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1.
Thermal decomposition of mixed ligand thymine (2,4-dihydroxy-5-methylpyrimidine) complexes of divalent Ni(II) with aspartate, glutamate and ADA ( N-2-acetamido)iminodiacetate dianions was monitored by TG, DTG and DTA analysis in static atmosphere of air. The decomposition course and steps of complexes [Ni(C 5H 6N 2O 2)(C 4H 5NO 4) 2−(H 2O) 2]·H 2O, [Ni(C 5H 6N 2O 2)(C 5H 7NO 4) 2−(H 2O) 2]·H 2O and [Ni(C 5H 6N 2O 2)(C 6H 8N 2O 5) 2−(H 2O) 2]·1.5H 2O were analyzed. The final decomposition products are found to be the corresponding metal oxides. The kinetic parameters namely, activation energy ( E*), enthalpy (Δ H*), entropy (Δ S*) and free energy change of decomposition (Δ G*) are calculated from the TG curves using Coats–Redfern and Horowitz–Metzger equations. The stability order found for these complexes follows the trend aspartate > ADA > glutamate. 相似文献
2.
TiO 2 nanoparticles and H 2Ti 2O 5·H 2O, Na 2Ti 2O 4(OH) 2 nanotubes were synthesized by solvothermal method and their applications in the degradation of active Brilliant-blue (KN-R) solution were investigated. The experimental results revealed that the synthesized TiO 2 nanoparticles had a good crystallinity and a narrow size distribution (about 4–5 nm); the obtained H 2Ti 2O 5·H 2O, Na 2Ti 2O 4(OH) 2 were tubelike products with an average diameter of 20–30 and 200–300 nm length. The three catalysts we synthesized had some hydroxyl groups and the maximum absorption boundaries of the samples were all red-shifted, which indicated the samples had a promising prospect in photocatalysis. The results of the photocatalytic experiments indicated that the photocatalytic activity of the samples was: TiO2 > H2Ti2O5·H2O > Na2Ti2O4(OH)2, which was in good accordance with the fact of FTIR and UV–vis absorption spectra. The formation mechanism of these nanostructures was also discussed. 相似文献
3.
Synthesized hydrated lamellar acidic crystalline magadiite (H 2Si 14O 29·2H 2O) nanocompound was used as host for intercalation of polar n-alkylmonoamine molecules of the general formula H 3C(CH 2) nNH 2 ( n = 1–6) in aqueous solution. The original interlayer distance ( d) of 1500 pm, determined by X-ray powder diffraction patterns, increases after intercalation. The values correlated with the number of aliphatic amine carbon ( nc) atoms: d = [(1312 ± 11) + (21 ± 2)] nc. The amount of intercalated amines ( Ns), decreased as nc increased: Ns = [(5.82 ± 0.04) − (0.45 ± 0.01)] nc. The acidic layered nanocompound was calorimetrically titrated with the amines and the thermodynamic data gave exothermic values for all guest molecules, as shown by the correlation: Δ intH = −[(24.45 ± 0.49) − (1.91 ± 0.10)] nc and d = [(1576 ± 16) − (10.8 ± 1.0)]Δ intH. The negative values of the Gibbs energies and the positive entropies also presented the correlations: Δ intG = −[(22.8 ± 0.2) − (0.2 ± 0.1)] nc and Δ intS = [(6 ± 1) + (5 ± 1)] nc, respectively. 相似文献
4.
The effects of calcination temperature and doping with K 2O on solid–solid interactions and physicochemical properties of NiO/Fe 2O 3 system were investigated using TG, DTA and XRD techniques. The amounts of potassium, expressed as mol% K 2O were 0.62, 1.23, 2.44 and 4.26. The pure and variously doped mixed solids were thermally treated at 300, 500, 750, 900 and 1000 °C. The catalytic activity was determined for each solid in H 2O 2 decomposition reaction at 30–50 °C. The results obtained showed that the doping process much affected the degree of crystallinity of both NiO and Fe 2O 3 phases detected for all solids calcined at 300 and 500 °C. Fe 2O 3 interacted readily with NiO at temperature starting from 700 °C producing crystalline NiFe 2O 4 phase. The degree of reaction propagation increased with increasing calcination temperature. The completion of this reaction required a prolonged heating at temperature >900 °C. K 2O-doping stimulates the ferrite formation to an extent proportional to its amount added. The stimulation effect of potassium was evidenced by following up the change in the peak height of certain diffraction lines characteristic NiO, Fe 2O 3, NiFe 2O 4 phases located at “d” spacing 2.08, 2.69 and 2.95 Å, respectively. The change of peak height of the diffraction lines at 2.95 Å as a function of firing temperature of pure and doped mixed solids enabled the calculation of the activation energy (Δ E) of the ferrite formation. The computed Δ E values were 120, 80, 49, 36 and 25 kJ mol −1 for pure and variously doped solids, respectively. The decrease in Δ E value of NiFe 2O 4 formation as a function of dopant added was not only attributed to an effective increase in the mobility of reacting cations but also to the formation of potassium ferrite. The calcination temperature and doping with K 2O much affected the catalytic activity of the system under investigation. 相似文献
5.
Since H 2O 2 decomposition can result in selectivity/yield loss in the direct H 2O 2 synthesis process from H 2 and O 2 over supported Pd catalysts, it is important to have an enhanced understanding about the factors affecting the H 2O 2 decomposition reaction. Herein, detailed studies have been undertaken to investigate the influence of different factors, such as (a) nature and concentration of acid in reaction medium, (b) nature and concentration of halide in presence and absence of acid in reaction medium, (c) pretreatment procedures and (d) catalyst modification by incorporation of different halides, on the H 2O 2 decomposition reaction over a 5% Pd/C catalyst in aqueous medium at 25 °C. This study has shown that the H 2O 2 decomposition activity is profoundly influenced by all the above factors. The effectiveness of the acids in suppressing the H 2O 2 decomposition activity decreased in the following order: hydroiodic acid > hydrobromic acid > hydrochloric acid acetic acid > phosphoric acid > sulfuric acid > perchloric acid. The ability of the acid to decrease the H 2O 2 decomposition activity was found to very strongly depend on the nature of its associated anion. Halides, such as iodide, bromide and chloride were particularly effective in suppressing the H 2O 2 decomposition activity. Oxidation pretreatment of the catalyst was found to strongly suppress its H 2O 2 decomposition activity, while a reduction treatment was found to promote its activity. A gradual decrease in the H 2O 2 decomposition activity of the catalyst was observed with each successive usage due to in situ sub-surface oxidation of Pd by H 2O 2. Halide incorporation either via the reaction medium or prior catalyst modification had a similar qualitative effect on the H 2O 2 decomposition activity. 相似文献
6.
Cd II complexes with glycine (gly) and sarcosine (sar) were studied by glass electrode potentiometry, direct current polarography, virtual potentiometry, and molecular modelling. The electrochemically reversible Cd II–glycine–OH labile system was best described by a model consisting of M(HL), ML, ML 2, ML 3, ML(OH) and ML 2(OH) (M = Cd II, L = gly) with the overall stability constants, as log β, determined to be 10.30 ± 0.05, 4.21 ± 0.03, 7.30 ± 0.05, 9.84 ± 0.04, 8.9 ± 0.1, and 10.75 ± 0.10, respectively. In case of the electrochemically quasi-reversible Cd II–sarcosine–OH labile system, only ML, ML 2 and ML 3 (M = Cd II, L = sar) were found and their stability constants, as log β, were determined to be 3.80 ± 0.03, 6.91 ± 0.07, and 8.9 ± 0.4, respectively. Stability constants for the ML complexes, the prime focus of this work, were thus established with an uncertainty smaller than 0.05 log units. The observed departure from electrochemical reversibility for the Cd–sarcosine–OH system was attributed mainly to the decrease in the transfer coefficient . The MM2 force field, supplemented by additional parameters, reproduced the reported crystal structures of diaqua-bis(glycinato-O,N)nickel(II) and fac-tri(glycinato)-nickelate(II) very well. These parameters were used to predict structures of all possible isomers of (i) [Ni(H 2O) 4(gly)] + and [Ni(H 2O) 4(sar)] +; and (ii) [Ni(H 2O) 3(IDA)] and [Ni(H 2O) 3(MIDA)] (IDA = iminodiacetic acid, MIDA = N-methyl iminodiacetic acid) by molecular mechanics/simulated annealing methods. The change in strain energy, Δ Ustr, that accompanies the substitution of one ligand by another (ML + L′ → ML′ + L), was computed and a strain energy Δ Ustr = +0.28 kcal mol −1 for the reaction [Ni(H 2O) 4(gly)] + + sar → [Ni(H 2O) 4(sar)] + + gly was found. This predicts the monoglycine complex to be marginally more stable. By contrast, for the reaction [Ni(H 2O) 3IDA] + MIDA → [Ni(H 2O) 3MIDA] + IDA, Δ Ustr = −0.64 kcal mol −1, and the monoMIDA complex is predicted to be more stable. This correlates well with (i) stability constants for Cd–gly and Cd–sar reported here; and (ii) known stability constants of ML complex for glycine, sarcosine, IDA, and MIDA. 相似文献
7.
The performance of a series of platinum black coated microdisk electrodes (Pt-Bs) was investigated in H 2O 2 solutions over the concentration range 0.1–500 mM, in phosphate buffer media pH 7. The Pt-Bs were prepared by electrodeposition of Pt onto the surface of microdisk electrodes 12.5 μm of nominal radius, from aqueous solutions containing hexachloroplatinic acid. The resulting roughness factors (RF, i.e., the ratio of the effective surface area to the geometric electrode area) varied between about 10 and 100. The voltammograms recorded with these electrodes, at relatively low H 2O 2 concentrations (up to 50–100 mM), displayed rather steep mixed anodic–cathodic waves, which attained well-defined and stable current plateaus. At the higher hydrogen peroxide concentrations, additional waves both in the anodic and cathodic region or dramatic current drop phenomena were observed. The wave split phenomenon was attributed to the insufficient buffering capacity of the base electrolyte solution within the pores of the platinum black, induced by the large amounts of hydrogen ions produced in the oxidation process. The current drop was attributed to either the formation of oxygen bubbles, which limit diffusion of H 2O 2 down the pores, or saturation of the active sites responsible for the decomposition of H 2O 2 to O 2 and H 2O. The H 2O 2 concentration at which the above phenomena occurred depended either on the phosphate buffer concentration in the bulk solution or the RF factor of the electrodes. The latter conditions also affected the dynamic range of detection, the sensitivity and low detection limits. Advantageous analytical characteristics were obtained with a Pt-B of RF of about 24, which provided a dynamic range between 0.5 and 230 mM, a sensitivity of 1.93(±0.06) A M −1 cm −2 and a low detection limit of 0.05 mM. The reproducibility was also very good, it being within 2–3%. The usefulness of the Pt-Bs for real samples analysis was tested in an antiseptic solution containing large amounts of H 2O 2. 相似文献
8.
The temperature dependence of the rate constants, for the reactions of hydrated electrons with H atoms, OH radicals and H 2O 2 has been determined. The reaction with H atoms, studied in the temperature range 20–250°C gives k(20°C) = 2.4 × 10 10M -1s 1 and the activation energy EA = 14.0 kJ mol -1 (3.3 kcal mol -1). For reaction with OH radicals the corresponding values are, k(20° C) = 3.1 × 10 10M -1s -1 and EA = 14.7 kJ mol -1 (3.5 kcal mol -1) determined in the temperature range 5–175°C. For reaction with H 2O 2 the values are, k(20° C) = 1.2 × 10 10M -1s -1 and EA = 15.6 kJ mol -1 (3.7 kcal mol -1) measured from 5–150°C. Thus, the activation energy for all three fast reactions is close to that expected for diffusion controlled reactions. As phosphates were used as buffer system, the rate constant and activation energy for the reaction of hydrated electron with H 2PO 4- was determined to k(20° C) = 1.5 × 10 7M -1s -1 and EA = 7.4 kJ mol -1 (1.8 kcal mol -1) in the temperature range 20–200°C. 相似文献
9.
A new synthetic method of sulfoxides and sulfones using solvent-free oxidations of sulfides with urea–hydrogen peroxide complex (urea–H 2O 2) and tetrabutylammonium phosphomolybdate catalyst on fluorapatite ((Bu 4N) 3[PMo 12O 40]/FAp). In the solid-phase system the oxidations of aromatic and alkyl sulfides proceeded at 4–25 °C and the corresponding sulfoxides or sulfones were selectively obtained in good yields by controlling the amount of urea–H 2O 2. 相似文献
10.
New types of supported Pd membranes were developed for high temperature H 2 separation. Sequential combinations of boehmite sol slip casting and film coating, and electroless plating (ELP) steps were designed to synthesize “Pd encapsulated” and “Pd nanopore” membranes supported on -Al 2O 3 hollow fibers. The permeation characteristics (flux, permselectivity) of a series of unaged and aged encapsulated and nanopore membranes with different Pd loadings were compared to those of a conventional 1 μm Pd/4 μm γ-Al 2O 3/-Al 2O 3 hollow fiber membrane. The unaged encapsulated membrane exhibited good performance with ideal H 2/N 2 separation factors of 3000–8000 and H 2 flux 0.4 mol/m 2 s at 370 °C and a transmembrane pressure gradient of 4 × 10 5 Pa. The unaged Pd nanopore membranes had a lower initial flux and permselectivity, but exhibited superior performance with extended use (200 h). At the same conditions the unaged 2.6 μm Pd nanopore membrane had a H 2 flux of 0.16 mol/m 2 s and separation factor of 500 and the unaged 0.6 μm Pd nanopore membrane had a H 2 flux of 0.25 mol/m 2 s and separation factor of 50. Both nanopore membranes stabilized after 40 h of operation, in contrast to a continued deterioration of the permselectivity for the other membranes. An analysis of the permeation data reveals a combination of Knudsen and convective transport through membrane defects. A phenomenological, qualitative model of the synthesis and resulting structure of the encapsulated and nanopore membranes is presented to explain the permeation results. 相似文献
11.
A novel hydrogen peroxide (H 2O 2) potentiometric sensor, made with a MnO 2-doped carbon paste electrode (CPE), is reported. Under optimum conditions, the electrode gives a Nernstian response for H 2O 2 in the concentration range 3.00×10 −7–3.63×10 −4 mol/l, with a slope of 21–19.4 mV/pH 2O 2 and a detection limit of 1.2×10 −7mol/l H 2O 2. In addition, this sensor offers some analytical characteristics such as sensitivity, good reproducibility and a simple preparation procedure. The effects of both the components of the electrode and other conditions on the potential response of the sensor, as well as the possible response mechanism, are discussed. 相似文献
12.
A new 1.75 μm infrared emission transition of Y 2O 3:Er 3+ is assigned to the 4S 3/2 → 4I 9/2 transition of Er 3+ ions situated at the C2 sites of cubic RE 2O 3 (RE = Y, Gd, Lu). The intensities of features in the 1.54 μm 4I 15/2– 4I 13/2 absorption transition due to Er 3+ at S6 and C2 sites are consistent with the site occupation ratio and the relative magnetic dipole–electric dipole intensity contributions of Er 3+ at the different sites. The 1.54 μm emission lines are predominantly from Er 3+ ions at C2 sites. The different behaviours of the emission intensities 1.75 and 1.54 μm groups with change in Er 3+ dopant ion concentration, preparation technique, Yb 3+ co-doping, temperature change and different excitation line are rationalized. 相似文献
13.
This work presents chemical modeling of solubilities of metal sulfates in aqueous solutions of sulfuric acid at high temperatures. Calculations were compared with experimental solubility measurements of hematite (Fe 2O 3) in aqueous ternary and quaternary systems of H 2SO 4, MgSO 4 and Al 2(SO 4) 3 at high temperatures. A hybrid model of ion-association and electrolyte non-random two liquid (ENRTL) theory was employed to fit solubility data in three ternary systems H 2SO 4–MgSO 4–H 2O, H 2SO 4–Al 2(SO 4) 3–H 2O at 235–270 °C and H 2SO 4–Fe 2(SO 4) 3–H 2O at 150–270 °C. Employing the Aspen Plus™ property program, the electrolyte NRTL local composition model was used for calculating activity coefficients of the ions Al 3+, Mg 2+ Fe 3+ and SO 42−, HSO 4−, OH −, H 3O +, respectively, as well as molecular species. The solid phases were hydronium alunite (H 3O)Al 3(SO 4) 2(OH) 6, hematite Fe 2O 3 and magnesium sulfate monohydrate (MgSO 4)·H 2O which were employed as constraint precipitation solids in calculating the metal sulfate solubilities. A correlation for the equilibrium constants of the association reactions of complex species versus temperature was implemented. Based on the maximum-likelihood principle, the binary interaction energy parameters for the ionic species as well as the coefficients for equilibrium constants of the reactions were obtained simultaneously using the solubility data of the ternary systems. Following that, the solubilities of metal sulfates in the quaternary systems H 2SO 4–Fe 2(SO 4) 3–MgSO 4–H 2O, H 2SO 4–Fe 2(SO 4) 3–Al 2(SO 4) 3–H 2O at 250 °C and H 2SO 4–Al 2(SO 4) 3–MgSO 4–H 2O at 230–270 °C were predicted. The calculated results were in excellent agreement with the experimental data. 相似文献
14.
The compound [Zn(H 2O) 4] 2[H 2As 6V 15O 42(H 2O)]·2H 2O (1) has been synthesized and characterized by elemental analysis, IR, ESR, magnetic measurement, third-order nonlinear property study and single crystal X-ray diffraction analysis. The compound 1 crystallizes in trigonal space group R3, a= b=12.0601(17) Å, c=33.970(7) Å, γ=120°, V=4278.8(12) Å 3, Z=3 and R1( wR2)=0.0512 (0.1171). The crystal structure is constructed from [H 2As 6V 15O 42(H 2O)] 4− anions and [Zn(H 2O) 4] 2+ cations linked through hydrogen bonds into a network. The [H 2As 6V 15O 42(H 2O)] 6− cluster consists of 15 VO 5 square pyramids linked by three As 2O 5 handle-like units. 相似文献
15.
Hydrogen peroxide (H 2O 2) is a valuable chemical commodity whose production relies on expensive and energy intensive methods. If an efficient, sustainable, and inexpensive solar-mediated production method could be developed from the reaction between dioxygen and water then the use of H 2O 2 as a fuel may be possible and gain acceptance. When concentrated at greater than 10 M, H 2O 2 possesses a high specific energy, is environmentally clean, and is easily stored. However, the current method of manufacturing H 2O 2 via the anthraquinone process is environmentally unfriendly making the unexplored nature of its photochemical production at high concentration from solar irradiation of interest. Towards this end, we studied the concentration and quantum yield of hydrogen peroxide produced in an ultraviolet (UV-B) irradiated environment using solid, Zn(II)-centered, complexes of amino-substituted isomers of indazole, pyridine, and phenylenediamine to catalyze the reaction. Aqueous suspensions in contact with air were exposed to 280–360-nm light from a low-power lamp. Of the ten complexes studied, Zn-5-aminoindazole had the greatest first-day production of 63 mM/day with a 37% quantum yield and p-phenylenediamine (PPAM) showed the greatest long-term stability. Isomeric forms of the catalysts’ organic components (e.g., amino groups) affected H 2O 2 production. For example, irradiation of diaminopyridine isomers indicated 2,3-diamino and 3,4-diamino structures were the most productive, each generating 32 mM/day H 2O 2, whereas the 2,5-diamino isomer generated no H 2O 2. A significant decrease in H 2O 2 production with time was observed for all but PPAM, suggesting the possibility of a catalyst-poisoning mechanism. We propose a reaction mechanism for H 2O 2 production based on the stability of the resonance structures of the different isomers. 相似文献
16.
A new family of heteropolytungstate complexes (NH 4) 21[Ln(H 2O) 5{Ni(H 2O)} 2As 4W 40O 140]· xH 2O(Ln=Y, Ce, Pr, Nd, Sm, Eu, Gd) were prepared by the reaction of Na 27[NaAs 4W 40O 140]·60H 2O with NiCl 2·6H 2O and Ln(NO 3) 3· xH 2O at pH≈4.5. The crystal structures of (NH 4) 21[Gd(H 2O) 5{Ni(H 2O)} 2As 4W 40O 140]·51H 2O was determined by X-ray diffraction analysis and element analysis. The compound crystallizes in the monoclinic space group P2 1/ n with a=19.754(3), b=24.298(4), c=39.350(6) Å, β=100.612(3)°, V=18564(5) Å 3, Z=2, R1( wR2)=0.0544(0.0691). The central site S1 and two opposite sites S2 of the big cyclic ligand [As 4W 40O 140] 28− are occupied by one Ln 3+and two Ni 2+, respectively, each site supply four O d coordinating to metal ion, another one water molecule and other five water molecules coordinate, respectively, to Ni 2+and Ln 3+. Polyanion [Ln(H 2O) 5{Ni(H 2O)} 2As 4W 40O 140] 21− has C2v symmetry. IR and UV–vis spectra of [NaAs 4W 40O 140] 27− of the title compounds are discussed. 相似文献
17.
The epoxidation of cyclopentene with hydrogen peroxide catalyzed by 12-heteropolyacids of molybdenum and tungsten (H 3PMo 12−nW nO 40, n = 1–11), 12-tungstophosphoric acid and 12-molybdophosphoric acid combined with cetylpyridinium bromide as a phase transfer reagent was carried out in acetonitrile. Among 13 heteropolyacids investigated, catalyst of H 3PMo 6W 6O 40 showed the highest activity, giving a conversion of 60% and a selectivity of 95% in the epoxidation of cyclopentene. The fresh catalysts and the catalysts under reaction condition were characterized by UV–vis, FT-IR and 31P NMR spectroscopy, which has revealed that all of the molybdotungstophosphoric acids were degraded in the presence of hydrogen peroxide to form a considerable amount of phosphorus-containing species. The active species resulted from H 3PMo 6W 6O 40 are new kinds of phosphorus-containing species, which is different from {PO 4[WO(O 2) 2] 4} 3−. 相似文献
18.
A novel strategy to construct a sensitive mediatorless sensor of H 2O 2 was described. At first, a cleaned gold electrode was immersed in thiol-functionalized poly(styrene- co-acrylic acid) (St- co-AA) nanosphere latex prepared by emulsifier-free emulsion polymerization St with AA and function with dithioglycol to assemble the nanospheres, then gold nanoparticles were chemisorbed onto the thiol groups and formed monolayers on the surface of poly(St- co-AA) nanospheres. Finally, horseradish peroxidase (HRP) was immobilized on the surface of the gold nanoparticles. The sensor displayed an excellent electrocatalytical response to reduction of H 2O 2 without the aid of an electron mediator. The biosensor showed a linear range of 8.0 μmol L −1–7.0 mmol L −1 with a detection limit of 4.0 μmol L −1. The biosensor retained more than 97.8% of its original activity after 60 days’ storage. Moreover, the studied biosensor exhibited good current reproducibility and good fabrication reproducibility. 相似文献
19.
The solid–solid interactions between pure and alumina-doped cobalt and ferric oxides have been investigated using DTA, IR and XRD techniques. Equimolar proportions of basic cobalt carbonate and ferric oxide and different amounts of aluminum nitrate were added as dopant substrate. The amounts of dopant were 0.75, 1.5, 3.0 and 4.5 mol% Al 2O 3. The results obtained revealed that solid–solid interaction between Fe2O3 and Co3O4 takes place at temperatures starting from 700°C to produce cobalt ferrite. The degree of propagation of this reaction increases progressively as a function of precalcination temperature and Al2O3-doping of the reacting solids. However, the heating of pure mixed solids at 1000°C for 6 h. was not sufficient to effect the complete conversion of the reacting solids into CoFe2O4, while the addition of a small amount of Al2O3 (1.5 mol%) to ferric/cobalt mixed solids followed by precalcination at 1000°C for 6 h conducted the complete conversion of the reacting solids into cobalt ferrite. The heat treatment of pure and the 0.75 mol%-doped solids at 900 and 1000°C effected the disappearance of most of IR transmission bands of the free oxides with subsequent appearance of new bands characteristic for the CoFe2O4 structure. An increase in the amount of Al2O3 added from 1.5–4.5 mol% to the mixed solids precalcined at 1000°C led to the disappearance of all bands of free oxides and appearance of all bands of cobalt ferrite. The promotion effect of Al2O3 in cobalt ferrite formation was attributed to an effective increase in the mobility of the various reacting cations. The activation energy of formation (ΔE) of CoFe2O4 phase was determined for pure and doped solids. The computed values of ΔE were, respectively, 99.6, 87.8, 71.9, 64.7 and 48.7 kJ mol−1 for the pure solid and those treated with 0.75, 1.5, 3 and 4.5 mol% Al2O3. 相似文献
20.
The syntheses and structural determination of Nd III and Er III complexes with nitrilotriacetic acid (nta) were reported in this paper. Their crystal and molecular structures and compositions were determined by single-crystal X-ray structure analyses and elemental analyses, respectively. The crystal of K 3[Nd III(nta) 2(H 2O)]·6H 2O complex belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5490(11) nm, b=1.3028(9) nm, c=2.6237(18) nm, β=96.803(10)°, V=5.257(6) nm 3, Z=8, M=763.89, Dc=1.930 g cm −3, μ=2.535 mm −1 and F(000)=3048. The final R1 and wR1 are 0.0390 and 0.0703 for 4501 ( I>2σ( I)) unique reflections, R2 and wR2 are 0.0758 and 0.0783 for all 10474 reflections, respectively. The Nd IIIN 2O 7 part in the [Nd III(nta) 2(H 2O)] 3− complex anion has a pseudo-monocapped square antiprismatic nine-coordinate structure in which the eight coordinate atoms (two N and six O) are from the two nta ligands and a water molecule coordinate to the central Nd III ion directly. The crystal of the K 3[Er III(nta) 2(H 2O)]·5H 2O complex also belongs to monoclinic crystal system and C2/ c space group. The crystal data are as follows: a=1.5343(5) nm, b=1.2880(4) nm, c=2.6154(8) nm, b=96.033(5)°, V=5.140(3) nm 3, Z=8, M=768.89, Dc=1.987 g cm −3, μ=3.833 mm −1 and F(000)=3032. The final R1 and wR1 are 0.0321 and 0.0671 for 4445 ( I>2σ( I)) unique reflections, R2 and wR2 are 0.0432 and 0.0699 for all 10207 reflections, respectively. The Er IIIN 2O 7 part in the [Er III(nta) 2(H 2O)] 3− complex anion has the same structure as Nd IIIN 2O 7 part in which the eight coordinate atoms (two N and six O) are from the two nta ligands and a water molecule coordinate to the central Nd III ion directly. 相似文献
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