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1.
An X-ray diffraction study of the single crystals of (C2H7N4O)2[(UO2)2(OH)2(C2O4)(CHO2)2] was carried out. The compound crystallizes in the triclinic system, space group $P\bar 1$ , Z = 2, a = 5.5621(8) Å, b = 8.1489(10) Å, c = 11.8757(16) Å, α = 88.866(7)°, β = 82.204(6)°, γ = 87.378(6)°, V = 532.7(1) Å3, ρcalcd = 2.988 g/cm3. The main structural units in the crystal are the [(UO2)2(OH)2(C2O4)(CHO2)2)]2? chains corresponding to the crystal chemical group A2M 2 2 K02M 2 1 (A = UO 2 2+ , M2 = OH?, K02 = C2O 4 2? , M1 = CHO 2 ? ) of uranyl complexes. The chains are united into a three-dimensional framework through the electrostatic interaction and hydrogen bonds involving uranyl, oxalate, and hydroxyl groups, formate ions, and 1-carbamoylguanidinium cations.  相似文献   

2.
[[UO2(L)(OH)] (I), (CN3H6)2[(UO2)2CrO4(L)4] · 2H2O (II), and [UO2(H2O)5][(UO2)2Cr2O7(L)4] (III) crystals, where L is picolinate ion C5H4NCOO?, have been synthesized and studied by X-ray diffraction and IR spectroscopy. Complex I crystallizes in triclinic system with the unit cell parameters a = 6.2858(5) Å, b = 7.9522(5) Å, c = 8.3598(6) Å, α = 79.527(6)°, β = 87.760(6)°, γ = 79.126(6)°, space group P $\bar 1$ , Z = 2, R = 0.0306, and complexes II and III crystalize in monoclinic system with a = 8.8630(9) Å, b = 13.4540(13) Å, c = 31.266(3) Å, β = 93.118(3)°, space group C2/c, Z = 4, R = 0.0187 (II), and a = 7.3172(4) Å, b = 15.4719(8) Å, c = 16.6534(10) Å, β = 98.943(4)°, space group P21/m, Z = 2, R = 0.0588 (III). The structure of complex I is built of electronegative [UO2(L)(OH)] chains, which belong to the AT11M2 crystallochemical group (A = UO 2 2+ , T11 = L, M2 = OH?) of uranyl complexes. The structure of complexes II and III contains [(UO2)2(L′)(L)4]2? dimers (L′ = CrO 4 2? or Cr2O 7 2? ), which belong to the A2B2B 4 01 group (A = UO 2 2+ ,B2 = L′, B01 = L). The specifics of intermolecular interactions in the structures of complexes I–III and some their analogues have been considered using molecular Voronoi-Dirichlet polyhedra.  相似文献   

3.
The transformations of platinum and a heteropoly acid (HPA) in binary systems prepared from H2PtCl6 or H2PtCl4 and H3PMo12O40 were studied using IR and UV-VIS spectroscopy, elemental analysis, XPS, EXAFS, TPR, and HREM. The calcination of platinum chloride with the HPA to 450°C resulted in the formation of a platinum salt of the HPA along with decomposition products (mixture I). The reduction of calcined samples containing Pt: HPA = 1: 1 with hydrogen at 300°C (mixture II) followed by exposure to air resulted in the regeneration of the HPA structure. The resulting solid samples of Pt 1?n 0 Pt n II ClmOxHy) (H3+p PMo 12?p VI Mo p V O40) (III) contained platinum and molybdenum in both oxidized and reduced states. The following association species were isolated from mixtures I and II by dissolving in water: [Pt n II PMo12O40] (I s) (n = 0.3?0.8) and [Pt n 0 PMo 12 red O40] (II s) (n ≈ 1). Under exposure to air, the solutions of I s were stable (pH ~2), whereas Ptmet was released from II s. After the drying of I s, the solid association species (Pt n II ClmOxHy). (H3PMo12O40), where n = 0.3?0.8, m = 0.2?1, and x = 3?0, (I solid) were obtained. The I solid/SiO2 supported samples were prepared by impregnating SiO2 with a solution of I s and drying at 100°C. Platinum metal particles of size ~20 Å and a mixed-valence association species of platinum with the HPA were observed after the reduction of I solid/SiO2 with hydrogen at 100–250°C. These samples were active in the gas-phase oxidation of benzene to phenol at 180°C with the use of an O2-H2-N2 mixture.  相似文献   

4.
Surface-impact dissociation of I 2 - (CO2)n was studied by a molecular dynamics simulation in comparison with the experimental results. The branching fraction, ? dis, of the I 2 - dissociation was calculated as a function of the parent cluster size, n. This computational result reproduces the experimental one. We calculated a number of the I 2 - dissociation events starting from given initial orientations. The most favorable molecular orientation obtained supports the wedge effect in which a CO2 molecule located at the waist position of the I 2 - core ion splits the I 2 - bond as if a piece of wood is split by a mechanical thrust against a wedge. The time profile of the wedge action calculated for the I 2 - (CO2) impact shows that more than 20 % of the collision energy is converted to the vibrational energy of the I 2 - .  相似文献   

5.
Single source precursor, antimony potassium tartrate, was used for the preparation of Sb2O3, KSb3O5, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3. Antimony trioxide (Sb2O3) was prepared by hydrothermal method, while potassium antimony oxides (KSbO3, K0.51Sb 0.67 III Sb 2 V O6.26, and KSbO3) were obtained from the thermal decomposition of antimony potassium tartrate. All the compounds were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR), UV–Vis diffuse reflectance spectra, and scanning electron microscopy (SEM). The decomposition process of antimony potassium tartrate with temperature was given. The product formation at different temperatures of thermal decomposition was monitored by PXRD and FT-IR. The TG profile of antimony potassium tartrate shows mass loss at three regions. The infrared spectra of parent and decomposed products gave characteristic Sb-O bands. The band gap energy of decomposed products was obtained. The SEM diagrams of Sb2O3 show different morphologies. Direct solid state preparation of KSb3O5 and K0.51Sb 0.67 III Sb 2 V O6.26 under identical experimental conditions was unsuccessful.  相似文献   

6.
A new quantitation method, based on the detection of M 2 + molecular ions, is presented. It has been shown that M 2 + molecular ions are formed by a recombination process between independently sputtered M and M+ particles. Based on this formation mechanism, it will be demonstrated that M 2 + molecular ions can be used to quantitate major elements. The method will be used for quantitation of an Al x Ga1?x As multilayer. Furthermore, it will be shown that some matrix effects can be explained by the energy dependence of instrument transmission.  相似文献   

7.
This work reports the principle, advantage, and limitations of analytical photoion spectroscopy which has been applied to dissociative photoionization processes for diatomic molecules such as H2, N2, CO, and NO. Characteristic features observed in the differential photoion spectra are summarized with a focus on (pre)dissociation of(i) multielectron excitation states commonly observed in the inner valence regions,(ii) shape resonances, and(iii) doubly charged parent ions. Possible origins for negative peaks in the differential spectra are discussed. This spectroscopy is applied to the reported photoion branching ratios for D2 (and H2 at high energies). The main findings are as follows: (1) The direct dissociation of theX 2Σ g + (1sσ g ) state of D 2 + , the two-electron excited state1Σ u + (2pσ u 2sσ g ) of D2, and the2Σ u + (2pσ u ) state of D 2 + appear clearly in the differential spectrum, as previously observed for H2. (2) Decay of H 2 + (D 2 + ) to H+ (D+) above 38 eV is due to the direct dissociation of highly excited states of H 2 + (D 2 + ) such as the2Σ g + (2sσ g ) and high-lying Rydberg states converging on H 2 2+ (D 2 2+ ). (3) In the ionization continuum of H 2 2+ (D 2 2+ ) peculiar dissociation pathways are observed. The differential photoion spectra for O2 derived from the reported photoion branching ratios are also presented. The (pre)dissociation of theb 4Σ g ? ,B 2Σ g ? , III2Π u ,2Σ u ? , and2,4Σ g ? states of O 2 + appears as the corresponding positive values in the spectra in accord with previous observations. Some other dissociation pathways possibly contributing to the spectra are discussed including dissociative double ionization.  相似文献   

8.
The reaction of pentaphenylantimony with mercury iodide affords the ionic complex [Ph4Sb] 2 + [Hg2I6]2?·Ph2Hg (I). The [Ph4Sb] 2 + [Hg2I6]2? (II) and [Ph4Sb] 2 + [Cd2I6]2? (III) complexes are synthesized from tetraphenylantimony iodide and mercury and cadmium iodides. The [Ph4Sb] 2 + [Hg4I10]2? complex (IV) is prepared from tetraphenylantimony 2,4-dimethylbenzenesulfonate and mercury iodide. According to the X-ray diffraction data, the Sb atom in the [Ph4Sb]+ cations of complex I has virtually ideal tetrahedral coordination (the CSbC angles are 108.09°–109.64°). In the central square fragment Hg2I2 of the [Hg2I6]2? anion, the Hg-Ibr bond lengths are 2.825 and 3.075 Å, and the terminal iodine atoms are more strongly bonded to the mercury atoms (Hg-Iterm 2.691 and 2.700 Å). The [Cd2I6]2? anion in complex III has a similar structure (the Cd-Ibridg and Cd-Iterm distances are 2.865, 2.872 and 2.723, 2.748 Å, respectively). The anions in complex IV are joined by I…Hg (3.651 Å) and I…I (4.058 Å) interactions into an infinite dimeric network.  相似文献   

9.
Complexes with antimony-containing anions, [Ph3MeP] + 2 [SbI5]2? (I), [Ph3MeP] + 2 [Sb3I12]3? (II), [Ph3MeP] + 3 [Sb3I12]3? · Me2C=O (III), and [Ph3MeP] + 3 [Sb2I9]3? (IV), were synthesized by reacting triphenylmethylphosphonium iodide with antimony iodide. The central atom in the cations of the complexes has a distorted tetrahedral coordination. In the trinuclear anions of complexes II and III, each of the terminal SbI3 groups is bound to the central Sb atom through two μ2- and one μ3 iodine bridges (SbSbSb angles are 103.0° and 102.2°, respectively). In the binuclear anion of complex IV, antimony atoms are linked with each other via three bridging iodine atoms.  相似文献   

10.
The molecular and crystal structure of four acyclic trisiloxane compounds, which differ in substituents at the silicon atoms (Ph-phenyl, mPh-methoxyphenyl, 2mPh-dimethoxyphenyl), was investigated by X-ray diffraction analysis. Due to intermolecular hydrogen bonding between the oxygen atoms of the diol fragments, the crystal structure of 1,1,5,5-tetramethyl-3,3-diphenyl-1,3,5-trisiloxane-1,5-diol (C16H24O4Si3) (I) is a double chain architecture with hydrogen-bonded dimeric motifs of C(8)R 4 4 (12) type in graph set representation. In 1,1,5,5-tetramethyl-3,3-(2-methoxybenzo)-1,3,5-trisiloxane-1,5-diol (C18H28O6Si3) (II) and 1,1,5,5-tetramethyl-3,3-(2,6-dimethoxybenzo)-1,3,5-trisiloxane-1,5-diol (C20H32O8Si3) (III), a double chain structure with a graph set R 3 3 (8)D 3 3 (10) is formed. In contrast to I–III, 1,1,3,3,5,5-hexaphenyl-1,3,5-trisiloxane-1,5-diol (C36H32O4Si3) (IV) has an intramolecular hydrogen bond S(8). The independent molecules are joined by O-H...O intermolecular hydrogen bonds into centrosymmetrical dimers; the system of hydrogen bonds in general may be described as S(8)R 4 4 (8).  相似文献   

11.
Single crystals of K4[(UO2)2(C2O4)3(NCS)2] · 4H2O(I) have been synthesized and studied by X-ray diffraction. The crystals are monoclinic with the unit cell parameters a = 8.0226(7) Å, b = 14.9493(11) Å, c = 11.1670(9) Å, β = 98.299(3)°, space group P21/n, Z = 2, V = 1325.26(19) Å3, R = 0.0186. The main structural units of the crystals of structure I are discrete binuclear groups [(UO2)2(C2O4)3(NCS)2]4? belonging to the crystal-chemical group A2K02B 2 01 M 2 1 (A =UO 2 2+ , K02 =C2O 4 2? , B01 =C2O 4 2? , M1 = NCS?) of the uranyl complexes. The uranium-containing complexes are linked into a three-dimensional framework through the potassium ions and a system of hydrogen bonds involving the outer-sphere water molecules.  相似文献   

12.
Guided ion beam mass spectrometry is used to measure the cross sections as a function of kinetic energy for reaction of SiH4 with O+(4S), O 2 + (2Πg,v=0), N+(3P), and N 2 + (2Σ g + ,v=0). All four ions react with silane by dissociative charge-transfer to form SiH m + (m=0?3), and all but N 2 + also form SiXH m + products where (m=0?3) andX=O, O2 or N. The overall reactivity of the O+, O 2 + , and N+ systems show little dependence on kinetic energy, but for the case of N 2 + , the reaction probability and product distribution relies heavily on the kinetic energy of the system. The present results are compared with those previously reported for reactions of the rare gas ions with silane [13] and are discussed in terms of vertical ionization from the 1t 2 and 3a 1 bands of SiH4. Thermal reaction rates are also provided and dicussed.  相似文献   

13.
Primary processes in the reduction of p-nitroacetophenone (p-NAP) by ascorbic acid (AA) in water photosensitized by thiacyanine dimers M 2 2? have been considered. For M 2 2? , the quantum yields of fluorescence and intersystem crossing to the triplet state (M 2 2? )T increases in comparison to the monomers M?. The dimers (M 2 2? )T enter into the reactions of both one-electron photoreduction by ascorbic acid to give AA and M 2 3? and one-electron photooxidation by p-nitroacetophenone to give p-NAP and the dimeric radical anion M 2 ? which dissociates to M? and M· within 25–30 μs. The primary oxidative or reductive photosensitization in the ternary systems containing (M 2 2? )T, p-NAP, and AA affords p-NAP and AA.  相似文献   

14.
The mixed carboxylate diruthenium complexes trans-[Ru 2 II,III (O2CCH3)2(O2CAr)2Cl] (I) and trans-[Ru 2 II,II (O2CCH3)2(O2CAr)2] (II) (O2CAr = 2,6-di(p-tolyl)benzoate) have been synthesised along with [Ru 2 II,III (O2CAr)4Cl] (III) and the homoleptic complex [Ru 2 II,II (O2CAr)4] (IV). The structures trans-[Ru2(O2CCH3)2(O2CAr)2Cl(thf)]·(thf) and [Ru2(O2CAr)4Cl(η 1-CH2Cl2)] were determined by X-ray crystallography, and display the expected paddlewheel arrangement of the carboxylate ligands around the diruthenium core. The structure of III is a rare example of a structurally characterised dichloromethane complex, highlighting the Lewis acidic nature of the diruthenium axial position. The bulky ?O2CAr ligand protects the axial positions from intermolecular interactions in the absence of strong nucleophiles for III and IV, and the effect this has on the electronic structure of the diruthenium core in these complexes was investigated by cyclic voltammetry, electronic absorption spectroscopy and magnetic susceptibility studies.  相似文献   

15.
The single crystals of (C2H7N4O)2[UO2(C2O4)2(H2O)] were studied by X-ray diffraction. The crystals are monoclinic, space group Pn, Z = 2, unit cell parameters: a = 9.4123(2) Å, b = 8.4591(2) Å, c = 11.8740(3) Å, β = 105.500(10)°, V = 911.02(4) Å3. The main structural units of the crystals of I are islet complex groups [UO2(C2O4)2(H2O)]2? corresponding to the crystal chemical group AB 2 01 M1 (A = UO UO 2 2+ , B01 = C2O 4 2? , M = H2O) of uranyl complexes. Uranium-containing mononuclear complexes are connected into a three-dimensional framework through the electrostatic interactions and hydrogen bonding system involving carbamyolguanidinium ions.  相似文献   

16.
Complexes [Ph3MeP] 2 + [BiI3.5Br1.5(C5H5N)]2? · C5H5N(I), [Ph4Bi] 4 + [Bi4I16]4? · 2Me2C=O (II), and [Ph3(iso-Am)P] 4 + [Bi8I28]4? · 2Me2C=O (III) were synthesized by reactions of bismuth iodide with triphenylmethylphosphonium bromide, triphenylbismuthonium sulfosalicylate, and triphenylisoamylphosphonium iodide, respectively. The crystal structures of complexes I–III were determined by X-ray crystallography. The complexes contain, in addition to cations and solvent molecules, mono-, tetra-, and octanuclear anions, in which bismuth atoms are in octahedral coordination.  相似文献   

17.
A hydrated crystalline ionized adduct of dibenzo-18-crown-6 and perchloric acid DB18C6 · H3O+ · CiO 4 ? · 3H2O (I) is synthesized and characterized by X-ray diffraction. The crystals of I are monoclinic: a = 17.760 Å, b = 12.922 Å, β = 124.27°, Z = 4, space group Cc. The structure of I is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.079 for 3294 independent reflections (CAD4 automated diffractometer, λMoK α radiation). A DB18C6 molecule has a butterfly conformation with the rough symmetry C 2v . An H3O+ · H2O dimer is situated on one side of the DB18C6 macrocycle, and the ClO 4 ? anion and two other water molecules are on the other side. In the crystal of I, the DB18C6 molecules, H3O+ and ClO 4 ? ions, and water molecules are linked through intermolecular (interionic) hydrogen bonds to form broad infinite chains running along the z axis.  相似文献   

18.
Crystals of [Cr3O(CH3COO)6(H2O)3][UO2(CH3COO)3]·3H2O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?3, space group P212121, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr3O(CH3COO)6(H2O)3]+ complexes and mononuclear [UO2(CH3COO)3]? complexes classified with crystal-chemical groups A3M3B 6 2 M 3 1 (A = Cr3+, M3 = O2?, B2 = CH3COO?, M1 = H2O) and AB 3 01 (A = UO 2 2+ , B01 = CH3COO?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.  相似文献   

19.
MRD-CI calculations were performed on Ga, Ga2, Ga3, Ga4 and on the corresponding positive and negative ions. In general, pseudopotentials were used, and 4s4p/2s2p basis sets withs andp diffuse functions and one or twod functions. For Ga2, all-electron calculations were also performed. For Ga 2 (±) , potential functions for ground and low-lying excited states are given. For Ga 3 (±) , geometries were optimized both inC 2v andD ∞h symmetry. The lowest state of Ga 3 + is found to be1Σ g + , of Ga3 4 A 2, and of Ga 3 ? 1 A 1 (D 3h ). Ionization potentials and electron affinities of Ga3 were evaluated. Many low-lying excited states of Ga 3 (±) were found. Rhombic (D 2h , including squareD 4h ), tetrahedral (T d ), T-shaped (C 2v ) and linear structures (D ∞h) were investigated in the search for the lowest state of Ga4. A square-planar arrangement of the nuclei, withR e = 5.30 a0, was found to have the lowest energy. The other geometries lie about 0.5 eV higher. InD 2h symmetry, low-lying excited states of Ga4, as well as ground and excited states of Ga 4 + and Ga 4 ? were studied. Geometries, ionization potentials, electron affinities, atomization and fragmentation energies of Ga n are compared with corresponding data for B n and Al n . Typical changes in going from first-row to third-row atoms are observed.  相似文献   

20.
Complexes [(4-MeC6H4)4Sb] 2 + [Hg2I6]2? (I), [(4-MeC6H4)4Sb] 2 + [HgI4]2? (II), [(4-MeC6H4)4Sb] 3 + [Sb3I12]2? (III), were synthesized by reactions of tetra-p-tolylantimony iodide with mercury iodide and antimony iodide, respectively. Tetra-p-tolylantimony perrhenate [(4-MeC6H4)4Sb]+[ReO4]? (IV) was prepared from tetra-p-tolylantimony chloride and sodium perrhenate in acetone. Crystal structures of complexes I, II, and IV were determined by X-ray crystallography. Mercury and rhenium atoms have tetrahedral coordinations in these complexes. The Hg-I and Re-O distances in the structures of I, II, and IV vary within 2.7719(13)–2.7908(12)Å, 2.7028(3)–2.9163(3) Å, and 1.693(3)–1.744(3) Å, respectively. Antimony atoms in two crystallographically independent trinuclear centrosymmetric [Sb3I12]2? anions of complex III have an octahedral environment. Each terminal SbI3 fragment (Sb-It, 2.8265(9)–2.8333(10)Å) is bound to the central atom through tree bridging iodine atoms (Sb(2)-Ibr, 3.2275(9)–3.3620(10)Å). The distances between the central Sb atom and bridging iodine atoms are much shorter (Sb(1)-Ibr, 3.0153(6)–3.0316(6) Å; Sb(3)-Ibr, 2.9926(6)–3.0074(6) Å).  相似文献   

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