LiMn3(SeO3)2(HSeO3)6

The title compound, lithium trimanganese bis­[trioxo­selenate(IV)] hexa­kis[hydrogentrioxoselenate(IV)], is built up from a vertex‐sharing network of distorted Mn^IIIO₆ octa­hedra, SeO₃ and HSeO₃ pyramids and unusual Li(OH)₆ octa­hedra, resulting in a dense three‐dimensional structure. Mn, Li and one Se atom have site symmetries of , , and 3, respectively. An O—H⋯O hydrogen bond helps to establish the crystal packing.     

Interactions in the Quinary System H2O-Y(NO3)3-La(NO3)3-Pr(NO3)3-Nd(NO3)3 to Very High Concentrations

Isopiestic measurements have been carried out for the quinary system H₂O-Y(NO₃)₃-La(NO₃)₃-Pr(NO₃)₃-Nd(NO₃)₃ at 298.15 K to near saturation. The measurements can be represented within experimental uncertainty over the full concentration range by a modified Pitzer ion-interaction model extending to the C ⁽³⁾ term. In addition, the system obeys the Zdanovskii–Stokes–Robinson model or partial ideal solution model within the accuracy of the isopiestic measurements, indicating zero interchange energy between the unlike salts, which is consistent with the nature of trivalent rare-earth elements.     

Dimethylarsenazid (CH3)2AsN3, Dimethylwismutazid (CH3)2BiN3 und Dimethylthalliumzid (CH3)2TiN3

The reaction of (CH₃)₂AsJ and AgN₃ yields (CH₃)₂AsN₃; a colourless liquid (b. p. 136°C) which dissolves as a monomeric in benzene. (CH₃)₂BiN₃ is precipitated in form of colourless needles (dec. temp. 150°C) from an etherical solution of Bi(CH₃)₃ and HN₃. According to its vibrational and mass spectra the molecules are not associated although the (CH₃)₂BiN₃ is not soluble; dipole association of this polar molecules is assumed for the crystal structure. (CH₃)₂TlN₃ can be obtained from TI(CH₃)₃ and ClN₃ as well as from (CH₃)₂TlOH and HN₃ in form of colourless needles and leaves (dec. temp. 245°C). According to its vibrational spectra it has an ionic structure, (CH₃? Tl? CH₃)⁺N^?₃.     

Analysis of the intermolecular interaction between CH(3)OCH(3), CF(3)OCH(3), CF(3)OCF(3), and CH(4): high level ab initio calculations

The intermolecular interaction energies of the CH₃OCH₃? CH₄, CF₃OCH₃? CH₄, and CF₃OCF₃? CH₄ systems were calculated by ab initio molecular orbital method with the electron correlation correction at the second order Møller–Plesset perturbation (MP2) method. The interaction energies of 10 orientations of complexes were calculated for each system. The largest interaction energies calculated for the three systems are ?1.06, ?0.70, and ?0.80 kcal/mol, respectively. The inclusion of electron correlation increases the attraction significantly. It gains the attraction ?1.47, ?1.19, and ?1.27 kcal/mol, respectively. The dispersion interaction is found to be the major source of the attraction in these systems. In the CH₃OCH₃? CH₄ system, the electrostatic interaction (?0.34 kcal/mol) increases the attraction substantially, while the electrostatic energies in the other systems are not large. Fluorine substitution of the ether decreases the electrostatic interaction, and therefore, decreases the attraction. In addition the orientation dependence of the interaction energy is decreased by the substitution. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 1472–1479, 2002     

Tris(tris(trimethylsilyl)silyl)gallium,Ga{Si(Si(CH3)3)3}3

The title compound has been prepared in good yield by the reaction of gallium trichloride with base‐free hypersilyl lithium (Li–Si(SiMe₃)₃, Me = CH₃) in a 1 : 3 molar ratio. Ga(Si(SiMe₃)₃)₃ is monomeric in solution and in the solid state. The compound has been characterized with NMR, IR and Raman techniques as well as by an X‐ray structure determination (planar GaSi₃‐skeleton, monoclinic space group P2₁/c, Z = 4, d(Ga–Si) = 249,8 ± 0,2 pm).     

3-(3＇-乙酰基-5＇-芳基-1＇,3＇,4＇-二氢噁二唑-2＇-)色酮的微波促进合成

将微波应用于促进有机合成是近年来兴起的新技术,已受到极大注意,我们采用简单的微波反应装置,成功地合成了3－杂环基取代的色酮,杂环基取代的色酮因其显著的生理活性,而成为近年来的研究特点,以3－甲酰基色酮为原料,与芳酰肼反应得到相应的芳酰腙,再用乙酸酐关环,合成了一系列3位为1,3,4－二氢恶二唑基取代的色酮（3）,为在合适的母体上引入杂环提供了一系新思路,合成路线如下。     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP(N(CH3)2)3 – OP(CH3)3 und SP(N(CH3)2)3 – SP(CH3)3

Vibrational Spectra and Force Constants of the Series OP(N(CH₃)₂)₃ – OP(CH₃)₃ and SP(N(CH₃)₂)₃ – SP(CH₃)₃ The vibrational spectra (IR and Raman) of the compounds of the title series are recorded and assigned to the normal vibrations. By a simplified force field the valence force constants are calculated and discussed. The results are compared with those of the NMR spectroscopy.     

High-resolution optical spectroscopy of Na(3)[Ln(dpa)(3)].13H(2)O with Ln = Er(3+), Tm(3+), Yb(3+)

The title compounds were synthesized and studied by solution and single-crystal absorption, luminescence, and excitation spectroscopy. The f-f luminescence is induced in the Tm(3+) and Yb(3+) complexes in solution by exciting into the (1)Pi-(1)Pi absorptions of the ligand in the UV. A single-configurational coordinate model is proposed to rationalize the nonradiative relaxation step from ligand-centered to metal-centered excited states in [Yb(dpa)(3)](3-) (dpa = 2,6-pyridinedicarboxylate). Direct f-f excitation is used in crystals of Na(3)[Tm(dpa)(3)].13H(2)O and Na(3)[Yb(dpa)(3)].13H(2)O to induce f-f luminescence. From low-temperature, high-resolution absorption, luminescence, and excitation spectra, the ligand-field splittings in the relevant states can be determined. It was impossible to induce NIR to VIS upconversion in any of the complexes. This is mainly due to the fact that nonradiative relaxation among the f-f excited states is highly competitive, even in [Yb(dpa)(3)](3-) with an energy gap between (2)F(5/2) and (2)F(7/2) of about 10000 cm(-1). It can be rationalized on the basis of an adapted energy gap law. No luminescence at all could be detected in Na(3)[Er(dpa)(3)].13H(2)O.     

Schwingungsspektren und Kraftkonstanten der Übergangsreihen OP (CH3)3–OP(OCH3)3 und SP(CH3)3–SP(OCH3)3

Vibrational Spectra and Force Constants of the Series OP(CH₃)₃? OP(OCH₃)₃ and SP(CH₃)₃? SP(OCH₃)₃ The vibrational spectra of OP(CH₃)₂(OCH₃), OP(CH₃)(OCH₃)₂, SP(CH₃)₂(OCH₃), and SP(CH₃)(OCH₃)₂, are recorded and assigned to the normal vibration. The valence force constants are calculated by a simplified force field. The results are disscussed for both series and compared with former results.     

Untersuchungen zur Metallierung der Cyclophosphane P4(Cme3)3(Sime3), P4(Cme3)2(Sime3)2, P4(Sime3)4

Investigations Concerning the Metallation of the Cyclotetraphosphanes P₄(Cme₃)₃(Sime₃), P₄(Cme₃)₂(Sime₃)₂, and P₄(Sime₃)₄ The reaction of white phosphorus with LiCme₃ and me₃SiCl yields P₄(Sime₃)(Cme₃)₃ 1 . With n-buLi this crystalline cyclotetraphosphane forms the crystalline LiP₄(Cme₃)₃. In the same manner, n-buLi, with trans-P₄(Sime₃)₂(Cme₃)₂ 2 to yields LiP₄(Sime₃)(Cme₃)₂, which in contrast to LiP₄(Cme₃)₃ decomposes within a few hours yielding P(Sime₃)₂n-bu 6 , P(Sime₃)₃ 8 , LiP(Sime₃)₂ 9 and also the cyclic compounds P₄(Sime₃)(Cme₃)₃ 10 , LiP₄(Cme₃)₃ 11 and LiP₃(Cme₃)₂ 12 . The composition of the product mixture depends on the molar ratio of 2 to LiC₄H₉. At a molar ratio of 1:1 11 and 12 are not jet observed. At molar ratios of 1:1.5 and 1:2 P(Sime₃)₃ is not found. The amount of 11 and 12 grows with increasing concentration of n-buLi. On addition of n-buLi the solution of P₄(Sime₃)₄ immediately turns red. Li₃P₇ and Li₂P₇(Sime₃) (among others) are formed so fast that the first intermediates in the lithiation sequence so far could not be elucidated. These results demonstrate clearly that replacement of two me₃Si groups in P₄(Sime₃)₄ by two me₃C groups excludes the rearrangement of LiP₄(Sime₃)(Cme₃)₂ to a P₇-molecule.     

Chalcogenide-halides of niobium (V). 1. Gas-phase structures of NbOBr(3), NbSBr(3), and NbSCl(3). 2. Matrix infrared spectra and vibrational force fields of NbOBr(3), NbSBr(3), NbSCl(3), and NbOCl(3)

The molecular structures of NbOBr(3), NbSCl(3), and NbSBr(3) have been determined by gas-phase electron diffraction (GED) at nozzle-tip temperatures of 250 degrees C, taking into account the possible presence of NbOCl(3) as a contaminant in the NbSCl(3) sample and NbOBr(3) in the NbSBr(3) sample. The experimental data are consistent with trigonal-pyramidal molecules having C(3)(v)() symmetry. Infrared spectra of molecules trapped in argon or nitrogen matrices were recorded and exhibit the characteristic fundamental stretching modes for C(3)(v)() species. Well resolved isotopic fine structure ((35)Cl and (37)Cl) was observed for NbSCl(3), and for NbOCl(3) which occurred as an impurity in the NbSCl(3) spectra. Quantum mechanical calculations of the structures and vibrational frequencies of the four YNbX(3) molecules (Y = O, S; X = Cl, Br) were carried out at several levels of theory, most importantly B3LYP DFT with either the Stuttgart RSC ECP or Hay-Wadt (n + 1) ECP VDZ basis set for Nb and the 6-311G basis set for the nonmetal atoms. Theoretical values for the bond lengths are 0.01-0.04 A longer than the experimental ones of type r(a), in accord with general experience, but the bond angles with theoretical minus experimental differences of only 1.0-1.5 degrees are notably accurate. Symmetrized force fields were also calculated. The experimental bond lengths (r(g)/A) and angles ( 90 degree angle (alpha)()/deg) with estimated 2sigma uncertainties from GED are as follows. NbOBr(3): r(Nb=O) = 1.694(7), r(Nb-Br) = 2.429(2), 90 degree angle (O=Nb-Br) = 107.3(5), 90 degree angle (Br-Nb-Br) = 111.5(5). NbSBr(3): r(Nb=S) = 2.134(10), r(Nb-Br) = 2.408(4), 90 degree angle (S=Nb-Br) = 106.6(7), 90 degree angle (Br-Nb-Br) = 112.2(6). NbSCl(3): r(Nb=S) = 2.120(10),r(Nb-Cl) = 2.271(6), 90 degree angle (S=Nb-Cl) = 107.8(12), 90 degree angle (Cl-Nb-Cl) = 111.1(11).     

Spectroscopic properties of Er(3+)/Yb(3+) co-doped Bi(2)O(3)-B(2)O(3)-GeO(2) glasses

Er(3+)/Yb(3+) co-doped 60Bi(2)O(3)-(40 - x)B(2)O(3)-xGeO(2) (BBG; x=0, 5, 10, 15 mol%) glasses that are suitable for fiber lasers, amplifiers have been fabricated and characterized. The absorption spectra, emission spectra, and lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition were measured and calculated. With the substitution of GeO(2) for B(2)O(3), both Delta lambda(eff) and sigma(e) decrease from 75 to 71 nm and 9.88 to 8.12 x 10(-21) cm(2), respectively. The measured lifetime of the (4)I(13/2) level and quantum efficiency of Er(3+):(4)I(13/2) --> (4)I(15/2) transition increase from 1.18 to 1.5 ms and 36.2% to 43.2%, respectively. The emission spectra of Er(3+):(4)I(13/2) --> (4)I(15/2) transition was also analyzed using a peak-fit routine, and an equivalent four-level system was proposed to estimate the stark splitting for the (4)I(15/2) and (4)I(13/2) levels of Er(3+) in the BBG glasses. The results indicate that the (4)I(13/2) --> (4)I(15/2) emission of Er(3+) can be exhibit a considerable broadening due to a significant enhance the peak A, and D emission.     

Li(VO2)3(TeO3)2

The title compound, lithium tris[dioxidovanadium(V)] bis[trioxidotellurium(IV)], contains chains of edge‐sharing distorted VO₆ octahedra. The pyramidal TeO₃ groups crosslink the chains into sheets. Finally, an Li⁺ cation adopting an unusual capped trigonal–bipyramidal LiO₆ geometry bridges the layers to complete a three‐dimensional structure.     

Synthesis and crystal structures of zirconium(IV) nitrate complexes (NO2)[Zr(NO3)3(H2O)3]2(NO3) 3, Cs[Zr(NO3)5], and (NH4)[Zr(NO3)5](HNO3)

The zirconium nitrate complexes (NO₂)[Zr(NO₃)₃(H₂O)₃]₂(NO₃)₃ (1), Cs[Zr(NO₃)₅] ((2), (NH₄)[Zr(NO₃)₅](HNO₃) (3), and (NO₂)_0.23(NO)_0.77[Zr(NO₃)₅] ((4) were prepared by crystallization from nitric acid solutions in the presence of H₂SO₄ or P₂O₅. The complexes were characterized by X-ray diffraction. The crystal structure of 1 consists of nitrate anions, nitronium cations, and [Zr(NO₃)₃(H₂O)₃]⁺ complex cations in which the Zr^IV atom is coordinated by three water molecules and three bidentate nitrate groups. The coordination polyhedron of the Zr^IV atom is a tricapped trigonal prism formed by nine oxygen atoms. The island structures of 2 and 3 contain [Zr(NO₃)₅]^? anions and Cs⁺ or NH₄ ⁺ cations, respectively. In addition, complex 3 contains HNO₃ molecules. Complex 4 differs from (NO₂)[Zr(NO₃)₅] in that three-fourth of the nitronium cations in 4 are replaced by nitrosonium cations NO⁺, resulting in a decrease in the unit cell parameters. In the [Zr(NO₃)₅]^? anion involved in complexes 2–4, the Zr^IV atom is coordinated by five bidentate nitrate groups and has an unusually high coordination number of 10. The coordination polyhedron is a bicapped square antiprism.     

Er~(3 ),Ho~(3 )和Tm~(3 )在硫氧化钆中的余辉发光

非放射性长余辉磷光粉作为美化和清洁光源在发光陶瓷、交通安全标志、紧急突发事件的照明设施、工艺美术涂料等众多领域得到越来越广泛的应用,引起人们的重视.到目前为止,文献报道的稀土长余辉磷光体的激活离子主要有铕离子(Eu3+和Eu2+[1-4]、三价铈离子(Ce3+)[5]、三价铽离子(Tb3+)[6]、三价镨离子(Pr3+)[7]、三价钐离子(Sm3+)[8].Ho3+,Er3+,Tm3+等稀土离子作为红外上转换发光材料的激活离子[9～12],而关于它们的长余辉发光的报道极少.最近,雷炳富等在Tm3+离子[13]激活的硫氧化钇体系中发现了长余辉发光.在此,我们通过高温固相法合成了Er3+,Ho3+和Tm3+掺杂的硫氧化钆长余辉磷光粉,观察到该体系中迄今未见文献报道的Er3+,Ho3+和Tm3+离子的长余辉发光.