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1.
Isothermal titration calorimetry has been used to determine the stoichiometry, formation constants and thermodynamic parameters
(ΔG
o, ΔH, ΔS) for the formation of the citrate complexes with the Mn2+, Co2+, Ni2+ and Zn2+ ions. The measurements were run in Cacodylate, Pipes and Mes buffer solutions with a pH of 6, at 298.15 K. A constant ionic
strength of 100 mM was maintained with NaClO4. The influence of a metal ion on its interaction energy with the citrate ions and the stability of the resulting complexes
have been discussed. 相似文献
2.
Nizam M. El-Ashgar Issa M. El-Nahhal Mohamed M. Chehimi Michel Delamar Florence Babonneau Jacques Livage 《Journal of Sol-Gel Science and Technology》2007,41(1):3-10
A new insoluble solid functionalized ligand system bearing chelating ligand group of the general formula P-(CH2)3-N[CH2CONH(C6H4)NH2]2, where P represents [Si–O]
n
polysiloxane network, was prepared by the reaction of the immobilized diethyliminodiacetate polysiloxane ligand system, P-(CH2)3N(CH2CO2Et)2 with 1,2-diaminobenzene in toluene. 13C CP-MAS NMR, XPS and FTIR results showed that most ethylacetate groups (–COOEt) were converted into the amide groups (–N–C=O).
The new functionalized ligand system exhibits high capacity for extraction and removal of the metal ions (Fe3+, Co2+, Ni2+, Cu2+ and Zn2+) with efficiency of 95–97% after recovery from its primary metal complexes. This functionalized ligand system formed 1:1
metal to ligand complexes. 相似文献
3.
Veronika Janíková Eugen Jóna Róbert Janík Viliam Pavlík Darina Ondrušová Michaela Ďurčeková 《Chemical Papers》2016,70(1):131-134
The influence of Ca2+-, Cu2+- and Fe3+-exchanged montmorillonite (MMT) on the type of interaction with aniline in the interlayer space of MMT has been studied by means of X-ray powder diffraction and infrared spectra. Results of X-ray diffraction showed that aniline was successfully intercalated into the interlayer space of MMT. Based on IR spectra evaluation, aniline was indirectly coordinated through a water-bridge in Ca2+- and Fe3+-MMT and it was indirectly coordinated through a water-bridge as well as protonated in Cu2+-MMT (the spectrum of protonated aniline showed deformation and changes in the NH 3 + absorption at approximately 1521 cm?1). It is important to point out that Cu2+-MMT indirect coordination and protonation occur simultaneously. 相似文献
4.
Gholam Hossein Rounaghi Mohammad Hossein Arbab Zavvar Kataneh Badiee 《Russian Journal of Inorganic Chemistry》2008,53(4):660-664
The equilibrium constants and thermodynamic parameters for complex formation of 18-Crown-6 (18C6) with Tl+, Pb2+, Hg2+, and Zn2+ metal cations have been determined by conductivity measurements in methanol (MeOH)-water (H2O) binary solutions. 18-Crown-6 forms 1:1 complexes with Hg2+ and Zn2+ cations, but in the case of Tl+ and Pb2+ cations, in addition to 1:1 stoichiometry, 1:2 (ML2) complexes are formed in some binary solvents. The thermodynamic parameters (ΔH
c0 and ΔS
c0), which were obtained from the temperature dependences of equilibrium constants, show that in most cases the complexes are
enthalpy destabilized but entropy stabilized. Non-linear behavior is observed between the equilibrium constants (log K
f
) of complexes and the composition of the mixed solvent. The selectivity of the ligand for these metal cations is sensitive
to the solvent composition, and, in some cases, the selectivity order is reversed in certain compositions of the mixed solvent.
The results also show that the mechanism of complexation reactions and the stoichiometry of complexes of some metal cations
change with the nature and even with the composition of the mixed solvent.
The article was submitted by the authors in English. 相似文献
5.
The absorption of Fe3+ ions from Fe3+-Zn2+ mixture with zinc and calcium phosphates was studied. 相似文献
6.
S. A. Bychkova A. V. Katrovtseva E. V. Kozlovskii 《Russian Journal of Coordination Chemistry》2008,34(2):93-96
The process of complex formation of maleic acid (H2L) with the ions Zn2+, Ni2+, Co2+, Cu2+ was studied by potentiometric titration in a wide range of concentration ratios at 298 K and I = 0.1 mol/l (NaNO3). The moieties ZnL, CoL, NiL, NiL 2 2? , CuL, and CuL 2 2? were detected and their stability constants were determined. 相似文献
7.
A. A. Medzhidov P. A. Fatullaeva S. M. Peng R. G. Ismaiylov G. H. Lee S. R. Garaeva 《Russian Journal of Coordination Chemistry》2012,38(2):126-133
Reactions of N-(2-hydroxy-3,5-R1,R2-benzyl)-4-aminoantipyrines with copper acetate in ethanol gave complexes with Schiff bases (SBs) rather than the expected
complexes with reduced SBs; i.e., the starting ligands undergo oxidative dehydrogenation during the complexation reaction.
The corresponding complexes with reduced SBs were obtained from sodium salts of the ligands and cupric sulfate in aqueous
solutions. Kinetic measurements showed that oxidative dehydrogenation occurs in the heteroleptic complexes Cu(L
i
)(CH3COO)(X) (L
i
H are derivatives of N-(2-hydroxy-3,5-R1,R2-benzyl)-4-aminoantipyrines; i = 6–10; X = H2O, CH3OH, CH3CH2OH) but does not occur in the complexes CH3OH, CH3CH2OH. The absence of oxidative dehydrogenation of the ligands in Cu(L
i
)2 · H2O can be explained by the octahedral environment of the Cu2+ ion and, accordingly, the absence of the coordination site for molecular oxygen. The molecular structures of two Cu(II) complexes
with SBs were determined by X-ray diffraction. 相似文献
8.
9.
We have investigated the presence of foreign ions into the bulk structure and the external surfaces of aragonite using periodic
ab-initio methods. Four cations isovalent to Ca2+ were studied: Mg2+, Sr2+, Ba2+ and Zn2+. The calculations were performed at structures (bulk, surface) that contain four and eight CaCO3 units. Our results, at the Hartree-Fock level, show that the incorporation of those ions into aragonite depends strongly
on their size. Mg2+ and Zn2+, due to their smaller size, can substitute Ca2+ ions in the crystal lattice while the incorporation of Sr2+ and Ba2+ into aragonite is energetically less favoured. Examination of the [011], [110] and [001] surfaces of aragonite revealed that
the surface incorporation reduces the energetic cost for the larger ions. These systems provide challenging examples for most
shape analysis methods applied in Mathematical Chemistry. 相似文献
10.
11.
12.
O. B. Belskaya L. N. Stepanova T. I. Gulyaeva N. N. Leont’eva V. I. Zaikovskii A. N. Salanov V. A. Likholobov 《Kinetics and Catalysis》2016,57(4):546-556
The effect of the cationic composition of MgAl(Ga) layered double hydroxides on the structure, texture, and acid–base properties of related oxide supports for platinum catalysts has been investigated. As gallium is progressively substituted for aluminum in the mixed oxide, the properties of the support change only slightly, while the activity of the Ga–Pt catalysts in propane conversion increases, the propylene selectivity remains high (99%), and C–C bond hydrogenolysis is hampered. 相似文献
13.
E. N. Demidova A. I. Drachev N. A. Borshch 《Russian Journal of Coordination Chemistry》2008,34(10):789-793
The process of Gd3+ complexation with 4-dihydroxyborophenylalanine (DHBPA) in aqueous solutions was studied by the contact conductometry, IR, and X-ray photoelectronic spectroscopy methods. The complex formation reactions of Gd3+ with DHBPA were found to occur in steps, depending on the metal: ligand ratio. In the final reaction product, i.e., the chelate complex [Gd(DHBPA)3], each molecule of a ligand occupies two coordination sites. 相似文献
14.
Saeedeh Hashemian 《Russian Journal of Inorganic Chemistry》2011,56(3):397-401
The imidazol side group of histidine has two nitrogen atoms capable of being protonated or participating in metal binding.
Hence, histidine can take on various metal-bound and protonated forms in proteins. Because of its variable structural state,
histidine often functions as a key amino acid residue in enzymatic reactions. Ab initio (HF and MP2) calculations were done
in modeling the cation (H+, Li+, Na+, K+, Mg2+, Ca2+) interaction with side chain of histidine. The region selectivity of metal ion complexation is controlled by the affinity
of the side of attack. In the imidazol unite of histidine the ring nitrogen has much higher metal ion (as well as proton)
affinity. The complexation energies with the model systems decrease in the following order: Mg2+ > Ca2+ > Li+ > Na+ > K+. The variation of the bond lengths and the extent of charge transfer upon complexation correlate well with the computed interaction
energies. 相似文献
15.
V. S. Kolosnitsyn E. A. Minnikhanova E. V. Karaseva Yu. K. Dmitriev M. M. Muratov 《Russian Journal of Applied Chemistry》2005,78(5):737-740
The effect of Ca2+, Mg2+, Fe3+, and Al3+ ions on the deposition of electrolytic manganese dioxide from chloride solutions was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 751–754.Original Russian Text Copyright © 2005 by Kolosnitsyn, Minnikhanova, Karaseva, Dmitriev, Muratov. 相似文献
16.
S. M. Masloboeva N. V. Sidorov M. N. Palatnikov L. G. Arutyunyan P. G. Chufyrev 《Russian Journal of Inorganic Chemistry》2011,56(8):1194-1198
Methods for direct doping of niobium pentoxide with photovoltaically inactive Mg2+ and Gd3+ cations were developed for subsequent use in the synthesis of a stock for growing single crystals of lithium niobate with
improved optical characteristics. The Raman spectra of doped pentoxides Nb2O5: Mg and Nb2O5: Gd revealed their island structures. 相似文献
17.
M. K. Khosa P. T. Wood S. M. Humphrey W. T. A. Harrison 《Journal of Structural Chemistry》2015,56(6):1130-1135
The syntheses and crystal structures of the layered coordination polymers M(C8H8NO2)2 [M = Mn (1), Co (2), Ni (3) and Zn (4)] are described. These isostructural compounds contain centrosymmetric trans-MN2O4 octahedra as parts of infinite sheets; the ligand bonds to three adjacent metal ions in μ3-N,O,O′ mode from both its carboxylate O atoms and its amine N atom. In each case, weak intra-sheet N–H?O and C–H?O hydrogen bonds may help to consolidate the structure. Crystal data: 1, C16H16MnN2O4, M r = 355.25, monoclinic, P21/c (No. 14), a = 10.6534(2) Å, b = 4.3990(1) Å, c = 15.5733(5) Å, β = 95.1827(10)°, V = 726.85(3) Å3, Z = 2, R(F) = 0.026, wR(F 2) = 0.067. 2, C16H16CoN2O4, M r = 359.24, monoclinic, P21/c (No. 14), a = 10.6131(10) Å, b = 4.3374(4) Å, c = 15.3556(17) Å, β = 95.473(4)°, V = 703.65(12) Å3, Z = 2, R(F) = 0.041, wR(F 2) = 0.091. 3, C16H16N2NiO4, M r = 359.02, monoclinic, P21/c (No. 14), a = 10.6374(4) Å, b = 4.2964(2) Å, c = 15.2827(8) Å, β = 95.9744(14)°, V = 694.66(6) Å3, Z = 2, R(F) = 0.028, wR(F 2) = 0.070. 4, C16H16N2O4Zn, M r = 365.68, monoclinic, P21/c (No. 14), a = 10.6385(5) Å, b = 4.2967(3) Å, c = 15.2844(8) Å, β = 95.941(3)°, V = 694.89(7) Å3, Z = 2, R(F) = 0.038, wR(F 2) = 0.107. 相似文献
18.
The heats of interaction of Cu2+ ions with L-phenylalanine in aqueous solution were determined by calorimetry at ionic strengths of 0.50, 0.75, 1.00 (KNO3) and a temperature of 298.15 K. The results of thermochemical study were interpreted taken into account complexation reactions, protolytic processes, and complexation with the competing ligand (OH?) taking place in parallel. The effect of supporting electrolyte concentration on the heats of Cu2+ complexation with the amino acid was considered. The standard enthalpies of complexation were found by extrapolation to zero ionic strength. The standard enthalpies of formation of complex species in an aqueous solution were calculated. 相似文献
19.
V. V. Yanilkin N. V. Nastapova A. S. Stepanov A. A. Kalinin V. A. Mamedov 《Russian Chemical Bulletin》2009,58(1):89-94
The binding of cations Li+, Na+, K+, Cs+, Ag+, Zn2+, Ni2+, Co2+, NH4
+ (group I), H+, Mg2+, Al3+, Ga3+ (group II), and Ca2+, Pb2+ (group III) by 21,31-diphenyl-l 2,42-dioxo- 7,10,13-trioxa-l,4(3,1)-diquinoxalina-2(2,3),3(3,2)-diindolizinacyclopentadecaphane (1), which contains two indolizine and two quinoxaline fragments and 3,6,9-trioxaundecanes spacer, and by its acyclic analog
(2) was studied using cyclic voltammetry in MeCN/0.1 M Bu4NBF4. It was concluded that the ions of group I are not bound by these compounds, the ions of group II exhibit the reversible
redox-switched binding by the carbamoyl groups of the quinoxaline fragments, whereas the ions of group III are bound not only
by the initial compounds and radical cations 1 and 2, but also by dication 1. This binding of the Ca2+ and Pb2+ ions stabilizes dication 1. 相似文献
20.
M. Clara Gonçalves Luis M. Fortes Rui M. Almeida Alessandro Chiasera Andrea Chiappini Maurizio Ferrari Shivakiran Bhaktha 《Journal of Sol-Gel Science and Technology》2010,55(1):52-58
Er3+ photoluminescence (PL) and Yb3+ → Er3+ energy transfer (ET) phenomena in the near infrared (NIR) have been studied in three-dimensional (3-D) inverse opal (IO)
structures synthesized by a colloidal/sol–gel route, starting with the deposition of polystyrene microsphere (235 nm and 460 nm
diameter) direct opal templates by convective self-assembly, followed by infiltration of the interstices with Er3+/Yb3+-doped silica, titania and silica-titania sols and heat-removal of the polymeric template material. The crystalline quality
of the IOs has been optimized through suitable substrate treatments, plus the control of temperature and humidity during deposition
of the templates. The structural and optical properties of the 3-D opal and IO structures have been studied by field emission
scanning electron microscopy and visible-NIR reflection spectroscopy, in order to assess the relationship between microstructure
and the photonic properties obtained. Photonic bandgaps have been evidenced by the corresponding stop bands in the reflection
spectra. The shape and the intensity of the Er3+
4I13/2 → 4I15/2 transition at ~1.5 μm were modified in most IOs relatively to similar matrix deposits without a photonic crystal structure,
particularly in the case of pure silica and titania IOs, where the PL peak narrowed and intensified. It was not possible at
this stage to detect Yb3+ → Er3+ ET phenomena in the IOs structures. 相似文献