A New Organic-Inorganic Hybrid Nanocomposite, BEDT-TTF Intercalated into Layered FePS3

A new inorganic–organic hybrid compound, Fe_0.76PS₃(BEDT-TTF)_0.48 (BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene), has been synthesized by the reaction of the pre-intercalate Fe_0.90PS₃(Phen)_0.41 (phen=1,10-phenanthroline) with (BEDT-TTF)₂I_x. The powder X-ray diffraction (XRD) results show that the expansion of the lattice spacing (Δ d) is about 4.0 Å compared with the pristine FePS₃, indicating that the molecular ring plane of the guest is parallel to the layer of the host. The infrared spectrum of the intercalate shows the existence of BEDT-TTF as a guest between the interlayer region of the layered FePS₃. The room-temperature electrical conductivity of the compressed pellet of Fe_0.76PS₃(BEDT-TTF)_0.48 is about 10^?7 S/cm, which is in the same order of magnitude as that of the pristine FePS₃(10^?7 S/cm). The magnetic properties measured with a SQUID-magnetometer indicate that Fe_0.76PS₃(BEDT-TTF)_0.48 exhibits the paramagnetism from 120 to 300 K and Curie-Weiss Law was obeyed above 140 K, but a strong antiferromagnetic phase transition occurs at T_N of 100 K.     

The Intercalation of 4-Aminopyridine into Layered FePS 3

A new intercalation compound,Fe_0.81PS₃(4-aminopyridineH)_0.38, issynthesized by the direct reaction of4-aminopyridine with layered FePS₃ inthe presence of acetic acid.From the XRD results it was found that there aretwo phases (Phase I and Phase II)in this intercalation compound and that4-aminopyridines as the guests adopt twodifferent orientations between theinterlayer region of the host (FePS₃).In one of them with the latticeexpansion (d) of 6.0 Å thering plane of the guest is perpendicular to thelayer and in the other with d of3.4 Å the ring plane of the guest is parallel tothe layer of the host. The IR spectraimply that the inserted guests take theprotonated form to maintain the charge balanceof the intercalation compound.Magnetic measurements indicate thatFe_0.81PS₃(4-aminopyridineH)_0.38 exhibitsparamagnetism in the range of measurementtemperature (1.8 : 300 K),where the magnetic behavior is wellin agreement with the Curie-Weiss Lawabove 55 K.     

The Intercalation Reaction of 1,10-Phenanthroline with Layered Compound FePS3

The intercalation reaction of 1,10-phenanthroline with FePS₃ in ethanol and in the presence of anilinium chloride has been monitored in detail with the X-ray powder diffraction (XRD) method to study the reaction mechanism. It is revealed that during the intercalation period there are three phases: the 001 phase (corresponding to the perpendicular orientation of the 1,10-phenanthroline ring with the layer of the host FePS₃), the 001′ phase (standing for the parallel orientation of the 1,10-phenanthroline ring with the layer), and the 001″ phase (pristine FePS₃), but as the period of the reaction is prolonged, the 001′ and 001″ phases diminish gradually and finally disappear, and the 001 phase is intensified and a complete intercalate is obtained for Series A, in which excess 1,10-phenanthroline is used. However, for Series B in which the optimum amount of 1,10-phenanthroline is used, the 001 and 001″ phases diminish gradually, and another intercalate is obtained that exhibits the 001′ phase. Moreover, if the amount of phenanthroline used in the reaction is more than that in Series B but not in excess, another intercalate containing 001 and 001′ phases is obtained. In these intercalation reactions, the results of IR spectroscopy indicate that anilinium chloride serves only as the source of protons for 1,10-phenanthroline, but 1,10-phenanthroline acts as both the complexing agent of Fe²⁺ ions removed from FePS₃, confirmed by UV spectra of the filtrates, and the inserted guest, some of which exists in the form of protonated cation to maintain the charge balance of the intercalates. From the experimental evidence we find that the arranged orientation of 1,10-phenanthroline between the layers is controlled by the amount of guest used in the reaction, and a possible intercalation mechanism is proposed for the reaction.     

Mössbauer spectra of (Fe0.5Zn0.5)PS3 and its pyridine intercalate

Mössbauer spectra of (Fe_0.5Zn_0.5)PS₃, which is isomorphous with FePS₃, were measured at 300 and 80 K, and were compared with those of FePS₃. We succeeded in preparing (Fe_0.5Zn_0.5)PS₃ intercalated with pyridine. In the XRD pattern of the intercalate the diffraction peaks corresponding to (Fe_0.5Zn_0.5)PS₃ were completely missing, suggesting that the intercalation was completely performed with pyridine. The Mössbauer spectra were changed significantly by the intercalation suggesting the charge transfer from guest molecules to the host matrix. The replacement of iron by zinc has no influence on the electronic state of the iron atom, except for the magnetic interaction.     

An inorganic–organic intercalated nanocomposite, BEDT-TTF into layered MnPS3

In this paper we report the synthesis and magnetic properties of an inorganic–organic hybrid, Mn_0.84PS₃(BEDT-TTF)_0.35 (BEDT-TTF = bis(ethylenedithio) tetrathiafulvalene), which is obtained by the intercalation of pre-intercalation compound Mn_0.90PS₃(Phen)_0.32 (Phen = 1,10-phenanthroline) with (BEDT-TTF)₂I_x. The lattice spacing expansion (Δd) of 4.0 Å compared with the pristine MnPS₃ indicates that the molecular plane of BEDT-TTF is arranged parallel to the host layer. From the magnetic measurements it was found that two magnetic phase transitions occur. Above 50 K it shows paramagnetism in well agreement with Curie–Weiss law. Around 40 K it exhibits spin-glass transition and at 5 K a ferrimagnetic phase transition occurs, which is confirmed by M–H at different temperatures.     

Properties of the perovskites, SrMn1−xFexO3−δ (x=1/3, 1/2, 2/3)

The SrMn_1−xFe_xO_3−δ (x=1/3, 1/2, 2/3) phases have been prepared and are shown by powder X-ray and neutron (for x=1/2) diffraction to adopt an ideal cubic perovskite structure with a disordered distribution of transition-metal cations over the six-coordinate B-site. Due to synthesis in air, the phases are oxygen deficient and formally contain both Fe³⁺ and Fe⁴⁺. Magnetic susceptibility data show an antiferromagnetic transition at 180 and 140 K for x=1/3 and 1/2, respectively and a spin-glass transition at 5, 25, 45 K for x=1/3, 1/2 and 2/3, respectively. The magnetic properties are explained in terms of super-exchange interactions between Mn⁴⁺, Fe^(4+δ)+ and Fe⁽³⁺⁾⁺. The XAS results for the Mn-sites in these compounds indicate small Mn-valence changes, however, the Mn-pre-edge spectra indicate increased localization of the Mn-e_g orbitals with Fe substitution. The Mössbauer results show the distinct two-site Fe⁽³⁺⁾+/Fe^(4+δ)+ disproportionation in the Mn- substituted materials with strong covalency effects at both sites. This disproportionation is a very concrete reflection of a localization of the Fe-d states due to the Mn-substitution.     

Synthesis of [(μ-RS)(μ-S){Fe2(CO)6}2(μ4-S)] and their reactivity toward electrophiles

Reaction of the Et₃NH⁺ salts of the [(μ-RS)(μ-CO)Fe₂(CO)₆]⁻ anions (R=Bu^t, Ph or PhCH₂) with (μ-S₂)Fe₂(CO)₆ gives reactive intermediates [(μ-RS)(μ-S){Fe₂(CO)₆}₂(μ₄-S)]⁻. Reactions of the latter with alkyl halides, acid chlorides and Cp(CO)₂FeI have been studied. X-Ray structure of (μ-Bu^tS)(μ-PhCH₂S)[Fe₂(CO)₆]₂(μ₄-S) was determined.     

以[M(DETA)2)]n+(M=Cu2+, Ni2+, Co3+)为客体的MnPS3夹层化合物的合成、结构表征与磁性研究

将过渡金属配合物阳离子([M(DETA)₂]ⁿ⁺(M=Cu²⁺,Ni²⁺,Co³⁺;DETA=Diethylenetriamine,二乙烯三胺)作为客体插入层状MnPS₃层间得到了相应的3个夹层化合物。通过X-射线粉末衍射、元素分析和红外光谱对夹层化合物的结构进行了表征。结果表明,与主体MnPS₃ 0.65 nm的层间距相比较,夹层化合物(Mn_0.88PS₃[Cu(DETA)₂]_0.12)的层间距扩大了0.32 nm,由此推测客体[Cu(DETA)₂]²⁺在层间以平面四方的配位形式存在,而另2个夹层化合物(Mn_0.79PS₃[Ni(DETA)₂]_0.21和Mn_0.74PS₃[Co(DETA)₂]_0.17)的层间距扩大了0.48 nm,说明客体[(M(DETA)₂]ⁿ⁺,M=Co³⁺,Ni²⁺) 在主体层间以八面体配位形式存在。磁性测试结果表明过渡金属离子[(M(DETA)₂]ⁿ⁺(M=Cu²⁺,Co³⁺)的插入能引起主体MnPS₃的磁性在35~40 K发生由顺磁向亚铁磁性的转变并表现自发磁化,而客体[Ni(DETA)₂]²⁺却使夹层化合物的反铁磁相互作用增强,抑制了自发磁化的发生。     

Chitosan–iron oxide nanobiocomposite based immunosensor for ochratoxin-A

The rabbit immunoglobulin antibodies (IgGs) have been immobilized onto nanobiocomposite film of chitosan (CH)–iron oxide (Fe₃O₄₎ nanoparticles prepared onto indium–tin oxide (ITO) electrode for detection of ochratoxin-A (OTA). Excellent film forming ability and availability of –NH₂ group in CH and affinity of surface charged Fe₃O₄ nanoparticles for oxygen support the immobilization of IgGs. Differential pulse voltammettry (DPV) studies indicate that Fe₃O₄ nanoparticles provide increased electroactive surface area for loading of IgGs and improved electron transport between IgGs and electrode. IgGs/CH–Fe₃O₄ nanobiocomposite/ITO immunoelectrode exhibits improved characteristics such as low detection limit (0.5 ng dL⁻¹), fast response time (18 s) and high sensitivity (36 μA/ng dL⁻¹ cm⁻²) with respect to IgGs/CH/ITO immunoelectrode.     

Energetics of copper diphosphates – Cu2P2O7 and Cu3(P2O6OH)2

Differential scanning calorimetry and high temperature oxide melt solution calorimetry are used to study enthalpy of phase transition and enthalpies of formation of Cu₂P₂O₇ and Cu₃(P₂O₆OH)₂. α-Cu₂P₂O₇ is reversibly transformed to β-Cu₂P₂O₇ at 338–363 K with an enthalpy of phase transition of 0.15 ± 0.03 kJ mol⁻¹. Enthalpies of formation from oxides of α-Cu₂P₂O₇ and Cu₃(P₂O₆OH)₂ are −279.0 ± 1.4 kJ mol⁻¹ and −538.8 ± 2.7 kJ mol⁻¹, and their standard enthalpies of formation (enthalpy of formation from elements) are −2096.1 ± 4.3 kJ mol⁻¹ and −4302.7 ± 6.7 kJ mol⁻¹, respectively. The presence of hydrogen in diphosphate groups changes the geometry of Cu(II) and decreases acid–base interaction between oxide components in Cu₃(P₂O₆OH)₂, thus decreasing its thermodynamic stability.     

X-ray diffraction and Mössbauer spectroscopy studies of LiFe0.5Ti1.5O4 – A new primitive cubic ordered spinel

LiFe_0.5Ti_1.5O₄ was synthesized by solid-state reaction carried out at 900 °C in flowing argon atmosphere, followed by rapid quenching of the reaction product to room temperature. The compound has been characterized by X-ray powder diffraction (XRD) and ⁵⁷Fe Mössbauer effect spectroscopy (MES). It crystallizes in the space group P4₃32, a = 8.4048(1) Å. Results from Rietveld structural refinement indicated 1:3 cation ordering on the octahedral sites: Li occupies the octahedral (4b) sites, Ti occupies the octahedral (12d) sites, while the tetrahedral (8c) sites have mixed (Fe/Li) occupancy. A small, about 5%, inversion of Fe on the (4b) sites has been detected. The MES data is consistent with cation distribution and oxidation state of Fe, determined from the structural data.The title compound is thermally unstable in air atmosphere. At 800 °C it transforms to a mixture of two Fe³⁺ containing phases – a face centred cubic spinel Li_(1+y)/2Fe_(5−3y)/2Ti_yO₄ and a Li_(z−1)/2Fe_(7−3z)/2Ti_zO₅ – pseudobrookite. The major product of thermal treatment at 1000 °C is a ramsdellite type lithium titanium iron(III) oxide, accompanied by traces of rutile and pseudobrookite.     

Ion Transfer in CdF<Subscript>2</Subscript>-based Iso- and Polyvalent Solid Solutions

The ionic conductivity of solid solution Cd_0.77Sr_0.23F₂ is 1.6 × 10⁻⁴ S/cm at 500 K. The conduction mechanism changes from a vacancy mechanism to an interstitial one at 523–553 K. In solid solutions Cd_0.9R_0.1F_2.1 (R = La-Lu, Y), the activation enthalpy of conduction decreases from 0.9 to 0.8 eV with decreasing ionic radius of R³⁺, raising the 500-K conductivity from 6 ×10⁻⁶ S/cm for La³⁺to 6 × 10⁻⁵ S/cm for Lu³⁺. For crystalline Cd_0.95In_0.05F_2.05, ionic and electronic conductivities at 313 K equal 5 × 10⁻⁴ and 5 − 10⁻⁶ S/cm.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 627–632.Original Russian Text Copyright © 2005 by Sorokin, Buchinskaya, Sul’yanova, Sobolev.     

Kinetics of adsorption of Saccharomyces cerevisiae mandelated dehydrogenase on magnetic Fe3O4–chitosan nanoparticles

The adsorption of Saccharomyces cerevisiae mandelated dehydrogenase (SCMD) protein on the surface-modified magnetic nanoparticles coated with chitosan was studied in a batch adsorption system. Functionalization of surface-modified magnetic particles was performed by the covalent binding of chitosan onto the surface of magnetic Fe₃O₄ nanoparticles. Characterization of these particles was carried out using FTIR spectra, transmission electron micrography (TEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM). Magnetic measurement revealed that the magnetic Fe₃O₄–chitosan nanoparticles were superparamagnetic and the saturation magnetization was about 37.3 emu g⁻¹. The adsorption capacities and rates of SCMD protein onto the magnetic Fe₃O₄–chitosan nanoparticles were evaluated. The adsorption capacity was influenced by pH, and it reached a maximum value around pH 8.0. The adsorption capacity increased with the increase in temperature. The adsorption isothermal data could be well interpreted by the Freundlich isotherm model. The kinetic experimental data properly correlated with the first-order kinetic model, which indicated that the reaction is the adsorption control step. The apparent adsorption activation energy was 27.62 kJ mol⁻¹ and the first-order constant for SCMD protein was 0.01254 min⁻¹ at 293 K.     

Etude des propriétés de conduction électrique des polyphosphates: Li3Ba2(PO3)7, LiPb2(PO3)5, LiCs(PO3)2, et αLiK(PO3)2

The electrical conductivity of the crystallized polyphosphates Li₃Ba₂(PO₃)₇, LiPb₂(PO₃)₅, LiCs(PO₃)₂, and αLiK(PO₃)₂ has been determined at different temperatures by impedance spectroscopy. The conductivity, σ, spreads within a range of 1.59 × 10⁻⁸ to 1.79 × 10⁻⁷ S cm⁻¹ at 573 K, and from 1.71 × 10⁻⁵ to 9.86 × 10⁻⁴ S cm⁻¹ at 773 K. The transport should be assumed in the majority by the lithium ions with regard to the structural characteristics of these polyphosphates. The results are discussed and compared to the conductivity properties of other lithium ion conductors.     

Electron spin resonance spectra observed in the course of grafting iron carbonyls on sodium-Y zeolites

The adsorption and/or decomposition pathway of Fe₂(CO)₉ or Fe₃(CO)₁₂ on hydrated or dehydrated NaY zeolites has been studied by an ESR technique. The adsorption resulted in the formation of three paramagnetic species withg _iso=2.0450, 2.0378, and 2.0016, which were attributable to Fe₃(CO)₁₁ ^–, Fe₂(CO)₈ ^–, and Fe(CO)₄ ^– anion radicals, respectively. These radicals have been suggested as intermediates in the formation of HFe₃(CO)₁₁ ^– on the hydrated NaY zeolite and Fe₃(CO)₁₂ on the dehydrated NaY zeolite.     

Magnetic behavior of MnPS3 phases intercalated by [Zn2L] (LH2: macrocyclic ligand obtained by condensation of 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and 1,2-diaminobenzene)

The intercalation of the cationic binuclear macrocyclic complex [Zn₂L]²⁺ (LH₂: macrocyclic ligand obtained by the template condensation of 2-hydroxy-5-methyl-1,3-benzenedicarbaldehyde and 1,2-diaminobenzene) was achieved by a cationic exchange process, using K_0.4Mn_0.8PS₃ as a precursor. Three intercalated materials were obtained and characterized: (Zn₂L)_0.05K_0.3Mn_0.8PS₃(1), (Zn₂L)_0.1K_0.2Mn_0.8PS₃(2) and (Zn₂L)_0.05K_0.3Mn_0.8PS₃(3), the latter phase being obtained by an assisted microwave radiation process. The magnetic data permit to estimate the Weiss temperature θ of ≈−130 K for (1); ≈−155 K for (2) and ≈−130 K for (3). The spin canting present in the potassium precursor remains unperturbed in composite (3), and spontaneous magnetization is observed under 50 K in both materials. However composites (1) and (2) do not present this spontaneous magnetization at low temperatures.The electronic properties of the intercalates do not appear to be significantly altered. The reflectance spectra of the intercalated phases (1), (2) and (3) show a gap value between 1.90 and 1.80 eV, lower than the value observed for the K_0.4Mn_0.8PS₃ precursor of 2.8 eV.     

Electrophilic attacks on μ3-bridging acetyl in a triiron carbonyl cluster; C---O bond cleavage to give μ3-ethylidyne and μ-methoxo groups

The triiron carbonyl cluster anion, [Fe₃(CO)₉(μ₃-CH₃CO)]⁻ react with fluoroboric acid to give the neutral cluster Fe₃(CO)₉(μ-H)(μ₃-CH₃CO). Methylfluorosulphate reacts to give the compound Fe₃(CO)₉(μ₃-CCH₃) (μ₃-OCH₃) in which the μ₃-acetyl group has undergone stoichiometric C---O bond cleavage.     

Solubility of (UO2)3(PO4)2?4H2O in H+-Na+-OH?-H2PO?4-HPO2?4-PO3?4-H2O and Its Comparison to the Analogous PuO2 +2 System

The objectives of this study were to address uncertainties in the solubility product of (UO₂)₃(PO₄)₂⋅4H₂O(c) and in the phosphate complexes of U(VI), and more importantly to develop needed thermodynamic data for the Pu(VI)-phosphate system in order to ascertain the extent to which U(VI) and Pu(VI) behave in an analogous fashion. Thus studies were conducted on (UO₂)₃(PO₄)₂⋅4H₂O(c) and (PuO₂)₃(PO₄)₂⋅4H₂O(am) solubilities for long-equilibration periods (up to 870 days) in a wide range of pH values (2.5 to 10.5) at fixed phosphate concentrations of 0.001 and 0.01 M, and in a range of phosphate concentrations (0.0001–1.0 M) at fixed pH values of about 3.5. A combination of techniques (XRD, DTA/TG, XAS, and thermodynamic analyses) was used to characterize the reaction products. The U(VI)-phosphate data for the most part agree closely with thermodynamic data presented in Guillaumont et al.,⁽¹⁾ although we cannot verify the existence of several U(VI) hydrolyses and phosphate species and we find the reported value for formation constant of UO₂PO⁻₄ is in error by more than two orders of magnitude. A comprehensive thermodynamic model for (PuO₂)₃(PO₄)₂⋅4H₂O(am) solubility in the H⁺-Na⁺-OH⁻-Cl⁻-H₂PO⁻₄-HPO²⁻₄-PO³⁻₄-H₂O system, previously unavailable, is presented and the data shows that the U(VI)-phosphate system is an excellent analog for the Pu(VI)-phosphate system.     

Reactions of M3Te7 (M = Mo, W) clusters with electrophilic reagents: Chalcogen exchange in the Te2 ligand and the first complexes of (TeS)

Reactions of triangular telluride-bridged Mo and W clusters [M₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺ (M = Mo, W; dtp = (EtO)₂PS₂) with S₂Cl₂ or Br₂ lead to Te/S exchange in the Te₂ ligands, with the formation of complexes with a novel TeS²⁻ ligand. Reaction of [W₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺ with Br₂ or S₂Cl₂ gives a mixture of complexes formulated as [W₃Te_4.25S_2.75(dtp)₃]⁺ and [W₃Te_4.30S_2.70(dtp)₃]⁺, respectively, on the basis of X-ray structural analysis. Reaction of the Mo homolog, namely [Mo₃(μ₃-Te)(μ₂-Te₂)₃(dtp)₃]⁺, with S₂Cl₂ gives rise to [Мо₃Te_4.74S_2.26((EtO)₂PS₂)₃]⁺. Electrospray ionization mass spectrometry (ESI-MS) complements the information gathered from X-ray analysis regarding the degree of Te by S substitution; moreover, detailed insights on the regioselectivity of such replacement are also obtained from ESI-MS analysis. These experimental evidences indicate that Te by S replacement in W complexes display high regioselectivity (as evidenced by the exclusive formation of a W₃Te₄S₃⁴⁺ core), the equatorial Te ligands being preferentially replaced over the Te_ax and μ₃-Te ligands. Conversely, for the Mo homologs, a broad distribution of Mo₃Te_7−xS_x⁴⁺ cluster species ranging from x = 0 to 6 is observed. Bond distance analysis as well as crystal packing trends as a function of the cluster core M₃Te_7−xS_x⁴⁺ (M = Mo, W; x = 0–6) composition are also reported.     

Magnetic/Conducting Hybrid Compound Composed of 1-D Chain [Mn2Cl5(EtOH)]∞ and BEDT-TTF Stacking Layer

An assembled compound (BEDT-TTF)₂[Mn₂Cl₅(EtOH)] (1) consisting of two structural lattices of Mn(II)-Cl one-dimensional (1-D) chains and bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) stacking layers was synthesized by electrochemical crystallization. Compound 1 crystallized in triclinic space group P-1 (#2) with a=13.1628(5) Å, b=20.3985(9) Å, c=7.4966(3) Å, α=98.3498(8)°, β=104.980(1)°, γ=74.602(2)°, V=1868.3(1) ų, and Z=2. The 1-D chains and the stacking layers are aligned along the c-axis of the unit cell. The 1-D chain is described as [Mn₂Cl₅(EtOH)]_∞⁻ in which two Mn(II) ions and four Cl⁻ ions form a ladder-like chain with Kagomé (cuboidal) sublattices, and the remaining Cl⁻ ion and an ethanol molecule cap the edge-positioned Mn(II) ions of the chains. The BEDT-TTF molecules are packed between the Mn-Cl chains (ac-plane), the intermolecular S·S contacts of which are approximately found in the range 3.440(2)-3.599(2) Å. The packing feature of BEDT-TTF molecules is very similar to that of (BEDT-TTF)₂ClO₄(TCE)_0.5 (TCE=1,1,2-trichloroethane) (J. Am. Chem. Soc., 105, 297 (1983)). Regarding the electronic state of each BEDT-TTF molecule, Raman spectroscopic analysis and ESR study revealed the presence of half-valence BEDT-TTF molecules (charge delocalization) in 1. Magnetic measurements clearly demonstrated that the paramagnetic spins on the 1-D chain [Mn₂Cl₅(EtOH)]_∞⁻ arrange antiferromagnetically in the low-temperature region. Additionally, 1 exhibits metallic conductivity in the temperature range 2.0-300 K (σ=21 S cm⁻¹ at 300 K and 1719 S cm⁻¹ at 2.0 K), due to the contribution of the stacked BEDT-TTFs. Consequently, these peculiarities that correspond to antiferromagnetic/metallic conductivity demonstrate the “bi-functionality” of 1.