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1.
An organic–inorganic hybrid Cu II–Er III heterometallic arsenotungstate Na 3[Cu(en) 2(H 2O)][Cu(en) 2] 1.5[H 3Er(α-AsW 11O 39) 2]·4H 2O ( 1) (en = ethylenediamine) has been hydrothermally synthesized and structurally characterized by elemental analyses, IR and UV spectra, X-ray photoelectron spectroscopy (XPS), cyclic voltammetry and single-crystal X-ray diffraction. 1 displays an organic–inorganic 2-D sheet structure constructed by sandwich-type [H 3Er(α-AsW 11O 39) 2] 8− fragments and [Cu(en) 2] 2+ connectors. From the topological viewpoint, if the [H 3Er(α-AsW 11O 39) 2] 8− fragments are viewed as 3-connected nodes and [Cu(en) 2] 2+ connectors are considered as linkers, the 2-D sheet can be simplified into a 2-D (6,3)-network topology. 相似文献
2.
Reaction of copper powder, manganese(II) nitrates and multidentate Schiff-base ligands in hot methanol solution led to the isolation of two new Mn III–Cu II heterometallic aggregates, [Mn 2 IIICu 2 II(H 2L) 4] · (NO 3) 2 · 2CH 3OH ( 1) (H 4L=2-[(2-hydroxy-benzylidene)-amino]-2-hydroxymethyl-proane-1,3-diol) and [Mn IIICu II 3(sae) 4(MeOH)(H 2O) 3] · NO 3 · MeOH ( 2) (H 2sae = salicylidene-2-ethanolamine). Both compounds were characterized by elemental analysis, IR, XPS, EPR, XRPD and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group P 1 with a = 11.1268(4) Å, b = 11.6153(4) Å, c = 11.8129(5) Å, α = 88.435(10)°, β = 80.203(10)°, γ = 77.572(10)°, V = 1469.13(10) Å 3, Z = 1, R1( wR2) =0.0300(0.0771). Compound 2 crystallizes in the monoclinic space group P2 1/ n with a = 18.1715(7), b = 12.9931(5), c = 19.5903(8) Å, β = 97.1980(10)°, V = 4588.9(3) Å 3, Z = 4, R1( wR2) = 0.0667 (0.1998). The magnetic susceptibilities of 1 and 2 display the antiferromagnetic interactions in both compounds. 相似文献
3.
New liquid-crystalline heteropolynuclear complexes L 2M (M=Cu 2+ ( 2a), Pd 2+ ( 2b)) were synthesized by the reactions of C 5H 5FeC 5H 4−C 6H 4NH−C 2H 2−(CO)−C 6H 4OC 12H 25 ( 1, LH) with copper( ii) and palladium( ii) acetates. Compound 2b was found to possess monotropic nematic and smectic phases; 2a exhibits the monotropic nematic phase and a phenomenon of “double melting”. The compositions and structures of compounds 1 and 2a,b were established by elemental analysis, 1H and 13C NMR, ESR, and IR spectroscopy.
Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 381–383, February, 1999. 相似文献
4.
Catalytic enantioselective α-fluorination reactions of carbonyl compounds are among the most powerful and efficient synthetic methods for constructing optically active α-fluorinated carbonyl compounds. Nevertheless, α-fluorination of α-nonbranched carboxylic acid derivatives is still a big challenge because of relatively high p Ka values of their α-hydrogen atoms and difficulty of subsequent synthetic transformation without epimerization. Herein we show that chiral copper(II) complexes of 3-(2-naphthyl)-l -alanine-derived amides are highly effective catalysts for the enantio- and site-selective α-fluorination of N-(α-arylacetyl) and N-(α-alkylacetyl) 3,5-dimethylpyrazoles. The substrate scope of the transformation is very broad (25 examples including a quaternary α-fluorinated α-amino acid derivative). α-Fluorinated products were converted into the corresponding esters, secondary amides, tertiary amides, ketones, and alcohols with almost no epimerization in high yield. 相似文献
5.
Rational design of high nuclear copper cluster-based metal–organic frameworks has not been established yet. Herein, we report a novel MOF ( FJU-112 ) with the ten-connected tetranuclear copper cluster [Cu 4(PO 3) 2( μ2-H 2O) 2(CO 2) 4] as the node which was capped by the deprotonated organic ligand of H 4L (3,5-Dicarboxyphenylphosphonic acid). With BPE (1,2-Bis(4-pyridyl)ethane) as the pore partitioner, the pore spaces in the structure of FJU-112 were divided into several smaller cages and smaller windows for efficient gas adsorption and separation. FJU-112 exhibits a high separation performance for the C 2H 2/CO 2 separation, which were established by the temperature-dependent sorption isotherms and further confirmed by the lab-scale dynamic breakthrough experiments. The grand canonical Monte Carlo simulations (GCMC) studies show that its high C 2H 2/CO 2 separation performance is contributed to the strong π-complexation interactions between the C 2H 2 molecules and framework pore surfaces, leading to its more C 2H 2 uptakes over CO 2 molecules. 相似文献
6.
To find the factors favorable for the appearance of chemomechanical activity of heterospin crystals, a series of new heterospin complexes were synthesized and characterized. It includes [Cu(tfac) 2L Im 2]·2CH 2Cl 2, [Cu(tfac) 2L Im 2]·2EtOH, [[Cu(pfu) 2] 2L Im 3]·1/2CH 2Cl 2, [Cu(pfh) 2L Im 2]·1/2CH 2Cl 2, [Cu(piv) 2L Im 2]·2MeOH, [Co(piv) 2L Im 2], [ $ Cu(hfac)_2 L^{CD_3 } _2 $ ], [Cu(hfac) 2L Tr] 2·CH 2Cl 2, and [Cu(hfac) 2L Tr 2] (L Im, $ L^{CD_3 } $ , and L Tr are N-methylimidazolyl-, N-trideuteriomethylimidazolyl-, and N-methyltriazolyl-substituted nitronyl nitroxides, respectively; tfac, hfac, pfu, pfh, and piv are the charged coordinated diamagnetic ligands 1,1,5,5-tetrafluoropentane-2,4-dionate, 1,1,1,5,5,5-hexafluoropentane-2,4-dionate, 1,1,1,2,2,3,3,4,4,8,8,9,9,10,10,11,11,11-octadecafluoroundecane-5,7-dionate, 1,1,1,5,5,6,6,6-octafluorohexane-2,4-dionate, and 2,2-dimethylpropionate, respectively). The crystal and molecular structures of all compounds were determined. The results of the X-ray diffraction study of the complex [Ni(hfac) 2L Im 2] synthesized earlier are reported. In the solid state of the complexes [Cu(pfh) 2L Im 2] and [Co(piv) 2L Im 2], the paramagnetic ligands are cis-coordinated to the central atom in a monodentate fashion via the donor N atom of the imidazole ring. In the dinuclear complexes [[Cu(pfu) 2] 2L Im 3] and [Cu(hfac) 2L Tr] 2, the paramagnetic ligands are also in cis positions but act as bridges through coordination of the donor N atoms of the azole ring and the O atom of the nitronyl nitroxide moiety to different Cu 2+ ions. In the solid complexes $ Cu(hfac)_2 L^{CD_3 } _2 $ , [Cu(hfac) 2L Tr 2], [Cu(tfac) 2L Im 2]·2CH 2Cl 2, [Cu(tfac) 2L Im 2]·2EtOH, and [Cu(piv) 2L Im 2]·2MeOH, the nitronyl nitroxide radicals in the mononuclear heterospin molecules are in trans positions. The packing motif in the crystal structures of the complexes $ Cu(hfac)_2 L^{CD_3 } _2 $ , [Cu(tfac) 2L Im 2]·2CH 2Cl 2, and [Cu(tfac) 2L Im 2]·2EtOH is the same as that in the previously studied complexes [M(hfac) 2L Im 2] exhibiting chemomechanical activity. Among the complexes under consideration, only crystals of $ Cu(hfac)_2 L^{CD_3 } _2 $ can exhibit chemomechanical activity, that is to make jumps upon heating or irradiation. The results of the present study suggest that the packing of the solid-state structure plays a key role in the generation of mechanical activity of the crystals. 相似文献
7.
Cu(x)O (x=1,2) nanomaterials with tailored composition and properties-a hot topic in sustainable technologies-may be fabricated from molecular sources through bottom-up processes that involve unexpected changes in the metal oxidation state and open intriguing challenges on the copper redox chemistry. How copper(II) sources may lead to copper(I) species in spite of the absence of any explicit reducing agent, and even in the presence of oxygen, is one such question-to date unanswered. Herein, we study copper "reduction without reductants" within one molecule and reveal that the actual reducing agent is abstracted atomic hydrogen. By investigating the fragmentation of a copper(II) precursor for copper oxide nanostructures by combined ESI-MS with multiple collisional experiments (ESI/MS(n)) and theoretical calculations, we highlight a copper-promoted C-H bond activation, leading to reduction of the metal center and formation of a Cu(I)-C-NCCN six-membered ring. Such a novel ring system is the structural motif for a new family of cyclic copper(I) adducts, which show a bonding scheme, herein reported for the first time, that may shed unprecedented light on copper chemistry. Beyond the relevance for the preparation of copper oxide nanostructures, the hydrogen-abstraction/proton-delivery/electron-gain mechanism of copper(II) reduction disclosed herein appears to be a general property of copper and might help to understand its redox reactivity. 相似文献
8.
[Cu(4)L(2)(bpy)(4)(H(2)O)(3)](ClO(4))(4).2.5H(2)O, 1, a new tetranuclear Cu(II) cluster showing square planar geometry, formed with aspartate bridging ligand (L) has been synthesized. The global magnetic coupling is ferromagnetic but theoretical DFT/B3LYP calculations are necessary to assign which Cu-L-Cu side is ferro or antiferromagnetically coupled. 相似文献
9.
Electrochemical reductive dissolution of Li–Mn–O and Li–Fe–Mn–O spinels and Li + extraction/insertion in these oxides were performed using voltammetry of microparticles. Both electrochemical reactions are
sensitive to the Fe/(Fe+Mn) ratio, specific surface area, Li content in tetrahedral positions, and Mn valence, and can be
used for electrochemical analysis of the homogeneity of the elemental and phase composition of synthetic samples. The peak
potential ( E
P) of the reductive dissolution of the Li–Mn–O spinel is directly proportional to the logarithm of the specific surface area. E
P of Li–Fe–Mn–O spinels is mainly controlled by the Fe/(Fe+Mn) ratio. Li + insertion/extraction can be performed with Mn-rich Li–Fe–Mn–O spinels in aqueous solution under an ambient atmosphere and
it is sensitive to the regularity of the spinel structure, in particularly to the amount of Li in tetrahedral positions and
the Mn valence.
Electronic Publication 相似文献
10.
Bubble points of the HCl–water–isopropanol and the HCl–water–isopropanol–benzene systems and liquid–liquid equilibria (LLE) of the HCl–water–benzene and the HCl–water– isopropanol–benzene systems were measured at 25–85°C and 30–70°C, respectively. The electrolyte nonrandom two-liquid model proposed by Chen et al. [C.-C. Chen, H.I. Britt, J.F. Boston, L.B. Evans, AIChE J. 28 (1982) 588–596] can satisfactorily correlate bubble points and liquid–liquid equilibria of the present mixed-solvent electrolyte systems over the entire range of temperature and concentrations using only binary adjustable parameters. 相似文献
11.
Fundamentally different behavior of Ba–Bi–O (Ba : Bi = 11 : 4, 1 : 1, 2: 3, and 1 : 5 mol/mol) and K nBa mBi m+nO y ( m = n = 1, 2,...; exhibiting superconducting properties with Tc = 28–32 K) oxides and BaO 2 in hydrolysis reactions has been revealed by means of potentiometry and chemical analysis. Products of the oxides treatment with water do not contain H 2O 2, evidencing the absence of peroxide ions in their structure. The perovskite-type barium-bismuth(III) oxides are completely hydrolyzed into Ba(OH) 2 and Bi 2O 3 at room temperature. 相似文献
12.
Two novel examples of sandwich type heteropolyanions were synthesized and characterized by X-ray crystal structure and elemental analysis as well as infrared spectroscopy. Na 13[H 3Cu 4(H 2O) 2(CuW 9O 34) 2]39H 2O ( 1) and Na 9K[Fe 4(H 2O) 2(FeW 9O 34) 2]32H 2O (2) were prepared in aqueous solution by reaction of sodium tungstate with Fe III and Cu II cations, respectively. 1 crystallizes in the monoclinic space group P2 1/ n ( a=13.054(3) Å, b=17.729(4) Å, c=20.998(4) Å, =93.50(3)°), while 2 is triclinic, space group P¯1 ( a=12.316(2) Å, b=13.716(3) Å, c=14.925(3) Å, =99.36(3)°, =104.21(3)°, =101.55(3)°). Each anion consists of two [XW 9O 34]
n– moieties (X=Fe III, n=11 ( 1) and Cu II, n=12 ( 2)) which can be described as -B-isomers of the defect Keggin anion. These units are linked via a belt of four Fe IIIO 6 or Cu IIO 6 groups. Two transition metal atoms fill their octahedral coordination sphere with one additional water ligand. 相似文献
13.
Cooling a melt of a Bi–Sr–Ca–Cu–O system (Bi:Sr:Ca:Cu = 4:3:3:4 or 2:2:2:4) from 1000°C-1050°C yielded crystals of a new red-colored nonsuperconducting phase, accompanying the superconducting 2212 and 2201 phases. Based on the EPR spectra, it was concluded that copper is univalent in this compound. The new phase has a composition Bi 2.2Sr 1.6Ca 1.3Cu 2O x. The X-ray diffraction pattern has been indexed, and the unit cell parameters of the phase have been determined: space group P2/m, a = 12.93, b = 4.55, c = 10.94 ; = 102.72°. 相似文献
14.
The high nitrogen compound 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine and the high energy density material hexanitrohexaazaisowurtzitane (HNIW), were used as substitute of hexogen (RDX) in the composite modified double base (CMDB) propellant formulations, the propellant samples were prepared, the thermal behaviors, nonisothermal reaction kinetics, and thermal safety were carried out, and the eight important parameters were calculated and obtained as the self-accelerating decomposition temperature ( T SADT), thermal ignition temperature ( T TIT), critical temperatures of thermal explosion ( T b), critical temperature of hot-spot initiation ( T cr,hot-spot), characteristic drop height of impact sensitivity ( H 50), critical thermal explosion ambient temperature ( T acr), safety degree ( S d), and thermal explosion probability ( P TE). It shows that the content of HNIW has a large effect on the decomposition reaction mechanism of the CMDB propellant, when the content of HNIW is 10 %, the decomposition reaction are controlled by the random nucleation and subsequent growth ( n = l), and the reaction mechanism obeys Mampel law; but when the content of HNIW is 20 %, the decomposition reaction are controlled by the chemical reaction ( n = 1/4). The mechanism can not be changed by the catalysts, and they just make the apparent activation energy change slightly. For the sample, from BC01 to BC04, the values of T SADT and T TIT making an upward tendency, show the resistivity to heat: BC04 > BC03 > BC02 > BC01; the values of T acr and S d, BC01 are the maximum and BC02 are the minimum, show the heat sensitivity: BC01 > BC03 > BC04 > BC02. For the same radius, the thermal safety of the sphere sample is greater than that of the infinite cylinder one. 相似文献
15.
The perovskite (BA) 4[Cu II(Cu IIn III) 0.5]Cl 8 ( 1 BA ; BA +=butylammonium) allows us to study the high-pressure structural, optical, and transport properties of a mixed-valence 2D perovskite. Compressing 1 BA reduces the onset energy of Cu I/II intervalence charge transfer from 1.2 eV at ambient pressure to 0.2 eV at 21 GPa. The electronic conductivity of 1 BA increases by 4 orders of magnitude upon compression to 20 GPa, when the activation energy for conduction decreases to 0.16 eV. In contrast, Cu II perovskites achieve similar conductivity at ≈50 GPa. The solution-state synthesis of these perovskites is complicated, with more undesirable side products likely from the precursor mixtures containing three different metal ions. To circumvent this problem, we demonstrate an efficient mechanochemical synthesis to expand this family of halide perovskites with complex composition by simply pulverizing together powders of 2D Cu II single perovskites and Cu IIn III double perovskites. 相似文献
16.
CuAl layered double hydroxide (CuAl-LDH) was synthesized by co-precipitation. Sodium phenyl phosphate (SPP) and sodium dodecyl sulfate (SDS) are used to modify CuAl-LDH for preparing CuAl-(SPP)LDH and CuAl-(SDS)LDH, which were incorporated into epoxy resin (EP) to obtain EP/CuAl-(SPP)LDH and EP/CuAl-(SPP)LDH nanocomposites. The results indicate that SPP and SDS are intercalated into the interlayers of CuAl-LDH, and CuAl-(SPP)LDH has larger layer spacing than CuAl-(SDS)LDH. The thermal stability and flame-retardant performances of EP/CuAl-(SPP)LDH nanocomposites were better than those of EP/CuAl-(SDS)LDH composites. Compared with those of EP/4CuAl-(SDS)LDH nanocomposites, the peak heat release rate (PHRR) of EP/4CuAl-(SPP)LDH nanocomposites is reduced 25.8% and 55.6%, and peak smoke production rate (PSPR) value of EP/4CuAl-(SPP)LDH nanocomposites is reduced 27.6% and 46.2%, value of EP/4CuAl-(SPP)LDH nanocomposites is reduced 27.6% and 46.2%, respectively. The improved flame retardancy and smoke suppression performances of EP/CuAl-(SPP)LDH nanocomposites were attributed to the combination of copper compounds and SPP, promoting the formation of swollen, continuous and compact char layers on the surface of EP nanocomposites during combustion, eventually restraining the decomposition of EP nanocomposites. 相似文献
17.
T– x diagrams of polythermal GeAs–SnAs, GeAs–Sn 4As 3 sections of the Sn–As–Ge system and Sn 4P 3–Sn 4As 3 section of the Sn–As–P system were constructed using the results of X-ray powder diffraction and differential thermal analyses. It was found that the section GeAs–Sn 4As 3 is not quasi-binary due to realization of four-phase peritectic transformation L + SnAs ? GeAs + Sn 4As 3 at the temperature of 834 K. The quasi-binary section GeAs–SnAs represents a phase diagram of the eutectic type with the following coordinates of eutectic reaction: temperature of the eutectic point is 840 K, and composition is 20 mol% GeAs. In the Sn–As–P system, the existence of the solid-solution range indicated as (Sn 4As 3) x (Sn 4P 3) 1?x was defined. The polythermal section Sn 4P 3–Sn 4As 3 is not quasi-binary due to the fact that in the composition range with a high content of tin arsenide discussed section intersects the peritectic part of the three-phase volume (L + SnAs + α) of the ternary diagram. 相似文献
18.
The study explored the compatibility between the main product of Portland cement hydration and the main product of the alkali
activation of fly ash: C–S–H and N–A–S–H gels, respectively. Both gels were synthesized with laboratory reagents at different
pH values. Blends of the two were synthesized as well, using the sol–gel procedure. All the gels were characterized with Fourier
transform IR spectroscopy (FTIR). The gels synthesized with this procedure were shown to precipitate together with a silica-rich
gel. In addition, the pH level was found to play a determinant role in both C–S–H and N–A–S–H gel synthesis. The C–S–H gel
is the major phase formed at pH > 11 and N–A–S–H gel for pH > 12. The results relating to the joint synthesis of the two (C–S–H
and N–A–S–H) gels were not conclusive. Technique used for the characterization failed to differentiate between them in the
blended material.
相似文献
19.
Rod-shaped amorphous bulk Ni–Cr–Mo-22 at.%Ta-14 at.%Nb–P alloys resistant to concentrated hydrochloric acids were prepared
by copper-mold casting. Alloys of amorphous single phase and mixture of nanocrystalline phases in the amorphous matrix were
all spontaneously passive in 6 and 12 M HCl and were immune to corrosion in 6 M HCl, although the corrosion weight loss was
detected for heterogeneous alloys in 12 M HCl. Spontaneous passivation is due to presence of stable air-formed films in which
chromium was particularly concentrated in addition to enrichment of tantalum and niobium. The angle resolved X-ray photoelectron
spectroscopy revealed that chromium and molybdenum are rich in the inner part of the film. The major molybdenum species is
in the tetravalent state, although penta- and hexavalent state molybdenum is also included. The high corrosion resistance
was interpreted in terms of the high stability of the outer triple oxyhydroxide, Cr 1−x−yTa xNb yO z(OH) 3+2x+2y−2z, and the effective diffusion barrier of the inner Mo 4+ and Cr 3+ oxide layer.
Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on Electrochemical/Chemical
Reactivity of Metastable Materials, Warsaw, 17th-21st September, 2007. 相似文献
20.
Two complex lanthanide(III) transition metal(II) tellurium(IV) oxyhalides, Cu 3Yb 2(TeO 3) 4Cl 4 and Cu 3Yb 3(TeO 3) 4Cl 6 have been synthesized and the crystal structures were determined by single-crystal X-ray diffraction. Both compounds are layered with only weak connections in between the layers. The layers are made up of [YbO 8], [TeO 3] and [CuO xCl y] polyhedra. In both compounds the strong Lewis acid cations Yb 3+ and Te 4+ only form bonds to oxygen while Cu 2+ form bonds to both oxygen and chlorine. This leads the Cl ? ions to be expelled from the bonding volumes of the crystal structures and protrude from the layers. Magnetic susceptibility measurements were performed on a powder sample of Cu 3Yb 2(TeO 3) 4Cl 4. The Curie–Weiss law found at low temperatures indicates a Curie–Weiss temperature of ca. ?5(1) K. However, indication for long-range magnetic ordering could not be observed down to 1.87 K. The two new phases are to the best of our knowledge the first containing all three of Cu, Yb and Te. 相似文献
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