Crystal Structure and Vibrational Spectra of Erbium Trisodium Bis(Cyclotriphosphate) Nonahydrate,ErNa<Subscript>3</Subscript>(P<Subscript>3</Subscript>O<Subscript>9</Subscript>)<Subscript>2</Subscript> · 9H<Subscript>2</Subscript>O

Abstract The cyclotriphosphate salt, ErNa₃(P₃O₉)₂ · 9H₂O, has been characterized by single-crystal X-ray diffraction [hexagonal, space group , with unit cell parameters of a = b = 30.8451(14), c = 12.8063(8) ?; Z = 18]. The structure consists of alternating layers of [P₃O₉]³⁻ groups, ErO₈ dodecahedra, Na(1)O₆ and Na(2)O₇ polyhedra linked together by water molecules. The P₃O₉ rings are grouped along the c-axis in a P₃O₉–ErO₈ arrangement thereby producing broad, hexagonal channels of diameter of 6.65 ? with a side dimension of 3.907 ?. The absence of coincidences for the majority of the IR and Raman bands observed for the cyclotriphosphate salt is in accord with the centrosymmetric structure of the material. The vibrational spectra have been interpreted on the basis of factor group effects. Graphical abstract We report the crystal structure and vibrational spectra of erbium trisodium bis(cyclotriphosphate)nanohydrate salt ErNa ₃ (P ₃ O ₉ ) ₂ · 9H ₂ O H. Assaaoudi, M. Ijjaali, A. Ennaciri, I. S. Butler* and J. A. Kozinski Crystal structure and vibrational spectra of erbium trisodium bis(cyclotriphosphate) nonahydrate,ErNa₃(P₃O₉)₂ · 9H₂O. Projection of the coordination polyhedra of ErNa₃(P₃O₉)₂ · 9H₂O down the c axis     

Synthesis and structure of 4,7,13-trioxa-1,10-diaza-5,6-benzocyclopentadecane monohydrate

4,7,13-T4ioxa-1,10-diaza-5,6-benzocyclopentadecane, C₁₄H₂₂N₂O₃·H₂O (7) was synthesized by reduction of macrocyclic diamides (3) or (6). The compound crystallized in the orthorhombic space group Pbca witha=9.361(3),b=9.175(3),c=37.152(11) Å. The structure was solved by direct methods and refined to anR value of 0.048 and wR of 0.038 for 1875 reflections. The molecule itself is internally hydrogen bonded by N–H...O connections. In the crystal structures water molecules form hydrogen bonds with amine nitrogen atoms of adjacent molecules.     

Synthesis and Crystal Structure of the Fluorite-Related Ruthenate, Trilanthanum Ruthenium Septaoxide La3RuO7

Abstract Single crystals of the lanthanum-containing ruthenate, trilanthanum ruthenium septaoxide, La₃RuO₇, were prepared via high-temperature flux growth and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group Cmcm with a = 11.2077(6) ?, b = 7.4531(4) ?, and c = 7.6042(4) ? and is a member of a well-known family of compounds with the general formula Ln₃MO₇. Graphical abstract Synthesis and crystal structure of the fluorite-related ruthenate, trilanthanum ruthenium septaoxide La ₃ RuO ₇ William R. Gemmill, Mark D. Smith and Hans-Conrad zur Loye* Single crystals of La₃RuO₇ were isolated from a high-temperature KCl flux and characterized by single crystal X-ray diffraction. A view of the crystal structure approximately along [001] of La₃RuO₇ and displacement ellipsoids drawn at 50% probability level. The vertex-sharing RuO₆ octahedra are shown in blue, La³⁺ are shown in yellow, and O²⁻ are shown in red.      

EXAFS and XANES Studies on 3d Transition Metal Intercalation Compounds M x TiS2

Abstract

EXAFS and XANES spectra of Ti K-edge have been measured for 3d transition metal intercalation compounds M _x TiS₂ (M = Mn, Fe, Co and Ni; x ≤ 0.33). We have found that the interatomic distance between Ti and the first nearest neighbor S atoms, R(Ti-S), increases with the guest concentration x. The variation in XANES spectra with x reveals the reduction of the valence state of Ti atoms upon intercalation of M. From these results as well as the M K-edge EXAFS data studied previously, we have proposed a simple model on the local structure of M _x TiS₂ to reproduce the observed values of R(Ti-S) by averaging local shift of S atoms caused by intercalation.     

Thermodynamic Approach to Electrochemical Lithium Intercalation into Li1-δMn2O4 Electrode Prepared by Sol-Gel Method

Abstract

Electrochemical lithium intercalation into Li_1-δMn₂O₄ electrode prepared by sol-gel method was investigated from the thermodynamic view point by using galvanostatic intermittent titration technique (GITT) combined with EMF-temperature measurement. The electrode potential vs. lithium content curve was theoretically calculated with the aid of the lattice gas model based upon the Bragg-Williams approximation for the cubic spinel composed of two sub-lattices. Considering the considerable difference between both lithium contents in two sub-lattices due to the ordering of the intercalated lithium ions, the theoretical partial molar enthalpy and entropy were calculated at various lithium contents by a numerical method. From the comparison between the theoretical partial molar quantities and experimental results, the electrochemical lithium intercalation into the Li_1-δMn₂O₄ electrode was discussed in terms of the ordering of the intercalated lithium ions.     

Transport and Electrochemical Properties of Bi2Sr2CaCu2O8 Superconductors

Abstract

Electrical conductivity and thermoelectric power measurements (77–300K) of both the pure and electrochemically doped with lithium Bi₂Sr₂CaCu₂O₈ system, are presented. Clear correlation between transport and electrochemical properties of Li_xBi₂Sr₂CaCu₂O₈ was shown.     

Electronic Properties of Ba-Intercalated Fullerides

Abstract

Raman spectra have been measured on Ba_xC₆₀ binary systems for x=3, 4 and 6. The pentagonal pinch Ag(2) mode exhibits a softening in an approximately proportional manner to the formal valence of C₆₀ molecule. This result suggests that the valence of C₆₀ in Ba doped systems are understood by the naive ionic crystal model based on Ba²⁺. The broader Raman peaks in superconducting Ba₄C₆₀ indicates that the electron-phonon interaction is considerably large comparing to those for Ba₃C₆₀ and Ba₆C₆₀.     

Synthesis and Photocatalytic Properties of TiO2 Intercalated H4Nb6O17

Abstract

TiO₂ intercalated H₄Nb₆O₁₇ has been synthesized by the reactions of H₄Nb₆O₁₇ with a titanyl acylate complex followed by UV irradiation. The gallery height, specific surface area and Ti content of the sample synthesized by using titanyl acylate complex were larger than that using TiO₂ sol solution. Furthermore, the photocatalytic activity of the TiO₂ pillared H₄Nb₆O₁₇ prepared using a titanyl acylate precursor was twice larger than that fabricated using a TiO₂ sol solution.     

Synthesis and structure of 4,7,13,16-tetraoxa-1,10-diaza-5,6-benzocyclooctadeca-11,18-dione monohydrate

4,7,13,16-tetraoxa-1,10-diaza-5,6-benzocyclooctadeca-11,18-dione, C₁₆H₂₂N₂O₆·H₂O, (3) was synthesized under thermal conditions, starting from ,-diamine (1) and ,-diester (2). The hydrate of compound (3) was investigated in the solid state by X-ray structural analysis. Crystal data: monoclinic system, space group P2₁/c,a=12.342(4) Å,b=15.978(7) Å,c=8.960(3) Å, =96.72(3)°,Z=4. The structure was solved by direct methods and refined to finalR=0.056,R _w=0.069 for 1962 observed reflections. The structure exhibits internal hydrogen bonds between the etheral O(16) atom and the neighboring amide group. The water molecule connects diamide molecules by one strong hydrogen bond with carbonyl oxygen, and four weak hydrogen bonds with the amide groups and etheral oxygen atoms.     

Structural Influence on the Intensitiy Ratio of the T′ and T87Rb NMR Lines and the Superconductivity in Rb3C60

Abstract

The intensity ratio of the T′/T⁸⁷Rb NMR lines in Rb₃C₆₀ could be changed by different cooling rates after annealing at 380 °C. The results are discussed with respect to magnetically different surroundings of the Rb ions through the two standard orientations of the C₆₀ ^3-ions. Additionally, the superconducting volume fraction is influenced by the different cooling procedures.     

The Electronic Structures of (PH4)3C60 and (ClO4)3C60

Abstract

We have studied theoretically the electronic structures of a hypothetical donor-type material, (PH₄)₃C₆₀, and a hypothetical acceptor-type material, (ClO₄)₃C₆₀ from first principles by using a full-potential linear-combination-of-atomic-orbitals method based on the density-functional theory within the local-density approximation. It is found that the charge transfer from the PH₄ molecules to the C₆₀ molecules is perfect while the charge transfer from the ClO₄ molecules to the C₆₀ molecules is not perfect. We compare the latter result with the electronic structures of two typical acceptor-type organic conductors, (TMTSF)₂ClO₄ and (TMTSF)₂PF₆, and discuss the differences.     

Superconductivity in the Organic Charge Transfer Salts: (TMTSF)2X and (TMTTF)2X

Abstract

We report pressure dependent studies of the a-axis resistivity as a function of temperature for several members of the isostructural families of organic charge transfer salts, (TMTSF)₂X and (TMTTF) ₂X. For a typical (TMTSF)₂X material the low temperature metal-insulator transition seen at 1 bar is suppressed above some critical pressure, P_c, where a superconducting transition is observed near 1 K. We find a correlation between P_c and the ambient pressure c lattice parameter which reflects the anion size. The (TMTTF) _cX salts exhibit very different ambient pressure behaviour but we find that with the application of sufficiently high pressures (～30 kbar) their behaviour resembles that seen in the (TMTSF)₂X family but at lower pressures. In particular we find evidence of a possible superconducting transition near 4 K in (TMTTF)₂Br at 25 kbar. At this pressure the conductivity near 4 K is extremely high with a value approaching 10⁶ (Ωcm)^?1 and the resistivity ratio is about 400.     

Synthesis of Layered-Structure LiFeO2

Abstract

LiFeO₂, with a layered rocksalt structure of α-NaFeO₂-type was prepared by ion exchange reaction from Na⁺ ion to Li⁺ ion using α-NaFeO₂. α-NaFeO₂-type LiFeO₂ was synthesized by using the mixture of LiI and KI in the temperature range 220 to 480 °C. The heat treatment temperature of 600 °C gave α-LiFeO₂-type LiFeO₂ as a main product. As a result of Rietveld analysis, the structure of LiFeO₂ which assigned to α-NaFeO₂-type by an XRD measurement, was the mixture of α-NaFeO₂-type and Li-intercalated spinel-type structures.     

The effect of Zn-acetate molar variation on phase formation and photocatalytic degradation activity of Fe3O4/ZnO core-shell nanocomposite

Abstract

The aim of this research is to investigate the photodegradation of Methylene Blue with Fe₃O₄/ZnO core-shells. Fe₃O₄/ZnO core-shells were synthesized by a simple two-step chemical method (co-precipitation and precipitation) using a molar variation of Zn-acetate precursor. We found that the presence of Fe₂O₃ plays an important role in enhancement of photocatalytic activity due to the existence of higher concentration of surface oxygen vacancies and the suppressing effect of the Fe²⁺ ions on the recombination of photoinduced electron-hole pairs. The core-shell photocatalyst can be easily separated by using a commercial magnet without reduces photocatalytic efficiency within three times of recycling process.     

A novel Zn(II) coordination polymer based on tetra-carboxylates ligand and N-donor ligand: synthesis,structure and photocatalytic properties

Abstract

Novel film polymeric composites based on the non-photoconducting polyvinyl butyral with heterometallic complexes (NH₄)_4n{[Cu(en)(H₂O)][P₂Mo₅O₂₃]}_n·3.5nH₂O (1) and (NH₄)_2n{[Cu(en)₂][Cu(en)(H₂O)][P₂Mo₅O₂₃]}_n·3nH₂O (2) [en?=?ethylenediamine] have been prepared. Both compounds are similar and contain Strandberg anions [P₂Mo₅O₂₃]^6– linked to Cu-diamine species. The main structural difference between complexes is the presence of additional bridging [Cu(en)₂] fragments in 2, which provide an extra connectivity between the neighboring polyoxometalates. However, the different saturations and relaxation times of the photoresponse, as well as different activation energies, are shown. The variability of the photoconducting properties can be explained by the influence of a chain rigidity on the transport of non-equilibrium charge carriers.     

Advanced nanostructure Ti0.7In0.3O2 support enhances electron transfer to Pt: Used as high performance catalyst for oxygen reduction reaction

ABSTRACT

The slow rate of the oxygen reduction reaction (ORR) and the instability of Pt based catalysts are two of the most important issues which must be solved in order to make proton exchange membrane fuel cells (PEMFCs) a reality. Here, we present a new approach by exploring robust non-carbon Ti_0.7In_0.3O₂ used as a novel functionalised co-catalytic support for Pt. This approach is based on the novel nanostructure Ti_0.7In_0.3O₂ support with “electronic transfer mechanism” from Ti_0.7In_0.3O₂ to Pt that can modify surface electronic structure of Pt, owing to a shift in the d-band centre of the surface Pt atoms. The 20 wt% Pt/Ti_0.7In_0.3O₂ catalyst shows high activity than that of that of the commercial 20 wt% Pt/C (E-TEK). Our data suggest this enhancement is a result of both the electronic structure change of Pt upon its synergistic interaction with Ti_0.7In_0.3O₂ and the inherent structural and chemical stability and the corrosion-resistance of the Ti_0.7In_0.3O₂ in acidic and oxidative environments.     

Structural Analysis of the Layered Compounds Cu x TiS2

Abstract

A structural analysis of single crystals of the layered compounds Cu _x TiS₂ (x=0. 0.21 and 0.38), which were prepared by the iodine transport and the electrochemical methods, has been performed by X-ray diffraction. The displacement parameters of Ti and S atoms along the c axis are larger than those along the a axis. It is understood that the intra-layer bonding between Ti-Ti and S-S atoms is stronger than the inter-layer bonding between Ti-and S-layers. Both distances between Ti-and S-layers and between Cu-and S-layers are enlarged without changing the structure of the mother phase after intercalating Cu atoms.     

The molecular and crystal structure of endo-2-methyl-7-hydroxy-7-oxo-N-phenyl-7-phosphabicyclo-[2.2.1] hept-2-ene-5,6-dicarboximide

The structure of the title compound1 has been determined by X-ray crystallography analysis. The following crystal data were found: orthorhombic,Pca2_l,a=9.60691),b=16.356(1),c=8.686(1) . Both the phospholane and phospholene rings involved in the 7-phosphabicyclo-[2.2.1] hept-2-ene system have almost regular envelope conformations, and the cyclohexene ring has a significantly deformed boat conformation. The low value of the C–P–C angle, 84.2(2)°, reflects the steric strain around the phosphorus bridge and may be responsible for the reactivity of esters and amides derived from1 in the O-insertion reaction with m-chloro-perbenzoic acid. The dihedral angle between the plane of the benzene and succinimide rings is 82.4(2)°.     

Photocatalytic properties of TiO2/ZnO thin film

ABSTRACT

TiO₂, ZnO and ZnO/TiO₂ thin films have been prepared by radio frequency magnetron sputtering method under different temperatures. Their photo catalytic activities have been investigated. The structural of the thin films were characterized by X-ray diffraction and Raman spectroscopy. The photo catalytic activities of TiO₂ and ZnO/TiO₂ samples were evaluated by the photo decomposition of methylene blue. We note that the structural proprieties of the thin films showed a perfect crystallization along the (002) for ZnO, Rutile (110) for TiO₂ and Anatase (101) for TiO₂. The experimental results show that the bilayer ZnO/TiO₂ were the most efficient photo catalysts compared to the layer of TiO₂. This increased catalytic effect can attributed to the interface between the ZnO layer and the TiO₂ one, which modify significantly the chemical potential of the bilayer.     

Crystal structure of 5-(p-methoxyphenylamino)indane and AM1 calculations on N-arylamines derivatives, precursors of phenothiazine drugs

The structural determination by X-ray crystallography of the titled N-arylamine 4a, as well as AM₁ calculations on a series of derivatives (4b–c, 5a–c), are reported. The compound 4a is monoclinic P2₁/c with a = 7.656(3), b = 23.655(5), c = 7.686(9) Å, = 112.59(6)°, V = 1285.2(2) ų and Z = 4. This structure has been used as a template for the building of some others derivatives used for AM₁ calculations. The results show that the cyclization position on the aromatic rings, which can lead to two regioisomers, depends on the nature of the benzylic substituants.