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1.
The synthesis and X-ray determination of two sulfur bridged copper clusters with the known compositions of [Cu12S6(PnPr3)8] and [Cu20S10(PnBu1Bu2)8] but new molecular structures allow a comparison of these isomeric copper sulfide clusters. The Cu-S frameworks of the clusters with twelve copper atoms are highly topologically related and can both be derived flom a hypothetical naked [Cu12,S6] cluster that results from theoretical investigations. More dificult is the comparison of the two clusters containing 20 metal atoms. The two cluster types can be called either a prolate or an oblate isomer of [Cu20S10(pR3)8].  相似文献   

2.
A cordierite ceramic with a thermally stable pore structure was prepared by a simple modification of a sol-gel reaction of alkoxide precursors, synthesized from Mg metal or Mg acetate, Al(i-OPr)3, and partially prehydrolyzed Si(OEt)4. For aging and drying, wet cordierite gel was treated with water vapor at 150°C to strengthen the gel network through enhanced hydrolysis and condensation reactions. The cordierite xerogels showed BET surface areas between 220–410 m2/g, depending on the catalyst and treatment conditions used. In particular, water vapor treated xerogel displayed comparatively thermally stable pore characteristics, which exhibited only a 4–17% decrease in BET surface area up to 700°C, while samples prepared using the conventional sol-gel method showed a 55–91% reduction. Both the DTA and XRD patterns showed that crystallization began at 900°C leading to the -Cordierite phase and the subsequent phase transition to -cordierite at temperatures between 1050 to 1250°C.  相似文献   

3.
Piperidine octamolybdate [C5H5NH2]4[Mo8O26]·4H2O (I) has been synthesized and characterized by X-ray diffraction analysis. Crystals I are monoclinic, space group P21/n, a=12.892(3), b=9.283(2), c=19.184(4) , =92.50(3)°, V=2293.7(9) 3, Z=2,calc = 2.317 g/cm3.  相似文献   

4.
A new ligand, 1-(2-furanthiocarbo)-3-thiosemicarbazide (H2ftsc), prepared from thiosemicarbazide and carboxymethyl-2-furandithioate, forms complexes [Mn(ftsc)(H2O)2], [Pd(ftsc)] · 2H2O, [M(Hftsc)(acac)2] (M=CoIII or CrIII), [M(Hftsc)2(acac)] (M=MnIII or FeIII) and [Zn(Hftsc)2] · 2H2O, which were characterized by elemental analyses, magnetic susceptibility, i.r., electronic and n.m.r. spectral data. The Mössbauer spectra of [Fe(Hftsc)2(acac)] at 298K and 80K suggest the presence of high-spin iron(III) with an S=5/2 state. In vivo and in vitro antitumour activity of the ligand and the complexes have been screened towards several tumour cell-lines.  相似文献   

5.
Compounds of the general formula [Pt(2-L) {P(O)Ph2}- {P(OH)Ph2}], where 2-L={2-S2P(OEt)2}- (1) and {2-S2CNEt2}- (2), react in THF solution with the dinuclear complex [{(cod)M(-OMe)}2] (M = RhI or IrI) to give new heterodinuclear compounds of the type [(2-L)Pt{-P(O)Ph2}2M(cod)], where 2-L={2-S2P- (OEt)2}-;; M=RhI (3), IrI (4) and 2-L = {2-S2C-NEt2}-; M=RhI (5) and IrI (6). Compounds (3) and (4) react with an excess of CO, leading to displacement of the coordinated -diolefin (cod) and the formation of the dicarbonyl derivatives [{2-S2P(OEt)2}Pt{-P(O)-Ph2}2]M(CO)2] [M=RhI (7), IrI (8)].All products were characterized by carbon and hydrogen microanalysis and by i.r. and n.m.r. spectroscopy {1H and31 P(1H)}.  相似文献   

6.
A method has been developed for photometric detection of cyclodextrins (CD) in liquid chromatography using iodine (I2) generated electrochemically in-situ. Iodide ion in the mobile phase was electrochemically oxidized to I2 which was subsequently reacted with I, in an electrochemical flow cell, forming I3. The absorbance of I3 was found to be greatly enhanced when CD were present in the mobile phase. The absorbance enhancement was caused by the change in the mole fraction of I3, because of the inclusion reaction of I3 with CD. On the basis of this phenomenon, CD were detected by means of a photodiode-array UV–visible detector positioned downstream of the electrochemical flow cell. The signals were found to be linearly dependent on CD concentration. Because the formation constants of I3 with CD decrease in the order -CD>-CD>-CD, -CD was most detectable by the method. Detection limits were 1.0 mol L–1 for -CD, 65 mol L–1 for monoG1--CD, 100 mol L–1 for -CD, and 200 mol L–1 for -CD.  相似文献   

7.
Fe(III) hydrolysis and fluoride complexation behavior was examined in 0.68 molal sodium perchlorate at 25°C. Our assessment of the complexation of Fe(III) by fluoride ions produced the following results: logF1 = 5.155, logF2 = 9.107, logF3 = 11.96, logF4 = 13.75, where logFn = 5.155=[FeF n (3-n)+ ][Fe3+]–1[F]–n. The stepwise fluoride complexation constants,FK n+1, obtained in our work (where logF K n+1 =logFn) indicate that K n+1/K n =0.072±0.01. Formation constants for equilibria, Fe3++nH2OFe(OH) n (3–n)+ +nH+, expressed in the form n * [Fe(OH) n (3-n)+ ][H+]n ,[Fe 3+]-1, were estimated as 1 * = –2.754, and 2 * –7. Our study indicates that the results of previous hydrolysis investigations include very large overestimates of Fe(OH) 2 + formation constants.  相似文献   

8.
Four d10 metal polymers, cluster [AgI2(bpe)] n (1), complexes [Zn(tmp)I2] n (2), [Cd(tmp)I2] n (3), and [Hg(tmp)Br2] n (4) (bpe=1,2-bis(4-pyridyl)ethane, tmp=4,4-trimethylene dipyridine) have been synthesized and structurally characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. 1 is a cluster polymer, and exhibits a two-dimensional open structure consisting of the staircase clusters connected by regular bpe bridges. While complexes 2, 3, and 4 are one-dimensional wave-shaped coordination polymers. In contrast, 3 also displays a 2D structure with large supramolecular cavities. The diverse coordination properties of d10 metals make them good building blocks for the construction of coordination polymers with diverse architectures, which is dependent on both the rigidity and length of the bifunctional ligand and the coordination geometry of the metal ions.  相似文献   

9.
Four copper(II) complexes of betaines, [Cu2(BET)4Cl2][Cu(BET)2Cl2]Cl2 (2), [Cu2(pyBET)4Cl2]3[CuCl4]2Cl2 (3), [Cu, (pyBET)4 (H2O)2] (NO3)4 · 2H2O (4), and [Cu2(ppBET)4(H2O)2](ClO4)4 · 4H2O (5), (BET = Me3N+CH2COO; pyBET = C5H5N+CH2COO; ppBET=C5H5N+CH2CH2COO), have been prepared and characterized by X-ray crystallography. These complexes all contain dimeric [Cu2 (carboxylato-O,O)4L2] structures [basal Cu-O=1.955(4) 1.991(2), Cu Cu=2.602(1) 2.759(1) Å] with the apical ligand L=Cl in (2) and (3) [Cu-Cl=2.415(1) 2.436(3) Å] and L = H2O in (4) and (5) [Cu-OH2=2.158(4) 2.192(3) Å]; also present are a discrete [Cu(BET)2Cl2] molecule with a compressed tetrahedral CuO2Cl2 chromophore involving two unidentate carboxylate ligands [Cu-O=1.916(2), Cu-Cl=2.254(1) Å] in (2), and a discrete C3v [CuCl4]2– anion in (3). Generally the intradimer Cu Cu distance may be correlated to the electronic repulsion of the metal-ligand bonds in the CuO4L chromophore, as well as the steric interaction between the carboxylate moieties and the apical ligand.  相似文献   

10.
Summary The formation equilibria of nickel(II) violurato-complexes in water and dimethylsulphoxide-water (8020) as well as deprotonation of the coordinated ligands and related stereochemical changes are reported. The stability constants of the Ni2+-H2V complexes log1=5.06, Iog2=9.38, log3=12.98 as well as the acidity constants of the [Ni(H2V)3] complex, logj1= 8.37, logj2=15.76, logj3=22.37 are determined at 25 °C and 0.1M NaClO4. A new violurato-complex of Ni2+, Na4[Ni(HV)3]5H2O, is isolated and characterized.  相似文献   

11.
Treatment of [W(CO)(MeC2Me)2(-C5H5)][PF6] with ONMe3 in acetonitrile yields [W(NCMe)(MeC2Me)2(-C5H5)][PF6] which undergoes irreversible reduction at a Pt electrode in THF. Sodium amalgam reduction of [W(NCMe) (MeC2Me)2(-C5H5)][PF6] gives orange crystals of [W2(µ-,, 2, 2-C4Me4)2 (-C5H5)2] X-ray studies on which reveal pairwise alkyne coupling and a novel bis(metallacyclopentadiene) structure.Dedicated to Professor L. F. Dahl on the occasion of his 65th birthday.  相似文献   

12.
Summary The complexes Rh(5-C5Me5)(CNR)Cl2, [Rh(5 - C5Me5)(CNR)2Cl][PF6], (R = Me, Et, i-Pr, t-Bu, C6H11, , p-CIC6H4 and 1-naphthyl), and [Rh(5-C5Me5)(CNR)3][PF6] (R = Et, i-Pr and t-Bu)] have been prepared by treatment of [Rh(5-C5Me5)Cl2]2 with RNC in the presence of [PF6] (as appropriate). These complexes do not react with alcohols or amines to yield carbenes, but withm-MeC6H4SNa and NaS2CNR2, the species Rh(5-C5H5)(CNEt)(SC6M4Me-m)2 and [Rh(5-C5Me5)(CNR)(S2CNR2)][PF6] (R = Me, R1 = Me or Et; R =p-ClC6H4, R1 = Me) are formed. Treatment of [Rh(5-C5H5)(CNR)2Cl][PF6] with NaBH4 gave low yields of compounds tentatively formulated as [Rh(5-C5Me5)(CNR)2(BH4)][PF6] (R = Me or Et).Reprints of this article are not available.  相似文献   

13.
Two novel copper (I) -complexes containing the SiF 6 2– anion have been synthesized and studied by X-ray structure analysis. The crystals of the first title compound (A) are monoclinic, space group P21/b with a=13.039(5), b=10.586(4), c=6.072(2) Å, =100.23(2)°, and Z=2. The crystals of the second title compound (B) are triclinic, space group with a=14.495(5), b=7.633(2), c=6.429(8) Å, =90.67(8), =81.80(8), =94.05(3)°, and Z=1. In structure A, the copper cations and the bridge formiate anions form infinite [Cu(HCOO)]n spirals, which are cross-linked due to the -interaction between copper and the double bond AA and the strong hydrogen bonds N–H... F(SiF 6 2– ) to form a three-dimensional framework. In structure B, allylammonium similarly acts as a bridge linking the SiF 6 2– and Cu4Cl 6 2– anions into layers.Lvov State University. Institute of Physical Chemistry, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 4, pp. 141–148, July–August, 1993.Translated by T. Yudanova  相似文献   

14.
Studies on C-C bond formation between simple hydrocarbon species such as CH2, C=CH2, CH=CH2, CH2=CH2, CH2=C=CH2 and CHCH at a diruthenium center suggest that the process is promoted when the dimetal center can readily compensate for the two electrons lost in the formation of the new C-C bond. Thus, whereas -CH2 and ethene combine only under forcing conditions, the combination of -CH2 with allene or ethyne, which have additional -electrons available for coordination, occurs readily at room temperature. Likewise, the availability of uncoordinated -electrons in -C=CH2 allows vinylidene to link rapidly with ethene at room temperature. Alkyne complexes [Ru2(CO)(-RCCR)(-C5H5)2] (R=CF3 or Ph) react only under vigorous conditions with additional alkyne to give [Ru2(CO)(-C4R4) (-C5H5)2], but give these same species at room temperature in the presence of acid, shown to be due to the intermediacy of highly reactive 30-electron -vinyl cations. Thermally, alkyne linking proceedsvia three-alkyne species [Ru2(-C6R6)(-C5H5)2] to a four-alkyne complex [Ru2(-C8R8)(-C5H5)2], containing an unprecedented C8 ligand composed of a C6 ring with a C2 tail. Treatment of [Ru2(CO)(-RCCR)(-C5H5)2] with unsaturated metal fragments gives trimetal complexes such as [Ru3(CO)5(3-CF3CCCF3) (-C5H5)2]. The MeCN derivative of this species undergoes unusual linking processes on reaction with additional alkyne to giveinter alia [Ru3(CO)3(3-CCF3){3-C3(CF3)3}(-C5H5)2], arising from alkyne cleavage, and [Ru3(CO)3{3-C4(CF3)2(CO2Me)2}(-C5H5)2], a closo-pentagonal bipyramidal Ru3C4 cluster.  相似文献   

15.
Summary Complex formation in iron(III)-L-alanine solutions was studied by emf glass electrode and spectrophotometric measurements, in 0.5 mol dm –3 (Na)NO3 medium, at 25 ° C. In the concentration range 0.5 [Fe]0 20.0, 5.0 [Ala]0 1000.0 (mmol dm–3) and 1.0 -log [H+] 3.5; {[Ala]/[Fe] = 10:1-100:1| the equilibria in the title system were explained by the model including the species FeHL, FeL, Fe(OH)L, Fe2(OH)2L2 (where HL denotes L-alanine) and several hydrolytic products. The stability constants of complexes are given. The mechanism of formation and structure of complexes in solution is proposed.Abbreviations Ala alaninate ion - HAla alanine (zwitterion) - AlaH alanine (neutral) - H2Ala+ alanine cation  相似文献   

16.
The synthesis of six mononuclear palladium complexes of general formula [Pd(ox)/(mal)L2] and [Pd(ox)/(mal)L] (ox = oxalate, mal = malonate, both L and L are vitamin-B6 molecules (I), L = pyridoxine, pyridoxal and L = pyridoxamine) has been achieved. The structures of these compounds were established by elemental analysis, i.r. and 13C-n.m.r. [Pd(oxalate)(pyridoxine)2] was analyzed by single crystal X-ray diffraction. It exhibits square planar coordination with bond lengths 2.015 (2) Å for Pd—N and 2.010 (2) Å for Pd—O. The interaction of [Pd(ox)2]2– and [Pd(mal)2]2– with L has been followed kinetically in order to look into the nature of products and the mechanism of formation under the conditions [PdII-chelate] [L] and [L].  相似文献   

17.
Summary Eight new compounds of the- and- MaHb[SiW9Fe3 (H2O)3O37]·xH2O type, where M = K, Me4N, Et4N or Na n-Bu4N, and a + b = 7, have been synthesized from trivacant heteropoly tungstate- and- [SiW9O34]10– precursors, and characterized by i.r., u.v., x-ray photoelectron (x.p.e.) and Mössbauer spectroscopy, and polarography, and by their magnetic moments and thermal behavior. The i.r. and u.v. spectra confirm that the-and- [SiW9Fe3(H2O)3O37]7– isomers possess the Keggin structure. The main i.r. bands shift regularly with the changes of cation-size. The charge transfer energies of the easily reduced-isomers are lower than those of the-isomers. The x.p.e. results indicate-bond back-donation between iron and oxygen. The Mössbauer parameters obtained for the-isomer show that the three iron atoms in the polyanion are of two types; the lower magnetic moments suggest the presence of anti-parallel coupling via iron d-orbitals overlap with the p-orbitals of the bridging oxygens. All compounds decompose atca. 600°C.  相似文献   

18.
Summary The formation of copper(II) ternary complexes [Cu(tpy)(L)] (tpy = 2,2,2-terpyridine; L = oxydiacetate, thiodiacetate, iminodiacetate or dipicolinate) has been studied by potentiometric measurements in aqueous solution at 25° and I = 0.1 mol dm–3 (NaNO3 or NaClO4). All the systems investigated also form protonated species of the [Cu(tpy)(L)H]+ type. The effect of the different heteroatoms (donor atoms) in the ligands L (i.e. O, S or N), other than oxygens of the carboxylic groups, on the stability of the mixed complexes has been evaluated and compared with the trends observed for the analogous complexes of copper(II) with 2,2-bipyridine (bpy).The stabilization of ternary complexes of copper(II) with respect to the different coordination levels is also discussed.  相似文献   

19.
Summary The complextrans-[ReCl(N2)(dppe)2], (1) reacts with the thiolate salts Li[SC6H4Me-4], Tl[SC6H4Me-4] and [Pb(SBu-t)2] to yield [ReCl(SC6H4Me-4)(dppe)2], [Re(SC6H4Me-4) (dppe)2] and [{ReO(dppe)}2(-Cl)(-S)(-SBu-t)] (tentative formulation), respectively. The [ReCl(2-CS2)(dppe)2] complex appears to be formed by reaction of (1) with CS2.  相似文献   

20.
Salts of trimesic (1,3,5-benzenetricarboxylic) acid generally formulated as 3[C6H3(COO)3] · 5H2O, where Me = Rb and Cs, are synthesized and their structure and conductivity are examined. Both salts are ionic conductors with conductivities of 4.6 × 10–7 and 2.2 × 10–9 –1 cm–1 at 298 K and activation energies of conduction equal to (1.09 ± 0.02) and (1.07 ± 0.01) eV, respectively.  相似文献   

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