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1.
The infrared (IR) spectra of Co(HCOO)2 x 2H2O, Ni(HCOO)2 x 2H2O and Cu2Co(Ni)1-x (HCOO)2 x 2H2O mixed crystals (0 < x < or = 0.5) have been recorded and the internal modes of the formate groups and the water molecules are discussed. The analysis of the spectra of the mixed crystals reveals that when copper ions replace cobalt and nickel ions in Co(HCOO) x 2H2O and Ni(HCOO)2 x 2H2O, the Cu2+ ions are localized at the two available positions. However, the occupancy degree of the Me(1) and Me(2) sites by the different cations needs X-ray diffraction (XRD) studies of the single crystals. The new crystal phase Co0.17Cu0.83(HCOO)2 x 2H2O obtained from the Co(HCOO)2 x 2H2O-Cu(HCOO)2 x 2H2O-H2O system at 50 degrees C crystallizes in the monoclinic system with lattice parameters: a = 12.329(4); b = 7.241(2); c = 8.707(5) A and beta = 103.13(3) degrees (SG probably P2/c). The number of the bands corresponding to the uncoupled OD vibrations and the water librations shows that probably more than two water molecules are expected to exist in the structure. Furthermore, it is assumed that the water molecules bonded to the copper ions form stronger hydrogen bonds (stronger Cu-OH2 interaction) than those bonded to the cobalt ions.  相似文献   

2.
以堇青石蜂窝陶瓷为基底,A12O3浆料为过渡胶体,Cu和Co为催化活性组分,制备了一系列CuxCo1-x/Al2O3/堇青石(x=0~1)整体式催化剂.采用X射线衍射、X射线光电子能谱、扫描电镜和程序升温还原等手段对催化剂进行了表征.以甲苯为模型化合物.在微型固定床反应器上评价了催化剂的催化性能.结果表明,当Cu含量较...  相似文献   

3.
Puri BK  Balani S 《Talanta》1995,42(3):337-344
Iron, cobalt and copper form coloured water soluble anionic complexes with disodium 1-nitroso-2-naphthol-3-6-disulphonate (nitroso R-salt). The anionic complex is retained quantitatively as a water insoluble neutral ion associated complex (M-nitroso R-TDBA) on tetradecyldimethylbenzylammonium iodide on naphthalene (TDBA(+)I(-)-naphthalene) packed column in the pH range of: Fe(III): 3.1-6.5, Co: 3.4-8.5 and Cu 5.9-8.0 when their solutions are passed individually over this adsorbent at a flow rate of 0.5-5.0 ml/min. The solid mass consisting of an ion associated metal complex along with naphthalene is dissolved out of the column with 5 ml dimethylformamide/chloroform and metals are determined spectrophotometrically. The absorbance is measured at 710 nm for iron, 425 nm for cobalt and 480 nm for copper. Beers law is obeyed in the concentration range 9.2-82 mug of iron, 425 nm for cobalt cobalt and 3.0-62 mug of copper in 5 ml of final DMF/CHCl(3) solution. The molar absorptivities are calculated to be Fe: 7.58 x 10(3), Co: 1.33 x 10(4) and Cu: 4.92 x 10(4)M(-1)cm(-1). Ten replicate determinations containing 25 mug of iron, 9.96 mug of cobalt and 3.17 mug of copper gave mean absorbances 0.677, 0.450 and 0.490 with relative standard deviations of 0.88, 0.98 and 0.92%, respectively. The interference of large number of metals and anions on the estimations of these metals has been studied. The optimized conditions so developed have been employed for the trace determination of these metals in standard alloys, waste water and fly ash samples.  相似文献   

4.
Summary Two new quadridentate sulphur-nitrogen chelating agents have been prepared and characterized. These ligands yield stable complexes of general formulae, M(ONNS)·xH2O (M=Ni, Cu, Zn, Cd, Pd and Pt; ONNS–2=ligand dianion; x=0, 1 or 2) and M(ONNS)X (M=Co or Fe; X=Cl or AcO). The nicke(II) complexes are diamagnetic and squareplanar. Based on magnetic and spectral data a square-planar structure is also assigned to the copper(II) complexes. The iron(III) complexes, Fe(ONNS)Cl are high-spin and five-coordinate. Magnetic and spectral evidence support an octahedral structure for the cobalt(III) complex, Co(ONNS)OAc.  相似文献   

5.
Cobalt and nickel oxide cluster cations, Co(x)O(y)(+) and Ni(x)O(y)(+), are produced by laser vaporization of metal rods in a pulsed nozzle cluster source and detected using time-of-flight mass spectrometry. The mass spectra show prominent stoichiometries of x = y for Co(x)O(y)(+) along with x = y and x = y - 1 for Ni(x)O(y)(+). The cluster cations are mass selected and multiphoton photodissociated using the third harmonic (355 nm) of a Nd:YAG laser. Although various channels are observed, photofragmentation exhibits two main forms of dissociation processes in each system. Co(x)O(y)(+) dissociates preferentially through the loss of O(2) and the formation of cobalt oxide clusters with a 1:1 stoichiometry. The Co(4)O(4)(+) cluster seems to be particularly stable. Ni(x)O(y)(+) fragments reveal a similar loss of O(2), although they are found to favor metal-rich fragments with stoichiometries of Ni(x)O(x-1). The Ni(2)O(+) fragment is produced from many parent ions. The patterns in fragmentation here are not nearly as strong as those seen for early or mid-period transition-metal oxides studied previously.  相似文献   

6.
Cefadroxil (CD) is an essential pharmaceutical drug used in curing many diseases. Due to its popular use in many pharmaceutical forms, attention is paid in this research to the synthesis and stereochemistry of new iron, cobalt, nickel, copper, and zinc complexes of this drug both in solution and the solid states. The spectra of these complexes in solution and the study of their stoichiometry refer to the formation of 1:1 and 1:2 ratios of metal (M) to ligand (L). The calculated stability constants (Kf) of these complexes (1.5x10(7) to 5x10(13)) and the change in free energy of formation (deltaGf=2.5-12.5 kcal mol(-1) degree(-1)) are indicative of their high stability. The stereo chemical structure of the solid complexes was studied on the basis of their analytical, spectroscopic, magnetic, and thermal data. Infrared spectra proved the presence of M-N and M-O bonds. Magnetic susceptibility and solid reflectance spectral measurements were used to infer the structure. The prepared complexes were found to have the general formulae [ML(OH)x(H2O)y](H2O)z-M: Fe(II), x=0, y=2, z=1; M: Fe(III) and Co(III), x=1, y=2, z=1; M: Co(II) and Zn(II), x=0, y=1, z=0; M: Ni(II) and Cu(II), x=1, y=0, z=1; L: CD. Octahedral and tetrahedral structures were proposed for these complexes depending upon the magnetic and reflectance data and were confirmed by detailed mass and thermal analyses comparative studies.  相似文献   

7.
Keypour  H.  Sedighi  B.  Asadi  A.  Parish  R. V. 《Transition Metal Chemistry》1997,23(1):7-12
The synthesis and characterisation of the title ligands (MXBDP and PXBDP) are described. The successive protonation constants (log Kn) are: for MXBDP, 10.77, 10.44, 9.82, 8.88, 3.19 and 1.48; for PXBDP, 10.94, 10.58, 9.90, 9.38, 3.37 and 2.27 (n=16). With copper(II), nickel(II) and cobalt(II) both ligands preferentially form binuclear complexes, M2L4+ (L=MXBDP, PXBDP), for which the formation constants [logβ(M2L), M=Cu, Ni, Co] are: for MXBDP, 22.16, 16.20, 11.07; for PXBDP, 25.48, 17.18 and 12.74, respectively. The copper complexes Cu2(MXBDP)Cl4· 4H2O and Cu2(PXBDP)Cl4·2H2O have been isolated. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

8.
The complexes ML2 · 2H2O and CrL3 · 8H2O were synthesized by the reaction of Cu(II), Ni(II), Co(II), Cd(II), and Cr(III) nitrates with 3-hydroxypyridine (HL) and identified. The spectroscopic characteristics of neutral, anionic, and cationic forms of the ligand were determined. It was shown that 3-hydroxypyridine enters the complex as an anion to give polymeric chains due to the ligand coordination through the N and O atoms. Complexation of copper, cobalt, and chromium nitrates with 3-hydroxypyridine in ethanol solutions was studied, and the formation constant of the copper complex was calculated. It was found that Cu(II) and Cr(III) complexes are formed in the solid state and in solutions (M : L = 1 : 2 and 1 : 3, respectively; in the case of Cu(II), the M : L ratio is 1 : 3).  相似文献   

9.
The effects of the addition of manganese to a series of TiO(2)-supported cobalt Fischer-Tropsch (FT) catalysts prepared by different methods were studied by a combination of X-ray diffraction (XRD), temperature-programmed reduction (TPR), transmission electron microscopy (TEM), and in situ X-ray absorption fine structure (XAFS) spectroscopy at the Co and Mn K-edges. After calcination, the catalysts were generally composed of large Co(3)O(4) clusters in the range 15-35 nm and a MnO(2)-type phase, which existed either dispersed on the TiO(2) surface or covering the Co(3)O(4) particles. Manganese was also found to coexist with the Co(3)O(4) in the form of Co(3-x)Mn(x)O(4) solutions, as revealed by XRD and XAFS. Characterization of the catalysts after H(2) reduction at 350 degrees C by XAFS and TEM showed mostly the formation of very small Co(0) particles (around 2-6 nm), indicating that the cobalt phase tends to redisperse during the reduction process from Co(3)O(4) to Co(0). The presence of manganese was found to hamper the cobalt reducibility, with this effect being more severe when Co(3-x)Mn(x)O(4) solutions were initially present in the catalyst precursors. Moreover, the presence of manganese generally led to the formation of larger cobalt agglomerates ( approximately 8-15 nm) upon reduction, probably as a consequence of the decrease in cobalt reducibility. The XAFS results revealed that all reduced catalysts contained manganese entirely in a Mn(2+) state, and two well-distinguished compounds could be identified: (1) a highly dispersed Ti(2)MnO(4)-type phase located at the TiO(2) surface and (2) a less dispersed MnO phase being in the proximity of the cobalt particles. Furthermore, the MnO was also found to exist partially mixed with a CoO phase in the form of rock-salt Mn(1-x)Co(x)O-type solid solutions. The existence of the later solutions was further confirmed by scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) for a Mn-rich sample. Finally, the cobalt active site composition in the catalysts after reduction at 300 and 350 degrees C was linked to the catalytic performances obtained under reaction conditions of 220 degrees C, 1 bar, and H(2)/CO = 2. The catalysts with larger Co(0) particles ( approximately >5 nm) and lower Co reduction extents displayed a higher intrinsic hydrogenation activity and a longer catalyst lifetime. Interestingly, the MnO and Mn(1-x)Co(x)O species effectively promoted these larger Co(0) particles by increasing the C(5+) selectivity and decreasing the CH(4) production, while they did not significantly influence the selectivity of the catalysts containing very small Co(0) particles.  相似文献   

10.
A series of organic-inorganic hybrid compounds, K2H7[{Ln(PW11O39)2}{Cu2(bpy)2(mu-ox)}].xH2O (Ln = La, x approximately = 18 (1); Ln = Pr, x approximately = 18(2); Ln = Eu, x approximately = 16(3); Ln = Gd, x approximately 22(4); Ln = Yb, x approximately = 19 (5); bpy = 2,2'-bipyridine and ox = oxalate), have been isolated by the conventional solution method. Single-crystal X-ray diffraction studies reveal that compounds 1-5 are isomorphic and consist of one-dimensional chains, which are constructed by alternating bis(undecatungstophosphate) lanthanates [Ln(PW11O39)2](11-) and dinuclear copper(II)-oxalate complexes [Cu2(bpy)2(mu-ox)]2+.pi-pi interactions of the bpy ligands from adjacent chains lead to their three-dimensional structures. An analogue of potassium K2H9[{K(PW11O39)2}{Cu2(bpy)2(mu-ox)}1].approximately 20.5H2O(6) has also been obtained. The syntheses and structures of these compounds are reported here. Magnetic properties of 1, 2 and 3 are discussed as well. Attempts to crystallize similar compounds containing Co(II) and Ni(II) were unsuccessful.  相似文献   

11.
Neutral dimeric metallocyclic complexes of type [M(2)(L(1))(2)B(n)] (where M = cobalt(II), nickel(II) and zinc(II), L(1) is the doubly deprotonated form of a 1,3-aryl linked bis-beta-diketone ligand of type 1,3-bis(RC(O)CH(2)C(O))C(6)H(4) (R=Me, n-Pr, t-Bu) and B is pyridine (Py) or 4-ethylpyridine (EtPy)) have been synthesised, adding to similar complexes already reported for copper(II). New lipophilic ligand derivatives with R = octyl or nonyl were also prepared for use in solvent extraction experiments. Structural, electrochemical and solvent extraction investigations of selected metal complex systems from the above series are reported, with the X-ray structures of [Co(2)(L(1))(2)(Py)(4)] x 2.25CHCl(3) x 0.5H(2)O (R=Pr), [Co(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Ni(2)(L(1))(2)(EtPy)(4)] (R=t-Bu), [Zn(2)(L(1))(2)(EtPy)(2)] (R=Me) and [Zn(2)(L(1))(2)(EtPy)(4)] (R=t-Bu) being presented. The electrochemistry of H(2)L(1) (R=t-Bu) and of [Fe(2)(L(1))(3)], [Co(2)(L(1))(2)(Py)(4)], [Ni(2)(L(1))(2)(Py)(4)], [Cu(2)(L(1))(2)] and [Zn(2)(L(1))(2)(Py)(2)] has been examined. Oxidative processes for the complexes are dominantly irreversible, but several examples of quasireversible behaviour were observed and support the assignment of an anodic process, seen between +1.0 and +1.6 V, as a metal-centred oxidation. The reduction processes for the respective metal complexes are not simple, and irreversible in most cases. Solvent extraction studies (water/chloroform) involving variable concentrations of metal, bis-beta-diketone and heterocyclic base have been performed for cobalt(II) and zinc(II) using a radiotracer technique to probe the stoichiometries of the extracted species in each case. Synergism was observed when 4-ethylpyridine was added to the bis-beta-diketone ligand in the chloroform phase. Competitive extraction studies show a clear uptake preference for copper(II) over cobalt(II), nickel(II), zinc(II) and cadmium(II).  相似文献   

12.
Most of the first-row transition-metal oxides, M(A)O(B) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) were examined by static secondary ion mass spectrometry (s-SIMS) and laser ablation/ionization Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS). Positive and negative ions show strong correlation between the studied oxide and the detected cluster ions. Specific M(x)O(y) (+/-) species were systematically observed with both MS techniques for each investigated M(A)O(B) transition-metal oxide. Moreover, the ion composition and ion distribution are greatly dependent on the ionization technique. Laser ablation (LA)/ionization leads to larger cluster ions (ionic species with nearly hundred atoms were in particular detected for Sc2O3 and Y2O3 oxides), whereas hydrogenated, dihydrogenated, and sometimes trihydrogenated species were observed in s-SIMS. However, the ion distribution for a given M(x)O(y) (+/-) ion series (i.e. ions including the same number of metal atoms M) generally presented important similarities in both techniques.Finally, it was demonstrated that the chemical state of metal atoms in the observed ionic species is closely dependent on the metal electronic valence shell. High valence states (+III, +IV, +V, and +VI) are favored for metals with a less-than-half full valence shell configuration, whereas for other first-row transition metals (manganese, iron, cobalt, nickel, copper and zinc) lower metal valence states (0, +I or, +II) are involved.  相似文献   

13.
Colloidal cobalt-doped TiO(2) (anatase) nanocrystals were synthesized and studied by electronic absorption, magnetic circular dichroism, transmission electron microscopy, magnetic susceptibility, cobalt K-shell X-ray absorption spectroscopy, and extended X-ray absorption fine structure measurements. The nanocrystals were paramagnetic when isolated by surface-passivating ligands, weakly ferromagnetic (M(s) approximately 1.5 x 10(-)(3) micro(B)/Co(2+) at 300 K) when aggregated, and strongly ferromagnetic (up to M(s) = 1.9 micro(B)/Co(2+) at 300 K) when spin-coated into nanocrystalline films. X-ray absorption data reveal that cobalt is in the Co(2+) oxidation state in all samples. In addition to providing strong experimental support for the existence of intrinsic ferromagnetism in cobalt-doped TiO(2), these results demonstrate the possibility of using colloidal TiO(2) diluted magnetic semiconductor nanocrystals as building blocks for assembly of ferromagnetic semiconductor nanostructures with potential spintronics applications.  相似文献   

14.
M?ssbauer spectroscopy and magnetization studies of YBaCo(4-x)Fe(x)O(7+δ) (x = 0-0.8) oxidized at 0.21 and 100 atm O(2), indicate an increasing role of penta-coordinated Co(3+) states when the oxygen content approaches 8-8.5 atoms per formula unit. Strong magnetic correlations are observed in YBaCo(4-x)Fe(x)O(8.5) from 2 K up to 55-70 K, whilst the average magnetic moment of Co(3+) is lower than that for δ ≤ 0.2, in correlation with the lower (57)Fe(3+) isomer shifts determined from M?ssbauer spectra. The hypothesis on dominant five-fold coordination of cobalt cations was validated by molecular dynamics modeling of YBaCo(4)O(8.5). The iron solubility limit in YBaCo(4-x)Fe(x)O(7+δ) corresponds to approximately x ≈ 0.7. The oxygen intercalation processes in YBaCo(4)O(7+δ) at 470-700 K, analyzed by X-ray diffraction, thermogravimetry and controlled-atmosphere dilatometry, lead to unusual volume expansion opposing to the cobalt cation radius variations. This behavior is associated with increasing cobalt coordination numbers and with rising local distortions and disorder in the crystal lattice on oxidation, predicted by the computer simulations. When the oxygen partial pressure increases from 4 × 10(-5) to 1 atm, the linear strain in YBaCo(4)O(7+δ) ceramics at 598 K is as high as 0.33%.  相似文献   

15.
Garg BS  Sharma RK  Bist JS  Bhojak N  Mittal S 《Talanta》1999,48(1):49-55
o-Vanillin-immobilized silica gel has been used for the adsorption and estimation of copper, cobalt, iron and zinc by both batch and column techniques. Metal ions were quantitatively retained on the column packed with immobilized silica gel in the pH range 4.0-6.0 for Cu, 5.0-6.0 for Co, 4.5-6.0 for Fe and 6.0-8.0 for Zn. The distribution coefficient D determined for each metal was as follows (ml g(-1)): Fe, 5.4x10(2); Cu, 4.9x10(2); Zn, 4.4x10(2); Co, 3.8x10(2). Methods have been developed to estimate zinc, copper and cobalt in milk, steel and vitamin samples, respectively.  相似文献   

16.
过渡金属氧化物[1,2]及负载型贵金属催化剂[3~13]是催化氧化消除CO的有效催化剂,一直是研究的热点. 虽然对MOx和Au/MOx上CO的氧化性能研究得较多,但大多是在无水条件下进行的;涉及催化剂抗水性能的报道较少[3,9,10],且仅限于对催化剂活性的研究. Haruta等[3]对Au/Fe2O3,Au/Co3O4和Au/TiO 2等体系开展了一些工作, 认为水对CO氧化活性有促进作用. 本文重点考察了水对MOx(M=Al,Ca,Co,Cr,Cu,Fe,La,Mn,Ni和Zn)催化剂上CO氧化活性的影响,以及水对Au/MOx 催化剂活性及稳定性的影响.  相似文献   

17.
Codeine is an analgesic with uses similar to morphines, but it is of much less effect, i.e., it had a mild sedative effect; codeine is usually used as the phosphate form (Cod.P) and is often administrated by mouth with aspirin of paracetamol. Due to its serious use, if it is in large dose, attention is paid in this research to the synthesis and stereochemistry of new iron, cobalt, nickel, copper, and zinc complexes of this drug in both solution and the solid states. The spectra of these complexes in solution and the study of their stoichiometry refer to the formation of 1:1 ratio of metal (M) to ligand (L). The steriochemical structures of the solid complexes were studied on the basis of their analytical, spectroscopic, magnetic, and thermal data. Infrared spectra proved the presence of MO bonds. Magnetic susceptibility and solid reflectance spectral measurements were used to infer the structures. The prepared complexes were found to have the general formulae [ML(OH)(x)(H2O)(y)](H2O)(z)H3PO4, M: Co(II), Ni(II), and Cu(II), x = 1, y = 0, z = 0; M: Fe(II), x = 1, y = 2, z = 1; Fe(III), x = 2, y = 1, z = 0; Co(III), x = 0, y = 2, z = 1; Zn(II), x = 1, y = 0, z = 3; and L: (Cod.P) of the general formula C18H24NO7P (anhydrate). Octahedral, tetrahedral, and square planer structures were proposed for these complexes depending upon the magnetic and reflectance data and were confirmed by detailed mass and thermal analyses comparative studies.  相似文献   

18.
19.
The synergistic effect of Ni(II) and Co(II) on the sulfite induced autoxidation of Cu(II)/tetraglycine was investigated spectrophotometrically at 25.0 degrees C, pH = 9.0, 1 x 10(-5) mol dm(-3) < or = [S(IV)] < or = 8 x 10(-5) mol dm(-3), [Cu(II)]= 1 x 10(-3) mol dm(-3), 1 x 10(-6) mol dm(-3) < or = [Ni(II)] or [Co(II)] < or = 1 x 10(-4) mol dm(-3), [O2] approximately 2.5 x 10(-4) mol dm(-3), and 0.1 mol dm(-3) ionic strength. In the absence of added nickel(II) or cobalt(II), the kinetic traces of Cu(III)G4 formation show a large induction period (about 3 h). The addition of trace amounts of Ni(II) or Co(II) increases the reaction rate significantly and the induction period drastically decreases (less than 0.5 s). The effectiveness of Cu(III)G4 formation becomes much higher. The metal ion in the trivalent oxidation state rapidly oxidizes SO3(2-) to SO3*-, which reacts with oxygen to produce SO5*-. The strongly generated oxidants oxidize Cu(II)G4 to Cu(III).  相似文献   

20.
Complexes of formula M(L)2·nH2O [M=Co or Ni; L=indole-3-carboxylic (I3CH), indole-3-acetic (I3AH), indole-N-acetic (INAH), indole-N-methyl-2-carboxylic (INMH) and M=Co or Ni and Cu, L=indole-3-β-acrylic acids (I3βH)] were pepared and characaterized by i.r. and electronic spectroscopy and by susceptibility measurements and e.s.r. at room and low temperature. The cobalt and nickel complexes exhibit a distorted octahedral coordination except the Co(I3C)2 complex for which a tetrahedral coordination was suggested. The Cu(I3β)2·H2O shows e.p.r. features that can be interpreted if the triplet state, S=1, depending on the temperature, is able to migrate through the crystal lattice of carboxylate dimers such as the copper(II) acetate monohydrate.  相似文献   

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