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1.
Summary White crystalline complexes of general formula Cu2L4X2 (where X = Cl, Br and L = 1, 3-oxazolidine-2-thione, pyrrolidine-2-thione,N-methyl-1,3-imidazolidine-2-thione andN-ethyl-1,3-imidazolidine-2-thione) and CuLX (where L = 1,3-imidazolidine-2-thione) were prepared by reduction of copper(II) halides and studied by i.r. spectroscopy in the 4000–200 cm– range. Evidence for ligand coordination to the metal through sulphur was found in each case. The(CuCI) vibration in all the chloro derivatives falls atca. 240 cm–. 相似文献
2.
Juan Padilla William E. Hatfield John R. Wasson Williams E. Estes 《Transition Metal Chemistry》1989,14(3):217-220
Summary The magnetic properties of copper(II) maleate monohydrate, Cu(C4H2O4)·H2O, have been measured in the 1.8–66 K range. Magnetic susceptibility and isothermal magnetization measurements on powdered samples reveal a transition to a ferromagnetic state in this layered compound. The transition to the ordered state occurs at Tc=4.0 K. The positive value of 8.0 K for the Weiss constant in the paramagnetic region confirms the ferromagnetic nature of the interactions. The magnetic susceptibility data above 3Tc may be fitted with a Heisenberg quadratic layer expression with the best-fit parameters J=+4.3 cm–1, g=2.0, and zJ=+0.42 cm–1. The e.p.r. spectrum at room temperature indicates orthorhombic symmetry. A complex containing the isomeric form of the ligand, copper(II) fumarate dihydrate, has also been prepared and its magnetic properties determined in the 80–300 K range. The data may be accomodated by two-dimensional theory with J=+1.05 cm–1, g=2.09, and zJ=+0.10 cm–1. 相似文献
3.
The resonance Raman spectra of tris(acetylacetonatoiron(III)) and ruthenium(III) complexes in various solvents and in water-acetonitrile (W-AN) mixtures were measured. The resonance Raman spectra of both complexes indicated peaks near 460 and around 1580 cm–1. Thev(C-O) peak (around 1580 cm–1) is shifted to low frequency with an increase in the dielectric constant T of the solvents, whereas thev(M-O) (M=Fe and Ru, near 460 cm–1) are constant, independent of T. It implies that the C-O bond in the acac– ligand is lengthened by the polarizability effect of the solvents, while both the Fe-O and Ru-O bonds, which are located in the inside of the complexes, are not influenced by the solvents indicating that the interaction does not depend on the properties of individual solvent molecules but on those of the aggregate. 相似文献
4.
Summary Copper(II) complexes with the Schiff bases derived from Salicylaldehyde and its 5-chloro-, 5-bromo-, 5-nitro-, 3-ethoxy- and 3,5-dichloro derivatives, or from 2-hydroxy-1-naphthaldehyde ando-hydroxybenzylamine, have been synthesized and characterized on the basis of elemental analysis, i.r. and electronic spectra and magnetic susceptibility measurements. The Schiff bases behave as tridentate dibasic O, N and O donor ligands and form complexes with 11 metal: ligand stoichiometry which exhibit subnormal magnetic moments (
eff=0.88–0.98 B.M.) and are involved in strong antifer-romagnetic exchange (–J=482–525 cm–1). The complexes exhibit a d-d band atca. 1600 cm–1. A dimeric structure with aminophenolic oxygen atoms as the bridging atoms is proposed on the basis of i.r. and magnetic data. 相似文献
5.
G. A. Abakumov V. K. Cherkasov M. P. Bubnov O. G. Éllert Yu. V. Rakitin L. N. Zakharov Yu. T. Struchkov Yu. N. Saf'yanov 《Russian Chemical Bulletin》1992,41(10):1813-1818
The title complexes of Ni and Cu with symmetrical 3,6-di-tert-butyl-o-benzosemiquinone are synthesized. Their EPR spectra and magnetic properties are investigated. The x-ray structure studies [Siemens R3/PC diffractometer, MoK, /20-scanning in the rang 2 2 54°, 2084 reflections withF > 4(F),R = 0.034,R
w = 0.039, monoclinic crystals,a = 9.982(2),b = 11.548(2),c = 12.145(2) Å, = 95.05(3)°,Z = 2,d
calc = 1.19 g/cm–3, space groupP2
l/c) demonstrated that the complex is monomeric with square-planar coordination for the Ni with theo-semiquinone ligands. The Cu complex is isostructural with the Ni (a = 9.88,b = 11.60,c = 12.15 Å, = 95°]. The dependence of the magnetic moment of the Cu complex on temperature is consistent with the presence in it of two pathways for exchange interaction. These are antiferromagnetic ligand-ligandJ
12 = –179 cm–1 and ferromagnetic metal-ligandJ
13 = 100 cm–1 (mean-square deviation 2%). The Ni complex is diamagnetic over the whole studied temperature range despite the fact that it contains free-radicalo-semiquinone ligands. Such an effect involving electrons belonging to the free-radical ligands is observed for the first time in the magnetochemistry ofd
8- andd
9-transition-metal complexes. It is explained by incorporation of vacantp
z- and/or occupiedd
xz- andd
yz-orbitals of Ni in molecular orbitals containing the -MO of the semiquinone ligands.Institute of Organometallic Chemistry, Russian Academy of Sciences, 603600 Nizhnii Novgorod, Russia. N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow, Russia. A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow, Russia. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2315–2323, October, 1992. 相似文献
6.
Li Licun Jiang Zonghui Liao Daizheng Yan Shiping Wang Genglin Zhao Qihua 《Transition Metal Chemistry》2000,25(6):630-634
Single crystals of a copper(II) chain compound**, [Cu(phen)(N3)2]
n
(phen = 1,10-phenanthroline), were obtained and its crystal structure was determined by X-ray diffraction methods. The complex crystallizes in the space group P1¯ and is made up of neutral chains of copper(II) ions bridged by two azide groups exhibiting an asymmetrical tri-dentate (1,1,3) coordination mode. The copper atoms have a distorted CuN6 octahedral environment: the basal plane is built of two nitrogen atoms from a chelating phen molecule and two azide nitrogens from one bridging and one terminal azide, whereas two nitrogens from two bridging azides fill the axial positions. The intrachain copper(II)–copper(II) separation is 3.396(1) and 5.700(1) Å. The magnetic behavior was investigated in the 5–300 K range. Weak intrachain alternating antiferromagnetic (J = –6.56 cm–1) and ferromagnetic (J = 12.76 cm–1) interactions were observed. 相似文献
7.
A chiral Schiff base ligand (H2L) was obtained by condensing 2-hydroxynaphthalene-1-carbaldehyde with substituted (1R,2R)-(–)-diaminocyclohexane. Chiral Schiff base complexes [CuL], [NiL], [ZnL] and [MnLOH] have been synthesized and characterized by elemental analyses,
M, i.r., u.v.–vis. and 1H-n.m.r. and magnetic measurements. 相似文献
8.
The hydrazino complex {methoxo[4-phenylbutane-2,4-dione(p-nitrobenzoyl)hydrazonato(2-)]oxovanadium(V)}, VO(p-NO2bhbzac)OCH3, (1), has been prepared by the direct reaction of bis(benzoylacetonato) oxovanadium(IV), VO(bza)2, with p-NO2-C6H4C(O)NHNH2, p-NO2bh, in CH3OH. The resulting compound contains benzoylacetone-(p-NO2)benzoyl hydrazone as tridentate Schiff base-type ligand and OCH3 group as Lewis base, both ligated to vanadium. The crystals are orthorhombic, with Z = 8, space group Pbca, a = 11.699(5) Å, b = 14.035(5) Å, c = 22.564(5) Å, R1 = 0.0756 and wR2 = 0.1302. The crystal structure demonstrated the square-pyramidal geometry of the VOoxo(ONO)O coordination sphere with the oxo ligand at the apical position. The electronic absorption spectra revealed a ligand-to-metal charge-transfer (LMCT) band in the near UV region at max = 23,700 cm–1 (B = 5640 dm3 mol–1 cm–1) in CH3CN, max = 23,420 cm–1 (B = 5550 dm3 mol–1 cm–1) in DMSO, and max near 26,950 (sh) cm–1 (B = 10,550 dm3 mol–1 cm–1) in CH2Cl2. The FT-IR spectra of (1) show the characteristic strong (V = O) stretching vibration at 993 cm–1 and support the view that the oxovanadium complex is pentacoordinated and monomeric. 相似文献
9.
Summary In NH4NO3+NH4OH buffered 10% (v/v) dioxan-water media (pH 7.0–8.5), thePseudo-first-order rate constant for the formation of the title complexes M(baen),i.e. ML, conforms to the equation 1/kobs=1/k+1/(kKo.s · TL), where TL stands for the total ligand concentration in the solution, Ko.s is the equilibrium constant for the formation of an intermediate outer sphere complex and k is the rate constant for the formation of the complex ML from the intermediate. Under the experimental conditions the free ligand (pKa>14) exists virtually exclusively in the undissociated form (baenH2 or LH2) which is present mostly as a keto-amine in the internally hydrogen-bonded state. Although the observed formation-rate ratio kCu/kNi is of the order of 105, as expected for systems having normal behaviour, the individual rate constants are very low (at 25°C, kCu=50 s–1 and kNi=4.7×10–4s–1) due to the highly negative S values (–84.2±3.3 JK–1M–1 for CuL and –105.8±4.1 JK–1M–1 for NiL); the much slower rate of formation of the nickel(II) complex is due to higher H value (41.2±1.0 kJM–1 for CuL and 78.2±1.2 kJM–1 for NiL) and more negative S value compared to that of CuL. The Ko.s values are much higher than expected for simple outer-sphere association between [M(H2O)6] and LH2 and may be due to hydrogen bonding interaction.In acid media ([H+], 0.01–0.04 M) these complexes M(baen) dissociate very rapidly into the [M(H2O)6]2+ species and baenH2, followed by a much slower hydrolytic cleavage of the ligand into its components,viz. acetylacetone and ethylenediamine (protonated). For the dissociation of the complexes kobs=k1[H+]+k2[H+]2. The reactions have been studied in 10% (v/v) dioxan-water media and also ethanolwater media of varying ethanol content (10–25% v/v) and the results are in conformity with a solvent-assisted dissociativeinterchange mechanism involving the protonated complexes. 相似文献
10.
The kinetics of the interaction of thiourea with [Pt(en)(H2O)2]2+ have been studied spectrophotometrically as a function of [Pt(en)(H2O)2]2+, [thiourea] and temperature at a particular pH(4.0), where the substrate complex exists predominantly as the diaqua species and the thiourea ligand as a neutral molecule. The reaction proceeds via a rapid outer sphere association followed by two slow consecutive steps, the second step exhibiting first order dependence on the aqua ion and thiourea concentrations. The activation parameters for both the steps have been evaluated: (H
1
= 54.8 ± 1.2 kJ mol–1, S
1
= –96 ± 4 J K–1 mol–1, H
2
= 27.9 ± 0.8 kJ mol–1 and, S
2
= –183 ± 2.6 J K–1 mol–1). The low enthalpy of activation and large negative values of entropy of activation indicate an associative mode of activation for both consecutive steps. 相似文献
11.
Summary The stepwise stability constants of 1:1 and 2:1 complexes of selenomethionine (SeMet) with CuII and ZnII ions have been determined in NaNO3 (0.1m) supporting electrolyte by potentiometric titration at 25 °C. The overall log stability constant (logML2 = [ML2]/[M2+][L–1]2) for CuII and ZnII complexes are 14.50 and 8.75, respectively. Two new solids were prepared and identified by elemental microanalysis as (SeMet)2Cu and (SeMet)2Zn. I.r. and Raman spectral studies indicated metal coordination with the nitrogen and oxygen atoms of the amino acidato group of SeMet. The corresponding stretching bands were assigned at 341.1cm– for Cu-O, 352.9 cm– for Zn-O, 497.3 cm– for Cu-N and 475.2 cm– for Zn-N bonds. 相似文献
12.
P. Spacu Margareta Teodorescu D. Ciomârtan 《Monatshefte für Chemie / Chemical Monthly》1972,103(1):1-8
Zusammenfassung Die magnetischen, spektralen und strukturellen Eigenschaften des gemischten Amminkomplexes [Fe(II)py
2
phen(NCS)2] werden diskutiert. Der Orbitalparamter liegt mit 11 700 cm–1 nahe der Spinpaarungsenergie für den mittleren kovalenten Fall 11 000 bis 12 000 cm–1 und erlaubt so ein Spingleichgewicht zwischen den Spektralzuständen5T2–1A1. Dieses Gleichgewicht wird durch magnetische Messungen bei verschiedenen Temperaturen nachgewiesen.
Mit 3 Abbildungen
Herrn Prof. Dr.H. Nowotny gewidmet. 相似文献
On the spin equilibrium5T2–1A1 in [Fe(II)py2phen(NCS)2]
The magnetic, spectral and structural properties of the mixed ammine [Fe(II)py 2 phen(NCS)2] are discussed. The orbital parameter of about 11 700 cm–1 near to the spin-pairing energy for the mean covalent case 11 000 to 12 000 cm–1 allows a spin equilibrium between the spectral states5T2–1A1, put in evidence by the magnetic measurements at different temperatures.
Mit 3 Abbildungen
Herrn Prof. Dr.H. Nowotny gewidmet. 相似文献
13.
Ming-Ming Miao Dai-Zheng Liao Zong-Hui Jiang Geng-Lin Wang 《Transition Metal Chemistry》1994,19(6):643-645
Summary Four novel heterotrinuclear complexes were prepared, namely {[Ni(L)2]2[Cu(pba)]}(ClO4)2, where pba = pro-pylene-1,3-bis(oxamato) and L = 1,10-phenanthroline (phen), 5-nitro-1,10-phenanthroline (NO2-phen), 2,2-bipyridyl (bpy), 4,4-dimethyl-2,2-bipyridyl (Me2bpy). Based on i.r., elemental analyses, conductivity measurements and electronic spectra oxamato-bridged structures are proposed for these complexes, consisting of two nickel(II) ions, each in a distorted octahedral environment, and a copper(II) ion in a square planar environment, respectively. The temperature dependence of the magnetic susceptibility of {[Ni(phen)2]2[Cu(pba)]}(ClO4)2·H2O was studied in the 4–300 K range, giving the exchange integral J = - 106 cm–1. TheX
scm
T versusT plot exhibited a minimum at ca. 98 K, characteristic of this kind of coupled polymetallic complex with an irregular spin-state structure. E.s.r. spectra of these complexes clearly indicated a strong rhombicity withg
1 = 5.20,g
2 = 2.29 andg
3 = 2.02 (approximately), which agrees with an anisotropicS = ±1/2 Kramer doublet in the ground state. 相似文献
14.
Summary The aquation ofcis-[(en)2Co(CO2H)2]+ tocis-[(en)2Co(OH2)(CO2H)]2+ is catalysed by Cu2+ and the rate equation, –d[complex]t/dt=(kCu[Cu2+]+kH [H+]) [complex)T is valid at [Cu2+]T=0.01–0.1, I=0.5 and [HClO4]=0.005 mol dm–3. The rate measurements are reported at 30, 35, 40 and 45°C and the rate and activation parameters for the Cu2+ and H+-catalysed paths are: kH(35°C)=(2.44±0.09)×10–2 dm3 mol–1 s–1, H=83±13 kJ mol–1, S=–8±42 JK–1 mol–1, k
Cu
(35°C)=(3.30±0.09)×10–3 dm3 mol–1 s–1, H=73.2±6.1 kJ mol–1, S=–55±20 JK–1 mol–1. The formate-bridged innersphere binuclear complex,cis-[(en)2Co{(O2CH)2Cu}]3+ may be involved as the catalytically active intermediate in the copper(II)-catalysed path, just as the corresponding H+-bridged species presumed to be present in the acidcatalysed path. 相似文献
15.
van Albada Gerard A. Riggio Ivonne Reedijk Jan Mutikainen Ilpo Turpeinen Urho 《Transition Metal Chemistry》2002,27(3):341-345
The compound [Cu2(bipym)3(sac)2(H2O)2](sac)2(H2O)4 (bipym = 2,2-bipyrimidine and sac = saccharin) crystallizes in the space group P-1, with a = 10.710(3), b = 10.725(3), c = 13.637(5) Å, a = 70.07(3), = 80.31(2), g = 82.87(3)° and Z = 2. The geometry in the centrosymmetric dinuclear complex around each CuII ion is a distorted octahedron, in which the equatorial plane is formed by a nitrogen atom of a bis-didentate bridging bipym ligand, two nitrogen atoms of a didentate bipym ligand, and the nitrogen atom of a coordinating sac ligand. The axial positions in the octahedron are occupied by a second nitrogen of the bis-didentate bridging bipym ligand and a water molecule. The lattice contains two saccharinate anions and four water molecules held together in a hydrogen-bonded network. The i.r vibrations of the bipym ligand are found as a quasi-symmetric doublet at 1558 and 1580 cm–1, while the most important i.r vibrations of the sac ligand are observed at 1629 and 1644 cm–1 (carbonyl vibrations) and at 1285 and 1159 cm–1 (sulfonyl vibrations). The magnetic exchange interactions between the Cu ions is very weak and is ferromagnetic (J < 0.1 cm–1). 相似文献
16.
Udovenko A. A. Zemnukhova L. A. Gorbunova Yu. E. Mikhailov Yu. N. Davidovich R. L. 《Russian Journal of Coordination Chemistry》2002,28(1):12-14
The crystal structure of a novel antimony(III) fluoride complex, ammonium undecafluorotriantimonate(III) (NH4)2Sb3F11, was determined. The crystals are triclinic: a = 7.780(2) Å, b = 8.370(2) Å, c = 10.620(1) Å, = 71.06(1)°, = 89.03(1)°, = 63.58(1)°, V = 579.1(2) Å3, Z = 2, (calcd) = 3.500 g/cm3, (exp) = 3.51 g/cm3, F(000) = 548.0, space group P
. The structure consists of anionic [Sb3F11]2– chains and ammonium cations combined into a framework by the N–H···F hydrogen bonds. 相似文献
17.
Summary Base hydrolysis of methyl ethylenediaminemonoacetate has been studied at I=0.1 mol dm–3 (NaClO4) over the pH range 7.4–8.8 at 25 °C. The proton equilibria of the ligand can be represented by the equations, where E is the free unprotonated ester species. Values of pK1 and pK2 are 4.69 andca. 7.5 at 25° (I=0.1 mol dm–3). For base hydrolysis of EH+, kOH=1.1×103 dm3 mol–1 s–1 at 25 °C. The species E is shown to undergo lactamisation to give 2-oxopiperazine (klact
ca. 1×10–3 s–1) at 25 °C. Formation of the lactam is indicated both by u.v. measurements and by isolation and characterisation of the compound.Base hydrolysis of the ester ligand in the complex [CuE]2+ has been studied over a range of pH and temperature, k
OH
25
=9.3×104 dm3 mol–1 s–1 with H=107 kJ mol–1 and S
298
=209 JK–1 mol–1. Base hydrolysis of [CuE]2+ is estimated to be some 1055 fold faster than that of the free ester ligand. The results suggest that base hydrolysis occursvia a chelate ester species in which the methoxycarbonyl group of the ligand is bonded to copper(II). 相似文献
18.
H. G. M. Edwards V. Fawcett M. T. Lung 《Journal of inclusion phenomena and macrocyclic chemistry》1991,11(3):267-279
Force constants were determined for the C8, C10, C12 and C14 series ofn-alkanes C
n
H2n + 2 using an approximate SVFF calculation and observed LAM = 1 wave numbers. In this calculation the hydrogen atoms were neglected and only the carbon backbone chain and terminal atoms were considered; this was valid since only low-frequency vibrations were under consideration. Using force constant transfer, the wavenumbers of the LAM = 1 accordion modes for the analogous -Cn H2n + 1 X and ,-Cn H2nX2 species, where X = C1, Br or I were calculated. For -chloroalkanes and ,-dichloroalkanes, them = 1 accordion modes are calculated to be in the 220–130 cm–1 and 200–120 cm–1 regions, respectively. For the bromo- and iodo-analogues them = 1 accordion modes are calculated to be in the 200–100 cm–1, 150–90 cm–1 and in the 170–100, 135–80 cm–1 regions, respectively. 相似文献
19.
Zhu Hai-Liang Tong Ye-Xiang Chen Xiao-Ming Ren Chun-Xia 《Transition Metal Chemistry》2001,26(4-5):528-531
Two 2-terephthalate (tp) bridged complexes, [Cu2(tp)(pren)4](ClO4)2 (pren = 1,3-diaminopropane) (1) and [Ni2(tp)(pren)4(Him)2](ClO4)2 (Him = imidazole) (2), have been synthesized and characterized by X-ray single-crystal structural analysis. In the discrete dinuclear [Cu2(tp)(pren)4]2+ cation of complex (1), each CuII atom has a square-pyramidal geometry, being coordinated by four nitrogen atoms (avg. 2.031 Å) from two pren ligands at the basal plane and one oxygen atom [2.259(3) Å] from a bis-monodentate tp group at the axial position. In the discrete dinuclear [Ni2(tp)(pren)4(Him)2]2+ cation of complex (2), each NiII center is coordinated by five nitrogen atoms [Ni—N 2.069(3)–2.109(2) Å] from one Him group and two pren groups, and completed by one oxygen atom [Ni—O 2.138(3) Å] from a bis-monodentate tp group to furnish a distorted octahedron. Magnetic susceptibility studies show that the pair of metal atoms, although being separated by >11.5 Å, exhibit weak intramolecular antiferromagnetic interactions in complexes (1) (g = 2.07 and J = –3.4 cm–1) and (2) (g = 2.10 and J = –0.7 cm–1). The electrochemical behaviors of the complexes have also been studied by cyclic voltammogram processes. 相似文献
20.
The3
A
2g →3
T
1g(F) transition in the spectrum of some oxygen-ligated octahedral nickel(II) species
Summary In sodium phosphate glasses, nickel(II) is octahedrally coordinated by the oxygens of the phosphates with 0 = 7600 cm–1 and B = 920 cm–1. Contrary to the case of many other oxygen-coordinated systems including [Ni(H2O)6]2+ and low alkali borate glasses, the second spin-allowed transition to3
T
1g(F) appears as a single-peaked band well-separated from the spinforbidden transition to1
E
g(D). Variation of the glass composition does not change the main features of the spectrum. Dissolving the glasses in water results in a shift of all the bands to higher energies with the second spin-allowed band becoming triple-peaked. This supports Liehr and Ballhausen's explanation of the structure of this band.Part of a thesis submitted by T. Genena in partial fulfillment of the M.Sc. degree in Solid State Science, 1985. 相似文献