Ring and Cluster Structures of {Li[C(NtBu)2(HNtBu)]}2·(THF) and {Li2[C(NtBu)3]}2, Containing the Novel Anions [C(NtBu)2(HNtBu)]−- and [C(NtBu)3]2−

The reaction of tert.-butyl carbodiimide with one equivalent of LiNH^tBu in tetrahydrofuran at-78 °C produces {Li[C(N^tBu)₂(HN^tBu)]}₂-(THF) (1), which is an eight-membered Li₂C₂N₄ ring; the deprotonation of (1) with two equivalents of n-BuLi in tetrahydrofuran at -78 °C and recrystallisation of the product from n-pentane yielded the unsolvated dimer {Li₂[C(N^tBu)₃]}₂ (2), which adopts the structure of a distorted hexagonal prism.     

Synthesis and properties of bis(indenyl) derivatives of ytterbium and lutetium. Molecular structures of the complexes (C9H7)2Ln(μ-Cl)2Li(Et2O)2 (Ln = Yb, Lu) and [(C9H7)2YbCl2][Li(DME)3]

The heterobimetallic bis(indenyl) chloride complexes of ytterbium and lutetium (C₉H₇)₂Ln(μ-Cl)₂Li(Et₂O)₂ (Ln = Yb or Lu) were synthesized by the metathesis reaction of LnCl₃ with two equivalents of indenyllithium in diethyl ether. In the case of ytterbium, the analogous reaction in 1,2-dimethoxyethane afforded the ionic complex [(C₉H₇)₂YbCl₂]⁻[Li(DME)₃]⁺. The reaction of YbCl₃ with indenylpotassium in a molar ratio of 1: 2 in THF is accompanied by reduction of the metal atom to give the bis(indenyl) derivative of Yb^II, (C₉H₇)₂Yb(THF)₂. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 39–44, January, 2008.     

Mechanism of structural phase transitions in the Li4GeO4-ZnGeO4 system: Computer modeling and identification of invariant nanocluster structures in Li4GeO4, LISICON Li6Zn(GeO4)2, and Li4Zn2(GeO4)2 (γ phase)

The cluster modeling of structural phase transitions Li₄GeO₄ ?? LISICON Li₆Zn(GeO₄)₂ ?? ??-Li₄Zn₂(GeO₄)₂ was carried out using computer-assisted methods (the TOPOS program package). The precursor nanoclusters of crystal structures were recognized in an automated data processing mode using an algorithm developed for selecting combinations from nonintersecting suprapolyhedral clusters. 3D macro-structure modeling employed the principle of maximal space filling and, accordingly, took into account the requirement for the maximal complementary connectivity of precursor nanoclusters in crystal structure self-assembly followed by consecutive primary chain-microlayer-microframework assembly. A crystallochemically correct structure model was advanced for superionic LISICON Li₆Zn(GeO₄)₂ as a 2D analogue of Li₄GeO₄ containing only two types of voids in a layer, which are most likely to be sites for Li atoms to reside. A migration map was constructed to characterize the 2D set of conductivity channels in superionic LISICON.     

Electronic Structure and Chemical Bonding in Monoclinic and Cubic Li2-xHxTiO3 (0≤ x ≤ 2)

The linear muffintin orbitals method in a tight binding approximation and extended Huckel theory are used to study the electronic structure and chemical bonding of lithium titanate (Li₂TiO₃) and its protonated analogs (Li_1.75H_0.25TiO₃ and H₂TiO₃). The effect of protons on electron spectrum characteristics and bond strength are investigated for the monoclinic and cubic phases of lithium titanate. Phase stability is evaluated by cohesion energy calculations.     

Thermal studies on Li(CH3CN)4PF6 and Li(C4H10O2)2PF6 complexes by the TG–DTA–MS and DSC

Journal of Thermal Analysis and Calorimetry - Li(CH3CN)4PF6 and Li(C4H10O2)2PF6 complexes are important intermediates created in the synthetic process of high-purity LiPF6 electrolyte via...     

Thermal decomposition kinetics and reversible hydration study of the Li2Zn(HPO4)2·H2O

The dilithium zinc hydrogen phosphate monohydrate (Li₂Zn(HPO₄)₂·H₂O) was synthesized at the ambient temperature by using zinc acetyl acetonate monohydrate, phosphoric acid and lithium hydroxide monohydrate. The thermal stability of the Li₂Zn(HPO₄)₂·H₂O was studied by non-isothermal kinetic method (Ozawa and Kissinger) from the differential scanning calorimetric (DSC) data. The studied hydrate undergoes two endothermic thermal transformations, which the first transformation is due to the release of water molecule of crystallization and the second one is due to the release of water of constituent from HPO₄^2? anions and transforms to P₂O₇^4?. The activation energies (E_a) calculated for the dehydration step and decomposition step of the Li₂Zn(HPO₄)₂·H₂O from different methods were found to be consistent. The dehydration and rehydration processes of the synthesized compound were investigated and found that the water of crystallization can be removed and rehydrated without the disrupting the structure of the material, provided it is not heated beyond 200 °C. The dehydration and rehydration processes of the synthesized Li₂Zn(HPO₄)₂·H₂O exhibits similar property to the zeolite.     

Synthesis and Characterization of Li(11)Nd(18)Fe(4)O(39-δ)

Li(11)Nd(18)Fe(4)O(39-δ) has been synthesized by the solid-state reaction of pellets, covered with powder of the same composition to avoid lithium loss, with a final reaction temperature of 950 °C. This phase has been reported previously to have various stoichiometries: Li(5)Nd(4)FeO(10), Li(8)Nd(18)Fe(5)O(39), and Li(1.746)Nd(4.494)FeO(9.493). The crystal structure of Li(11)Nd(18)Fe(4)O(39-δ) is closely related to that reported previously for two of the other three compositions but contains extra Li and differences in Li/Fe site occupancies. Fe is present in a mixture of 3+ and 4+ oxidation states, as confirmed by M?ssbauer spectroscopy. The oxygen content of 39 - δ is variable, depending on the processing conditions. Samples slow-cooled in air from 800 °C are semiconducting, attributed to the presence of Fe(4+) ions, whereas samples quenched from 950 °C in N(2) are insulating.     

[Flu(Me)2CCp]2Yb(μ-Br)2Li(THF)2·THF的合成和晶体结构

为考察取代环戊二烯基或桥联环戊二烯基有机稀土化合物的性质,研究了碳桥联芴基环戊二烯基配体与卤化稀土的反应,其中,[2-(9-芴基)异丙基]环戊二烯基锂[Flu(Me)2CCpLi]与三溴化镱(YbBr3)在四氢呋喃(THF)中反应,分离得到了标题配合物[Flu(Me)2CCp]2Yb(μ-Br)2Li(THF)2·THF.X射线单晶结构测定表明配合物属单斜晶系,空间群为P2(1)/n,晶胞参数为a=1.4676(3) nm,b=1.2618(4) nm,c=2.9736(9) nm,β=98.172(18)°,Z=4,V=5.451(2) nm3,Mr=1098.84,Dc=1.339 mg·m-3,R=0.0695,wR=0.1721.中心Yb原子分别与两个环戊二烯基和两个溴原子成键,形成扭曲的四面体配位构型.Yb-Br1和Yb-Br2键长分别为0.2765(1)和 0.2738(1) nm,两个环戊二烯基平面的夹角为125.7°,中心Yb原子与两个环戊二烯基环中心的平均距离分别为0.232和0.231 nm.     

Guanidinate borohydride derivatives of lanthanides: synthesis and molecular structures of the [(Me3Si)2NC(NCy)2]Gd(BH4)2DME and [{(Me3Si)2NC(NPri)2}2Sm(BH4)2]−[Li(DME)3]+ complexes. Catalytic activity of the [(Me3Si)2NC(NCy)2]2Ln(BH4)2Li(THF)2 complexes (Ln = Nd, Sm, or Yb) in methyl methacrylate polymerization

The reaction of Gd(BH₄)₃(THF)₂ with two equivalents of sodium N,N′-dicyclohexyl-N″-bis(trimethylsilyl)guanidinate in THF followed by the treatment of the reaction product with 1,2-dimethoxyethane produced the monoguanidinate bis(borohydride) complex [(Me₃Si)₂NC(NCy)₂]Gd(BH₄)₂DME (1) (Cy is cyclohexyl). The treatment of the heterobimetallic samarium complex {(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂Li(THF)₂, in which the lanthanide and lithium atoms are linked by two bridging borohydride groups, with 1,2-dimethoxyethane afforded the ionic complex [{(Me₃Si)₂NC(NPrⁱ)₂}₂Sm(BH₄)₂]^?[Li(DME)₃]⁺ (2). The structures of complexes 1 and 2 were established by X-ray diffraction. The [(Me₃Si)₂NC(NCy)₂]₂Ln(BH₄)₂Li(THF)₂ complexes (Ln = Nd (3), Sm (4), or Yb (5)) were found to catalyze methyl methacrylate polymerization.     

Synthesis and Crystal Structure of[Li(dme)3][(t-BuC_5H_4)_2Gd(NPh_2)_2]·1/2dme

1INTRODUCTIONIntherecentyears,organolanthanideamideshaveattractedagreatdealofat-tention.Forexample,theyareabletoreactwithCOtogiveinsertionproduct[(C,Me,)2SinjZt(PhN)OCCO(NPh)jti},withaminoolefinstoyieldcorrespondingheterocyclestZ),withmethylmethacrylate(MMA)toleadtoMMApolymeriza-tiont3'43.Inordertoexplorefurthertheirchemistry,wesynthesizedsomeanionicandneutrallanthanoceneamidestoinvestigatetheirchemicalreactivities(5--7).Inthispaper,wewouldliketodescribethepreparationofanotheranio…     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

Glass-forming region and structure in SiS2Li2SLiX (X = Br,I)

The glass-forming region in the SiS₂Li₂SLiX (X = Br, I) system, as determined by X-ray diffraction, has been extended to higher lithium content by the use of a direct liquid nitrogen quench. The base glass, 0.4SiS₂0.6Li₂S, was synthesized and doping up to 0.28SiS₂0.42Li₂S0.30LiBr and 0.24SiS₂0.36Li₂S0.40LiI was achieved. The properties of these glasses are compared to the glasses formed by previously reported quenching methods.Vibrational assignments have been made from infrared investigation of the glasses using FT-IR. The basic glass network consists of SiS₄ tetrahedra while the addition of Li₂S as a network modifier produced nonbridging sulfur. Doping with lithium halide did not significantly change the glass network, i.e., no changes in IR peak positions were observed. However, the higher lithium ion concentration resulted in higher mobility and ionic conduction.     

A theoretical study of hydrogen- and lithium-bonded complexes of F-H∕Li and Cl-H∕Li with NF3, NH3, and NH2(CH3)

Hydrogen- and lithium-bonded complexes of A-H∕Li (A = F, Cl) with the amine analogues NF(3), NH(3), and NH(2)(CH(3)) were studied at the MP2∕6-311++G(d,p) level of theory. Bond extensions and redshifts were obtained for the H-bonded complexes, while bond extensions and blueshifts were obtained for the Li-bonded species. The variation of these and other properties with the basicity of the amines was investigated and rationalized by comparing the ab initio results with predictions from a model derived from perturbation theory.     

~(11)B and ~7Li NMR Investigations of the Oxysulfide Glasses in Li_2S-B_2O_3 (-LiBr) Systems

Lithiumconductingborateglassesarebettersolidelectfolytesknowntoday.Thereplacementofoxygenbysulfurwhichispolarizedeasilyfurtherincreasestheionicconductivityoftheglass.Itisbelievedthattheplacementofoxygenwithsulfurgivesrisetosomemodificationofthemicrostructuresoftheglassnetworkl.Theincrementofconductivitymaymainlybecausedbythesestructuralchanges.Now,sulfideglassesareoneoftheLi ionicconductorsexhibitingthehighestconductivityandhavebeenexploredforitsapplicationsaselectrolytesinsolidstatebatteries…     

AC conductivity studies and relaxation behaviour in (LiX) y [(Li2O)0.6(P2O5)0.4](1 − y) glasses

The electrical conductivity of (LiX) _y [(Li₂O)_0.6(P₂O₅)_0.4]_(1???y) (X?=?Cl, Br, y?=?0, 0.1, 0.15, 0.2) glasses has been determined over a wide range of temperature and frequency by means of impedance spectroscopy. The real part of the frequency-dependent conductivity exhibits a simple power law feature, and the dimensionless frequency exponent n has been determined. The conductivity spectra show scaling behaviour when the conductivity spectra are scaled by ω/(σ _dc T) and ω/ω _p . The conductivity relaxation time and activation energy have been estimated from the modulus spectra. Increases of ionic conductivity values with addition of LiX content are in line with the decrease of activation energy and relaxation time.     

New Stable Germylenes,Stannylenes, and Related Compounds II. Bis(butylthio)tin(II) and ate-Complexes [(Me3Si)3CE(μ-SBu)2Li(THF)2] (E = Ge,Sn). Synthesis and Structure

By reaction of Me₃SiSBu with anhydrous tin(II) chloride bis(butylthio)tin was obtained that exemplified a coordination polymer [Sn(SBu)₂] _n , whose elementary unit contained according to X-ray diffraction study three independent four-membered rings Sn₂S₂ of unusual geometry. It was demonstrated that polymeric thiolates [E(SBu)₂] _n (E = Ge, Sn) readily reacted with TsiLi (Tsi = C(SiMe₃)₃) in a mixed solvent ether THF affording in a good yield ate-complexes [(Me₃Si)₃CE(-SBu)₂Li(THF)₂]. Both complexes contain a four-membered ring in a butterfly conformation where the lithium atom is symmetrically bonded to both sulfur atoms, and the coordination polyhedra of Ge and Sn atoms may be regarded as distorted tetrahedra AB₃X, where one of coordination places is occupied by unshared electron pair. The structure of the ate-complexes observed in a crystal is conserved also in solution of nonpolar solvents.     

Synthesis, structure and reactivity of binuclear metal-metal bonded molybdenum(V) and tungsten(V) thioselenohalides: Molecular structure of Mo2(μ-S2)2Cl6(SeCl2)2 and W2(μ-S2)2Cl6(SeCl2)2

Thioselenohalide complexes Mo₂(μ-S₂)₂Cl₆(SeCl₂)₂ (I), Mo₂(μ-S₂)₂Br₆(SeBr₂)₂ (II), and W₂(μ-S₂)₂Br₆(SeBr₂)₂ (III) were synthesized by the reactions of corresponding metal halides or carbonyls or molybdenum metal with excesses of S₂ X ₂+Se₂ X ₂ mixtures. The complex W₂(μ-S₂)₂Cl₆(SeCl₂)₂ (IV) was obtained by an exchange reaction between (III) and excess of Se₂Cl₂. Coordination of the neutral SeX ₂ ligands to thiohalidesM ₂(μ-S₂)₂ X ₆ results in higher thermal stability, and suggests the possibility to synthesize SeX ₂ complexes of the unstable parent tungsten thiohalides. An unusual oxidative addition reaction of (I) was detected: {fx27-1} Both (I) and (IV) were characterized by X-ray crystal structure analysis. They are isostructural and form discrete molecules. Bridging S ₂ ^2? ligands are coordinated perpendicularly to the metal-metal bond;d(M?M)=2.8066 Å and 2.793 Å for I and IV, respectively. Nonequivalence of chlorine atoms which are bound to the metal atom, relate to nonequivalence of halogen atoms in the complexesM ₂(μ?S₂)₂ X ₈ ^2? . Chlorine atomstrans to SeCl₂ ligands form short bonds with the metal; the corresponding³⁵Cl NQR frequency is increased. The selenium dichloride ligand is ambidentate. The selenium atom binds as a donor to the metal and as an acceptor to two chlorine atoms which are also bound covalently to the same metal atom.     

Syntheses and characterization of three mercury(II) complexes, [Hg(phen)2(SCN)2], [Hg(2,2′-bipy)2(SCN)2] and [Hg(phen)2(NO3)2], thermal and fluorescence studies

Mercury(II) complexes of 1,10-phenanthroline (phen) and 2,2′-bipyridine (bipy), [Hg(phen)₂(SCN)₂] (1), [Hg(2,2′-bipy)₂(SCN)₂] (2) and [Hg(phen)₂(NO₃)₂] (3) have been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The thermal stability of 1–3 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The structure of 1 has been confirmed by X-ray crystallography. The complex is a monomer and the Hg atom has an unsymmetrical six-coordinate geometry, formed by four nitrogen atoms of the two phen ligands and two sulfur atoms of the two thiocyanate anions. Solid-state luminescent spectra of phen, 2,2′-bipy and 1–3 indicate emission with the maximum intensity at ca 467 nm upon excitation at 295 nm.     

Synthesis and properties of guanidinate derivatives of rare-earth metals. Molecular structures of the { (Me3Si)2NC(NPri)2}2Y(µ-Cl)2Li(THF)2, [{ (Me3Si)2NC(NPri)2}2SmCl]2 and {(Me3Si)2NC(NPri)2} Sm(µ3-BH4)2(DME) complexes

The reaction of anhydrous SmCl₃ with two equivalents of lithium N,N′-diisopropyl-N″-bis(trimethylsilyl)guanidinate in THF afforded the [{(Me₃Si)₂NC(NPrⁱ)₂}₂SmCl]₂ complex (1) in 82% yield. Analogous reactions with YCl₃ and GdCl₃ produced the ate-complexes { (Me₃Si)₂NC(NPrⁱ)₂}₂Ln(µ-Cl)₂Li(THF)₂ (Ln = Y (2) and Gd (3)). The structures of complexes 1 and 2 were established by X-ray diffraction. The reaction of complex 1 with NaBH₄ in hexane (20 °C) followed by treatment with dimethoxyethane yielded the unexpected product, { (Me₃Si)₂NC(NPrⁱ)₂}Sm(µ³-BH₄)₂(DME) (5). X-ray diffraction study showed that both borohydride ligands in complex 5 are tridentate.