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22.
Christos Apostolidis Dr. Bernd Schimmelpfennig Dr. Nicola Magnani Dr. Patric Lindqvist‐Reis Dr. Olaf Walter Dr. Richard Sykora Dr. Alfred Morgenstern Dr. Eric Colineau Dr. Roberto Caciuffo Prof. Dr. Reinhardt Klenze Dr. Richard G. Haire Dr. Jean Rebizant Dr. Frank Bruchertseifer Dr. Thomas Fanghänel Prof. Dr. 《Angewandte Chemie (International ed. in English)》2010,49(36):6343-6347
23.
Branson A. Maynard Philip A. Smith Ayesha Jaleel LeAnn Ladner Richard E. Sykora 《Journal of chemical crystallography》2010,40(7):616-623
Abstract
The synthesis of four different lanthanide tetracyanoplatinates all incorporating 2,2′:6′,2″-terpyridine have been carried out in acetonitrile/water mixtures by reaction of an appropriate Ln3+ salt with 2,2′:6′,2″-terpyridine and potassium tetracyanoplatinate. The use of different Ln3+ salts as reactants results in the isolation of {La(tpy)(H2O)3}2[Pt(CN)4]3·2CH3CN·2H2O (La-1) space group P[`1] P\bar{1} , a = 9.3862(15) ?, b = 12.186(1) ?, c = 13.493(1) ?, α = 88.082(7)°, β = 80.22(1)°, γ = 74.88(1)°, {Pr(tpy)(H2O)3}2[Pt(CN)4]3·2H2O (Pr-2) space group P[`1] P\bar{1} , a = 9.2458(15) ?, b = 10.8068(9) ?, c = 13.6178(14) ?, α = 84.554(8)°, β = 74.905(10)°, γ = 79.490(9)°, Ho(tpy)(H2O)2(NO3)[Pt(CN)4] · CH3CN (Ho-3) space group P21/c, a = 12.867(1) ?, b = 15.1046(15) ?, c = 13.651(4) ?, β = 105.39(1)°, or Yb(tpy)(H2O)2(NO3)[Pt(CN)4]·0.5CH3CN·1.5H2O (Yb-4) space group Pbcn, a = 13.226(7) ?, b = 15.870(2) ?, c = 24.276(3) ? under quite similar reaction conditions. All four of these compounds have been isolated as single crystals and X-ray diffraction has been used to investigate their structural features. None of these compounds are isostructural with one another, but all contain one-dimensional, polymeric structures that contain tris chelation of the Ln3+ cations by terpyridine and bridging of the Ln3+ ions by tetracyanoplatinate. La-1 and Pr-2 contain both cis- and trans-bridging of Ln3+ cations by tetracyanoplatinate resulting in double chains with a ladder-type structure. Ho-3 and Yb-4 are similar in that they contain chelation of Ln3+ by both terpyridine and a nitrate anion and both structure types only contain cis-bridging by tetracyanoplatinate. All four structures contain Pt–Pt interactions in the form of dimeric units. 相似文献24.
ER Badman GE Patterson JM Wells RE Santini RG Cooks 《Journal of mass spectrometry : JMS》1999,34(8):889-894
Dual-detector differential non-destructive Fourier transform detection in a quadrupole ion trap is shown to improve signal intensity and reduce noise compared with spectra recorded using a single detector. A larger area detector in each end-cap electrode is machined to fit its hyperbolic shape and so minimize field imperfections on the z-axis. Argon, acetophenone and bromobenzene spectra were recorded to allow a comparison between single- and dual-detector (differential) modes of detection and to demonstrate the improvement achieved with differential detection. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
25.
A chromophore-donor-acceptor assembly [Ru(bpyCOOH)(bpyCH(2)MV(2+)) (bpyCH(2)PTZ)](4+)(1) (where bpyCOOH = 4-carboxylic acid-4'-methyl-2,2'-bipyridine, bpyCH(2)MV(2+) = 1-[(4'-methyl-2,2'-bipyridin-4-yl)methyl]-1'-methyl-4,4'-bipyridinediium, and bpyCH(2)PTZ = 10-[(4'-methyl-2,2'-bipyridin-4-yl)methyl]phenothiazine) has been adsorbed on the surface of nanocrystalline ZrO(2) and its excited state properties studied by emission and transient absorption spectroscopy. In deaerated acetonitrile solution, the complex emits weakly with an emission quantum yield of phi(em) approximately equal to 0.01 with an excited-state lifetime of tau approximately equal to 20 ps. Emission from the surface-adsorbed complex is intense, with phi(em) approximately equal to 0.4 and tau approximately equal to 40 ns. The increase in emission on the surface is likely due to a significant inhibition to the electron-transfer quenching of the metal-to-ligand charge transfer (MLCT) excited state caused by surface adsorption-induced changes in the redox potentials. Transient (nanosecond time scale) absorption monitoring, following laser flash photolysis, reveals the presence of a transient or transients that are formed during the flash. Transient spectral changes that occur during and after the flash are consistent with the formation and decay of the intermediate ZrO(2)-[Ru(bpyCOOH)(bpyCH(2)MV(+*))(bpyCH(2)PTZ(+*))](4+). It returns to the ground state by both intramolecular and intermolecular processes. Intramolecular electron transfer occurs with k(BET) = 6.3 x 10(6) s(-1) (tau = 160 ns), which is comparable to the rate constant for back-electron transfer in solution. The back-electron transfer is a second-order process and is much slower, with k(BET) = 390 M(-1) s(-1) (tau = 2.6 ms). 相似文献
26.
Almond PM Sykora RE Skanthakumar S Soderholm L Albrecht-Schmitt TE 《Inorganic chemistry》2004,43(3):958-963
The reaction of NpO(2) with SeO(2) in the presence of CsCl at 180 degrees C results in the formation of Np(NpO(2))(2)(SeO(3))(3) (1). The structure of 1 consists of three crystallographically unique Np centers with three different coordination environments in two different oxidation states. Np(1) is found in a neptunyl(V), O[double bond]Np[double bond]O(+), unit that is further ligated in the equatorial plane by three chelating SeO(3)(2-) anions to create a hexagonal bipyramidal NpO(8) unit. A second neptunyl(V) cation also occurs for Np(2); it is bound by four bridging selenite anions and by the oxo atom from the Np(1) neptunyl cation to form a pentagonal bipyramidal, NpO(7), unit. The third neptunium center, Np(3), which contains Np(IV), is found in a distorted NpO(8) dodecahedron. Np(3) is bound by five bridging selenite anions and by three neptunyl units via cation-cation interactions. The NpO(7) pentagonal bipyramids and NpO(8) hexagonal bipyramids share both corners and edges. Both of these polyhedra share corners via cation-cation interactions with the NpO(8) dodecahedra creating a three-dimensional structure with small channels that house the stereochemically active lone pair of electrons on the selenite anions. Magnetic susceptibility data follow Curie-Weiss behavior over the entire temperature range measured (5 < or = T < or = 320 K). The effective moment, mu(eff) = 2.28 mu(B), which represents an average over the three crystallographically inequivalent Np atoms, is within the expected range of values. There is no evidence of long-range ordering of the Np moments at temperatures down to 5 K, consistent with the negligible Weiss constant determined from fitting the susceptibility data. Crystallographic data: 1, orthorhombic, space group Pbca, a = 10.6216(5), b = 11.9695(6), and c = 17.8084(8) A and Z = 8 (T = 193 K). 相似文献
27.
The reaction of the molecular transition metal iodate, Cs[CrO(3)(IO(3))], with UO(3) under mild hydrothermal conditions provides access to a new low-dimensional, mixed-metal U(VI) compound, Cs(2)[(UO(2))(CrO(4))(IO(3))(2)] (1). The structure of 1 is quite unusual and consists of one-dimensional (1)(infinity)[(UO(2))(CrO(4))(IO(3))(2)](2-) ribbons separated by Cs(+) cations. These ribbons are formed from [UO(7)] pentagonal bipyramids that contain a uranyl core, [CrO(4)] tetrahedra, and both monodentate and bridging iodate anions. Crystallographic data: 1, monoclinic, space group P2(1)/n, a = 7.3929(5) A, b = 8.1346(6) A, c = 22.126(2) A, beta = 90.647(1) degrees, Z = 4 (T = 193 K). 相似文献
28.
We have pursued the fundamental chemistry of actinide pyrochlore oxides, An2Zr2O7 (An=Am, Cm, Bk, and Cf), using X-ray diffraction as well as optical spectroscopy. One recent facet of our studies has been to observe the structural changes of these materials under self-irradiation as a function of time. It has been reported that both titanate and silicate materials transform from a crystalline to an amorphous state under irradiation. With the Zr-based actinide pyrochlores studied here, we have observed a phase change from a pyrochlore structure to a fluorite-type structure with the retention of crystallinity. We focus here on the impact of α-radiation (243Am and 249Cf), rather than that from neutrons (248Cm) or β-radiation (249Bk), on the An2Zr2O7 pyrochlore structures. As a result of this phase change, the local coordination environments of both the actinide and zirconium atoms are altered. We consider a defect/ion deficiency driven mechanism and also address the occurrence of oxidation of the trivalent actinides during the self-irradiation process as being potential mechanisms responsible for the observed phase change. 相似文献
29.
Multidimensional residual distribution schemes for the convection–diffusion equation are described. Compact upwind cell vertex schemes are used for the discretization of the convective term. For the diffusive term, two approaches are compared: the classical finite element Galerkin formulation, which preserves the compactness of the stencil used for the convective part, and various residual-based approaches in which the diffusive term, evaluated after a reconstruction step, is upwinded along with the convective term. 相似文献
30.
The composition, formation conditions and stability constants of metal complexes of 2-(3'-sulfobenzoyl)pyridine-2-pyridylhydrazone are reported. Two types of complexes are formed having net charges of 0 and 2 - with divalent cations. The anionic form of the complex is quantitatively retained by anion-exchange resins and can be recovered by acid solution. 相似文献