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1.
Summary Light pink-white microcrystalline ammonium and potassium fluoromonooxalatomanganates(II), A[MnF(C2O4)] (A = NH4 or K), and sodium fluoromonooxalatomanganate(II) dihydrate, Na[MnF(C2O4)] · 2H2O, have been synthesized by two different methods. Either KMnO4 is reduced in the presence of 40% HF and alkali metal oxalate, A2C2O4 (A = NH4, Na or K), or MnO(OH) in 40% HF reacts with A2C2O4. Characterisation was made by elemental analyses, determination of oxidation states, magnetic susceptibility measurements and infrared spectral studies. 相似文献
2.
Hu Chuanjiang Duan Chunying Meng Qingjin Liu Yongjiang Lu Changsheng Reng Xiaoming Chen Yijun Cao Mi 《Transition Metal Chemistry》2000,25(2):141-144
The mixed-valence molybdovanadate compound Na2(NH4)4[VIVVV
8Mo)O28] · 10H2O [Vanadata(6-)tetradeca--oxotetra-3-oxodi-6-oxoheptaoxo(oxomolybdate) nonatetrammonium disodium, decahydrate] has been synthesized from sodium molybdate(VI) dihydrate and sodium metavanadate dihydrate in aqueous solution by adding NH2OH · HCl. The molecular structure has been determined by X-ray diffraction and is based on the isopolydecavanadate structure. The molybdate atom is crystallographically disordered over 6MO6 octahedral sites. The e.s.r. spectrum clearly indicates that one vanadium atom has the oxidation number +4. 相似文献
3.
L. Duvieubourg-Garela F. Abraham S. Grandjean 《Journal of solid state chemistry》2008,181(8):1899-1908
Crystals of uranium (IV) oxalate hydrates, U(C2O4)2·6H2O (1) and U(C2O4)2·2H2O (2), were obtained by hydrothermal methods using two different U(IV) precursors, U3O8 oxide and nitric U(IV) solution in presence of hydrazine to avoid oxidation of U(IV) into uranyl ion. Growth of crystals of solvated monohydrated uranium (IV) oxalate, U(C2O4)2·H2O·(dma) (3), dma=dimethylamine, was achieved by slow diffusion of U(IV) into a gel containing oxalate ions. The three structures are built on a bi-dimensional complex polymer of U(IV) atoms connected through bis-bidentate oxalate ions forming [U(C2O4)]4 pseudo-squares. The flexibility of this supramolecular arrangement allows modifications of the coordination number of the U(IV) atom which, starting from 8 in 1 increases to 9 in 3 and, finally increases, to 10 in 2. The coordination polyhedron changes from a distorted cube, formed by eight oxygen atoms of four oxalate ions, in 1, to a mono-capped square anti-prism in 3 and, finally, to a di-capped square anti-prism in 2, resulting from rotation of the oxalate ions and addition of one and two water oxygen atoms in the coordination of U(IV). In 1, the space between the ∞2[U(C2O4)2] planar layers is occupied by non-coordinated water molecules; in 2, the space between the staggered ∞2[U(C2O4)2·2H2O] layers is empty, finally in 3, the solvate molecules occupy the interlayer space between corrugated ∞2[U(C2O4)2·H2O] sheets. The thermal decomposition of U(C2O4)2·6H2O under air and argon atmospheres gives U3O8 and UO2, respectively. 相似文献
4.
Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates.
These oxalates form as a film like deposit on rocks and other host matrices. The anhydrous oxalate mineral moolooite CuC2O4 as the natural copper(II) oxalate mineral is a classic example. Another example of a natural oxalate is the mineral wheatleyite
Na2Cu2+(C2O4)2·2H2O.
High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition of wheatleyite at 255°C. Two
higher temperature mass losses are observed at 324 and 349°C. Higher temperature mass losses are observed at 819, 833 and
857°C. These mass losses as confirmed by mass spectrometry are attributed to the decomposition of tennerite CuO. In comparison
the thermal decomposition of moolooite takes place at 260°C. Evolved gas mass spectrometry for moolooite shows the gas lost
at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper(II)
oxalate as compared to the synthetic compound which is the dihydrate. 相似文献
5.
A. F. Seliverstov Yu. O. Lagunova B. G. Ershov S. G. Shashkovskii 《Russian Journal of General Chemistry》2017,87(11):2533-2536
The oxidation of oxalate ions with ozone in aqueous solution has been studied, and the effects of pH, temperature, and reactant concentrations on the reaction rate and efficiency have been estimated. The oxidative decomposition is most effective in alkaline medium (pH ≥ 10) at 50°C. Under these conditions, the consumption of ozone is 0.6±0.1 g per gram of oxalate or 1.1±0.1 mol per mole of oxalate, which corresponds to the stoichiometry (COO–)2 + O3 + H2O → 2CO32– + O2 + 2H+. 相似文献
6.
R. VaidhyanathanSrinivasan Natarajan C.N.R. Rao 《Journal of solid state chemistry》2002,167(2):274-281
The metathetic reaction between CdBr2 and rubidium oxalate under hydrothermal conditions yields [RbBr] [Cd6(C2O4)6]·2H2O, I, containing Cd6O24 clusters with the Br− ions in the center. The RbBr moiety forms a three-dimensional Fm3m structure, but with a unit cell double that of the normal stable phase. The hydrothermal reaction between rubidium oxalate and CdCl2 in the presence of NO−3 ions gives [Rb2Cd(NO3)(Cl)(C2O4)(H2O)], II, containing cadmium chloro-oxalate layers. The Rb+ ions present between the layers interact with the Cl atoms to form a one-dimensional RbCl chain decorated by NO−3 groups. 相似文献
7.
Martin U. Schmidt Edith Alig Lothar Fink Michael Bolte Robin Panisch Volodymyr Pashchenko Bernd Wolf Michael Lang 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(7):m361-m364
Double‐layer structures consisting of alternating polar and non‐polar layers have been prepared using Mn2+ ions and o‐hydroxynaphthoic acids. The polar layers contain the Mn2+ ions, carboxylate groups, hydroxy groups and water molecules. The non‐polar layers are built up from the naphthalene moieties. In catena‐poly[[diaquamanganese(II)]bis(μ‐3‐hydroxy‐2‐naphthoato‐κ2O:O′)] (also called manganese 3‐hydroxy‐2‐naphthoate dihydrate), [Mn(C11H7O3)2(H2O)2]n, (I), the Mn2+ ions are connected by carboxylate groups to form two‐dimensional networks. This compound shows distinct antiferromagnetic interactions and long‐range ordering at low temperature. In contrast, tetraaquabis(1‐hydroxy‐2‐naphthoato‐κO)manganese(II), [Mn(C11H7O3)2(H2O)4], (II), which lacks a close linkage between the Mn2+ ions, reveals purely paramagnetic behaviour. In (II), the Mn2+ ion lies on an inversion centre. 相似文献
8.
Ag. Stamatis P. Doutsi Ch. Vartzouma K.C. Christoforidis Y. Deligiannakis M. Louloudi 《Journal of molecular catalysis. A, Chemical》2009,297(1):44-53
Two new symmetrical acetylacetone-based Schiff bases, herein called LA and LB, have been synthesized. The complexes formed by their association with Mn(II) have been evaluated for catalytic alkene epoxidation with H2O2. The catalytic efficiency of Mn(II)/LA and Mn(II)/LB systems were shown to be switched on by ammonium acetate with remarkable effectiveness and selectivity towards epoxides. EPR spectroscopy for Mn(II)/LA shows that the catalytic centre is a mononuclear Mn complex. Additives that allow easier oxidation of Mn(II) to higher oxidation states, i.e. such as acetate and bicarbonate, can promote decisively the catalytic function. Additives that do not allow oxidation of Mn(II) to higher oxidation states, i.e. such as formate and oxalate, inhibit severely the catalytic function. Monocarboxylate ions, i.e. acetate, bicarbonate and formate do not disturb considerably the first coordination sphere of Mn(II). Dicarboxylate additives, i.e. such as oxalate, form strong complex with the Mn(II).Based on the catalytic and EPR data, a double role is suggested for ammonium acetate. This is to promote Mn(II) oxidation, and to function as a dual acid-base system, participating into the catalytic cycle. 相似文献
9.
The novel bis(cyclohexylaminium) cyclohexylaminebis(orotate–N,O)cuprate(II) dihydrate, (C6H15N)2[Cu(C5H2N2O4)2(C6H14N)] · 2H2O, has been prepared and characterized by elemental analysis, magnetic measurements, FT-IR and UV–Vis spectroscopy, thermal analysis and X-ray diffraction. The Cu(II) complex crystallizes in the monoclinic space group P21/c. The copper atom in the five-coordinated (chaH)2[Cu(HOr–N,O)2(cha)] · 2H2O is chelated by a deprotonated pyrimidine nitrogen atom and carboxylate oxygen atom as a bis(bidentate) ligand and the cyclohexylamine ligand completes the square-pyramidal coordination. The thermal decomposition of the complex has been predicted by the help of thermal analysis (TG, DTG and DTA). 相似文献
10.
Uwe Kolitsch 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):m129-m133
Rubidium chromium(III) dioxalate dihydrate [diaquabis(μ‐oxalato)chromium(III)rubidium(I)], [RbCr(C2O4)2(H2O)2], (I), and dicaesium magnesium dioxalate tetrahydrate [tetraaquabis(μ‐oxalato)magnesium(II)dicaesium(I)], [Cs2Mg(C2O4)2(H2O)4], (II), have layered structures which are new among double‐metal oxalates. In (I), the Rb and Cr atoms lie on sites with imposed 2/m symmetry and the unique water molecule lies on a mirror plane; in (II), the Mg atom lies on a twofold axis. The two non‐equivalent Cr and Mg atoms both show octahedral coordination, with a mean Cr—O distance of 1.966 Å and a mean Mg—O distance of 2.066 Å. Dirubidium copper(II) dioxalate dihydrate [diaquabis(μ‐oxalato)copper(II)dirubidium(I)], [Rb2Cu(C2O4)2(H2O)2], (III), is also layered and is isotypic with the previously described K2‐ and (NH4)2CuII(C2O4)2·2H2O compounds. The two non‐equivalent Cu atoms lie on inversion centres and are both (4+2)‐coordinated. Hydrogen bonds are medium‐strong to weak in the three compounds. The oxalate groups are slightly non‐planar only in the Cs–Mg compound, (II), and are more distinctly non‐planar in the K–Cu compound, (III). 相似文献
11.
《Polyhedron》1987,6(2):213-218
The previously reported preparation of some Anderson-type molybdopolyanions containing divalent metal ions (Zn, Cu, Co or Mn) as a heteroatom has been reinvestigated. The molybdopolyanions of Zn(II) and Cu(II) were confirmed, although the Cu(II) polyanion was not stable and could not be recrystallized. On the other hand, the polyanions of Co(II) and Mn(II) could not be reproduced. Another type of heteropoly compound, [X(H2O)6-x(Mo7O24)]4− [X = Cu(II), Co(II) or Mn(II)], was isolated as solids, which are not stable thermally. The mixed-type Anderson polyanions, [Ni(II)Mo6-xWx,O24H6]4−, which have been questioned as mixtures of species with different x values, were also reinvestigated using IR, UV absorption and MCD spectra. They are single species, but not mixtures, although some positional isomers may be present for the compounds where x = 2-4. The possibility of oxidation of the heteroatom with the Anderson structure maintained was examined. The oxidation of [Ni(II)Mo6O24H6]4− by the S2O2−8 ion in aqueous solution gave the Waugh-type [Ni(IV)Mo9O32]6− polyanion, whereas the oxidation of [Ni(II)W6O24H6]4− gave no heteropoly compound. 相似文献
12.
Gekhman A. E. Stolyarov I. P. Ershova N. V. Moiseeva N. I. Moiseev I. I. 《Kinetics and Catalysis》2004,45(1):40-60
In the V(V)H2O2/AcOH system, C5–C20
n-alkanes, isooctane, and neohexane undergo oxidation to ketones and alcohols; the oxidation products of branched alkanes are indicative of a C–C bond cleavage in these substrates. A concept is developed, according to which the peroxo complexes of vanadium(V) are responsible for alkane oxidation. These complexes can transfer the oxygen atom or the O+· radical cation to a substrate. The formation of nitrous oxide was found in the oxidation of molecular nitrogen in the H2O2/V(V)/CF3COOH system. 相似文献
13.
Solid state reactivity between iron/II/oxalate dihydrate, i.e., FeC2O4.2H2O and para-chloro aniline hydrochloride, i.e., p-ClC6H4NH2.HCl has been studied at 373, 393 and 413 K. The reaction seems to follow the diffusion controlled mechanism. The product, [FeCl/oxH/.AN–Cl], has been characterized by elemental analysis, infrared and Mössbauer spectroscopic techniques, mass spectrometry and derivatographic methods /TG, DTA/. 相似文献
14.
G. S. Zakharova N. V. Podval’naya M. V. Kuznetsov 《Russian Journal of Inorganic Chemistry》2011,56(2):267-272
Nanorods of vanadium oxide doped with alkali metal ions M
x
V2O5 · nH2O (M = Na, K, Rb, Cs, x = 0.31–0.44) have been obtained under hydrothermal conditions. The particles are 30–80 nm in diameter and a few micrometers
in length. The chemical state of atoms and their concentration ratios have been studied by XPS. It has been shown that vanadium
atoms are in two oxidation states V5+ and V4+ and the concentration of vanadium(IV) ions directly depends on the alkali metal. The X-ray photoelectron spectra of the valence
bands of M
x
V2O5 · nH2O (M = Na, K, Rb, Cs) nanorods have been measured and interpreted. 相似文献
15.
A. I. Karelin N. N. Krot R. D. Kozlova O. P. Lobas V. A. Matukha 《Journal of Radioanalytical and Nuclear Chemistry》1990,143(1):241-252
Thermal decomposition of Pu(C2O4)2·6H2O, Pu2(C2O4)3·10H2O and Np(C2O4)2 ·6H2O has been studied by using combination of gas chromatography, infrared spectroscopy, spectrophotometry and complex thermal analysis. We also investigated the decomposition of Pu oxalate under its -radiation. The reduction of Pu(IV) to Pu(III) has been confirmed. We found Np(V), which is formed from Np(IV), on the basis of infrared and absorption spectra of the intermediate compounds. 相似文献
16.
Novosad Josef Messimeri Argyro C. Papadimitriou Christos D. Veltsistas Panos G. Woollins J. Derek 《Transition Metal Chemistry》2000,25(6):664-669
Reaction of CuII salts with phenanthroline and oxalate (ox) or oxamate (oxm) gives [Cu(phen)(ox)(H2O)] · H2O or [Cu(phen)(oxm)(H2O)] · H2O complexes while direct treatment of CuII salts with oxalate or oxamate gives [NH4]2[Cu(ox)2] and [Cu(oxm)2(H2O)2] respectively. The X-ray structures of one example of each system, aquo-oxamato-phenanthroline-copper(II)-dihydrate and the polymeric ammonium-bis(aquo)-tetraoxalato-dicopper(II)-dihydrate, are reported. 相似文献
17.
M. Birzescu M. Niculescu Raluca Dumitru P. Budrugeac E. Segal 《Journal of Thermal Analysis and Calorimetry》2008,94(1):297-303
The paper presents the experimental results of the structural investigations and thermal analysis of copper(II) oxalate, a
polynuclear coordination compound, obtained by a new method, through the reaction of 1,2-ethanediol with Cu(NO3)2·3H2O.
The reaction between 1,2-ethanediol and Cu(NO3)2·3H2O occurs, under some working conditions, with the oxidation of 1,2-ethanediol to the oxalate anion (L). The synthesized polynuclear
coordination compound, [CuL·0.3H2O]n, was characterized by chemical analysis, electronic and vibrational spectra and thermal analysis. The thermal properties
of the polynuclear coordination compound have been investigated by TG, DTG and DSC. The obtained decomposition product is
CuO.
Powder XRD (X-ray diffraction), IR spectroscopy and TEM (transmission electron microscopy) were used to characterize the composition,
the crystalline structure and the surface morphology of the copper oxide obtained through thermolysis. The thermal conversion
product, copper(II) oxide, has a microporous structure with a large specific area. 相似文献
18.
Jing-Quan Sha Xin Li Ying-Hua Zhou Peng-Fei Yan Guang-Ming Li Cheng Wang 《Solid State Sciences》2011,13(11):1972-1977
Two new compounds based on polyoxometalates (POMs) and the quinolone antibacterial drug pipemidic acid (HPPA), {[Ni(PPA)2]H4[SiW12O40]}·HPPA·3H2O (1), and {[Zn(PPA)2]2H4[SiW12O40]}·3H2O (2), have been synthesized under hydrothermal conditions and structurally characterized by routine technique. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by Keggin clusters grafted by binuclear nickel clusters, isolated HPPA and water molecules, while compound 2 consists of Keggin clusters grafted by binuclear zinc clusters and water molecules. Due to the selection of different transition metal (TM) ions, compounds 1 and 2 exhibit different structures and antitumor activities. Compound 1 possesses 0D structure and shows no antitumor activities. However, compound 2 possesses 1D structure and exhibits higher antitumor activities than its parent compound. The results show that introduction of different TM-PPA moieties onto the polyoxoanion surface can affect not only the final structures but also their antitumor activities. 相似文献
19.
A new magnesium borate MgO·3B2O3·3.5H2O has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B6O9(OH)2]·2.5H2O. The enthalpy of solution of MgO·3B2O3·3.5H2O in approximately 1 mol dm−3 HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(5595.02±4.85) kJ mol−1 of MgO·3B2O33.5H2O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method. 相似文献
20.
In our effort to induce novel modifications in the structure of some important vanadium phosphate phases used as selective
oxidation catalysts, it has been observed that metal ions such as Zn2+, Ni2+, Pd2+can be incorporated into the vanadyl hydrogen phosphate VOHPO40.5H2O phase in very different ways depending upon the medium of preparation. It has been found that the metal ions are either
substituted into the lattice with retention of structure of the parent compound or intercalated between the layers of a new
mixed-valent phase. These new metal-incorporated phases are catalytically active and the palladium incorporated compound in
particular displays shape selective catalysis for different oxidation and reduction reactions. In another approach, the preparation
of VOHPO40.5H2O) has been modified to give a novel crystalline phase containing mixed-valentvanadium and having NH3 species bound to the lattice. This phase could be a potential catalyst for ammoxidation reactions. In addition, novel mesostructured
vanadium phosphate phases have been prepared using a long-chain amine as the templating agent involving a ligand templating
mechanism of formation. 相似文献