共查询到20条相似文献,搜索用时 15 毫秒
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Zelenin O. Yu. Kochergina L. A. Ratnikov S. V. 《Russian Journal of Coordination Chemistry》2003,29(7):478-483
Complexation of the Ni2+ ion with L-asparagine (HAsn±) is studied by potentiometric titration at 298.15 K and at the 0.3, 0.5 and 1.0 ionic strength of the solution (KNO3). The formation of the NiAsn+ and NiAsn2 complexes was established and their stability constants were determined. The thermodynamic stability constants of the mono- and bis(L-asparagine)nickel(II) complexes were obtained by extrapolation to zero ionic strength. The direct calorimetry method was used to measure the heat effect of the L-asparagine reaction with the Ni(II) nitrate solution in different pH intervals at 298.15 K and at the 0.5, 1.0, and 1.5 ionic strength (KNO3). The standard enthalpies of the NiAsn+ and NiAsn2 formation were found using extrapolation and the equation with one individual parameter. The enthalpies of the formation of the Ni(II) complexes with L-asparagine in aqueous solution were calculated in the standard hypothetically undissociated state. 相似文献
3.
Setareh Akbari Razieh Sanavi Khoshnood Elaheh Hatami 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2017,91(13):2569-2577
Complexatio of the La3+ cation with 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane(Kryptofix5) was studied in pure solvents acetonitrile (AN), methanol (MeOH), nitrobenzene (NB), tetrahydrofuran (THF), methyl acetate (MeOAC) and in various binary solvent mixtures of AN–MeOH, AN–NB, AN–THF, and AN–MeOAC systems at different temperatures using the conductometric method. The stoichiometry of the complex was found to be 1 : 1 (ML). In all cases, the variation of the log kf with composition of the solvent was non-linear. This behavior is probably due to a change in the structure of these binary mixed solvents as the composition of the medium is varied. The stability order of the complex in pure nonaqueous solvents at 25°C increases in the order: AN > THF > MeOAC > MeOH > NB. The values of thermodynamic data (ΔH c °,ΔS c °) formation of (Kryptofix5.La)3+ complex are definitely solvent dependent. 相似文献
4.
Amirov R. R. Skvortsova E. A. Saprykova Z. A. 《Russian Journal of Coordination Chemistry》2003,29(8):554-558
The formation of tetrahedral cobalt(II) thiocyanate complexes in aqueous solutions of nonionogenic surfactants was studied using electronic spectroscopy. The equilibrium constants were calculated in the framework of different schemes of complexation reactions. The influence of such factors as the oxyethylene chain length and the size of the alkyl substituent of the surfactant on the stability of the complexes was examined. 相似文献
5.
D. F. Pyreu E. S. Alekseeva T. A. Simagina M. S. Gruzdev R. S. Kumeev S. N. Gridchin 《Russian Journal of Inorganic Chemistry》2018,63(2):180-190
The formation of mixed-ligand complexes in the M(II)–Nta and Ida–L systems (M = Co, Zn; L = His, Orn, Lys, Gly, Im, en), where Ida and Nta are the residues of iminodiacetic and nitrilotriacetic acids, was studied by pH-metry, calorimetry, and NMR spectroscopy. The thermodynamic parameters (logK, Δ r G0, Δ r H, Δ r S) of formation for these complexes were determined at 298.15 K and an ionic strength I = 0.5 (KNO3). The most probable pattern of coordination between a complexone and an amino acid in mixed-ligand complexes was revealed. 相似文献
6.
7.
We report the synthesis, characterization, and thermal behavior of 1,1-diethyl-3-(4-(3,3-diethylthioureidocarbonyl)benzoyl)thiourea,
1,1-di-n-propyl-3-(4-(3,3-di-n-propylthioureido carbonyl)benzoyl)thiourea and 1,1-di-n-butyl-3-(4-(3,3-di-n-butylthioureidocarbonyl)benzoyl)thiourea and their Ni(II), Cu(II), and Co(II) complexes. The structure of the prepared compounds
was determined by elemental analysis, FT-IR, 1H NMR spectroscopy and mass spectrometry. The ligands are coordinated to metal atoms in a bidentate manner yielding an essentially
neutral complex of the type M3L3. Thermal decomposition of related compounds was investigated by DTA and TG techniques. The pyrolytic end product was identified by X-ray powder diffraction method.
The text was submitted by the authors in English. 相似文献
8.
The rate and activation parameters of tetraphenyltetrabenzoporphine (H2TPTBP) complexation with 3d-metal acetates and acetylacetonates are shown to be determined by the solvent nature. With an increase in the electron-donor properties of a solvent, the reaction rate increases due to protonation of N–H bonds and decreases as MA
m
(Solv)
n – m
salt solvates become more stable. As the result, the rate of a reaction with ZnAc2 increases in the series: DMF < dmso=">< py=">< proh-1="><>3CN <>6H6. In inert and weakly coordinating solvents, the transition state of a reaction is supposed to be formed according to the mechanism of contraction of the salt coordination sphere. The rate of H2TPTBP reaction with metal acetates in pyridine changes in the series: Cu(II) > Cd(II) > Zn(II) > Co(II), while the stability of the obtained complexes decreases in the series Cu(II) > Co(II) > Zn(II) > Cd(II). It is shown that the spectral criterion of the complex stability can be used in the series of metal complexes with one ligand, but it is violated if the ligand structure is changed. 相似文献
9.
Babashkina MG Safin DA Robeyns K Garcia Y 《Dalton transactions (Cambridge, England : 2003)》2012,41(5):1451-1453
Reaction of the deprotonated N-thiophosphorylated thiourea (4'-benzo-15-crown-5)NHC(S)NHP(S)(OiPr)(2) (HL) with NiCl(2) in aqueous EtOH leads to dark green [Ni(L-1,5-S,S')(2)]·2H(2)O crystals that were isolated by recrystallization from a mixture of CH(2)Cl(2) and n-hexane. 相似文献
10.
Equilibrium constants for formation of a cobalt(II) complex with the bidentate ligand dopamine have been studied with spectrophotometric
methods in water + ethanol cosolvent systems at 15, 25, and 35 (±0.1) °C and an ionic strength of 0.2 mol⋅dm−3. The ionic strength was maintained using sodium chloride and a phosphate buffer. The stability constants of the complex and
the resulting Gibbs energy changes are obtained. The results are discussed in terms of the effect of solvent on protonation
and complexation. 相似文献
11.
Zhilin A. Yu. Ilyushin M. A. Tselinskii I. V. 《Russian Journal of General Chemistry》2001,71(5):664-667
A series of cobalt(III) tetrazolate tetrammine complexes were prepared by reaction of cobalt(III) diaquatetraammine perchlorate with 5-(3-nitrophenyl)tetrazole. The factors affecting this reaction were studied. The reaction was thermally activated both by common heating with an external heater and microwave heating. Thermolysis of the tetrazolate complexes was studied. 相似文献
12.
S. S. Kandil F. I. Abdel-Hay R. M. Issa 《Journal of Thermal Analysis and Calorimetry》2001,63(1):173-180
The thermal decompositions of cobalt(II), nickel(II) and copper(II) complexes of4-(3'-sulfonylazido-6'-methoxyphenylazo)-1-phenyl-3-methyl-2-pyrazolin-5-one H(D1–SO2N3) and 4-(4'-sulfonylazido phenylazo)-3-phenyl-3-methyl-2-pyrazolin-5-one H(D2–SO2N3) were studied by thermogravimetry. The decomposition in all cases takes place along two stages. The first stage is due to the elimination of water and nitrogen molecules with the formation of tetracoordinate complexes containing nitrene reactive species[M(DSO2N:)2]. The second stage represents the decomposition of the material to the metal oxide. The kinetics of the decomposition were examined by using Coats–Redfern, the decomposition in all complexes was found to be first order for the first and second stages. The activation energies and other activation parameters (H* and S* and G*) were computed and related to the bonding and stereochemistry of the complexes.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
13.
1-(4-Chlorophenyl)-3-(4-methylbenzoyl)thiourea was synthesized and characterized by IR,1H and 13C NMR, mass spectroscopy and the elemental analysis. The crystal structure was confirmed from single crystal X-ray diffraction data. It crystallizes in the monoclinic space group P21/c with unit cell dimensions a=12.038(3), b=6.330(6), c=18.912(5) Å and β=100.32(3)°. There is a strong intramolecular hydrogen bond of the type N?H...O, with distance N1...O1=2.659(3) Å. The structure is composed of dimers related by inversion centers. The dimers are formed by intermolecular interactions of the type N?H...S with N...S separation of 3.440(2) Å. The mass fragmentation pattern has also been discussed. 相似文献
14.
Xin-Min Jiang Yong-Hong Hu Wen-Ge Yang Zi-Yu Lei Rong-Rong Tang Fei Shen 《Journal of solution chemistry》2013,42(2):272-281
1-(3-Bromopropoxy)-4-chlorobenzene is an important intermediate for the manufacture of omoconazole nitrate. The solubilities of 1-(3-bromopropoxy)-4-chlorobenzene in aqueous ethanol solutions were measured within the temperature range of (273.15–303.15) K using a laser monitoring system. For the temperature range investigated, the solubilities of 1-(3-bromopropoxy)-4-chlorobenzene in the aqueous ethanol mixtures increase with increasing temperature. The solubility data were regressed by the Buchowski–Ksiazaczak λh and the modified Apelblat models. The modified Apelblat equation and the Buchowski–Ksiazaczak λh equation provided accurate mathematical representations of the experimental results. The calculated solubilities showed good agreement with the experimental data. The root-mean-square deviations of the modified Apelblat model were lower than those of the Buchowski–Ksiazaczak λh model. This study provided valuable data for the purification of 1-(3-bromopropoxy)-4-chlorobenzene by crystallization. 相似文献
15.
The reaction of 1,1-dichloro-2,2-bis(4-nitrophenyl)ethene with sodium nitrite in polar aprotic solvents has been studied. Products of the reaction have been identified, and effects of different factors, including reactant dissociation and solvation, on the reaction rate constants have been analyzed. Thermodynamic parameters of the reaction have been determined, the multistep process has been simulated by quantum chemical calculations, and a plausible mechanism has been proposed. 相似文献
16.
The stability constants of cobalt(II) hydroxypropylenediaminetetraacetates at 298.15 K with ionic strength (I) equal to 0.1, 0.5, and 1.0 (KNO3) are determined using poteniometric and spectrophotometric methods. Heat effects for reactions of complex formation under the same conditions are measured using the direct calorimetric method. The standard thermodynamic parameters of the reactions under study are calculated. 相似文献
17.
Transition metal complexes of CoII, NiII and CuII with 4-(4-azidosulfophenylazo)-5-phenyl-3,4-dihydro-2H-pyrazol-3-oneHL1, 4-(4-azidosulfophenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL2 and 4-(3-azidosulfo-6-methoxyphenylazo)-5-methyl-2-phenyl-3,4-dihydro-2H-pyrazol-3-one HL3 were prepared and characterized by elemental analyses, molar conductances and magnetic susceptibilities and by i.r., electronic and e.s.r. spectral measurements as well as thermal (d.t.a and t.g.a.) analysis. The i.r. spectra indicate that HL acts as a bidentate ligand coordinating via the azo and enolic-oxygen linkages. The electronic spectral data and magnetic moments suggest a tetragonally distorted octahedral geometry for the complexes having the formula ML2·2H2O, (M = CoII, NiII and CuII), square pyramidal geometry for CuL
2
3
H2O and tetrahedral geometry for CoL
2
3
. The X-band e.s.r. spectra of the copper(II) complexes reveal anaxial symmetry for both CuL
2
2
2H2O and CuL
2
3
H2O while CuL
2
1
O is isotropic in the solid state at room temperature. The d.t.a. curves show two exothermic peaks for all three complexes CoL
2
3
,NiL
2
3
2H2O and CuL
2
3
H2O and one endothermic peak for the latter two aqua complexes. 相似文献
18.
S. R. Gadzhieva T. M. Mursalov K. T. Makhmudov F. G. Pashaev F. M. Chyragov 《Journal of Analytical Chemistry》2006,61(6):550-555
It is shown that 3-(2-hydroxyphenylazo)pentadione-2,4 (H2L) can exist in three tautomeric forms (enol-azo, keto-azo, and hydrazo). The effective atomic charges in the tautomeric forms
of H2L are calculated by the Hückel MO LCAO method. The molar fractions and molar absorptivities of the tautomers at different
pH are found. The complexation of copper(II) with H2L is studied by spectrophotometry. Beer’s law is obeyed for 0.51–5.12 μg/mL of copper. The assumed complex structure is given.
The effect of foreign ions and masking agents on the complexation is studied. A procedure for the photometric determination
of copper(II) in zinc-based alloys is proposed.
Original Russian Text ? S.R. Gadzhieva, T.M. Mursalov, K.T. Makhmudov, F.G. Pashaev, F.M. Chyragov, 2006, published in Zhurnal
Analiticheskoi Khimii, 2006, Vol. 61, No. 6, pp. 598–603. 相似文献
19.
Sakineh Asghari Azin Salimi Vali Taghipour 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):669-676
Abstract Stable crystalline phosphorus ylides of 1,1-diethyl 2,3-dimethyl 1-(acetylamino)-3-(1,1,1-triphenylphosphanilidine)-1,1,2,3-propanetetracarboxylates were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates in the presence of diethyl acetamidomalonate as a CH-acid. These stable ylides exist in solution as a mixture of two geometrical isomers (E and Z) as a result of restricted rotation around the carbon–carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group on the nuclear magnetic resonance (NMR) time scale at ambient temperature. The dynamic effects in the ylide moieties were investigated by 1H NMR spectra. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
20.
The synthesis of cobalt(II), nickel(II) and zinc(II) complexes of 2-pyridine-2-yl-3(pyridine-2-carboxylideneamino)-1,2-dihydroquinazolin-4(3H)-one is described. The ligand and metal complexes were characterized by elemental analysis, conductivity measurements, spectral (u.v.–vis., i.r., 1D n.m.r., 2D hetcor and mass) and thermal studies. The cobalt(II) complex crystallizes as pink crystals in the monoclinic crystal system, space group P21/n with a = 10.066(6) Å, b = 15.929(9) Å, c = 12.624(7) Å, α = 90.00(9)°, β = 110.850 (8)°, γ = 90.00, V = 1891.5 (18) Å3 and Z = 4. The geometry around the cobalt atom is distorted trigonal bipyramidal with τ = 0.83 [structural parameter, τ = (β − α)/60; where α and β are the two basal angles in a five coordinate complex]. 相似文献