Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response in Quaternary Diamond‐Like Selenide Networks

Two new selenides with diamond‐like structures, Li₇Cd_4.5Ge₄Se₁₆ and Li_6.4Cd_4.8Sn₄Se₁₆, were synthesized by using a conventional high‐temperature solid‐state reaction method. They crystallize in the space group Pna2₁ (no. 33) of the orthorhombic system. Their three‐dimensional frameworks consist of corner‐sharing LiSe₄, CdSe₄, and MSe₄ (M=Ge, Sn) tetrahedra. These two compounds exhibit strong powder second‐harmonic generation responses that are about 1.2 and 2.5 times that of the benchmark AgGaS₂ at a laser wavelength of λ=2.09 μm, and also demonstrate type I phase‐matchable behavior. The optical bandgaps were determined to be 2.18 and 1.95 eV for Li₇Cd_4.5Ge₄Se₁₆ and Li_6.4Cd_4.8Sn₄Se₁₆, respectively. Furthermore, these two materials exhibit congruent melting behavior at rather low temperatures of 985 and 1060 K, respectively, which makes bulk single crystal growth by using the Bridgman–Stockbarger method possible. Our study indicates that these two materials show advantages over the traditional IR NLO material CdSe and are promising for practical applications.     

Synthesis,Structural Characterization and Physical Properties of a New Member of Ternary Lithium Layered Compounds – Li2RhO3

Li₂RhO₃ was synthesized by solid state reaction and its crystal structure was refined from X‐ray powder data by the Rietveld‐method. The compound was obtained as a black powder and crystallizes in the monoclinic space group C2/m, with unit cell parameters a = 5.1198(1), b = 8.8497(1), c = 5.1030(1) Å, β = 109.61(2) °, V = 217.80(1), and Z = 4. The structure determination shows that the oxygen atoms in Li₂RhO₃ form an approximate cubic close packing, where all octahedral voids are occupied by Rh⁴⁺ and Li⁺ cations. The structure is closely related to the α‐NaFeO₂ and Li₂MnO₃ layered structure types (layered variants of the NaCl‐type), but in Li₂RhO₃ the lithium and rhodium atoms are partially disordered. Li₂RhO₃ behaves as a semiconductor with rather small activation energy of 7.68 kJ · mol^–1 and is thermally stable up to 1273 K in argon atmosphere. According to measurements of the magnetic susceptibility in the temperature range from 2 to 330 K, Li₂RhO₃ is paramagnetic, obeys the Curie–Weiss law at temperatures above 150 K, and has an effective magnetic moment of 1.97 μ_B at 300 K.     

Preparation of Li_(4.4)Al_(0.4)Si_(0.6)O_4-xLi_3BO_3 Solid Electrolytes by Sol-Gel Method and Their Ionic Conductivity

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Strong Photoelectric Properties of Mn-Based Seleniumstannates with Alkali Metals as Structure-Directing Agents

In recent years, chalcogenides have received a lot of attention because of their potential applications as photoelectric material. This work describes the synthesis of the quaternary seleniumstannates Cs₂MnSnSe₄ ( 1 ) and Rb₂MnSnSe₄ ( 2 ) using solvothermal methods. The structure of compound 1 consists of charge-balanced Cs⁺ cation and one-dimensional (1D) anion [MnSnSe₄]_n²⁻ chain. Compound 2 possesses a unique two-dimensional (2D) anion [MnSnSe₄]_n²⁻ layer. It is noteworthy that the compounds exhibit a strong photocurrent response (ca. 45 μA/cm² ( 1 ), ca. 80 μA/cm² ( 2 )). Moreover, methylene blue (MB) was investigated for its photocatalytic degradation properties. In order to better understand the relationship between optical properties and electronic structure, a theoretical study was conducted.     

Further Example of Diphosphates: Synthesis and Characterization of K2Li2P2O7

By the application of cation substitution, a new mixed‐alkali metal diphosphate, K₂Li₂P₂O₇, was successfully synthesized through high temperature solution method for the first time. The single‐crystal X‐ray structural analysis shows that it crystallizes in the monoclinic space group C2/c (no. 15), with lattice constants a = 9.814(3) Å, b = 5.5163(15) Å, c = 13.538(4) Å, Z = 4, and β = 110.47(2)°. Its open cage‐like _∞³[Li₂(P₂O₇)]^2– framework is built up from alternating arrangement of Li₂O₆ and P₂O₇ dimers that form eight and twelve‐membered‐ring channels along the [010] direction, and the K atoms are entrapped in the larger twelve‐membered‐ring channels. Detailed structure comparisons in the N₄P₂O₇ (N = mixed alkali metals) family are discussed. In addition, the structural validity was verified through the IR spectrum. Thermal analyses and UV/Vis/NIR diffuse reflectance spectrum are also performed on the reported compound.     

Multiscale Computational Study on the Adsorption and Separation of CO2/CH4 and CO2/H2 on Li+‐Doped Mixed‐Ligand Metal–Organic Framework Zn2(NDC)2(diPyNI)

The quantum mechanics (QM) method and grand canonical Monte Carlo (GCMC) simulations are used to study the effect of lithium cation doping on the adsorption and separation of CO₂, CH₄, and H₂ on a twofold interwoven metal–organic framework (MOF), Zn₂(NDC)₂(diPyNI) (NDC=2,6‐naphthalenedicarboxylate; diPyNI=N,N′‐di‐(4‐pyridyl)‐1,4,5,8‐naphthalenetetracarboxydiimide). Second‐order Moller–Plesset (MP2) calculations on the (Li⁺–diPyNI) cluster model show that the energetically most favorable lithium binding site is above the pyridine ring side at a distance of 1.817 Å from the oxygen atom. The results reveal that the adsorption capacity of Zn₂(NDC)₂(diPyNI) for carbon dioxide is higher than those of hydrogen and methane at room temperature. Furthermore, GCMC simulations on the structures obtained from QM calculations predict that the Li⁺‐doped MOF has higher adsorption capacities than the nondoped MOF, especially at low pressures. In addition, the probability density distribution plots reveal that CO₂, CH₄, and H₂ molecules accumulate close to the Li cation site. The selectivity results indicate that CO₂/H₂ selectivity values in Zn₂(NDC)₂(diPyNI) are higher than those of CO₂/CH₄. The selectivity of CO₂ over CH₄ on Li⁺‐doped Zn₂(NDC)₂(diPyNI) is improved relative to the nondoped MOF.     

Li9Al4Sn5 as a new ordered superstructure of the Li13Sn5 type

Alloys from the ternary Li–Al–Sn system have been investigated with respect to possible applications as negative electrode materials in Li‐ion batteries. This led to the discovery of a new ternary compound, a superstructure of the Li₁₃Sn₅ binary compound. The ternary stannide, Li₉Al₄Sn₅ (nonalithium tetraaluminium pentastannide; trigonal, P m 1, hP18 ), crystallizes as a new structure type, which is an ordered variant of the binary Li₁₃Sn₅ structure type. One Li and one Sn site have m . symmetry, and all other atoms occupy sites of 3m . symmetry. The polyhedra around all types of atoms are rhombic dodecahedra. The electronic structure was calculated by the tight‐binding linear muffin‐tin orbital atomic spheres approximation method. The electron concentration is higher around the Sn and Al atoms, which form an [Al₄Sn₅]^m− polyanion.     

Li2 Trapped inside Tubiform [n] Boron Nitride Clusters (n=4–8): Structures and First Hyperpolarizability

The geometries and electronic properties of tubiform [n] boron nitride clusters entrapping Li₂ (Li₂@BN‐cluster(n,0); n=4–8), obtained by doping BN‐cluster(n,0) with Li₂ molecules, are investigated by means of DFT. The effects of tube diameter n on the dipole moment μ₀, static polarizability α₀, and first hyperpolarizability β₀ are elucidated. Both the dipole moment and polarizability increase with increasing tube diameter, whereas variation of the static first hyperpolarizability with tube diameter is not monotonic; β₀ follows the order 1612 (n=4)<3112 (n=5)<5534 (n=7)<8244 (n=6)<12 282 a.u. (n=8). In addition, the natural bond orbital (NBO) charges show that charge transfer takes place from the Li₂ molecule to the BN cluster, except for BN‐cluster(8,0) with larger tube diameter. Since the large‐diameter tubular BN‐cluster(8,0) can trap the excess electrons of the Li₂ molecule, Li₂@BN‐cluster(8,0) can be considered to be a novel electride compound.     

Lithium barium silicate,Li2BaSiO4, from synchrotron powder data

The structure of lithium barium silicate, Li₂BaSiO₄, has been determined from synchrotron radiation powder data. The title compound was synthesized by high‐temperature solid‐state reaction and crystallizes in the hexagonal space group P6₃cm. It contains two Li atoms, one Ba atom (both site symmetry ..m on special position 6c), two Si atoms [on special positions 4b (site symmetry 3..) and 2a (site symmetry 3.m)] and four O atoms (one on general position 12d, and three on special positions 6c, 4b and 2a). The basic units of the structure are (Li₆SiO₁₃)⁵⁻ units, each comprising seven tetrahedra sharing edges and vertices. These basic units are connected by sharing corners parallel to [001] and through sharing (SiO₄)⁴⁻ tetrahedra in (001). The relationship between the structures and luminescence properties of Li₂SrSiO₄, Li₂CaSiO₄ and the title compound is discussed.     

Lithium zincopyrophosphate,Li2Zn3(P2O7)2

The title compound, dilithium(I) trizinc(II) bis[diphosphate(4−)], is the first quaternary lithium zincopyrophosphate in the Li–Zn–P–O system. It features zigzag chains running along c, which are built up from edge‐sharing [ZnO₅] trigonal bipyramids. One of the two independent Zn sites is fully occupied, whereas the other is statistically disordered by Zn²⁺ and Li⁺ cations, although the two Zn sites have similar coordination environments. Li⁺ cations occupy a four‐coordinated independent site with an occupancy factor of 0.5, as well as being disordered on the partially occupied five‐coordinated Zn site with a Zn²⁺/Li⁺ ratio of 1:1.     

Rb4Li2TiOGe4O12: A Titanyl Nonlinear Optical Material with the Widest Transparency Range

Practical mid‐infrared (MIR) coherent light beams generated by frequency conversion in nonlinear optical (NLO) crystals are indispensable in time‐resolved infrared vibrational spectroscopy, remote light detection and ranging, and free‐space communications. Herein, a new titanyl germanate Rb₄Li₂TiOGe₄O₁₂ (RLTG) MIR NLO crystal was obtained by heavier element substitution. It features a complicated structure network composed of compressed TiO₅ square pyramids and distorted GeO₄ tetrahedra, separated by Rb⁺ and Li⁺ cations. More importantly, RLTG exhibits concurrently short ultraviolet (0.28 μm) and long IR (5.58 μm) transmittance cutoffs, fully covering the atmospheric transparent window of 3–5 μm. Related to the short UV cutoff, it shows a higher laser‐induced damage threshold in comparison to commercial MIR NLO crystals, about twice that of KTiOPO₄ (KTP) and 50 times that of AgGaS₂ (AGS).     

Synthesis and Electronic Structures and Linear Optics of Solid State Compound SrB2O4

The cluster (SrB₂O₄)₂ existing in crystalline states is employed to model the electronic structure and linear optical properties of solid state compound SrB₂O₄. This compound is synthesized by high temperature solution reaction, and it crystallizes in the orthorhombic space group Pbcn with cell dimensions a = 1.1995(3), b = 0.4337(1), c = 0.6575(1) nm, V = 0.34202 nm³, and Z = 4, μ = 15.14 cm^?1, D_caled = 3.36 g/cm³. The dynamic refractive indices are obtained in terms of INDO/SCI following combination with the Sum‐Over‐States method. A width of the calculated gap is 4.424 eV between the valence band and conduction band, and the calculated average refractive index is 1.980 at a wavelength of 1.065 μm. The charge transfers from O^2‐ anion orbitals to Sr²⁺cation orbitals make the significant contributions to linear polarizability in terms of analyses of atomic state density contributing to the valence and conduction bands.     

Synthese und Kristallstrukturanalyse von NaSrMg2F7, einer vollständig fluorierten Verbindung des Pyrochlortyps

Synthesis and Crystal Structure Analysis of NaSrMg₂F₇, a Fully Fluorinated Compound of the Pyrochlore Family During our research on alkali‐fluorides, the compound NaSrMg₂F₇ has been prepared by a precipitation reaction of Sr²⁺, Mg²⁺ and Na⁺ with F^– for the first time. The powder crystallizes as a single phase in the form of spherical agglomerates ∼0.25 μm in diameter. The compound crystallizes in the space group Fd 3 m (Nr. 227) with lattice parameter a = 10.4379(4) Å. Structural analysis by the Rietveld method was done from X‐ray diffraction data. In agreement with the structure analysis, spectroscopical investigations confirm the presence of two coupled fluoride ions. The crystal structure corresponds to the pyrochlore structure type A₂B₂X₇ with 50% occupation of Sr²⁺ or Na⁺ at the A site.     

The New Homoleptic Tetracyanamidoaluminate LiBa2[Al(CN2)4]

The new tetracyanamidoaluminate LiBa₂[Al(CN₂)₄] was prepared by solid state metathesis reaction in a fused copper ampoule from a mixture of BaF₂, AlF₃, and Li₂(CN₂) at 550 °C. The crystal structure was solved and refined based on single‐crystal X‐ray diffraction data [P2₁2₁2₁, Z = 4, a = 6.843(1) Å, b = 11.828(2) Å, c = 11.857(2) Å]. The compound belongs to the known formula type LiM₂[Al(CN₂)₄] (M = Sr, Eu) containing the homoleptic [Al(CN₂)₄]^5– ion. However, LiBa₂[Al(CN₂)₄] forms a distinct crystal structure, containing a two‐dimensional [(NCN)_2/2Li(NCN)₂Al(NCN)_2/2] network with four‐coordinate Li⁺ and Al³⁺ ions. Two crystallographically independent Ba²⁺ ions are situated in eightfold environment of terminal nitrogen atoms of cyanamide ions.     

Simultaneous determination of homocysteine,methionine and cysteine in maternal plasma after delivery by HPLC‐fluorescence detection with DBD‐F as a label

An HPLC‐fluorescence (FL) method for determination of sulfur‐containing amino acids such as homocysteine (Hcy), methionine (Met) and cysteine (Cys) in human plasma was developed. The sulfur‐containing amino acids were labeled with 4‐(N,N‐dimethylaminosulfonyl)‐7‐fluoro‐2,1,3‐benzoxadiazole (DBD‐F). Calibration curves in the range of 1–100 µm (Hcy and Met) and 5–500 µm (Cys) indicated good linearities (r ≥ 0.998). The limits of detection at a signal‐to‐noise ratio of 3 were 0.13 (Hcy), 0.02 (Met) and 0.11 µm (Cys), respectively. Acceptable results for accuracy and precision of intra‐ and inter‐day measurements were obtained. The results of Hcy and Cys obtained by the proposed method indicated good correlations with the conventional method (r > 0.911, n = 20). Furthermore, the method was applied to determination of the sulfur‐containing amino acids in maternal plasma (n = 200) after delivery. The concentrations of Hcy, Met and Cys as a median (inter quartile range, Q₁ and Q₃) were 5.37 (3.32–7.79) μm , 25.20 (20.10–31.06) μm and 147.25 (102.81–189.31) μm , respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

Structural Characterisation of the Li Argyrodites Li7PS6 and Li7PSe6 and their Solid Solutions: Quantification of Site Preferences by MAS‐NMR Spectroscopy

Li₇PS₆ and Li₇PSe₆ belong to a class of new solids that exhibit high Li⁺ mobility. A series of quaternary solid solutions Li₇PS_6?xSe_x (0≤x≤6) were characterised by X‐ray crystallography and magic‐angle spinning nuclear magnetic resonance (MAS‐NMR) spectroscopy. The high‐temperature (HT) modifications were studied by single‐crystal investigations (both F$\bar 4$ 3m, Z=4, Li₇PS₆: a=9.993(1) Å, Li₇PSe₆: a=10.475(1) Å) and show the typical argyrodite structures with strongly disordered Li atoms. HT‐Li₇PS₆ and HT‐Li₇PSe₆ transform reversibly into low‐temperature (LT) modifications with ordered Li atoms. X‐ray powder diagrams show the structures of LT‐Li₇PS₆ and LT‐Li₇PSe₆ to be closely related to orthorhombic LT‐α‐Cu₇PSe₆. Single crystals of the LT modifications are not available due to multiple twinning and formation of antiphase domains. The gradual substitution of S by Se shows characteristic site preferences closely connected to the functionalities of the different types of chalcogen atoms (S, Se). High‐resolution solid‐state ³¹P NMR is a powerful method to differentiate quantitatively between the distinct (PS_4?nSe_n)^3? local environments. Their population distribution differs significantly from a statistical scenario, revealing a pronounced preference for P? S over P? Se bonding. This preference, shown for the series of LT samples, can be quantified in terms of an equilibrium constant specifying the melt reaction Se_P+S^2??S_P+Se^2?, prior to crystallisation. The ⁷⁷Se MAS‐NMR spectra reveal that the chalcogen distributions in the second and third coordination sphere of the P atoms are essentially statistical. The number of crystallographically independent Li atoms in both LT modifications was analysed by means of ⁶Li{⁷Li} cross polarisation magic angle spinning (CPMAS).     

Platinum and Palladium Complexes Bearing New (1R,2R)‐(–)‐1,2‐Diaminocyclohexane (DACH)‐Based Nitrogen Ligands: Evaluation of the Complexes Against L1210 Leukemia

The reaction of (1R,2R)‐(–)‐1,2‐diaminocyclohexane ( 1 ) [DACH] with the aldehyde (1R)‐(–)‐myrtenal ( 2 ) in MeOH afforded the bidentate diimine ligand, (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenylidene}‐1,2‐diaminocyclohexane ( 3 ) in a high yield. Reduction of 3 using LiAlH₄ led to the formation of the desired ligand ( 4 ) (1R,2R)‐(–)‐N¹,N²‐bis{(1R)‐(–)myrtenyl}‐1,2‐diaminocyclohexane. Treatment of compound 4 with K₂PtCl₄ or K₂PdCl₄ yielded the corresponding platinum(II) and palladium(II) complexes, Pt‐5 and Pd‐6 , respectively. The reaction of compound 3 with K₂PtCl₄ gave the diimine complex Pt‐7 . The cytotoxic activity of the complexes Pt‐5 , Pd‐6 and Pt‐7 was tested and compared to the approved drugs, cisplatin ( Cis ‐Pt ) and oxaliplatin ( Ox‐Pt ). The complexes ( Pt‐5 , Pd‐6 and Pt‐7 ) inhibit L1210 cell line proliferation with an IC₅₀ of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.     

Synthesis,Structure, and Properties of a New Calcium(II) Complex of 1,10‐Phenanthroline, 1,2,4,5‐Benzenetetracarboxylic Acid,and a New Precursor to Produce Pure Phase Micro‐crystalline Calcite Particles

The self‐assembly of 1, 0‐phenanthroline (phen) and 1,2,4,5‐benzenetetracarboxylic acid(H₄btc) with Ca(NO₃)₂ gives rise to a two‐dimensional network structure coordination polymer, [Ca(phen)(btc)_0.5(H₂O)] ( 1 ), which was characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. This compound is monoclinic, space group C2/c, with Z = 8 in a unit cell with dimensions a = 21.744(3) Å, b = 10.0151(12) Å, c = 14.7122(17) Å, β = 110.2850(10)°. The structure contains one crystallographic unique Ca^II atom, one phen coordinated molecule and a half of btc^4– anion. The phen molecule acts as a didentate ligand chelating with a Ca^II atom, whereas the btc^4– anion acts as a μ₆‐bridge linking six different Ca^II atoms to form a two‐dimensional network with (4, 4) topological structure. The three dimensional stacking structures are formed by C–H ··· O hydrogen bonding and π–π interaction. The thermal stability and fluorescent properties of 1 were investigated. Calcite particles are produced by calcination of compound 1 at 580 °C. The obtained calcite was characterized by XRD and SEM analyses.     

Synthesis,Crystal Structure and Lithium Motion of Li8SeN2 and Li8TeN2

The compounds Li₈EN₂ with E = Se, Te were obtained in form of orange microcrystalline powders from reactions of Li₂E with Li₃N. Single crystal growth of Li₈SeN₂ additionally succeeded from excess lithium. The crystal structures were refined using single‐crystal X‐ray diffraction as well as X‐ray and neutron powder diffraction data (I4₁md, No. 109, Z = 4, Se: a = 7.048(1) Å, c = 9.995(1) Å, Te: a = 7.217(1) Å, c = 10.284(1) Å). Both compounds crystallize as isotypes with an anionic substructure motif known from cubic Laves phases and lithium distributed over four crystallographic sites in the void space of the anionic framework. Neutron powder diffraction pattern recorded in the temperature range from 3 K to 300 K and X‐ray diffraction patterns using synchrotron radiation taken from 300 K to 1000 K reveal the structural stability of both compounds in the studied temperature range until decomposition. Motional processes of lithium atoms in the title compounds were revealed by temperature dependent NMR spectroscopic investigations. Those are indicated by significant changes of the ⁷Li NMR signals. Lithium motion starts for Li₈SeN₂ above 150 K whereas it is already present in Li₈TeN₂ at this temperature. Quantum mechanical calculations of NMR spectroscopic parameters reveal clearly different environments of the lithium atoms determined by the electric field gradient, which are sensitive to the anisotropy of charge distribution at the nuclear sites. With respect to an increasing coordination number according to 2 + 1, 3, 3 + 1, and 4 for Li(3), Li(4), Li(2), and Li(1), respectively, the values of the electric field gradients decrease. Different environments of lithium predicted by quantum mechanical calculations are confirmed by ⁷Li NMR frequency sweep experiments at low temperatures.     

Synthesis and Characterization of the Trisulfate Pb[S3O10] and Theoretical Analysis of H2S3O10

The reaction of (NH₄)₂PbCl₆ and fuming sulfuric acid (65 % SO₃) in a sealed glass tube at 250 °C led to colorless single crystals of Pb[S₃O₁₀] (orthorhombic, Pbcn, Z = 4, a = 10.9908(4), b = 8.5549(3), c = 8.0130(3) Å, V = 753.42(5) ų). The compound shows a three‐dimensional linkage of the tenfold oxygen coordinated Pb²⁺ ions and exhibits the unusual trisulfate anion, [S₃O₁₀]^2–, that consists of three vertex connected [SO₄] tetrahedra. The distances S–O within the S–O–S bridges of the anion are remarkable asymmetric with distances of 155 and 169 pm, respectively. This structural feature is well reproduced by calculations on a PBE0/cc‐pVTZ and a MP2/cc‐pVTZ level of theory. Similar calculations allow also for an inspection of the yet unknown corresponding acid, H₂S₃O₁₀. Also for this acid non‐symmetric S–O–S bridges are predicted. The thermal behavior of Pb[S₃O₁₀] is characterized by the loss of two equivalents of SO₃ at low temperature and the decomposition of intermediate Pb[SO₄] at higher temperature.