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1.
Summary Studies on the chelates of cobalt(II) with the bidentate ligands 1,4-diphenyl(2,3-dimethyl-1,4-diazabutadiene) (PMB) and 1,4-di(p-methoxyphenyl)-2,3-dimethyl-1,4-diazabutadiene (MPMB) have been carried out. On the basis of elemental analyses, the complexes are [Co(PMB)Cl2], [Co(PMB)2(C1O4)2], [Co(MPMB)Cl2] and [Co(MPMB)2(ClO4)2].Both ligands are bidentatevia nitrogen atoms in all the complexes. The magnetic susceptibility and i.r. and u.v.-visible spectra are reported and discussed. The chloro-compounds involving two chlorine ligands and, in the perchlorate compounds, the ClO 4 groups are bound to the cobalt(II) centre.  相似文献   

2.
The complexation of manganese(II), cobalt(II) and nikel(II) with bromide ions has been studied in N,N-dimethylacetamide(DMA) by calorimetry and spectrophotometry. The formation of [MBr]+, [MBr2] and [MBr3] (M=Mn, Co, Ni) was revealed in all the metal systems. Interestingly, the complexation is significantly enhanced in DMA over N,N-dimethylformamide (DMF). This is unusual because physicochemical properties of DMA and DMF as solvent are similar. Furthermore, extracted electronic spectra of individual complexes of NiII suggested the presence of a geometry equilibrium, [NiBr(DMA)5]+=[NiBr(DMA)4]++ DMA, in DMA. A similar geometry equilibrium is also suggested, [NiBr2(DMA)3]=[NiBr2(DMA)2]+DMA. Such geometry equilibria were not observed in DMF. With regard to cobalt(II), electronic spectra show the presence of the four-coordinated [CoBr(DMA)3]+ complex in DMA, unlike the six-coordinated [CoBr(DMF)5]+ one in DMF. These facts suggest that a specific strong steric interaction operates between coordinating solvent molecules, which plays a key role in the complexation behavior of the divalent transition metal ions in DMA.  相似文献   

3.
Zeolite encapsulated complex nanoparticles “[Co([18]py2N4)]2+, [Co([20]py2N4)]2+, [Co(Bzo2[18]py2N4)]2+ or [Co(Bzo2[20]py2N4)]2+” were successfully prepared by the template synthesis of 2,6-diacetylpyridine with [Co(N–N)2]2+ (N–N = 1,2-diaminoethane, 1,3-diaminepropane, 1,2-diaminobenzene, 1,3-diaminobenzene) within the zeolite-Y. These complex nanparticles were entrapped in the Y-zeolite by a two-step process in the liquid phase: (i) inclusion of a Co(II) precursor complex, [Co(N–N)2]2+@NaY, and (ii) template synthesis of the cobalt(II) precursor complex with the 2,6-diacetylpyridine. The new complex nanoparticles entrapped in the zeolite Y “[Co([18]py2N4)]2+@NaY, [Co([20]py2N4)]2+@NaY, [Co(Bzo2[18]py2N4)]2+@NaY, [Co(Bzo2[20]py2N4)]2+@NaY” were characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV/VIS, XPS, XRD, BET, DRS). Analysis of the data indicates that the cobalt(II) complex nanoparticles are encapsulated in the zeolite-Y and exhibit different property from those of the free complexes, which can arise from distortions caused by steric effects due to the presence of sodium cations, or from interactions with the zeolite matrix.  相似文献   

4.
Summary The reactions of [Ni(TPT)2]2+ and [Co(TPT)2]2+ with aqueous hydroxide ion involve the formation of pseudo-base species prior to the dissociation of a ligand molecule. The [M(TPT)(H2O)3]2+ or [M(TPT)(OH)3] species thus formed react further with hydroxide ion to yield compounds previously described. The kinetics of pseudo-base formation have been followed in each case and the results are compared with a number of other reactions of analogous compounds with hydroxide ion and with water.Part XXII, ref. 3.  相似文献   

5.

The complex [Cu(tn)2]2[Co(CN)6](ClO4)·2H2O (tn = trimethylenediamine) has been prepared and characterized by elemental analysis, IR, electronic and electronic spin resonance spectra and magnetic properties. The x-ray structure analysis shows that each [Co(CN)6]3? ion coordinates to four [Cu(tn)2]2+ cations through four cyano nitrogen atoms in the same plane, providing a two-dimensional square network structure, formed from Co-CN-Cu(tn)2-NC-Co linkages.  相似文献   

6.
Summary The electrochemical oxidation of anodic metal (nickel or cobalt) in MeCN solutions of 1-hydroxy-2-pyridinethione (HPT) gives [Ni(PT)2], [Co(PT)2] or [Co(PT)3]. When 1,10-phenanthroline (phen) or 2,2-bipyridine (bipy) are added to the electrolytic phase the product is a complex, [Ni(PT)2L] or [Co(PT)2L] (L = bipy or phen). The i.r., u.v. and 1H- and 13C-n.m.r. spectra of the complexes are discussed.This paper was presented at the 5th Inorganic Chemistry Meeting of the Royal Spanish Chemical Society, Tossa de Mar, Girona, Spain, September 1991.  相似文献   

7.
The compound [Co(En)3]2[Hg2(H2O)Cl6]Cl4 (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna21) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)3]3+ cations of opposite chirality). [Hg2(H2O)Cl6]2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl4]2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H2O)Cl2] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å).  相似文献   

8.
Complexation of cobalt(II) and nickel(II) with thiocyanate ions has been studied by precise spectrophotometry in aqueous and micellar solutions of a nonionic surfactant Triton X-100 of varying concentrations (20–100 mmol-dm–3). With regard to cobalt(II), the formation of [Co(NCS)]+, [Co(NCS)2], and [Co(NCS)4]2– was established. The formation constant of [Co(NCS)4]2–, is increased with increasing concentration of the surfactant, suggesting that the [Co(NCS)4]2– complex is formed in micelles. In contrast, the formation constants of [Co(NCS)]+ and [Co(NCS)2] are remained practically unchanged. On the other hand, with nickel(II), the formation of sole [Ni(NCS)]+ and [Ni(NCS)2] was established in both aqueous and micellar solutions examined, their formation constants being also remained unchanged. Interestingly, no higher complex was confirmed in the nickel(II) system, unlike cobalt(II). The unusual affinity of the [Co(NCS)4]2– complex with micelles will be discussed from thermodynamic and structural points of view.  相似文献   

9.
Poly[triaqua‐μ4‐fumarato‐cobalt(II)], [Co(C4H2O4)(H2O)3]n, (I), contains two symmetry‐independent octahedrally coordinated Co2+ ions, both on inversion centers. One Co2+ ion is coordinated by two water molecules and four fumarate dianions, whereas the other Co2+ ion is surrounded by four water molecules and two fumarate dianions. Each fumarate dianion is bonded to three Co2+ ions, leading to a two‐dimensional structure. The fumarate dianions are nonplanar; the angle between the planes of the two carboxylate groups is 54.9 (2)°. The cobalt(II) fumarate layers are connected by hydrogen bonding into a three‐dimensional network. Compound (I) is not isostructural with calcium(II) fumarate trihydrate [Gupta et al. (1972). Acta Cryst. B 28 , 135–139]. In poly[μ4‐fumarato‐dimethanolcobalt(II)], [Co(C4H2O4)(CH4O)2]n, (II), the Co2+ ions are octahedrally coordinated by four fumarate dianions and two methanol molecules, leading to a three‐dimensional structure. The fumarate group is planar. The Co2+ ions and the fumarate dianions both lie on inversion centers. Additionally, the one‐dimensional structure of catena‐poly[[[tetraaquacobalt(II)]‐μ2‐fumarato] monohydrate], {[Co(C4H2O4)(H2O)4]·H2O}n, (III), was redetermined at a higher resolution, and the space group C2/c was confirmed.  相似文献   

10.
《Polyhedron》1986,5(3):815-819
Stereoselective interactions between tris(acetylacetonato)cobalt(III) [Co(acac)3] and optically active Λ-(+)546-tris(1,10-phenanthroline)ruthenium(II) chloride [Λ-[Ru(phen)3]Cl2] were investigated by measuring the distribution coefficients of racemic Co(acac)3 between carbon tetrachloride and water containing Λ-[Ru(phen)3]2+ or pure water, and the optical rotations of the aqueous phase was measured over the temperature range 10–40° C. The Λ-isomer of Co(acac)3 is “salted-in” more strongly by Λ-[Ru(phen)3]2+ than the Δ-isomer. The association constants between Λ-[Ru(phen)]2+ and Λ- or Δ-Co(acac)3 were calculated by using the optical rotation to give K(Λ-Λ) = 3.86 and K(Λ-Δ) = 3.80 at 25°C, respectively. The temperature dependence of the association constants showed that the enthalpy and entropy changes for the Λ-Λ association is slightly more positive than those for the Λ-Δ association. This was discussed from the viewpoint of hydrophobic interactions.  相似文献   

11.
The complex formation of Co2+ and Ni2+ with m-methyl benzamide oxime was studied spectrophotometrically in 60% methanol. The complexes [Co(mMB)2] and [Ni(mMB)2] appear in alkaline solution. The formation constants are lgK=4.15±±0.04 for [Co(mMB)2] and lgK=4.08±0.04 for [Ni(mMB)2] at 25°. The decadic molar extinction coefficients are ε=5000 for [Co(mMB)2] and ε=560 for [Ni(mMB)2], resp.  相似文献   

12.
Summary The complexes M(acac)2(imidazole)2 (M = Co or NO and [M(acac)2B]n (M = Co, Ni or Zn; B = pyrazine or pyrimidine) have been prepared and their i.r. spectra determined over the 600–140 cm–1. range. The metal-oxygen and metal-nitrogen stretching frequencies, (M-O) and v(M-N), are assigned on the basis of the band shifts induced by deuteriation of the adducted base and by substitution of the metal ion. Three or fourv(M-O) bands are observed within the 600-200 cm–1 range. The twov(M-O) bands of higher frequency are considered to the coupled with internal ligand modes. TwovM-N) bands are observed within the 280–170 cm–1. range. The metal-ligand stretching frequencies are in good agreement with the values previously established for these vibrations in the [M(imidazole)6]2+ and Ni(acac)2(pyridine)2 complexes.  相似文献   

13.
Summary The kinetics of the reaction of [Cu(TPT)(H2O)3]2+ and [Ni(TPT)(H2O)3]2+ with H2O have been followed and it has been shown that the formation of covalent hydrates is important in the understanding of these systems. The [Co(TPT)(OH)3] compound and its Ni analogue are attacked by HO initially to form pseudo-base species and in, the case of Ni , the ligand then hydrolyses to yield a compound related to the carboximate formed when HO reacts with [Cu(TPT)(OH)3]. In this reaction too, the formation of a pseudo-base, involving attack of HO at the triazine ring in the ligand is significant.Part XXI, ref. 2.  相似文献   

14.
The results of an EXAFS investigation of methanol and ethanol solutions of CoBr2 are reported. The curve fitting analysis gives the coordination numbers and the Co–Br and Co-solvent distances. The results for both 0.2M and 3.8M CoBr2 in ethanol show the existence of [CoBr2(C2H5OH)2] as the dominant species, although a considerable amount of octahedral species also exists in the solutions. In 0.2 and 3.3M CoBr2 methanol solutions, the dominant species are [Co(CH3OH)6]2+ and [CoBr(CH3OH)5]+, respectively.  相似文献   

15.
The electrocarboxylation of chloroacetonitrile mediated by [Co(II)(phen)3]2+ has been investigated. Cyclic voltammetry studies of [Co(II)(phen)3]2+ have shown that [Co(I)(phen)3]+, an 18 electron complex, activates chloroacetonitrile by an oxidative addition through the loss of a phenanthroline ligand to give [RCo(III)(phen)2Cl]+. The unstable one-electron-reduced complex underwent Co–C bond cleavage. In carbon dioxide saturated solution, CO2 insertion proceeds after reduction of the alkylcobalt complex. A catalytic current is observed which corresponds to the electrocarboxylation of chloroacetonitrile into cyanoacetic acid. Electrolyses confirmed the process and gave faradic yield of 62% in cyanoacetic acid at potentials that are about 0.3 V less cathodic than the one required for Ni(salen).  相似文献   

16.
The IR spectra (3500—150 cm?1) of the complexes [M(aniline)2,X2 (M = Co, Ni, Cu, Zn; X = Cl, Br), [Zn(aniline)2I2] are discussed. Assignments of the internal ligand vibrations are based on the band shifts which result from 15N-labelling of the amino group. The metal—ligand stretching frequencies, ν(M—N) and ν(M—X), are assigned on the basis of the band shifts which occur on 15N-labelling and metal ion and halogen substitution. Two bands within the range 350–450 cm?1 are assigned to ν(M—N) while the ν(M—X) bands occur within the range 170–320 cm?1. The effects of structure and coordination number on ν(M—N) and ν(M—X) are discussed. The spectra of two ethanol adducts, [M(aniline)2-(ethanol)2Cl2] (M = Co, Ni) compared with those of the unsolvated species [M(aniline)2-Cl2], exhibit a unique band near 480 cm?1 which is insensitive to 15N-labelling and is assigned to ν(M—O).  相似文献   

17.
Four unsymmetrical vic-dioximes: [L1H2] N-(4-butylphenyl)amino-amphi-glyoxime, [L2H2] N-(4-butylphenyl)amino-anti-glyoxime, [L3H2] N-(4-phenylazophenyl)amino-amphi-glyoxime and [L4H2] N-(4-phenylazophenyl)amino-anti-glyoxime have been prepared from amphi-chloroglyoxime, anti-chloroglyoxime, 4-butylaniline and 4-(phenylazo)aniline respectively. The complexes of these vic-dioximes with NiII, CoII, CuII and CdII ions have been investigated. All are insoluble in common solvents. Their i.r. spectra and elemental analyses are given, together with mass and 1H-n.m.r. spectra of the ligands.  相似文献   

18.
On oxygenation of alcoholic solutions of tetraethylenepentamine cobalt(II) two isomeric forms of [(tetren)CoO2Co(tetren)]4+ are obtained in which the configuration of the pentadentate ligand is either α or β. The binuclear complex can be crystallized as thiocyanate or as perchlorate. Oxygenation at 35° produces the pure α isomer. At lower temperature a mixture of α and β is obtained. The isomers differ slightly in their absorption spectra and their reactivity. The ligand configuration has been elucidated by transforming the perchlorates into the [ZnCl4]2? salts of the corresponding mononuclear chelates [Co(tetren)Cl]2+. The latter have also been prepared starting from a compound of known configuration according to the literature. The IR. spectra of the α and β forms differ characteristically in the NH stretch bands.  相似文献   

19.
The structures and stability of outer-sphere associates of sulfonate derivatives of thiacalix[4]arene and calix[4]resorcinarene with coordinatively saturated cobalt(iii) bis- and tris-chelates ([Co(L-His)2]+, [Co(en)2ox]+, [Co(en)3]3+, and [Co(dipy)3]3+) were compared based on the data from UV, CD, 1D 1H NMR, and 2D (2D NOESY) 1H NMR spectroscopy and conductometry. Outer-sphere association is accompanied by partial penetration of the chelate rings of the complexes into the hydrophobic cavity of calixarene, which induces changes in the spectroscopic and spectropolarimetric properties of the cobalt(iii) complexes.  相似文献   

20.
Octahedral complexes of the general composition [M(II)(BAMQH)2]X2 (where M = Cu(II), Ni(II), Co(II); X = Cl, I, ClO4 and BAMQH is biacetalmonoquinolylhydrazone); [M(II)(BAMQH)Cl2.H2O] (where M = Mn(II), Fe(III)) and penta-coordinated [VO(BAMQH)2]SO4 have been synthesized and characterized by magnetic susceptibility, optical and ESR studies in the polycrystalline and frozen states. [Ni(II)(BAMQH)2]Cl2 has tetrahedral geometry. Bidentate nature of the ligand is assumed in [Ni(II)(BAMQH)2]Cl2 and [VO(BAMQH)2]SO4 complexes.  相似文献   

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