(η5-C6H7)Fe(ButNC)3]+ (3). The photochemical reaction of cation 1 with pentaphosphaferrocene Cp*Fe(η-cyclo-P5) afforded the triple-decker cation with the bridging pentaphospholyl ligand, [(η5-C6H7)Fe(μ-η:η-cyclo-P5)FeCp*]+ (4). The latter complex was also synthesized by the reaction of cation 2 with Cp*Fe(η-cyclo-P5). The structure of the complex [3]PF6 was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2088–2091, November, 2007.  相似文献   

19.
A novel polyoxometalate compound consisting of monolacunary Wells-Dawson anions and trivalent lanthanide cations, K4Na2H2[Ce2(H2O)12(α2-P2W17O61)]2·10H2O (1), has been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, IR spectrum, UV spectrum and TG analyses. Single crystal X-ray diffraction reveals that CeIII ions occupy the lacunary site in the ‘cap’ regions of the Wells-Dawson ions and at the same time combine with a terminal oxygen atom of another Wells-Dawson anion, forming a centrosymmetric dimeric cluster [{Ce(H2O)4(α2-P2W17O61)}2]14−. Furthermore, the dimeric clusters act as a bidentate ligand and coordinate two [Ce(H2O)8]3+ fragments with two terminal oxygen atoms. The bisupporting dimers are linked via K-bridge, W9–O9–K1–O13–W13, and Na-bridge, W1–O1–Na1–O15–W15, forming one-dimension (1D) chains and the chains are further connected into 3D architecture also by the potassium ions. Additionally, the electrochemistry activity of compound (1) is reported. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.  相似文献   

20.
Summary.  Single crystals of MgAl2F8(H2O)2 have been obtained under hydrothermal conditions (250°C, 14 d) from a starting mixture of AlF3 and MgAlF5(H2O)2 in a 5% (w/w) HF solution. The crystal structure has been determined and refined from single crystal data (Fmmm (#69), Z = 4, a = 7.2691(7), b = 7.0954(16), c = 12.452(2) ?, 281 structure factors, 27 parameters, R(F 2 > 2σ (F 2)) = 0.0282, wR(F 2 all) = 0.0885). The obtained crystals were systematically twinned according to (010/100/001) as twinning matrix, reflecting the pseudo-tetragonal metric. The crystal structure is composed of perowskite-type layers built of corner sharing AlF6 octahedra with an overall composition of AlF4 − which are connected via common fluorine atoms of [MgF4/2(H2O)2/1] octahedra. Group-subgroup relations of MgAl2F8(H2O)2 to WO3(H2O)0.33 and to other M(II)M(III)2 F8(H2O)2 structures are briefly discussed. Above 570°C, MgAl2F8(H2O)2 decomposes under elimination of water into α-AlF3, β-AlF3, and MgF2. Received October 29, 2001. Accepted (revised) December 6, 2001  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号