Die ersten oligomeren Anionen bei Fluoro-Litho-Metallaten mit Oktaeder-Sandwich-Motiv: Cs4K{[F3MIIIF3]Li[F3MIIIF3]}, MIII = Ga,Fe [1]

The First Oligomeric Anions of Fluoro-Litho Metallates with Octahedra Sandwich Motive: Cs₄K{[F₃M^IIIF₃]Li[F₃M^IIIF₃]}, M^III = Ga, Fe Colourless single crystals of Cs₄K{Li[Ga₂F₁₂]} ( A ) and Cs₄K{Li[Fe₂F₁₂]} ( B ) have been obtained by solid state reaction from intimate mixtures of the corresponding binary fluorides (Pt-tube, 750°C, 40 d). The trigonal unit cells with ( A ) a = 631,3(1)pm; c = 3059,9(6)pm and ( B ) a = 635,0(1)pm; c = 3089,2(7)pm, respectively (Z = 3, Guinier-Simon data, Cu-Kα₁), are confirmed by single crystal investigations. The compounds crystalize isostructural in the space group R3 m (No. 166). The structures were determined using four-circle diffractometer data (Siemens AED 2) with ( A ) R = 2.95%, 3627 I_o and ( B ) R = 1.86%, 4179 I_o, respectively (SHELX-76), and are characterized by triplets of facesharing octahedra parallel [00.1] with the cation-sequence M^III? Li? M^III, six of which are connected by [KF₆]-octahedra via common corners and each triplet is surrounded by six different [KF₆]-octahedra. The structure is completed by Cs⁺ filling the cavities. The Madelung Part of Lattice Energy (MAPLE), Mean Fictive Ionic Radii (MEFIR) and Effective Coordination Numbers (ECoN) are calculated and compared. The classification as lithometallate could be verified by a new MAPLE concept. The Charge Distribution (CHARDI) was calculated and compared with the results according to ‘bond length-bond strength’.     

新型双锂盐络合物的合成及其单晶结构的测定

报道了一种新的双锂盐络合物的合成及其X衍射单晶结构，该络合物含有2个 Li原子、一个（i-Pr2C6H3)2-dad配体及2个DME分子[triclinic,P-1,α=1.3478(4) ,b=1.5158(3),c=1.0730(3)nm,α=100.668(3)°,β=113.416(3)°，γ=97.128(3) °,Ⅴ=1.790(1)nm^3,Dc=1.06g/cm^3,Z=2,R/Rω=0.058/0.057]。     

锂嵌脱化合物LiMn2O4的微波烧结研究

本文用微波烧结法合成锂嵌脱材料ＬｉＭｎ２Ｏ４，研究了微波烧结功率，时间的固态产物相的影响，对ＬｉＭｎ２Ｏ４单相多晶粉末进行了ＸＲＤ，ＩＲＭ，ＸＰＳ，等离子体发射光谱及氧化还原等测试。     

Two new flavonoid diglycosides from Cephalotaxus sinensis

Two new acetylated flavonoid diglycosides, scutellarein-5-O-[a-L-rhamnopyranosyl-(1→ 4)-b-D-6-O-acetylglucopyranoside] (1), apigenin-5-O-[a-L-rhamnopyranosyl-(1→2)-b-D-3,6-di-O-acetylglucopyranoside] (2), were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS, 1H–1H COSY, HSQC and HMBC experiments.     

Die Phosphide LiR2P7, Li2RP7 (R = Me3Si,Et, iPr,iBu) und alkyliert-silylierte Heptaphosphane(3)

The Phosphides LiR₂P₇, Li₂RP₇ (R = Me₃Si, Et, iPr, iBu) as well as Mixed Alkylated and Silylated Heptaphosphanes(3) Formation and properties of LiR₂P₇ and Li₂PR₇ (R = Me₃Si, Et, iPr, iBu) and their reactions with Me₃SiCl or alkylhalides yielding mixed alkylated and silylated heptaphosphanes(3) are reported. Reactions of (Me₃Si)₃P₇ and Li₃P₇. 3 DME produce mixtures of Li(Me₃Si)₃P₇, Li₂(Me₃Si)P₇ and Li₃P₇ from which pure Li(Me₃Si)₂P₇ (s, as) can be isolated by means of an extraction with toluene. Similarly, the isomers of LiR₂P₇ (R = Et, iPr, iBu) can be extracted from the mixtures obtained by reacting Li₃P₇ with alkylbromides. The (s) isomers of LiR₂P₇ in solution at about 20°C from the (as) isomers whereas the latter up to 70°C do not show any inversion. The (as) lithiumdialkylphosphides can be obtained as ether free products (red brown powder, isoluble in toluene, soluble in THF) by repeated addition of toluene and removal of the solvents; the (s) isomers decompose during the procure. In reactions of LiEt₂P₇. THF (s, as) in toluene at ?30°C with EtBr only the (s) isomer is substituted and gives Et₃P₇ (s), however on warming to 20°C by inversion of P^e a ratio of (s) : (as( = 1 : 3 is obtained. With Li(iBu)₂P₇, (s) reaction begins above ?20°C the giving both the (s) and the (as) isomer. (iBu)₃P₇ (s) is the prefered isomer at higher temperatures. Li(Me₃Si)₂P₇ (s, as) with Me₃SiCl exclusively yields (Me₃Si)₃P₇ (s). Li₂RP₇ (R = alkyl, Me₃SI) is not available. From mixtures with LiR₂P₇ and Li₃P₇, it can be isolated only after repeated cumbersome extraction of LiR₂P₇ as was shown with Li₂(iPr)P₇ as an example. Ether free LiEt₂P₇(s, as) with Me₃SiCl exclusively gives Et₂(Me₃Si)P₇ (s, as) whereas LiEt₂P₇ ? THF due to its THF content does not. Similarly, ether free Li(iBu)₂P₇ yields (iBu)₂(Me₃Si)P₇ (s, as). The compounds R(Me₃Si)₂P₇ (R = alkyl) cannot be selectively prepared neither starting from Li₂RP₇ with Me₃SiCI) nor from Li(Me₃Si)₂P₇ with RX. Such, the reaction of Li(Me₃Si)₂P₇ ? THF with EtBr in toluene at ?78°C yield a mixture of Et(Me₃Si)₂P₇ (42%), Et₂(Me₃Si)P₇ (27010), (Me₃Si)₃P₇ (29%) and Et₃P₇ (2%). (Me₃Si)₃P₇ with MeI in a molar ratio of 1 : 1 at 70°C quantitatively produces Me(Me₃Si)₂P₇ whereas already using a molar ratio of 1 : 2 also Me₃P₇ is obtained. With EtBr mixtures of Et(Me₃Si)₂P₇ and Et₃P₇ are formed. iBuBr gives iBu₃P₇, but tBuBr does not yield any tBu₃P₇.     

Investigation of particle isolation in Li-ion battery electrodes using Li NMR spectroscopy

⁷Li MAS NMR spectroscopy was used to study the failure mechanisms of LiNi_0.8Co_0.15Al_0.05O₂ electrodes in Li-ion cells. Three sets of electrodes with different degrees of power fade (0%, 9% and 23%) were studied. The three electrodes were charged to various states of charge (0%, 40%, 60%, 80% and 100%) in pouch cells which were subsequently disassembled for NMR analysis. The lithium NMR shifts of the positive electrodes in the different states of charge were investigated. The results indicate that NMR spectroscopy can be used to probe particle isolation in these electrodes. Particle isolation is responsible for the capacity and power fades since some of the active material particles are disconnected from the matrix. This study also clearly showed the loss of electrochemically active lithium as the power fade increased.     

The System LiSO3CF3/RbSO3CF3: Phase Diagram,Solid State NMR Investigations,and Ionic Conductivity

In the system LiSO₃CF₃/RbSO₃CF₃ four different quasi‐ternary phases occur: Li_0.7Rb_0.3SO₃CF₃, Li_0.55Rb_0.45SO₃CF₃, LiRb₂(SO₃CF₃)₃, and Li_0.2Rb_0.8SO₃CF₃. These have been identified, and characterized by means of X‐ray powder diffractometry and DSC. LiSO₃CF₃ is trimorphic, LiRb₂(SO₃CF₃)₃ is dimorphic and RbSO₃CF₃ exists in four different modifications. The cation dynamics has been studied using ⁷Li‐NMR line shape analysis and ⁷Li‐spin lattice relaxation (T₁) measurements. The pure and mixed trifluoromethylsulfonates in the system LiSO₃CF₃/RbSO₃CF₃ are solid electrolytes. Their ionic conductivities below 475 K increase with the rubidium content. Above this temperature, the conductivity of β‐LiRb₂(SO₃CF₃)₃ exceeds the one of δ‐RbSO₃CF₃.     

Angle and bond-length dependent C6 coefficients for H2 interacting with H,Li, Be and rare gas atoms

Summary Accurate new C₆ dispersion energy coefficients, and their dependence on the diatom orientation and bond length, are calculated for molecular hydrogen interacting with an atom of H, Li, Be, He, Ne, Ar, Kr or Xe. They are generated from accurateab initio pseudo dipole oscillator strength distributions (DOSD) for H₂, H, He and Be, and reliable semiempirical ones for Li, Ne, Ar, Kr and Xe. Compact power series expansions for the diatom bond-length dependence of these coefficients, suitable for incorporation into representations of full potential energy surfaces for these systems, are determined and assessed.     

Li and Li MAS NMR Studies on Fast Ionic Conducting Spinel-Type Li2MgCl4, Li2-xCuxMgCl4, Li2-xNaxMgCl4, and Li2ZnCl4

⁶Li and ⁷Li MAS NMR spectra including 1D-EXSY (exchange spectroscopy) and inversion recovery experiments of fast ionic conducting Li₂MgCl₄, Li_2-xCu_xMgCl₄, Li_2-xNa_xMgCl₄, and Li₂ZnCl₄ have been recorded and discussed with respect to the dynamics and local structure of the lithium ions. The chemical shifts, intensities, and half-widths of the Li MAS NMR signals of the inverse spinel-type solid solutions Li_2-xM^I_xMgCl₄ (M^I=Cu, Na) with the copper ions solely at tetrahedral sites and sodium ions at octahedral sites and the normal spinel-type zinc compound, respectively, confirm the assignment of the low-field signal to Li^tet of inverse spinel-type Li₂MgCl₄ and the high-field signal to Lioct as proposed by Nagel et al. (2000). In contrast to spinel-type Li_2-2xMg_1+xCl₄ solid solutions with clustering of the vacancies and Mg²⁺ ions, the Cu⁺ and Na⁺ ions are randomly distributed on the tetrahedral and octahedral sites, respectively. The activation energies due to the various dynamic processes of the lithium ions in inverse spinel-type chlorides obtained by the NMR experiments are E_a=6.6-6.9 and ΔG^*>79 KJ mol⁻¹ (in addition to 23, 29, and 75 kJmol-1 obtained by other techniques), respectively. The largest activation energy of >79 KJ mol⁻¹ corresponds to hopping exchange processes of Li ions between the tetrahedral 8a sites and the octahedral 16d sites. The smallest value of 6.6-6.9 KJ mol⁻¹, which was derived from the temperature dependence of both the spin-lattice relaxation times T₁ and the correlation times τ_C of Li^tet, reveals a dynamic process for the Li^tet ions inside the tetrahedral voids of the structure, probably between fourfold 32e split sites around the tetrahedral 8a site.     

Das erste „Litho-Manganat(V)”︁ mit Schichtstruktur: Cs2{Li[MnO4]}

The First “Litho-Manganate(V)” with Layer-Structure: Cs₂{Li[MnO₄]} By heating intimate mixtures of the oxides [CsO_1,2, Li₂MnO₃; Cs: Mn = 2,3 : 1; Ag-Zylinder, 580°C, 62 d] blue-green single crystals of Cs₂{Li[VO₄]} were obtained for the first time. The new “Litho-Manganate(V)” crystallices orthorhombic (SG: Cmc2₁) with a = 596.08(7), b = 1202.6(1), c = 816.8(1) pm (Guinier-Simon data), Z = 4. It is isotypic with Cs₂{Li[VO₄]} [1]. The structure was determined by four-circle-diffractometer data [Mo? Kα , for 496I_o(hkl) R = 3.1%, R, = 2.4%], parameters see text. The Madelung Part of Lattice Energie, MAPLE and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, MEFIR, are calculated and disscussed.