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Intercalation of lithium and ammonia into the layered semi-conductor Bi2Se3 proceeds via a hyperextended (by >60%) ammonia-rich intercalate, to eventually produce a layered compound with lithium amide intercalated between the bismuth selenide layers which offers scope for further chemical manipulation. [ABSTRACT FROM AUTHOR]

A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. [ABSTRACT FROM AUTHOR]

In this work, a hexanuclear lithium compound, [Li6(MesalO)6] (1), supported by a chelating ligand, namely methyl salicylato (MesalOH), was used as a precursor for preparation of the monomeric lithium aryloxides [Li(MesalO)(MesalOH)] (2) and [Li(MesalO)(MeOH)2] (3) via reactions with MesalOH or MeOH. These aryloxides were characterized by single-crystal X-ray diffraction, and spectroscopic and other analytical methods. The diffusion-ordered 1H NMR measurements revealed the retention of solid-state structures of 1 and 2 in THF-d8 solution. Experimental data obtained for 3 showed its decomposition into compound 1 and free MeOH. Compound 1 generated from 3 was also used as a catalyst for the alcoholysis of L -lactide (L -LA) and glycolide (GA) for the preparation of α-hydroxy acid esters. We established that during methanolysis in the presence of 1, L -LA was selectively transformed into methyl (S,S)-O-lactyllactate (MeL2), and GA was converted to methyl glycolate (MeG1) and oligoglycolate esters MeGn (n = 2, 3, and 4). [ABSTRACT FROM AUTHOR]

This study explores the design of possible hypersalts starting from the hyperhalogen Li3F4 plus a Li atom and the hyperalkali Li4F3 plus a F atom. The investigation uses a multistep composite computational job that follows the same setup of the CBS-QB3 method, and uses B3LYP in combination with the CBSB7 + basis set for geometry optimizations. Adiabatic ionization energies (AIE), adiabatic electron affinities (AEA), HOMO–LUMO energy gaps, and NBO's are calculated for each presented species. Results confirm that the newly constructed hyperalkalis Li4F3, which has two isomers A and B, result in even lower AIE (3.83 eV and 3.65 eV for hyperalkali A and B, respectively) than the starting superalkali Li2F. The study also confirms the structures for the designed hyperhalogens Li3F4 (two isomers A and B) with higher AEA (7.70 eV and 5.63 eV for hyperhalogen A and B, respectively) than the superhalogen LiF2 building block. Hyperhalogens A and B in combination with a Li atom and hyperalkali A and B in combination with a F atom are used to create hypersalts. This yields three possible hypersalts A, B(C), and D with the formula Li4F4. Hypersalt A has the larger binding energy for dissociation into neutral fragments equal to 7.82 eV. Hypersalt C has the lower binding energy for dissociation into neutrals of 7.17 eV and hypersalt D the larger binding energy for dissociation into ions. [ABSTRACT FROM AUTHOR]

New and straightforward synthetic paths for the syntheses of [RNPNR]− anions (R = t-Bu (1) or CPh3 (6)) in the form of their tmeda- or thf-coordinated lithium salts are described. The attempts to isolate the sodium analogue [(Ph3CNPNCPh3)Na·(thf)x] (8) remained unsuccessful probably due to its high reactivity although its formation in the reaction of the parent cis-[(Ph3CNP)2(Ph3CNH)2] (5) with 2 eq. of sodium naphthalenide was corroborated by NMR spectroscopy. Importantly, when an excess of sodium naphthalenide was used in the reaction with 5, [(Ph3C)Na(thf)3] (9) was obtained along with a complex mixture of other by-products indicating the cleavage of the C–N bond in the starting material. Furthermore, the synthesis and the structural characterization of the [P(Nt-Bu)3]3− trianion as its trilithium salt [P(Nt-Bu)3Li3]2 (10) has been successfully achieved. [ABSTRACT FROM AUTHOR]

High-voltage LiNi0.5Mn1.5O4 is a promising cathode candidate for lithium-ion batteries (LIBs) due to its considerable energy density and power density, but the material generally undergoes serious capacity fading caused by side reactions between the active material and organic electrolyte. In this work, Li+-conductive Li2SnO3 was coated on the surface of LiNi0.5Mn1.5O4 to protect the cathode against the attack of HF, mitigate the dissolution of Mn ions during cycling and improve the Li+ diffusion coefficient of the materials. Remarkable improvement in cycling stability and rate performance has been achieved in Li2SnO3-coated LiNi0.5Mn1.5O4. The 1.0 wt% Li2SnO3-coated LiNi0.5Mn1.5O4 cathode exhibits excellent cycling stability with a capacity retention of 88.2% after 150 cycles at 0.1 C and rate capability at high discharge rates of 5 C and 10 C, presenting discharge capacities of 119.5 and 112.2 mAh g−1, respectively. In particular, a significant improvement in cycling stability at 55 °C is obtained after the coating of 1.0 wt% Li2SnO3, giving a capacity retention of 86.8% after 150 cycles at 1 C and 55 °C. The present study provides a significant insight into the effective protection of Li-conductive coating materials for a high-voltage LiNi0.5Mn1.5O4 cathode material. [ABSTRACT FROM AUTHOR]

Controlling the occupation sites of Mn2+ emitters by multiple-cation substitution, the Li2ZnGe3O8:Mn2+ phosphor could be optionally tuned in the green to NIR region. For the Mn2+ single doped Li2ZnGe3O8 phosphor, the tetrahedral coordinated Mn2+ (ZnO4 site) affords a green emission, and the octahedrally coordinated Mn2+ (ZnO6 site) shows an NIR (832 nm) emission. Interestingly, the Li2ZnGe3O8 host has three cation crystallographic sites, in which the octahedrally coordinated Mn2+ could exhibit a red emission by occupying GeO6 sites. The different luminescence centers for Mn2+ have been demonstrated using time-resolved emission spectra (TRES), excitation spectra and the decay curves. However, how to selectively regulate these fluorescence emissions corresponding to the different occupation sites is critical. In this paper, a common effect between the group's transition and energy transfer makes it possible to enhance the green emission (ZnO4 site) continuously and to restrain the NIR emission (ZnO6 site) through increasing the Zn/Li ratio in the Li2ZnGe3O8:Mn2+ phosphor. When Zn2+ is substituted by bigger ions from Ca to Sr and Ba, the local environments of Mn2+ around ZnO6 are influenced which leads to part of the Mn2+ emitters occupying the Ge4+ site, and it has the most enhanced effect on the Mn red-emission (GeO6 site). In general, we show that the spectral property of Mn2+ in different occupation sites could be efficiently regulated within the Li2ZnGe3O8 host, and provide a method for photoluminescence tuning. [ABSTRACT FROM AUTHOR]

A new 3D MOF [MnLi2(ip)2(H2O)2] (1) with a 1D heterometallic inorganic Mn(ii)–Li(i) chain is reported. With the assistance of diamagnetic {LiO4} connectors, which separate the paramagnetic Mn(ii) ions and act as magnetic spacers, very weak magnetic interactions were obtained. Remarkably, 1 showed a significant magnetocaloric effect (MCE) with a large entropy change value of 30.4 J kg−1 K−1 for ΔH = 8 T at 2 K. [ABSTRACT FROM AUTHOR]

1,2-Dihalodigermenes, (E)-(Eind)XGe=GeX(Eind) (X = Br and Cl), bearing the fused-ring bulky Eind group (Eind = 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) have been isolated as orange-yellow crystals by the ligand redistribution reaction between the diarylgermylene, (Eind)2Ge:, and GeX2·dioxane in toluene via the cleavage and recombination of the Ge–C and Ge–X bonds. The dihalodigermenes have a Ge=Ge double bond character in the crystalline state, but dissociate into halogermylenes, (Eind)XGe:, in solution. The addition of excess LiBr to the THF solution of the bromogermylene, (Eind)BrGe:, led to the formation of an equilibrium mixture containing the lithium bromogermylenoid, [Li+][(Eind)GeBr2]−. The bromogermylenoid can be isolated as a cryptand-separated potassium ion pair, [K+(crypt-222)][(Eind)GeBr2]−, which has been structurally characterized. [ABSTRACT FROM AUTHOR]

A core–shell structured LiNi0.5Mn1.5O4@LiCoO2 cathode material has been successfully synthesized by the combination of sol–gel and solid state methods. The coating of LiCoO2 has a significant effect on the electrochemical performance of the spinel LiNi0.5Mn1.5O4-based cathode material, especially the cycling stability at high temperature and rate capability. After modification, the ionic conductivity of the material is greatly improved due to the high ion conductivity of LiCoO2. The LiNi0.5Mn1.5O4@LiCoO2 with 1% LiCoO2 presents the optimal rate capability and delivers a relatively high discharge capacity of 122 mA h g−1 at 10C. On the other hand, the surface coating of LiCoO2 can effectively facilitate Li+ interfacial diffusion, and alleviate the side reactions between the active material and the electrolyte; as a result, the capacity retention of 96.17% for the LiNi0.5Mn1.5O4@LiCoO2 electrode with 1% LiCoO2 is much higher than that for the bare LiNi0.5Mn1.5O4 (74.93%) after 100 cycles at elevated temperature. Our study confirms that the core–shell structure construction caused by the coating of LiCoO2 plays a critical role in the improvement of the electrochemical cycling stability at elevated temperatures and rate capability. [ABSTRACT FROM AUTHOR]

A secondary diaminophosphane-borane (Et2N)2PH(BH3) was prepared from a chlorophosphane precursor and LiBH4 and metalated by reaction with anion bases (n-BuLi, KN(SiMe3)2) to yield the corresponding metal diaminophosphanide-boranes [(Et2N)2P(BH3)]M (M = Li, K). Multinuclear NMR studies permitted the first spectroscopic characterisation of the metalation products and revealed the presence of monomeric (for M = Li) contact ion pairs in solution. NMR spectroscopic evidence that the ions in each pair interact via Li…P- rather than Li…H3B-interactions as had been inferred for a Ph-substituted analogue was confirmed by DFT studies, which revealed also that the borane coordination plays a decisive role in boosting the PH-acidity of the original secondary diaminophosphane precursor. Transmetalation of the potassium and lithium diaminophosphanide-boranes with Cu(i) and Zn(ii) chlorides afforded the first functional transition metal complexes of a P-heteroatom-functionalised phosphanide-borane ligand. Both products were fully characterised. Thermolysis of the Cu-complex induced a reaction which involved transfer of an NHC ligand from the metal to the phosphorus atom and yielded a phosphaalkene NHC=PH (NHC = N-heterocyclic carbene) as the major phosphorus-containing product. [ABSTRACT FROM AUTHOR]

The effects of Li+ and Mg2+ on the electrochemical behaviour and photoreduction of N,N′-bis(2,6-diisopropylphenyl)naphthalene diimide (Dipp2NDI) have been investigated using cyclic voltammetry and UV-vis spectroscopy. Strong cation–anion interactions between Li+ or Mg2+ and [Dipp2NDI]2− result in solvent-dependent anodic shifts of the NDIṖ−/2− redox couple. In organic solvents of moderate dielectric constant and donor ability, the two, one-electron redox processes typically observed for Dipp2NDI merge into a single, two-electron process. This strong metal cation effect has been leveraged for the photoreduction of Dipp2NDI to [Dipp2NDI]2−via a disproportionation process. Chemical reduction of Dipp2NDI with iPrMgCl has allowed the isolation of Mg2+ complexes of [Dipp2NDI]2−. Single crystal X-ray diffraction was used to determine the structure of a dimeric complex, [(Dipp2NDI)Mg2(THF)3]2, that features strong coordination of Mg2+ by the oxygen atoms of the reduced NDI. [ABSTRACT FROM AUTHOR]

Fast ion conducting garnet materials have been identified as promising electrolytes for all solid-state batteries. However, reliable synthetic routes to materials with fully elucidated cation site occupancies where an enhancement in lithium conductivity is observed remains a challenge. Ca-Incorporation is developed here as a promising approach to enhance the ionic conductivity of garnet-type Li7−xLa3Zr2−xTaxO12 phases. Here we present a new sol–gel synthetic strategy as a facile route to the preparation of materials of a desired stoichiometry optimized for Li+ conductivity. We have found that the ionic conductivity of Li6.4La3Zr1.4Ta0.6O12 is increased by a factor of four by the addition of 0.2 mol of Ca per formula unit. Ca is incorporated in the garnet lattice where it has no effect on the sinterability of the material and is predominately located at the La sites. We anticipate that the ease of our synthetic route and the phases presented here represents a starting point for the further realization of solid state electrolyte compositions with similarly high Li+ conductivities using this methodology. [ABSTRACT FROM AUTHOR]

Impurity doping plays a critical role in altering the properties of target nanomaterials in terms of designed morphologies, crystal structures, and functionalities. In this work, we have performed a comprehensive investigation of the effect of Li+ doping on the morphology, crystal structure, and upconversion luminescence of NaYF4:Yb/Er nanocrystals. Different Li+ sources, e.g., LiOA and LiOH, were used and the Li+ doping concentration varied from 0 to 100 mol%. The final product changes from hexagonal NaYF4:Yb/Er to the mixture of cubic NaYF4:Yb/Er and tetragonal LiYF4:Yb/Er, and finally to pure tetragonal LiYF4:Yb/Er. More importantly, at an ultra-low concentration of 0.5 mol% Li+ doping, as high as 34 times green and 101 times red emission enhancements are achieved. [ABSTRACT FROM AUTHOR]

The macrocyclic polyamine 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane [LH = (Me3TACD)H] formed adducts with tetramethyl-silazides [M{N(SiHMe2)2}] (M = Li, Na, K) of light alkali metals. Upon heating, intramolecular dehydrocoupling occurred to give [M{(L)SiMe2N(SiHMe2)}]. BPh3 induced facile ring-opening of THF when reacted with [Li{(L)SiMe2N(SiHMe2)}]. [ABSTRACT FROM AUTHOR]

The macrocyclic polyamine 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane [LH = (Me3TACD)H] formed adducts with tetramethyl-silazides [M{N(SiHMe2)2}] (M = Li, Na, K) of light alkali metals. Upon heating, intramolecular dehydrocoupling occurred to give [M{(L)SiMe2N(SiHMe2)}]. BPh3 induced facile ring-opening of THF when reacted with [Li{(L)SiMe2N(SiHMe2)}]. [ABSTRACT FROM AUTHOR]

This paper focuses on ferrocene-based secondary diphosphines of the type [Fe{η5-C5H4(PHR)}2] with P-substituents of distinctly different steric and electronic properties, namely methyl, neopentyl (Np), tert-butyl, phenyl and 3,5-bis(trifluoromethyl)phenyl (XyF). The reaction of [Fe{η5-C5H4(PHPh)}2] (H21a) and [Fe{η5-C5H4(PHt-Bu)}2] (H21b) with n-BuLi in the presence of TMEDA afforded lithium diphosphides of the type [Li2(μ-1)(TMEDA)2], which contain a cyclic non-planar Li2P2 core. The analogous reactions of [Fe{η5-C5H4(PHMe)}2] (H21c) and [Fe{η5-C5H4(PHNp)}2] (H21d) furnished dimeric aggregates exhibiting a ladder-type Li4P4 motif, viz. [Li4(μ-1c)2(TMEDA)3] and [Li2(μ-1d)(TMEDA)]2. H21e (R = XyF) did not afford a stable lithium diphosphide. A Brønsted metathesis with Zr(NMe2)4 was possible with the aryl-substituted compounds H21a and H21e, leading to products of the type [{Zr(NMe2)3}2(μ-1)]. In contrast, the alkyl-substituted congeners H21b–H21d were inert towards Zr(NMe2)4. The reaction of [Fe{η5-C5H4(PHR)}2] with nickelocene afforded intractable mixtures of numerous products in the case of H21c and H21e. In the other three cases, compounds of the type [(NiCp)2(μ-1)] were isolated. For H21b and H21d a two-stepped reaction via a phosphino–phosphido intermediate of the type [NiCp(H1)] was observed, which could be isolated and fully characterised in the case of [NiCp(H1b)]. [ABSTRACT FROM AUTHOR]

A new rare-earth borate LiRb2LaB2O6 (LB-1) has been synthesized using a high-temperature solution method. Interestingly, it shares its topological structure with the famous porous material MOF-5, which is formed from Zn4O(BDC)3 (BDC = 1,4-benzenedicarboxylate). The nodes [OZn4] and organic linkers [BDC] of MOF-5 are carefully substituted with La3+ rare-earth cations and the inorganic linkers [BO3] and [LiO4], respectively, in order to construct a pure inorganic open framework. LB-1 exhibits good thermal and water stability. Moreover, it possesses a short cut-off edge (＜190 nm) and moderate birefringence (exp. 0.040@589.5 nm, cal. 0.038@589.5 nm). Further insights into the cut-off edge were given by first-principles calculations. The factors that influence the birefringence of LB-1 were discussed in view of the spatial arrangement of the [BO3] anionic groups. [ABSTRACT FROM AUTHOR]

The synthesis of a η5-coordinated LiCp complex by simple addition of a Li-salt in benzene is presented. A strongly zwitterionic fulvalene serves as the Cp-precursor. Evidence for the coordination of Li+ was obtained by the characterisitic 7Li NMR chemical shifts, variable temperature experiments in solution and by X-ray structure analysis in the solid state. [ABSTRACT FROM AUTHOR]

Treatment of the lithium salt of β-ketimine with FeCl2(THF)1.5 in the presence of LiN(SiMe3)2 and water affords the multimetallic iron(ii)–lithium complex 1, [(LMe)2Fe]3Li2O [where LMe = MeC(O)CHC(NMe)Me]. In complex 1 three separated (LMe)2Fe units are bound together by one Li2O species, which leads to the formation of an interesting {Fe3Li2O} core structure. Complex 1 can be used as a single-component initiator for the ring-opening polymerization of ε-caprolactone at room temperature, achieving a monomer conversion of 98% within 100 min, and a narrow molecular weight distribution (PDI = 1.28) of the resulting polymer. [ABSTRACT FROM AUTHOR]

The lithium-cyclopropylethynylamidinates Li[c-C3H5–C≡C–C(NR)2] (1a: R = iPr, 1b: R = cyclohexyl (Cy)) have been used as precursors for the preparation of five new series of half-sandwich complexes. These complexes contain the large flat cyclooctatetraenyl ligand (C8H82−, commonly abbreviated as COT), and were isolated as solvated, unsolvated and inverse sandwich complexes. Treatment of the halide precursors [(COT)Pr(μ-Cl)(THF)2]2 with 1b and [(COT)Nd(μ-Cl)(THF)2]2 with 1a and 1b in THF in a 1 : 2 molar ratio, respectively, afforded (COT)Ln[μ-c-C3H5–C≡C–C(NR)2]2Li(L) (2: Ln = Pr, R = Cy, L = Et2O; 3: Ln = Nd, R = iPr, L = THF; 4: Ln = Nd, R = Cy, L = THF). Treatment of the dimeric cerium(iii) bis(cyclopropylethynylamidinate) complexes [{c-C3H5–C≡C–C(NR)2}2Ce(μ-Cl)(THF)]2 (5: R = iPr; 6: R = Cy) in situ with K2C8H8 in a 1 : 1 molar ratio in THF at room temperature afforded the inverse-sandwich complexes (μ–η8:η8-COT)[Ce{c-C3H5–C≡C–C(NR)2}2]2 (7: R = iPr; 8: R = Cy). This reaction represents a new method for encapsulation of a planar (C8H8)2− ring in lanthanide complexes containing amidinate ligands in the outer decks. Novel unsolvated dinuclear lanthanide half-sandwich complexes were prepared by using the precursors 1a, 1b and COT2−. Unlike the complexes 2–4, the reaction of [(COT)Pr(μ-Cl)(THF)2]2 with 1a afforded the unsolvated centrosymmetric complex [(COT)Pr(μ-c-C3H5–C≡C–C(NiPr)2)]2 (9). These dimeric structures could be also accessed by reaction of LnCl3 (Ln = Ce or Nd) with 1a or 1b and K2COT in a 1 : 1 : 1 molar ratio as a one-pot reaction to give novel [(COT)Ln(μ-c-C3H5–C≡C–C(NR)2)]2 complexes (10: Ln = Ce, R = iPr; 11: Ln = Ce, R = Cy; 12: Ln = Nd, R = iPr). Similar treatment of HoCl3 with 1a or 1b and K2COT as three-component reactions in a 1 : 1 : 1 molar ratio afforded the solvated half-sandwich complexes (COT)Ho(c-C3H5–C≡C–C(NR)2)(THF) (13: R = iPr; 14: R = Cy). A unique multidecker sandwich complex [(μ–η8:η8-COT){Nd(c-C3H5–C≡C–C(NCy)2)(μ-Cl)}2]4 (15) was prepared by reaction of anhydrous NdCl3 with K2COT and 1b in a one-pot reaction. The solid state structure of 15 revealed the presence of an unprecedented macrocyclic sandwich compound (“giant neodymium wheel”) consisting of four COT rings sandwiched between eight Nd3+ ions, and each Nd3+ ion is bonded to one amidinate ligand and bridged by two chlorine atoms with the neighbouring Nd3+ ion. [ABSTRACT FROM AUTHOR]

A high-yield synthesis of [Li{S(H)C(PPh2S)2}]2 [Li2·(3)2] was developed and this reagent was used in metathesis with ZnCl2 and NiCl2 to produce homoleptic complexes 4 and 5b in 85 and 93% yields, respectively. The solid-state structure of the octahedral complex [Zn{S(H)C(PPh2S)2}2] (4) reveals notable inequivalence between the Zn–S(C) and Zn–S(P) contacts (2.274(1) Åvs. 2.842(1) and 2.884(1) Å, respectively). Two structural isomers of the homoleptic complex [Ni{S(H)C(PPh2S)2}2] were isolated after prolonged crystallization processes. The octahedral green Ni(ii) isomer 5a exhibits the two monoprotonated ligands bonded in a tridentate (S,S′,S′′) mode to the Ni(ii) centre with three distinctly different Ni–S bond lengths (2.3487(8), 2.4500(9) and 2.5953(10) Å). By contrast, in the red-brown square-planar complex 5b the two ligands are S,S′-chelated to Ni(ii) (d(Ni–S) = 2.165(2) and 2.195(2) Å) with one pendant PPh2S group. DFT calculations revealed that the energetic difference between singlet and triplet state octahedral and square-planar isomers of the Ni(ii) complex is essentially indistinguishable. Consistently, VT and 31P CP/MAS NMR spectroscopic investigations indicated that a mixture of isomers exists in solution at room temperature, while the singlet state square-planar isomer 5b becomes favoured at −40 °C. [ABSTRACT FROM AUTHOR]

The dilithium complex of N,N′-bis(2,6-diisopropylphenyl)-o-phenylenediamide, [Li2L(thf)3], reacts with TaMe3Cl2 in THF/Et2O to yield [Li(Et2O)(thf)LTaMe3Cl] in which the phenylene backbone of L2− is bound η4 to the Ta centre. This dinuclear species reacts with MeLi to yield the tetramethyltantalum complex [Li(Et2O)(thf)LTaMe4]. Double deprotonation of N,N′-bis(2,6-diisopropylphenyl)(4,5-dimethyl)-o-phenylenediamine (H2L′) in Et2O yielded the dilithium complex [Li2L′(OEt2)2]. The two additional methyl groups on L′2− change the observed reactivity towards TaMe3Cl2: rather than bridging between Ta and Li, ligand oxidation occurs to afford mononuclear [LiL′(OEt2)]. This monolithium radical species, which was characterized by EPR spectroscopy, can also be synthesized using the more conventional oxidant AgBF4. Double deprotonation of H2L with KCH2Ph in toluene followed by reaction with TaMe3Cl2 furnished [TaLMe3]. Preliminary reactivity studies show [TaLMe3] reacts with unsaturated substrates N,N′-dicyclohexylcarbodiimide and mesityl azide to undergo migratory insertion into one of the Ta–C bonds: the corresponding amidinate and triazenido ligands are generated. When subjected to UV irradiation, [TaLMe3] undergoes reduction accompanied by loss of a methyl group to yield the dimeric species [TaLMe2]2. [ABSTRACT FROM AUTHOR]

The deprotonation of aminophosphanes PhP(NHR)2 (R = t-Bu or Dip; Dip = 2,6-i-Pr2C6H3) and t-BuP(NHDip)2 using n-BuLi gave, depending on the stoichiometry, both the dilithium compounds {[PhP(Nt-Bu)2]Li2}2 (1), [PhP(Nt-Bu)(NDip)]Li2·(Et2O) (3), [t-BuP(NDip)2]Li2·(Et2O)2 (5) and [t-BuP(NDip)2]Li2·(tmeda)2 (5a), and the monolithium compounds [PhP(NHt-Bu)(NR)]Li·(tmeda) (R = t-Bu 2, Dip 4) and [t-BuP(NHDip)(NDip)]Li·(tmeda) (6). Treatment of 1, 3 and 5 with GeCl2·dioxane or SnCl2 in a 1 : 1 stoichiometric ratio gave the corresponding tetrylenes [PhP(Nt-Bu)2]E (E = Ge 7, Sn 10), [PhP(Nt-Bu)(NDip)]Ge (8) and [t-BuP(NDip)2]E (E = Ge 9, Sn 11). The heteroleptic germylene [Ph(H)P(Nt-Bu)2]GeCl (12) was obtained by the reaction of the monolithium compound [PhP(NHt-Bu)(Nt-Bu)]Li·(tmeda) (2) with GeCl2·dioxane in a 1 : 1 stoichiometric ratio, as a result of a spontaneous NH → PH tautomeric shift in the ligand backbone. In contrast, an analogous reaction with SnCl2 produced only stannylene 10 along with the PhP(NHt-Bu)2 starting material, suggesting scrambling of the ligands rather than a NH → PH tautomeric shift. Finally, heating 5a in solution led to P–C bond cleavage and formation of the bis(imino)phosphide [DipNPNDip]Li·(tmeda) (13). The reaction of 13 with GeCl2·dioxane, SnCl2 or PbCl2 in a 2 : 1 stoichiometric ratio yielded the unprecedented tetrylenes [DipNPNDip]2E (E = Ge 14, Sn 15 and Pb 16), in which the tetrylene center is incorporated within two N2PE rings. Treatment of the monolithium compound 2 with n-BuLi and K (or KC8) gave [t-BuNPNt-Bu]Li·(tmeda) (17) and{[t-BuNPNt-Bu]K(tmeda)}2 (18), respectively. In contrast to the reaction with 13, similar reactions of 17 with GeCl2·dioxane and SnCl2 resulted in the known compounds cis-[P(μ-Nt-Bu)2P(t-BuN)2]E (E = Ge, Sn); evidently the t-Bu groups do not provide sufficient steric shielding to protect the bis(imino)phosphide backbone as in the case of 14–16. The bonding situation in a set of selected compounds (8, 12–16) has been subjected to a theoretical survey with particular emphasis on the nature of the bonding between the ligand and the central metal and the bonding within the NPN core of the ligand, showing significant differences among the studied complexes. [ABSTRACT FROM AUTHOR]

The origin of the intricate nanostructure of La0.5−xLi0.5−xSr2xTiO3 (0.0625 ≤x≤ 0.25) perovskite-type Li ion conductors has been investigated. Reciprocal space electron diffraction analysis and aberration-corrected STEM by combining annular bright field (ABF) and high angle annular dark field (HAADF) imaging methods have been used to elucidate the complex local atomic arrangements which cannot be adequately described by average crystal structure models. Two different local crystal structures endotaxially-related at the nanoscale without compositional phase separation associated, constituting the crystals. Self-organization of the two different ordered regions arises as a consequence of the competition between two distortive forces in the crystal lattice: octahedral tilting and second-order Jahn–Teller distortion of TiO6 octahedra. Changes in the distribution of A species suggest different Li ion conduction pathways for the two structures and this scenario has difficult long-range Li mobility. The detailed study performed may be helpful in understanding the local structural changes affecting Li and their relation to the conductivity in LLTO-derived ionic conductors. [ABSTRACT FROM AUTHOR]

The salt metathesis reaction of LnCl3 with 1 equivalent of arylamido lithium [2,6-iPr2C6H3N(SiMe3)]Li followed by addition of 2 equivalents of LiN(SiHMe2)2 in THF at room temperature obtained neutral mono-arylamido-ligated rare-earth metal bis(silylamide) complexes [2,6-iPr2C6H3N(SiMe3)]Ln[N(SiHMe2)2]2(THF) (Ln = Y (1), Lu (2), La (3)) in good isolated yields. Treatment of 1–3 with excess AlMe3 produced the mono(arylamido) Ln/Al heterotrinuclear methyl complexes [2,6-iPr2C6H3N(SiMe3)]Ln[(μ-Me)2AlMe2]2 (Ln = Y (4), Lu (5), La (6)) via amide–alkyl exchange. All these complexes were well-characterized by elemental analysis, NMR spectroscopy and FT-IR spectroscopy. 2, 4 and 5 were further structurally authenticated by X-ray crystallography. In the presence of [Ph3C][B(C6F5)4] and AliBu3, 1–3 were highly active for cis-1,4-selective polymerization of isoprene, whereas 2/[Ph3C][B(C6F5)4]/AliBu3 promoted the polymerization in a living fashion. [ABSTRACT FROM AUTHOR]

Lithium and sodium compounds supported by tetradentate amino-bis(phenolato) ligands, [Li2(N2O2BuBuPip)] (1), [Na2(N2O2BuBuPip)] (2) (where [N2O2BuBuPip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4,6-tert-butylphenol), and [Li2(N2O2BuMePip)] (3), [Na2(N2O2BuMePip)] (4) (where [N2O2BuMePip] = 2,2′-N,N’-homopiperazinyl-bis(2-methylene-4-methyl-6-tert-butylphenol) were synthesized and characterized by NMR spectroscopy and MALDI-TOF mass spectrometry. Variable temperature NMR experiments were performed to understand solution-phase dynamics. The solid-state structures of 1 and 4 were determined by X-ray diffraction and reveal tetrametallic species. PGSE NMR spectroscopic data suggests that 1 maintains its aggregated structure in CD2Cl2. The complexes exhibit good activity for controlled ring-opening polymerization of rac-lactide (LA) both solvent free and in solution to yield PLA with low dispersities. Stoichiometric reactions suggest that the formation of PLA may proceed by the typical coordination–insertion mechanism. For example, 7Li NMR experiments show growth of a new resonance when 1 is mixed with 1 equiv. LA and 1H NMR data suggests formation of a Li-alkoxide species upon reaction of 1 with BnOH. [ABSTRACT FROM AUTHOR]

Addition of a minor quantity of CoO significantly reduces the dehydrogenation temperature, accelerates the dehydrogenation rate and increases the hydrogen purity of the LiBH4·NH3–3LiH system. The LiBH4·NH3–3LiH–0.1CoO sample exhibits optimal dehydrogenation properties because it releases 8.5 wt% of hydrogen below 250 °C, which is approximately 90 °C lower than that of the pristine sample. At 200 °C, approximately 8.0 wt% of hydrogen is released from the LiBH4·NH3–3LiH–0.1CoO sample within 100 min, whereas only 4.1 wt% is released from the pristine sample under identical conditions. The EXAFS analyses reveal that upon heating, CoO is first reduced to metallic Co at 130 °C and then partially combines with B to form a Co–B species. The in situ formed Co and Co–B are finely dispersed in the dehydrogenated intermediates, and they play critical roles as active catalysts in favour of breaking the B–H bonds of the Li–B–N–H species. This effectively decreases the thermodynamic and kinetic barriers of the dehydrogenation reaction of the LiBH4·NH3–3LiH system. [ABSTRACT FROM AUTHOR]

A near-UV excited phosphor, LiSr4(BN2)3:Eu2+ (LSBN:Eu2+), was synthesized using a solid-state reaction at 800 °C. The crystal structure of LSBN had been refined and determined from the XRD profiles by the Rietveld refinement method, which belongs to the space group Im3̅m with the lattice constants a = b = c = 7.46112(23) Å. The excitation spectra of the LSBN:Eu2+ phosphors were centered at around 370 nm and covered the range from 300 to 450 nm. Under 400 nm excitation, the emission spectra of the LSBN:Eu2+ phosphors show a red emission centered at about 640 nm (FWHM ≈ 130 nm). And the energy transfer between the Eu2+ ions is confirmed to arise from the electric dipole–dipole interactions. The nontypical emission blue-shift in the single luminescence center with increasing temperature luminescence properties is also investigated. The results indicate that LSBN:Eu2+ could be conducive to the development of white light emitting diodes. [ABSTRACT FROM AUTHOR]

Treatment of p-tert-butylcalix[6]areneH6 (L6H6) with in situ [LiVO(Ot-Bu)4] afforded, after work-up, the dark green complex [Li(MeCN)4][V2(O)2Li(MeCN)(L6H2)2]·8MeCN (1·8MeCN). On one occasion, the reaction led to the formation of a mixture of products, the bulk of which differing from 1 only in the amount of solvate, viz.2·9.67MeCN. The second minor, yellow product has the formula {[(VO2)2(L6H2)(Li(MeCN)2)2]·2MeCN}n (3·2MeCN), and comprises a 1D polymeric structure with links through the L6H2 ligand and Li2O2 units. When the reverse order of addition was employed such that lithium tert-butoxide (7.5 equivalents) was added to L6H6, and subsequently treated with VOCl3 (2 equiv.), the complex {[VO(THF)][VO(μ-O)]2Li(THF)(Et2O)][L6]}·2Et2O·0.5THF (4·2Et2O·0.5THF), which contains a trinuclear motif possessing a central, octahedral vanadyl centre linked via oxo bridges to two tetrahedral (C3v) vanadyl centres, was isolated. The calix[6]arene in 4 is severely twisted and adopts a ‘down, down, down, down, out, out’ conformation. Use of excess lithium tert-butoxide led to a complex very similar to 4, differing only in the solvent of crystallization, namely 5·Et2O·2THF. The ability of 1 and 5 to act as pre-catalysts for ethylene polymerization in the presence of a variety of co-catalysts and under various conditions has been investigated. Co-polymerization of ethylene with propylene and with 1-hexene have also been conducted; results are compared versus VO(OEt)Cl2. [ABSTRACT FROM AUTHOR]

Two new lithium-containing diamond-like semiconductors, Li2ZnGeSe4 and Li2ZnSnSe4, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz–kesterite structure type, crystallizing in the noncentrosymmetric space group Pn. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, χ(2), was estimated to be 19 and 23 pm V−1 for Li2ZnGeSe4 and Li2ZnSnSe4, respectively. Using a 1064 nm incident laser beam with a pulse width (τ) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm−2, which is higher than that of the AgGaSe2 reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li2ZnGeSe4 and Li2ZnSnSe4 have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding. [ABSTRACT FROM AUTHOR]

Two new lithium-containing diamond-like semiconductors, Li2ZnGeSe4 and Li2ZnSnSe4, have been prepared by high-temperature, solid-state synthesis. Single crystal X-ray diffraction reveals that both compounds adopt the wurtz–kesterite structure type, crystallizing in the noncentrosymmetric space group Pn. X-ray powder diffraction coupled with Rietveld refinement indicates the high degree of phase purity in which the materials are prepared. Both compounds display optical bandgaps around 1.8 eV, wide optical transparency windows from 0.7 to 25 μm and type-I phase matched second harmonic generation starting at 2500 nm and persisting deeper into the infrared. Using the Kurtz powder method, the second-order nonlinear optical coefficient, χ(2), was estimated to be 19 and 23 pm V−1 for Li2ZnGeSe4 and Li2ZnSnSe4, respectively. Using a 1064 nm incident laser beam with a pulse width (τ) of 30 ps both compounds exhibit a laser damage threshold of 0.3 GW cm−2, which is higher than that of the AgGaSe2 reference material measured under identical conditions. Differential thermal analysis shows that the title compounds are stable up to 684 and 736 °C, respectively. These properties collectively demonstrate that Li2ZnGeSe4 and Li2ZnSnSe4 have great potential for applications in tunable laser systems, especially in the infrared and even up to the terahertz regime. Electronic structure calculations using a plane-wave pseudopotential method within density functional theory provide insight regarding the nature of the bandgap and bonding. [ABSTRACT FROM AUTHOR]

Hierarchical LiZnVO4@C nanostructures composed of thin nanobelt aggregates were synthesized for the first time through an ethanol thermal and subsequent annealing route, and were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Furthermore, the synthesized hierarchical nanostructures were used as anode materials for Li-ion intercalation and exhibited a large reversible capacity, high rate performance, and excellent cycling stability. For instance, a high reversible capacity of 675 mA h g−1 was maintained after 60 cycles at a current density of 50 mA g−1. These results might be attributed to the following facts: (i) the hierarchical nanostructures could buffer the strain and volume changes during the cycling process; (ii) the thin nanobelts provide a shortened distance for Li-ion intercalation; (iii) the thin carbon layer on the surface of the nanobelts could provide a fast route for electron transportation, leading to an improved capacity and high rate performance. [ABSTRACT FROM AUTHOR]

Reaction of the sodium monoamido-bisalkylzincate [(TMEDA)Na(TMP)(But)Zn(But)] (TMEDA is N,N,N′,N′-tetramethylethylenediamine; TMP is 2,2,6,6-tetramethylpiperidide) and the related lithium zincate [(PMDETA)Li(TMP)Zn(But)2] (PMDETA is N,N,N′,N′′,N′′-pentamethyldiethylenetriamine) with the sensitive bio-relevant scaffold N,N-dimethylphenylethylamine, DMPEA, afforded the crystalline complexes [(TMEDA)Na(TMP)(NMe2)Zn(But)] and [(PMDETA)Li(NMe2)Zn(But)2], respectively, both of which have been characterized by NMR spectroscopic and X-ray crystallographic studies. Made by reaction of a LiTMP–(TMP)Al(Bui)2 mixture with DMPEA, a third dimethylamino-containing crystalline complex, the aluminate [(THF)Li(TMP)(NMe2)Al(Bui)2] has been similarly characterized. All three complexes can be regarded as products of cleave and capture chemistry whereby metallation at the benzylic position of DMPEA has led to a β-elimination of an anionic Me2N fragment that has been captured by a charge balancing cationic heterobimetallic entity. While a metallated intermediate prior to the elimination has proved elusive in all of these reactions, DMPEA has been captured fully intact in the novel Lewis acid–Lewis base crystalline complex [DMPEA·Li(TMP)Zn(Me)2], which has also been characterized by the aforementioned techniques. [ABSTRACT FROM AUTHOR]

Reactions of alkyl aryl sulfoxides H–CRR′S(O)Ar with n-BuLi–TMEDA (TMEDA = N,N,N′,N′-tetramethylethylenediamine) afforded α-sulfinyl functionalized alkyl aryl lithium compounds of the type [Li2{CRR′S(O)Ar}2(TMEDA)2] (1, R/R′ = H/H, Ar = Ph; 2, R/R′ = H/H, Ar = p-Tol; 3, R/R′ = Me/Me, Ar = Ph; 4, R/R′ = H/Ph, Ar = Ph; 5, R/R′ = Me/Ph, Ar = Ph). The compounds were characterized by 1H, 13C and 7Li NMR spectroscopy and, except for 5, by single-crystal X-ray diffraction analyses. In crystals of 1, 2, 3 and 4·Et2O dinuclear molecules with four-membered Li2O2 rings were found. There are no Li…Cα contacts, thus, “free” carbanions are the main structural feature. Reactions of 1–6 (6, R/R′ = H/Me, Ar = Ph) with benzaldehyde and benzophenone afforded the corresponding sulfoxides of the type ArS(O)CRR′CHPhOH (1a–6a) and ArS(O)CRR′CPh2OH (1b–6b), respectively. The reactions yielding 1a/3a and 4b/6b proceeded with high diastereoselectivities. By X-ray diffractometry it has been shown that in the case of 3a and 4b the diastereomers consisting of the two enantiomers SSRC and RSSC were formed. [ABSTRACT FROM AUTHOR]

The local structure of molten LaF3 - LiF - Li2O has been investigated by high temperature NMR spectroscopy. The 139La and 19F chemical shifts have been measured as a function of temperature and composition. The NMR spectra show that Li2O reacts completely with LaF3 to form a LaOF compound in the solid state below the melting temperature of the sample. LaOF is not completely dissolved in the fluoride melt and solid LaOF is observed in the 19F spectra for Li2O concentrations above 10 mol%. We discuss the local environment of lanthanum ions in molten LaF3 - LiF - Li2O and compare the results to those with the LaF3 - LiF - CaO system. The analysis of the temperature and Li2O concentration dependences of the 139La and 19F chemical shifts suggests that several kinds of lanthanum oxyfluoride long-lived LaOxFy 3-x-y units are present in the melt. [ABSTRACT FROM AUTHOR]

An iron-based mixed-polyanion compound, Li9Fe3(P2O7)3(PO4)2, is introduced as a possible cathode material for Li-ion batteries. Phase-pure Li9Fe3(P2O7)3(PO4)2 is successfully prepared by a sol-gel method, and its physicochemical properties are investigated in detail. Special attention is paid on making clear the variation of the phase composition with the annealing temperature and the effect of carbon coating on the electrochemical performance. Apparently phase-pure Li9Fe3(P2O7)3(PO4)2 can only be obtained in a narrow temperature range, either higher or lower annealing temperature outside this temperature range always leads to the impurity phase. The pristine Li9Fe3(P2O7)3(PO4)2 is suffering from its low electronic conductivity (10-9S cm-1) and theoretical capacity (85 mA h g-1), it has a first discharge capacity of only 36 mA h g-1. Carbon coating is employed to improve the electrochemical performance. When the carbon content is 10 wt%, the discharge capacity of Li9Fe3(P2O7)3(PO4)2/C reaches the maximum value of 60 mA h g-1. The electronic conductivity of the composite, the exact discharge capacity of Li9Fe3(P2O7)3(PO4)2 in the composite and the capacity retention of the composite after 30 cycles vary in the same fashion with an increase in carbon content, i.e. first quickly increase and then stabilize. [ABSTRACT FROM AUTHOR]

Na-doped Ni-rich LiNi0.5Co0.2Mn0.3O2 cathode material, Li0.97Na0.03Ni0.5Co0.2Mn0.3O2, is synthesized by a hydroxide co-precipitation route. The structural characterization reveals that the substitution of Na for Li results in a more ordered α-NaFeO2 structure, enlarges Li layer spacing, and reduces the degree of cation mixing. The Li0.97Na0.03Ni0.5Co0.2Mn0.3O2 material has a high tap density of 2.17 g cm-3 that meets the commercial requirement in lithium ion batteries (LIBs). The galvanostatic charge/discharge results show that the electrochemical performance of the Li0.97Na0.03Ni0.5Co0.2Mn0.3O2 is significantly improved. At 0.2, 1, 10, 30 and 50 C, the specific capacities of the Li0.97Na0.03Ni0.5Co0.2Mn0.3O2 are 228.43, 163.12, 121.43, 95.56 and 60.09 mA h g-1, respectively, which are superior to those of the undoped LiNi0.5Co0.2Mn0.3O2 due to the enlargement of Li layer spacing, the decreased degree of cation mixing, and the rapid diffusion of Li-ion in the bulk lattice after the substitution of Na for Li. Therefore, the Na-doped Ni-rich LiNi0.5Co0.2Mn0.3O2 material is a promising cathode candidate for the next generation of LIBs. [ABSTRACT FROM AUTHOR]

The alkali-metal ion extraction ability of an inert material, polytetrafluoroethylene (PTFE; empirical formula CF2), was clarified by characterizing a partially alkali-metal ion-extracted layered compound, K0.8(Li0.27Ti1.73)O4. Washing K0.8(Li0.27Ti1.73)O4 in water extracts only 44% of the interlayer K+ and no intralayer Li+; on the other hand, 53% of the interlayer K+ and approximately 10% of the intralayer Li+ ions were extracted from K0.8(Li0.27Ti1.73)O4 by the reaction with PTFE at 350 °C under flowing Ar. A systematic decrease in the lattice parameters a and c along the intralayer directions and an increase in b along the interlayer direction were observed, consistent with the alkali-metal ion deintercalation amount as a function of the reaction temperatures and the reacted PTFE amounts. After the reaction with K0.8(Li0.27Ti1.73)O4 : CF2 = 1 : 0.6 in mol, the lattice parameter b increased to 1.5607(3) nm from 1.5522(2) of the pristine K0.8(Li0.27Ti1.73)O4, and this change in the lattice parameter was approximately one order of magnitude larger than those in a and c. [ABSTRACT FROM AUTHOR]

The present work concerns the thermal structural characterization of the acentric Ruddlesden-Popper LiHSrTa2O7. A previous study, performed with powder neutron diffraction data, has revealed that at room temperature, LiHSrTa2O7 crystallizes in the Ama2 space group and that the acentric character is mainly due to the unequal distribution of the Li+ and H+ cations on their sites. In this new paper, the thermal behaviour has been studied by several techniques: powder X-ray and neutron diffraction, SHG experiments and Raman spectroscopy. All of them have revealed that LiHSrTa2O7 undergoes a reversible structural transition from an orthorhombic to a tetragonal symmetry around 200 °C. This transition is associated with the progressive vanishing of the TaO6 octahedra tilting, becoming completely straight in the high temperature form (S.G. I4/mmm), and with a variation of the Li+ and H+ distribution in the interlayer spacing. [ABSTRACT FROM AUTHOR]

Spinel oxides with composition LiMn2-xMxO4 (M, a transition metal) are intensively studied due to their remarkable electrochemical properties. This study deals with cathode materials based on the lithium iron manganese oxide LiFe0.5Mn1.5O4 synthesized by different methods (sol-gel, in solution and hydrothermal) in order to obtain samples with various morphologies. SEM results show microspheres, composed of nanosized/submicrometer-sized subunits, microrods with a less porous surface, and finally nanoparticles that form micro-sized aggregates. The samples obtained by both solution and hydrothermal methods provided the best electrochemical behavior. In all cases, the coulombic efficiency is around 90%, and it remains constant during the tested cycles. Specific capacities remain stable between 95% and 98% of capacity retention after series of cycles in samples formed by microspheres or micro-size aggregates. These values are notably higher than those obtained for the samples with particles of heterogeneous size (49%). A LiMn1.5Fe0.5O4/Li2MnO3 composite has been prepared by the solvothermal technique in order to increase its capacity and energy density. These cells show a good cyclability at different current densities. All cells based on these LiFe0.5Mn1.5O4 cathodes recover their discharge capacity when the current density returns to C/10. [ABSTRACT FROM AUTHOR]

The terpenols L(-)-borneol, (1S2S3S5R)-3-pinanol, (-)-menthol, and (-)-myrtenol are easily available chiral alcohols for the preparation of enantiomerically pure catechol esters 1-4-H2. Those ligands are used for the hierarchical assembly of triple lithium-bridged dinuclear titanium(IV) triscatecholate helicates Li[Li3(1-4)6Ti2]. In solution, the dimeric species are in a solvent dependent equilibrium with the monomer Li2[(1-4)3Ti]. The equilibrium is studied by ¹H NMR. CD spectroscopy indicates that the configuration at the complex units of the enantiomerically pure dimeric α-chiral derivatives Li[Li3(1-3)6Ti2] is opposite to the configuration of the monomers Li2[(1-3)3Ti]. For the γ-chiral complex Li2[(4)3Ti] only a de of 25% is observed and in this case no interpretation of the mechanism of stereocontrol is possible. [ABSTRACT FROM AUTHOR]

The crystal structure of Li2B3PO8 was determined by X-ray diffraction of a single crystal prepared by slow cooling from 943 K to 873 K. Li2B3PO8 crystallizes in a triclinic cell (space group P1, Z = 8). The sheets of ∞ 2[B3PO8]2-formed by the linkage of triangular BO3 and tetrahedral BO4 and PO4 groups stack along the b-axis direction. [ABSTRACT FROM AUTHOR]

Lithium organoamidocuprates of the general stoichiometry LiCuR(NR'2) are an important class of organocopper reagents and have found widespread application in conjugate addition and other bond-forming reactions. The dependence of the structures and equilibrium of these species on the steric and electronic properties of the amido group is reported in both the solid state and in solution. Three different cuprate complexes have been crystallographically characterized: the organoamidocuprate [Cu2Li2Mes2TMP2] (2) (TMP = 2,2,6,6-tetramethylpiperidide) which is shown to adopt a head-to-tail conformation; [Cu2Li2-(N(CH2Ph)CH2CH2NMe2)4] (3) which is a homoamidocuprate and contains additional coordination of the lithium centres from intra-molecular tertiary amine groups; and the diastereomeric organoamidocuprate [Cu2Li2Mes2(N(R-CH(Ph)Me)(CH2CF3))2] (4) which adopts a head-to-head conformation. Complex 4 is unique in being the first crystallographically characterised example of a head-to-head isomer of a heterocuprate, and its structure also has implications for the use of scalemic amidocuprates in asymmetrically induced conjugate addition. The solution equilibria of all new complexes have also been studied using 7Li NMR spectroscopy, and in each case the species observed in the crystal structure was shown to also be the predominant isomer in solution. [ABSTRACT FROM AUTHOR]

Synthetically important for introducing a picolyl scaffold into a molecular construction, alkali metallated picoline (methylpyridine) complexes are also interesting in their own right for the diversity of their ligand metal bonding possibilities. Here the syntheses of seven new such complexes are reported: namely three 4-picoline derivatives 4-picLi·Me6TREN, 1, 4-picNa·Me6TREN, 2, and [4-picK·2(4-picH)]∞, 3; and four 2-picoline derivatives, 2-picLi·Me6TREN, 4, 2-picLi·PMDETA, 4', 2-picNa·Me6TREN, 5, and [2-picK·PMDETA]2, 6' [where pic = NC5H4(CH2); Me6TREN = tris(N,N-dimethyl-2-aminoethyl)amine, (Me2NCH2CH2)3N; PMDETA = N,N,N',N'',N''-pentamethyldiethylenetriamine, (Me2NCH2CH2)2NMe]. X-ray crystallographic studies establish that the lighter alkali metal complexes 1, 2, 4' and 5 adopt monomeric structures in contrast to the polymeric and dimeric arrangements adopted by potassium complexes 3 and 6' respectively. All complexes have also been characterized by solution NMR spectroscopy (¹H, 13C, and where relevant 7Li). This study represents the first example of sodium and potassium picolyl complexes to be isolated and characterized. DOSY (Diffusion-Ordered Spectroscopy) experiments performed on 4 and 4' suggest both compounds retain their monomeric constitutions in C6D6 solution. Discussion focuses on the influence of the metal and neutral donor molecule on the structures and the nature of the ligand. metal (enamido versus aza-allylic) interactions. [ABSTRACT FROM AUTHOR]

We report the synthesis of the rock salt derived structures of Li4MSbO6 (M(III) = Cr, Mn, Al, Ga) oxides. These layered oxides are shown to have the formation of preferred cationic mixing in the (LiMSbO6)3- layers based on single crystal and powder XRD studies, in addition to the cation- (Li+ ions versus (Li+/M3+/ Sb5+) ions) ordering observed in several a-NaFeO2 type oxides. The additional ordering found in the honeycomb layer is justified by the oxygen octahedra formed by more Sb/less Li, more Li/less M and more M/less Li/less Sb. This preferential cation mixing is proven structurally for the first time in these oxides and is evident from the superstructure observed by the doubling of the c axis (C2/c: a 5.11; b 8.85; c 9.84 Å; ß 100°) compared to Li4FeSbO6 (C2/m: a = 5.165(6); b = 8.928(13); c = 5.155(7) Å; ß = 109.47(2)°). The driving force seems to be the minimization of the various cation-cation (Sb5+-Sb5+, Sb5+-M3+, M3+-M3+) interactions expected in the edge shared octahedral structures. The magnetic susceptibility of the oxides with magnetic metal ions in a triangular lattice follows the Curie-Weiss law in the temperature range of 300 K-75 K for Li4CrSbO6 and in the temperature range of 300 K-50 K for Li4CrSbO6, with negative Weiss constants at 67 K and 68 K respectively. At low temperatures (<7 K) antiferromagnetic interactions are expected because of the interaction between the layers. Ionic conductivity measurements of Li4CrSbO6 and ion-exchange experiments with Ag+ ions resulting in delafossite based oxides confirmed the mobility of interlayer lithium ions in these oxides. [ABSTRACT FROM AUTHOR]

B2O3-added Li1.5Al0.5Ge1.5(PO4)3 (LAGP) glass ceramics showing a room temperature ionic conductivity of 0.67 mS cm-1 have been synthesized by using a melt-quenching method. The prepared glass ceramics are observed to be stable in tetraethylene glycol dimethyl ether containing lithium bis(trifluoromethane) sulfonamide. The augmented conductivity of the B2O3-added LAGP glass ceramic has improved the plateau potential during discharge. Furthermore, the B2O3-added LAGP glass ceramics are successfully employed as a solid electrolyte in a Li-O2 battery to obtain a stable cycling lifetime of up to 15 cycles with the limited capacity protocol. [ABSTRACT FROM AUTHOR]

The three-coordinate iron(II) NHC complexes [(IPr)Fe(N")2] (1) and [(ItBu)Fe(N")2] (3) (N" = N(SiMe3)2) react with PhSeH or LiSePh to give the iron(II) selenolates [(IPr)Fe(N")(SePh)] (6) and [ItBu(H)]- [(aItBu)Fe(SePh)3], [ItBu(H)][7], with complex 7 containing an abnormal NHC ligand. [ABSTRACT FROM AUTHOR]

The reactions of dilithium 1,2-diamidobenzene, [1,2-(HN)2C6H4]Li2 (L1H2)Li2, and dilithium 1,8-diamidonaphthalene, [1,8-(NH)2C10H6]Li2 (L2H2)Li2, with Cp2Ni and Cp2V have been used to obtain the new complexes (L2H2)2Ni{Li(THF)2}2 (3), (L2H2)3V{Li(THF)2}3 (4) and (L1H2)6Ni6·{[(L1H2)3(L1H)3Ni6Li(THF)]2−·2[Li(THF)4]+} (5), in which retention or oxidation of the initial metal(ii) centre is observed. Whereas 3 and 4 contain one transition metal ion within ion-paired structures, 5 has a complicated co-crystalline composition which contains octahedral Ni6-cages constructed from six square-planar (16e) NiII centres. [ABSTRACT FROM AUTHOR]

Herein we report the synthesis of α-Dawson type POM, Li6[α-P2W18O62]·28H2O, directly from the use of Li2WO4 as the tungstate source. The salt obtained was soluble not only in water but also in a range of polar and non-polar organic solvents, such as benzene. [ABSTRACT FROM AUTHOR]