[Fe(CO)2P(OPh)32(CS)]. The first stable thiocarbonyl derivative of iron(0) pentacarbonyl

In some circumstances, P-nBu₃ pr P-nBu₃/CC1₄ desulphurises [Fe(CO)₂{P(OPh)₃}₂(CS₂)] to give [Fe(CO)₂{P(OPh)₃}₂(CS)] which has trigonal bipyramidal coordination about the iron atom with the phosphite ligands in axial positions.     

Investigation on The Thermal Properties of Fe2O(SO4)2. Part I

The data on the thermal decomposition of FeSO₄?H₂O upon various regimes of heating and gaseous environment prove the formation of intermediate products of the types Fe₂O(SO₄)₂ and FeOHSO₄, their stability and amount being determined mainly by temperature and oxygen-reduction potential.

This communication aims at presenting results on the synthesis and characterization of Fe₂O(SO₄)₂. The synthesis was carried out using a laboratory thermal equipment operating under isothermal conditions in the temperature range 713–813 K in a gaseous environment either poor in oxygen or containing 100% oxygen. The experimental conditions under which Fe₂O(SO₄)₂ is stable are established. The effect of three basic parameters on the synthesis of Fe₂O(SO₄)₂ is clarified: the oxygen partial pressure, the ratio P_H2O/P_O2 and the temperature and the mode of heating. Mössbauer spectroscopy and X-ray diffraction data for Fe₂O(SO₄)₂ are presented.

     

Investigation on The Thermal Properties of Fe2O(SO4)2. Part II

Fe₂O(SO₄)₂ is a secondary product of the decomposition of FeSO₄⋅H₂O. Part I of this study presents results on the synthesis of Fe₂O(SO₄)₂ in gaseous environment containing either low or high concentration of oxygen. In this paper the existence of differences between the structures of Fe₂O(SO₄)₂ and Fe₂(SO₄)₃ is proved on the basis of a detailed thermal study of Fe₂O(SO₄)₂ upon dynamic heating (differential thermal analysis) and upon isothermal heating (thermal-analytic balance) in various gaseous environments as well as by presenting kinetic data on the processes of decomposition of both compounds. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kinetics of Fe(III) → Fe(0) Reduction on Aluminum in Aqueous Solutions

The reduction of iron(III) ions by dispersed aluminum in chloride-containing aqueous solutions and the influence exerted by the initial iron(III) ion concentration and the degree of aluminum dispersion on the kinetics of the process were studied.     

常温自旋交叉配合物[Fe(dpp)(Mepy)2(NCS)2]的合成与磁性研究

设计制备了一个新的常温自旋交叉配合物[Fe(dpp)(Mepy)2(NCS)2]。通过元素分析、红外光谱、电喷雾质谱和紫外光谱等方法对该配合物进行结构表征。变温磁化率研究发现该配合物的自旋转换温度Tc为330K。通过与同体系其他配合物的比较发现,配体的修饰对自旋交叉临界温度以及回滞宽度都有显著影响。     

Reactions at the interface of ultrathin Fe films deposited on ZnO(0 0 0 1) and ZnO(0 0 0−1) single crystal substrates

In this work we focus on the chemical interactions at the interface formed during the room temperature deposition of thin Fe films on polar ZnO surfaces via electron beam evaporation. The Fe is found to grow in layers and to form polycrystalline, disordered films. At the interface a considerable reaction takes place. By X-ray photoelectron spectroscopy, the formation of Fe²⁺ and metallic zinc species is detected.     

Sorption of ruthenium-97 on Fe2O3, Fe(OH)3 and Fe(OH)2 precipitates

Summary The effect of pH on the sorption of ruthenium-97 on Fe₂O₃, Fe(OH)₃ and Fe(OH)₂ precipitates was studied by radiotracer technique. The sorption characteristics of Fe₂O₃, Fe(OH)₃ and Fe(OH)₂ sorbents have been established. Iron(II) hydroxide can be used for the preconcentration of ruthenium-97 or generally of trace amounts of ruthenium, without regard to the oxidation state of ruthenium. The effect of duration of the contact between the hydroxide sorbent and ruthenium-97 in solution was also studied.

---

Zusammenfassung Der Einfluß des pH auf die Adsorption von⁹⁷Ru an Fe₂O₃,- Fe(OH)₃-und Fe(OH)₂-Niederschlägen wurde radiochemisch untersucht. Die Sorptionsmerkmale der erwähnten Adsorptionsmittel wurden festgestellt. Eisen-(II)hydroxid kann für die Anreicherung von⁹⁷Ru oder allgemein von Rutheniumspuren ohne Rücksicht auf deren Oxydationsstufe verwendet werden. Der Einfluß der Berührungsdauer zwischen adsorbierendem Hydroxid und⁹⁷Ru in der Lösung wurde gleichfalls untersucht.

     

Magnetic susceptibility measurements on K2Pt(CN)4Br0.3 · nH2O single crystals

Static magnetic susceptibilities of single crystals of the mixed-valence platinum compound K₂Pt(CN)₄Br_0.3 · nH₂O (KCP) are reported exemplifying the difficulties encountered at the measurements. The measurements have been carried out by means of a vacuum microbalance following the Faraday method at temperatures between 4 and 148 K and at field strengths between 6 and 20 kOe. The difficulties relate to: (1) the possible contamination by ferromagnetic impurities; (2) the non-cylindrical symmetry of the field around the axis of rotation of the magnet and the off-axis location of the sample holder; (3) the occurrence of free radicals after degradation of the material; (4) the parasitic effect of microgram quantities of oxygen adsorbed on the samples below 50 K; (5) the determination of the weak Pauli paramagnetism of the “quasi one-dimensional metallic” conductor above 65 K; and (6) the need for more accurate susceptibility references for the determination of n, the water content, by susceptibility measurements.The gram-susceptibility of KCP at 65 K, for which n is estimated to be 1.5, is analysed to be ? 3.60 × 10^?7 emu g^?1 and ? 3.83 × 10^?7 emu g^?1 for the magnetic field vector being respectively parallel and perpendicular to the c-axis of the crystals. The 6 percent anisotropy is mainly attributed to the triple bond in the CN group.     

A stable carbonyl-pyrazine-metal(0) complex: Synthesis and characterization of cis-tetracarbonylpyrazinetrimethylphosphitetungsten(0)

Pentacarbonylpyrazinetungsten(0), (CO)₅W(pyz), is not stable in solution in polar solvents such as acetone or dichloromethane and undergoes conversion to a bimetallic complex, (CO)₅W(pyz)W(CO)₅ plus free pyrazine. These three species exist at equilibrium. Using the quantitative ¹H NMR spectroscopy, the equilibrium constant could be determined to be K_eq = (5.9 ± 0.8) × 10⁻² at 25 °C. Introducing a second pyrazine ligand into the molecule does not stabilize the complex, as cis-W(CO)₄(pyz)₂ was found to be less stable than W(CO)₅(pyz) and, therefore, could not be isolated. However, introducing trimethylphosphite as a donor ligand into the complex leads to the stabilization of the carbonyl-pyrazine-metal(0) complexes, as shown by the synthesis of cis-W(CO)₄[P(OCH₃)₃](pyz). This complex could be isolated from the reaction of the photogenerated W(CO)₄[P(OCH₃)₃](tetrahydrofuran) with trimethylphosphite upon mixing for 2 h at 10 °C in tetrahydrofuran and characterized by elemental analysis, IR, MS, ¹H, ¹³C, and ³¹P NMR spectroscopy.     

Synthesis and Magnetic Properties of Fe(II) and Nd(III) Complexes of Poly(N-2-thiazolylacrylamide)

In recent years,the organic ferromagnets have drawn growing attention due to their characteristics of structural diversities,low density,and readily processing1-3.Design and synthesis of magnetic polymers are one of great challenges in today′s magnetic material research,and some significant achievements have been made in this field4,5.In this article,we describe the synthesis of acrylamide-type polymer with pendent thiazolyl groups(Scheme1).The as-prepared polymer exhibited better solubility …     

常温自旋交叉配合物[Fe(dpp)(Mepy)2(NCS)2]的合成与磁性

设计制备了一种新的常温自旋交叉配合物[Fe(dpp)(Mepy)2(NCS)2]. 通过元素分析、红外光谱、电喷雾质谱和紫外光谱等测试技术对该配合物进行了结构表征. 变温磁化率研究发现,该配合物的自旋转换温度Tc=330 K. 通过与同体系其它配合物的比较发现,配体的修饰对自旋交叉临界温度以及回滞宽度均有显著影响.     

Redox chemistry of [Fe2(CN)10]4−. Part 5. Reaction with thiourea

The reaction of the dimeric iron(III) complex [Fe2(CN)10]4– with a large excess of thiourea, tu, takes place in a series of stages, the first two of which have been examined in detail. The first stage is a one equivalent outer sphere electron transfer to form [Fe2– (CN)10]5– and the radical cation tu+· which dimerises to form the disulfide tu22+. There is kinetic evidence for the formation of a significant proportion of a precursor complex [Fe2(CN)10]4–·tu at high concentrations of tu. The second stage involves cleavage of the mixed valence dimer to yield [Fe(CN)5tu]2– and [Fe(CN)5H2O]3–. On standing, substitution of H2O by tu and oxidation by air occurs slowly, and finally all of the original iron is observed as [Fe(CN)5tu]2–.     

Redox chemistry of [Fe2(CN)10]4−. Part I. Reaction with iodide

The iron(III) dimeric complex [Fe₂(CN)₁₀]⁴⁻ is reduced to the iron(III)iron(II) species [Fe₂(CN)₁₀]⁵⁻ by iodide ion, the equilibrium constant being strongly dependent upon the nature of the alkali metal cation, reduction being favoured in the sequence: Cs⁺>NH ₄ ⁺ ≥K⁺>Na⁺>Li⁺. The reaction kinetics are autocatalytic in character, the catalytic species being the mixed valence dimer. The rates of reactions are also strongly catalysed by alkali metal cations, in the same sequence as for the equilibrium constants. The reaction mechanism involves the formation of I ₂ ⁻ as a reactive intermediate which can be oxidised by both [Fe₂(CN)₁₀]⁴⁻ and [Fe₂(CN)₁₀]⁵⁻.     

Formal Co(0), Fe(0), and Mn(0) complexes with NHC and styrene ligation

The limited knowledge on low-coordinate zero-valent transition-metal species has intrigued great synthetic efforts in developing ligand sets for their stabilization. While the combined ligand set of N-heterocyclic carbene (NHC) with vinylsilanes was the only known ligand system amenable to the stabilization of three-coordinate formal zero-valent cobalt, iron, and manganese complexes, the exploration on other ligands has proved that the ligand set of NHCs with styrene is equally effective in stabilizing three-coordinate formal zero-valent metal complexes in the form of (NHC)M(η²-CH₂CHPh)₂ (NHC = IPr, IMes; M = Co, Fe, Mn). These styrene complexes can be prepared by the one-pot reactions of MCl₂ with styrene, NHC and KC₈, and have been characterized by various spectroscopic methods. Preliminary reactivity study indicated that the interaction of [(IMes)Fe(η²-CH₂CHPh)₂] with DippN₃ produces the iron(IV) bisimido complex [(IMes)Fe(NDipp)₂] and styrene, which hints at the utility of these zero-valent metal styene complexes as synthons of the mono-coordinate species (NHC)M(0).     

自旋交叉配合物[Fe(ttd)2(NCS)2]·H2O的合成和磁性研究

The ligand ttd(ttd=1,4,8,9-Tetraaza-triphenylene-2,3-dicarbonitrile) and a novel spin crossover complex [Fe(ttd)₂(NCS)₂]·H₂O were synthesized, and characterized by elemental analysis, IR, MS, and UV-vis spec-troscopy. The temperature dependence of magnetic susceptibility shows that there are a little break between 150～190K and an unusual step transition with a 50K width between 190～240K. Compared with the other complexes with the resemble structure, it can be found that the influence of ligand is very notable.     

Studies on the solvatochromism of Fe(CN)2(phen)2

Summary The influence of organic solvents on the electronic spectra of Fe(CN)₂(phen)₂ has been investigated by trichromatic colorimetry. The color parameters of these solutions have been calculated on the basis of the absorption spectra and are described in the CIE and CIELAB color spaces. It has been shown that one of the parameters (the so-called hue angle) could be related to some acidity parameters of solvents. Thus, it is possible to calculate the hue angle and, therefore, to predict the color of solution if the solvent acceptor number is known, or vice versa.

---

Untersuchung zur Solvatochromie von Fe(CN)₂(phen)₂

Zusammenfassung Der Einfluß organischer Lösungsmittel auf die UV-Spektren von Fe(CN)₂-(phen)₂ wurde mittels trichromatischer Kolorimetrie untersucht. Die Farbparameter der Lösungen wurden aus den Absorptionsspektren berechnet und werden in den CIE- und CIELAB-Farbräumen beschrieben. Es konnte gezeigt werden, daß einer der Farbparameter (der sogenannte Farbtonwinkel) zu den Aciditätsparametern des jeweiligen Lösungsmittels in Beziehung gesetzt werden kann. Es ist daher z.B. möglich, die Farbe der Lösung vorherzusagen, wenn die Akzeptorzahl des Lösungsmittels bekannt ist und umgekehrt.