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1.
Two kinds of solids were obtained for Sc(PMBP) 3 by precipitation from different solvents. They were light-yellow crystal and yellowish-white powder, and their melting points were 209 and 217 °C, respectively. Raman spectra of six anhydrous samples prepared from these materials were measured and classified into two types of spectral patterns. Raman solute spectra of these two materials were measured in a dilute solution of dichloromethane, in which the solute is a free molecule in a solvent cage. Their spectra were considerably similar to each other, but they indicated clear differences in some pairs of bands. One of these two molecules was concluded to be a facial form of Sc(PMBP) 3, because the other constituent has been established to be a meridional form of Sc(PMBP) 3 by X-ray analysis of a single crystal. Structural optimization for mer- and fac-Sc(PMBP) 3 and their vibrational calculation of frequencies and intensities were carried out with the density functional method of B3LYP/6-31G**. Their computed Raman spectra were well coincident with their observed spectra. The existence of fac-Sc(PMBP) 3 has been established by thermal analysis, Raman spectroscopy and ab initio calculation. 相似文献
2.
Microdifferential thermal analysis (μ-DTA), X-ray diffraction (XRD) and infrared (IR) spectroscopy were used for the first time to investigate the liquidus and solidus relations in the KPO 3–Y(PO 3) 3 system. The only compound observed within the system was KY(PO 3) 4 melting incongruently at 1033 K. An eutectic appears at 13.5 mol% Y(PO 3) 3 at 935 K, the peritectic occurs at 1033 K and the phase transition for potassium polyphosphate KPO 3 was observed at 725 K. Three monoclinic allotropic phases of the single crystals were obtained. KY(PO 3) 4 polyphosphate has the P2 1 space group with lattice parameters: a=7.183(4) Å, b=8.351(6) Å, c=7.983(3) Å, β=91.75(3)° and Z=2 is isostructural with KNd(PO 3) 4. The second allotropic form of KY(PO 3) 4 belongs to the P2 1/ n space group with lattice parameters: a=10.835(3) Å, b=9.003(2) Å, c=10.314(1) Å, β=106.09(7)° and Z=4 and is isostructural with TlNd(PO 3) 4. The IR absorption spectra of the two forms show a chain polyphosphates structure. The last modification of KYP 4O 12 crystallizes in the C2/ c space group with lattice parameters: a=7.825(3) Å, b=12.537(4) Å, c=10.584(2) Å, β=110.22(7)° and Z=4 is isostructural with RbNdP 4O 12 and contains cyclic anions. The methods of chemical preparations, the determination of crystallographic data and IR spectra for these compounds are reported. 相似文献
3.
The phase diagram of the system CePO 4–K 3PO 4 has been determined based on investigations by differential thermal analysis, X-ray powder diffraction, IR spectroscopy and optical microscopy. The system contains only one intermediate compound K 3Ce(PO 4) 2, which melts incongruently at (1500±20)°C. This compound is stable down to room temperature and exhibits a polymorphic transition at 1180°C. It was confirmed that the low-temperature form β-K 3Ce(PO 4) 2 crystallizes in a monoclinic system, space group P2 1/m with unit cell parameters a=9.579 (5), b=5.634 (6), c=7.468 (5) Å; =γ=90°, β=90.81 (3)°; V=403.083 Å 3. 相似文献
4.
The reaction of Re 2(CO) 8(μ-H)2 with CH 2(NMe 2) 2 in chloroform at 25°C yielded the new compound Re 2(CO) 8(NHMe 2)(Cl)(μ-H) (1) in 31% yield. Compound 1 was characterized by IR, 1H NMR and a single-crystal X-ray diffraction analysis. Crystal data: orthorhombic, Pbca, a = 13.787(4), b = 19.884(5), c = 12.296(2) Å. Solution by direct methods (MITHRIL), R = 0.035 for 1800 reflections. The complex contains two rhenium atoms linked by an unsupported hydride bridge, Re Re = 3.362(1) Å, Re(1)---H = 1.8(1) Å and Re(2)---H = 2.0(1) Å. A chloride ligand abstracted from the solvent is terminally bonded to Re(1), and a dimethylamine ligand abstracted from the CH 2(NMe 2) 2 is coordinated to Re(2). When heated to 68°C, the dimethylamine ligand was eliminated and the chloride ligand became a bridge in the new compound Re 2(CO) 8(μ-H)(μ-Cl) (2), yield 76%. 相似文献
5.
We have synthesized in a single-step procedure from available copper(I) precursor at RT two Cu(I) thiolato clusters of the formula [Cu 4(μ-SCH(CH 3) 2) 6] 2− and [Cu 5(μ-SC(CH 3) 3) 6] − as revealed by X-ray crystallography, where increased steric bulk leads to a bigger cage with some two-coordinate metal centers. In addition, we identified a mononuclear two coordinate thiolato complex with the bulkier ligand, of the formula NEt 4[Cu(SC(CH 3) 3) 2]. This is only the second example of such a complex of an aliphatic ligand that is structurally characterized. The X-ray structure reveals an S–Cu–S angle of 176.7–179.5°, with Cu–S distances of 2.14 Å. 相似文献
6.
Thermal events encountered throughout the heat treatment of praseodymium acetate, Pr(CH 3COO) 3·H 2O, were studied in nitrogen and air atmospheres. The samples calcined at the 300–700 °C temperature range were characterized using XRD, IR and N 2 adsorption. Moreover, in situ electrical conductivity was employed to follow up the formation of the different decomposition intermediates. The results indicated that the anhydrous salt decomposes to the final product, PrO 1.833, through the formation of the following intermediates: Pr(OH)(CH 3COO) 2, PrO(CH 3COO) and Pr 2O 2(CO 3). PrO 1.833 formed at 500, 600, and 700 °C possesses a surface area of 17, 16 and 10 m 2/g and crystallites size of 14, 17 and 30 nm, respectively. 相似文献
7.
Reaction of phosphorus ylides Ph 3PCHC(O)C 6H 4NO 2 (Y′) and ( p-tolyl) 3PCHC(O)C 6H 4Cl (Y″) with HgX 2 (X = Cl, Br and I) in equimolar ratios using methanol as solvent leads to binuclear products. The bridge-splitting reaction of binuclear complex [(Y″) · HgI 2] 2 by DMSO yields the mononuclear complex [(Y″) · HgI 2 · DMSO]. This bridge-splitting reaction can be also a method for the synthesis of mononuclear products. C-coordination of ylides and O-coordination of DMSO are demonstrated by single crystal X-ray analyses of binuclear complexes of [(Y′) · HgI 2] 2 and [(Y″) · HgI 2] 2 and mononuclear complex of [(Y″) · HgI 2 · DMSO]. Characterization of the obtained compounds was also performed by elemental analysis, IR, 1H, 31P, and 13C NMR. Theoretical studies on Hg(II) complexes of Y′ show that the cis-like isomers are about 4–12 kcal/mol less stable than the trans-like structures and the relative energy of cis- and trans-like isomers significantly depends on the size of the bridging halide. These studies on mercury complexes of Y″ show that, formation of mononuclear complexes in DMSO solution in which DMSO acts as a ligand, energetically is more favorable than that of binuclear complexes. 相似文献
8.
The main product of the thermal reaction between the title oxatetraene (I) and Fe 2(CO) 9 in ether/pentane is the bimetallic complex (C 10H 10O)Fe 2(CO) 6- diexo (II), which has C2υ symmetry both in the solid state (X-ray analysis) and in solution. Whereas the protonation of the free ligand leads usually to polymerisation, the addition of a protic acid such as CF 3CO 2H to II proceeds cleanly at 0°C giving first a (η 3-allyl)Fe(CO) 3O 2CCF 3 complex (III). The intermediate III adds a second equivalent of acid in a slower step ( k2/ k1 = 0.1, CF 3CO 2D/CHCl 3, 0°C) giving the trans-bis(η 3-allyl) isomer IV with high regioselectivity. The addition of CF 3CO 2D yields the corresponding deuteriomethylallyliron tricarbonyl trifluoroacetates III′ and IV′. No further deuterium incorporation is observed at 0°C, thus confirming the kinetic control of the regioselective double addition of protic acid to II. 相似文献
9.
Carnosine (β-alanyl-L-histidine) is a biologically active molecule involved in muscular metabolism. It crystallises in the C; space group with a = 24.725 Å b = 5,427 Å c = 8,004 Å β = 100,2° ( Z = 4) In the crystal, acid and basic groups are engaged in hydrogen bonds whose strength is evaluated through IR frequencies. Molecular conformation in the solid state is defined by τ1 = /t-177° τ2 = −38° φ = −96° ψ = +131° χ1 = 181° χ21 = 62° NMR study of carnosine in aqueous solution indicates that rotation about CH2-CH2 is free and that the other angles take the following values: Ø −150° or −90° and X1 = 165° or 315°. Infrared and Raman spectra suggest that τ2 undergoes small changes when going from crystal to solution while ψ is close to +150°. 相似文献
10.
Irradiation of the 30-electron Mo 2(η 5-C 5Me 5) 2(CO) 4 and Re 2(CO) 10 in toluene solution (containing H 2O) afforded (in 1–2% yields) a novel triangular metal cluster, (η 5-C 5Me 5) 3Mo 3(CO) 4(η 2-H)(η 3-O) (1), which was characterized by a single-crystal X-ray diffraction study. Compound 1, of pseudo Cs- m symmetry, has a triangulo-Mo 3(η 3-O) core with composite Mo---H---Mo and Mo---Mo electron-pair bonds along one unusually short edge (2.660(1) Å) and Mo--- electron-pair bonds along the other two edges (2.916(1) and 2.917(1) Å). The edge-bridged hydride ligand, which displays a characteristic high-field proton NMR resonance at δ −17.79 ppm, was not found from the crystallographic determination but was located via a quantitative potential-energy-minimization method. This procedure unambiguously established that the optimized hydrogen position, which corresponds to a distinct coordination site with identical Mo---H distances of 1.85 Å, is the only one that can be sterically occupied by a metal-bound hydride ligand. This 46-electron species is the first electron-deficient trimolybdenum cluster containing a monoprotonated Mo---Mo double bond; its existence is attributed to ligand overcrowding due to the bulky pentamethylcyclopentadienyl rings. Black (η 5- C 5Me 5) 3Mo 3(CO) 4(η 2-H)(η 3-O) · 1/2THF crystallizes with two formula species in a triclinic unit cell of P1 symmetry with a 8.603(4), b 11.115(4), c 19.412(11) Å, 80.69(4)°, β 101.10(4)°, and γ 98.88(3)° at −40° C. Least-squares refinement (RAELS with 221 variables) of one independent Mo 3 molecule and a centrosymmetrically-disordered THF molecule converged at R1( F) 5.62%, R2( F 6.88% for 8460 independent diffractometry data ( I0 ρ 3σ( I0 collected at −40° C with Mo- K radiation 相似文献
11.
Reaction of (μ 3-CCH 3)CO 3(CO) 9 (I) with dppm (dppm = bis-(diphenylphosphino)methane) affords the cluster (μ 3-CCH 3)Co 3(CO) 7-dppm (II). The crystal and molecular structure of II have been determined at −160°C. The dppm ligand bridges one of the three metal—metal edges in the equatorial plane to give a five-membered ring, which adopts an envelope conformation. Cluster II functions as a catalyst for the hydroformylation of 1-pentene (80 bar of H2/CO (1/1); 110°C). The results indicate that the dppm bridging ligand stabilizes and activates the cluster for catalysis, and open the way to the synthesis of chiral clusters. 相似文献
12.
1H NMR spectra of binuclear metallocene hydride complexes, (η 5 : η 5-C 10H 8)(C 5H 5) 2M 2(μ-H) 2 (M = Nb, 20°C and Ti, (−60 to +25°C), were studied. The Nb complex is diamagnetic and gives a high resolution spectrum. The coordination of bridging hydride H atoms provides Nb atoms with complete 18 electron configuration. In its ground state, the Ti complex is also diamagnetic (the spectrum at −60°C agrees to that) in spite of only 17 electron configuration of each Ti atom. However, the population of the excited triplet state in the case of the Ti complex is appreciable at temperatures higher than −30°C, the proton resonance lines being shifted downfield and significantly broadened as compared with the spectrum at −60°C. 相似文献
13.
Novel isonitrile derivatives of a diruthenium carbonyl complex, (μ 2,η 3:η 5-guaiazulene)Ru 2(CO) 5 (2), were synthesized by substitution of a CO ligand by an isonitrile, and were subjected to studies on thermal and photochemical haptotropic interconversion. Treatment of 2 (a 45:55 mixture of two haptotropic isomers, 2-A and 2-B) with RNC at room temperature resulted in coordination of RNC and alternation of the coordination mode of the guaiazulene ligand to form (μ 2,η 1:η 5-guaiazulene)Ru 2(CO) 5(CNR), 5d–5f, [5d; R= tBu, 5e; 2,4,6-Me 3C 6H 2, or 5f; 2,6- iPr 2C 6H 3] in moderate to good yields. Thermal dissociation of a CO ligand from 5 at 60 °C resulted in quantitative formation of a desirable isonitrile analogue of 2, (μ 2,η 3:η 5-guaiazulene)Ru 2(CO) 4(CNR), 4d–4f, [4d; R= tBu, 4e; 2,4,6-Me 3C 6H 2, or 4f; 2,6- iPr 2C 6H 3], as a 1:1 mixture of the two haptotropic isomers. A direct synthetic route from 2 to 4d–4f was alternatively discovered; treatment of 2 with one equivalent of RNC at 60 °C gave 4d–4f in moderate yields. All of the new compounds were characterized by spectroscopy, and structures of 5d (R= tBu) and 4d-A (R= tBu) were determined by crystallography. Thermal and photochemical interconversion between the two haptotropic isomers of 4d–4f revealed that the isomer ratios in the thermal equilibrium and in the photostatic state were in the range of 48:52–54:46. 相似文献
14.
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
15.
The XeOSeF 5+ cation has been synthesized for the first time and characterized in solution by 19F, 77Se and 129Xe NMR spectroscopy and in the solid state by X-ray crystallography and Raman spectroscopy with AsF 6− as its counter anion. The X-ray crystal structures of the tellurium analogue and of the Xe(OChF 5) 2 derivatives have also been determined: [XeOChF 5][AsF 6] crystallize in tetragonal systems, P4/ n, a=6.1356(1) Å, c=13.8232(2) Å, V=520.383(14) Å 3, Z=2 and R1=0.0453 at −60°C (Te) and a=6.1195(7) Å, c=13.0315(2) Å, V=488.01(8) Å 3, Z=2 and R1=0.0730 at −113°C (Se); Xe(OTeF 5) 2 crystallizes in a monoclinic system, P2 1/ c, a=10.289(2) Å, b=9.605(2) Å, c=10.478(2) Å, β=106.599(4)°, V=992.3(3) Å 3, Z=4 and R1=0.0680 at −127°C; Xe(OSeF 5) 2 crystallizes in a triclinic system,
, a=8.3859(6) Å, c=12.0355(13) Å, V=732.98(11) Å 3, Z=3 and R1=0.0504 at −45°C. The energy minimized geometries and vibrational frequencies of the XeOChF 5+ cations and Xe(OChF 5) 2 were calculated using density functional theory, allowing for definitive assignments of their experimental vibrational spectra. 相似文献
16.
Hafnium β-diketonatochlorides HfCl 2(thd) 2 (1), HfCl(thd) 3 (2) as well as β-diketonato-silylamide and/or siloxide derivatives of 1 namely Hf(thd) 2[N(SiMe 3) 2] 2 (3), Hf(thd) 2(OSiMe 3) 2 (4) and Hf(thd) 2(OSi tBuMe 2) 2 (5) (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) were synthesized and characterized by elemental analysis, FT-IR, 1H NMR and TGA. 2 and 5 were also characterized by single-crystal X-ray diffraction. The siloxide ligands are in cis position for 5 and exert a strong trans effect. The new volatile compounds were tested as single-source precursors for the deposition of HfSi xO y films by pulsed liquid injection MOCVD on Si(1 0 0) and R plane sapphire. The as-deposited at 600–800 °C films were essentially amorphous, Hf-rich (Hf/Hf + Si = 0.7–0.85) and smooth. 相似文献
17.
One-dimensional Co(dien) 2(VO 3) 3·(H 2O) was prepared from the hydrothermal reaction of NH 4VO 3, Co 2O 3, diethylenetriamine (dien) and H 2O at 130 °C. The compound crystallizes in the monoclinic system, space group P2 1/ c with a=16.1581(6) Å, b=8.7006(3) Å, c=13.9893(4) Å, β=103.1483(11)°, V=1915.13(11) Å 3, Z=4, and R1=0.0268 for 3060 observed reflections. Single crystal X-ray diffraction revealed that the structure is composed of infinite one-dimensional chains formed by corner-sharing VO 4 tetrahedra with Co(dien) 3+ complex cations and crystallization water molecules occupying the interchain positions, which are held together to a three-dimensional network via extensive hydrogen-bonding interactions. The compound, with a new zig-zag conformation of metavanadate chains, is the first example of vanadium oxides incorporating trivalent transition metal coordination groups. Other characterizations by elemental analysis, IR and thermal analysis are also described. 相似文献
18.
The reaction of {HB(Me 2pz) 3}Mo(NCS)(S 4) [HB(Me 2pz) 3− = hydrotris(3,5-dimethylpyrazolyl)borate anion] with dicarbomethoxyacetylene in refluxing toluene results in the formation of the brown, diamagnetic complex {HB(Me 2pz) 3}Mo(NCS){S 2C 2(CO 2Me) 2} (1) (the reactants above also yield 1 upon prolonged reaction in dichloromethane at 25°C), which has been characterized by X-ray crystallography. The mononuclear pseudo-octahedral complex contains a facially tridentate HB(Me 2pz) 3− ligand, a monodentate N-bound NCS − ligand, and a bidentate S 2C 2(CO 2Me) 22− ligand having a near planar MoS 2C 4 fragment and a SC=CS bond distance of 1.342(15) Å. Solutions of 1 are unstable in air and decompose to produce {HB(Me 2pz) 3}MoO 2(NCS) and {HB(Me 2pz) 3}MoO(NCS) 2. 相似文献
19.
The reaction of [ R-( R, R)]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(NCMe)]PF 6 with (±)-AsHMePh in boiling methanol yields crystalline [ R-[( R)-( R, R)]-(+) 589)-[(η5-C5H5){1,2-C6H4(PMePh)2}Fe(AsHMePH)PF 6, optically pure, in ca. 90% yield, in a typical second-order asymmetric transformation. This complex contains the first resolved secondary arsine. Deprotonation of the secondary arsine complex with KOBu t at −65°C gives the diastereomerically pure tertiary arsenido-iron complex [ R-[( R),( R, R)]]-[((η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}FeAsMePh] · thf, from which optically pure [ R-[( S),( R, R)]]-(+) 589-[(η 5-C 5H 5){1,2-C 6H 4(PMePh) 2}Fe(AsEtMePh)PF 6 is obtained by reaction with iodoethane. Cyanide displaces ( R)-(−) 589-ethylmethylphenylarsine from the iron complex, thereby effecting the asymmetric synthesis of a tertiary arsine, chiral at arsenic, from (±)-methylphenylarsine and an optically active transition metal auxiliary. 相似文献
20.
Organolanthanide chloride complexes [(CH 3OCH 2CH 2C 5H 4) 2Ln(μ-Cl)] 2 (Ln = La, Pr, Ho and Y) react with excess NaH in THF at 45°C to give the dimeric hydride complexes [(CH 3OCH 2CH 2C 5H 4) 2Ln(μ-H)] 2, which have been characterized by IR, 1H NMR, MS and XPS spectroscopy, elemental analyses and X-ray crystallography. [(CH 3OCH 2CH 2C 5H 4) 2Y(μ-H)] 2 crystallizes from THF/n-hexane at −30°C, in the triclinic space group P1 with a = 8.795(2) Å, b = 11.040(1) Å, c = 16.602(2) Å, = 93.73(1)°, β = 91.82(1)°, γ = 94.21(1)°, Dc = 1.393 gcm −3 for Z = 2 dimers. However, crystals of [(CH 3OCH 2CH 2C 5H 4) 2Ho(μ-OH)] 2 were obtained by recrystallization of holmium hydride in THF/n-hexane at −30°C, in the orthorhombic space group Pbca with a = 11.217(2) Å, b = 15.865(7) Å, c = 17.608(4) Å, Dc = 1.816 gcm −3 for Z = 4 dimers. In the complexes of yttrium and holmium, each Ln atom of the dimers is coordinated by two substituted cyclopentadienyl ligands, one oxygen atom and two hydrogen atoms (for the Y atom) or two hydroxyl groups (for the Ho atom) to form a distorted trigonal bipyramid if the C(η 5)-bonded cyclopentadienyl is regarded as occupying a single polyhedral vertex. 相似文献
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