Phase ratios in the K2O-V2O4-SO3 system at high sulfur trioxide concentrations

Phase ratios in the three-component oxide system K₂O-V₂O₄-SO₃ in the region of the sulfur trioxide concentrations corresponding to its concentrations in the active component of vanadium catalysts for SO₂ to SO₃ conversion have been studied using powder X-ray diffraction, IR spectroscopy, microscopy, and chemical analysis. Four individual compounds (K₂VO(SO₄)₂, K₂(VO)₂(SO₄)₃, K₂VO(SO₄)₂S₂O₇, and K₂(VO)₂(SO₄)₂S₂O₇) and K₂(VO)₂(SO₄)₂S₂O₇ and VOSO₄-base solid solutions of composition K₂(VO)_2+x (SO₄)_2+x S₂O₇ (0 ≤ x ≤ 1.5) were found in the system. K₂VO(SO₄)S₂O₇ and K₂(VO)₂(SO₄)₂S₂O₇ lose their sulfur trioxide when heated above 350°C under an inert atmosphere, and convert to K₂VO(SO₄)₂ and K₂(VO)₂(SO₄)₃, respectively. This implies that K₂VO(SO₄)₂S₂O₇ and K₂(VO)₂(SO₄)₂S₂O₇, as well as K₂(VO)_2+x (SO₄)_2+x S₂O₇ solid solution, cannot exist in the active component of real industrial catalysts.     

Reaktionen von Zinnchloriden mit Polysulfiden. Die Kristallstrukturen von (PPh4)2[SnCl2(S6)2], (PPh4)2[Sn4Cl4S5(S3)O] und (PPh4)2[SnCl6] · S8 · 2CH3CN

Reaction of Tin Chlorides with Polysulfides. Crystal Structures of (PPh₄)₂[SnCl₂(S₆)₂], (PPh₄)₂[Sn₄Cl₄S₅(S₃)O], and (PPh₄)₂[SnCl₆] · S₈ · 2CH₃CN . The reaction of PPh₄[SnCl₃] with Na₂S₄ in acetonitrile in the presence of small amounts of water yields (PPh₄)₂[Sn₄Cl₄S₅(S₃)O] and minor amounts of (PPh₄)₂[SnCl₂(S₆)₂], PPh₄Cl · 2S₈ and (PPh₄)₂[SnCl₆]. SnCl₄ is partially reduced by (PPh₄)₂S_x, PPh₄[SnCl₃] and (PPh₄)₂[SnCl₆] · S₈ · 2CH₃CN being produced. According to the X-ray crystal structure determination the [Sn₄Cl₄S₅(S₃)O]^2?-ion consists of an O atom that is coordinated by four Sn atoms which in turn are liked with one another by five single S atoms and one S₃ group. In the [SnCl₂(S₆)₂]^2?-ion the Sn atom is octahedrally coordinated by two Cl atoms in trans arrangement and by two chelating S₆ groups. Octahedral [SnCl₆]^2? ions and S₈ molecules in the crown conformation are present in (PPh₄)₄[SnCl₆] · S₈ · 2CH₃CN.     

Chemie polyfunktioneller liganden LXIII. Adamantankäfigverbindungen mit den heteroelementen arsen,stickstoff und silizium

The reaction of 1,1,1-tris(diiodarsinomethyl)ethane, CH₃C(CH₂AsI₂)₃ (I), with i-C₃H₇NH₂, n-C₄H₉NH₂, C₆H₅NH₂, p-CH₃C₆H₄NH₂ and [(CH₃)₃Si]₂NH in the presence of (C₂H₅)₃N as auxiliary base in THF gives the adamantane cage compounds CH₃C(CH₂AsNC₃H₇)₃ (III), CH₃C(CH₂AsNC₄H₉)₃ (IV), CH₃C(CH₂AsNC₆H₅)₃ (V), CH₃C(CH₂AsNC₆H₄CH₃)₃ (VI) and CH₃C[CH₂AsNSi(CH₃)₃]₃ (VII). VII is also obtained in the reaction of I with NaN[Si(CH₃)₃]₂. The by-product (CH₃)₃SiO(CH₂)₄I (VIII) could be isolated in both syntheses of VII. All compounds have been characterized by mass spectrometry and infrared, Raman and ¹H NMR spectroscopy.     

Untersuchung der Cokristallisation in den Systemen. Mn(OOCCH3)2-Co(OOCCH3)2-H2O,Mn(OOCCH3)2-Ni(OOCCH3)2-H2O,Mn(OOCCH3)2-Zn(OOCCH3)2-H2O bei 60°C

Investigation of Cocrystallization in the Systems Mn(OOCCH₃)₂-Co(OOCCH₃)₂-H₂O, Mn(OOCCH₃)₂-Ni(OOCCH₃)₂-H₂O, Mn(OOCCH₃)₂-Zn(OOCCH₃)₂-H₂O at 60°C The three-component systems Mn(OOCCH₃)₂-Co(OOCCH₃)₂-H₂O, Mn(OOCCH₃)₂-Ni(OOCCH₃)₂-H₂O and Mn(OOCCH₃)₂-Zn(OOCCH₃)₂-H₂O at 60°C were investigated by physio-chemical analysis. There is an interruption in the series of mixed crystals formed in the three-component systems. The inclusion of Co²⁺- and Ni²⁺ in Mn(OOCCH₃)₂ · 2 H₂O of Mn²⁺ in Co(OOCCH₃)₂ · 2 H₂O, Zn(OOCCH₃)₂ · 2 H₂O and Ni(OOCCH₃)₂ · 4 H₂O is based on isodimorphic substitution. It was found that in the system Mn(OOCCH₃)₂-Zn(OOCCH₃)₂-H₂O crystallizes Zn(OOCCH₃)₂ · Mn(OOCCH₃)₂ · 2 H₂O. It was identified by the X-ray and differential thermal analysis.     

Thermogravimetric study of uranium phosphates

The thermal decomposition of (UO₂)₃(PO₄)₂ and U(HPO₄)₂ ·xH₂O in the temperature range 25–1600?, was investigated. (UO₂)₃(PO₄)₂ decomposed first to 1/3[U₃O₈ + 3U₂O₃P₂O₇] and then to U₃O₅P₂O₇ before a loss of phosphorus was observed above 1350?. Decomposition in air and in inert atmospheres was nearly identical. Reduction with H₂ or with carbon black in argon gave U₃O₅P₂O₇ and [UO₂ + + (UO)₂P₂O₇] before pure UO₂ was formed. U(HPO₄)₂ ·xH₂O decomposed to UP₂O₇ in argon. It oxidized partly in air before the same product was obtained. The high temperature stability of UP₂O₇ and U₃(PO₄)₄ was also investigated.     

Acetylenic derivatives of metal carbonyls of the triad Fe,Ru, Os—XI Mass spectra of some binuclear complexes

The mass spectra of the following acetylenic derivatives of iron, ruthenium and osmium carbonyls are reported: the iron compounds Fe₂(CO)₆[C₂(C₆H₅)s₂]₂, Fe₂(CO)₆[C₂(CH₃)₂]₂ and Fe₂(CO)₆[C₂(C₂H₅)₂]₂, the ruthenium compounds Ru₂(CO)₆[C₂(C₆H₅)₂]₂, and Ru₂(CO)₆[C₂(CH₃)₂]₂ and the osmium compounds Os₂(CO)₆[C₂(C₆H₅)₂]₂, Os₂(CO)₆[C₂HC₆H₅]₂ and Os₂(CO)₆[C₂(CH₃)₂]₂. Iron compounds exhibit breakdown schemes where binuclear, mononuclear and hydrocarbon ions are present. On the other hand, ruthenium and osmium compounds fragment in a similar way and give rise to singly and doubly charged binuclear ions. Phenylic derivatives of ruthenium and osmium also give weak triply charged ions. The results are discussed in terms of relative strengths of the metal-metal and metal-carbon bonds.     

Reactions of metal carbonyl derivatives : XIII. Reaction of bis[μ-(tert-butylsulphido)tricarbonyl-iron] with tertiary and ditertiary phosphines and phosphites

The ligands L  P(C₂H₅)₃, P(C₆H₅)₃, P(OCH₃)₃ and P(OC₆H₅)₃ react with [Fe(CO)₃(S-t-C₄H₉)]₂ to give mono-substituted Fe₂(CO)₅L(S-t-C₄H₉)₂ or bis-substituted [Fe(CO)₂L(S-t-C₄H₉)]₂ depending on the reaction conditions. With the exception of [Fe(CO)₂P(C₂H₅)₃(S-t-C₄H₉)]₂, the latter derivatives occur both in solution and in the solid state as a single isomer in which the ligands L are bonded trans to the metal-metal bond. Whereas an asymmetrically bis-substituted product, Fe(CO)₃(S-t-C₄H₉)₂Fe(CO)L' is formed in the reaction of [Fe(CO)₃(S-t-C₄H₉)]₂ with L' &2.dbnd; cis-(C₆H₅)₂PC₂H₂P(C₆H₅)₂, symmetrically bis-substituted derivatives [Fe(CO)₂(S-t-C₄H₉)]₂L', in which the ligand bridges the two iron atoms are produced in the corresponding reactions involving L'  (C₆H₅)₂P(CH_2nP(C₆H₅)₂ (n  1 and 2). The NMR spectrum of [Fe(CO)₂P(OCH₃)₃(S-t-C₄H₉)]₂, as well as those of the complexes [Fe(CO)₂P(OCH₃)₃SR]₂ (R  CH₃ and i-C₃H₇) which have also been synthesised in this study, is interpreted in terms of a virtual coupling effect.     

Dimethylphosphinato and dimethylarsinato complexes of Sb(III) and Bi(III) and their chemistry

Abstract  

The reaction of Me₂PO₂H and Me₂AsO₂H with SbCl₃, BiCl₃, and Bi(NO₃)₃·5H₂O gave the complexes Sb(Me₂PO₂)₃, Sb(Me₂AsO₂)₃, (Me₂PO₂)₂Bi-Cl, Bi(Me₂AsO₂)₃, (Me₂PO₂)₂Bi(NO₃), and (Me₂AsO₂)₂Bi(NO₃)·H₂O, respectively. The arsinato complexes did not react with the Lewis bases pyridine, Ph₃P, and Ph₃As in acetone. The compounds Sb(Me₂AsO₂)₃ and (Me₂AsO₂)₂Bi(NO₃)·H₂O reacted to a small extent with nicotinic acid in methanol but Bi(Me₂AsO₂)₃ gave (Me₂AsO₂-BiO) _x in good yields. (Me₂AsO₂)₂Bi(NO₃)·H₂O in methanol quantitatively rearranged to new complexes with the same composition, [(Me₂AsO₂)₂Bi(NO₃)·H₂O]′ and [(Me₂AsO₂)₂Bi(NO₃)·H₂O]″ in the presence of pyridine. With thiophenol in air, Sb(Me₂AsO₂)₃ gave PhSSPh and Me₂As-SPh (1:1 mol ratio), (Me₂AsO₂-SbO) _x and some Sb(Me₂AsO₂)₃ was reformed, Bi(Me₂AsO₂)₃ gave (Me₂AsO₂-BiO) _x , PhSSPh, and Me₂As-SPh (1:0.6 mol ratio), whereas (Me₂AsO₂)₂Bi(NO₃)·H₂O quantitatively gave PhSSPh, thus acting as a catalyst for the air oxidation of thiophenol.     

Structure of the La12GdEuB6Ge2O34 borogermanate as probed by NMR and IR spectroscopy

The structure of fine crystalline borogermanate La₁₂GdEuB₆Ge₂O₃₄ has been studied by NMR and IR spectroscopy. It has been demonstrated that this compound is isostructural to the homonuclear Ln₁₄B₆Ge₂O₃₄ compounds (Ln = Pr-Gd) and crystallizes in space group P3₁. The rare-earth elements have been distributed over the LnO _n polyhedra in La₁₂GdEuB₆Ge₂O₃₄ by analogy with the known structures. Lanthanum can occupy positions with CN 7–10, and the symmetry of these LnO _n coordination polyhedra is not higher than C _2v . In the La₁₂GdEuB₆Ge₂O₃₄ structure, the LnO _n coordination polyhedra are formed by oxygen atoms of oxo groups and anions, some of the oxygen atoms being shared by LnO _n polyhedra. The BO₃ and GeO₄ groups in the structure are also bridging, i.e., are involved in bonding of LnO _n polyhedra. One of the B-O bonds in La₁₂EuGd(BO₃)₆(GeO₄)₂O₈ is elongated as compared with the B-O bond lengths in homonuclear compounds Pr₁₄(BO₃)₆(GeO₄)₂O₈ and Nd₁₄(BO₃)₆(GeO₄)₂O₈. In the La₁₂GdEuB₆Ge₂O₃₄ structure, germanium is located in isolated GeO₄ tetrahedra with distorted T _d symmetry. The local symmetry of lanthanum in fine crystalline La₁₂GdEuB₆Ge₂O₃₄ have been assessed using ¹³⁹La NMR (B ₀ = 7.04 T, room temperature). For comparison, binary lanthanum compounds with a simpler structure— LaBO₃, La(BO₂)₃, and La₂GeO₅—have been used. The spectra of all compounds are rather broad (ν_1/2 = 180–240 kHz). The ¹³⁹La NMR spectra of the LaBO₃, La(BO₂)₃, and La₁₂GdEu(BO₃)₆(GeO₄)₂O₈ borates show a signal at (1080 ± 40) ppm, which is absent in the spectrum of La₂GeO₅. The shape of the ¹³⁹La NMR spectra of La₁₂GdEu(BO₃)₆(GeO₄)₂O₈ and LaBO₃ is characterized by the second-order quadrupole splitting with a downfield shoulder. The similarity of these spectra points to close ¹³⁹La NMR chemical shifts of La₁₂GdEu(BO₃)₆(GeO₄)₂O₈ and LaBO₃. No quadrupole splitting was observed in the spectra of La(BO₂)₃ and La₂GeO₅.     

Water‐soluble and Halogen‐free Hexaammine Complexes of Metal Ions of Group 9 – Synthesis,Crystal Structures,and Vibrational Spectra

Reaction of [M(NH₃)₆]Cl₃ (M = Co, Rh, Ir) and [Ir(NH₃)₅(OH₂)]Cl₃ with (NH₄)₂C₂O₄ · H₂O in aqueous solution resulted in the isolation of [M(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively. The complexes have been characterized by X‐ray crystallography, IR and UV/VIS spectroscopy. The isomorphous compounds crystallize in the orthorhombic space group Pnnm (No. 58). Four molecules of crystal water are involved in an extended three‐dimensional hydrogen bonding network. The librational modes of the lattice water around 600 cm^–1 allow the characterization of [Ir(NH₃)₆]₂(C₂O₄)₃ · 4 H₂O and [Ir(NH₃)₅(OH₂)]₂(C₂O₄)₃ · 4 H₂O, respectively, by IR spectroscopy. The band around 600 cm^–1 shows a significant frequency shift in the IR spectra of the hexaammine and aquapentaammine complex of iridium(III) and, by that, a distinction is possible.     

Group 6 Oxyfluoro-Anion Salts of [XeF5]+ and [Xe2F11]+: Syntheses and Structures of [XeF5][M2O2F9] (M=Mo,W), [Xe2F11][M′OF5] (M′=Cr,Mo, W), [XeF5][HF2]⋅CrOF4, and [XeF5][WOF5]⋅XeOF4

The reactions of the fluoride-ion donor, XeF₆, with the fluoride-ion acceptors, M′OF₄ (M′=Cr, Mo, W), yield [XeF₅]⁺ and [Xe₂F₁₁]⁺ salts of [M′OF₅]⁻ and [M₂O₂F₉]⁻ (M=Mo, W). Xenon hexafluoride and MOF₄ react in anhydrous hydrogen fluoride (aHF) to give equilibrium mixtures of [Xe₂F₁₁]⁺, [XeF₅]⁺, [(HF)_nF]⁻, [MOF₅]⁻, and [M₂O₂F₉]⁻ from which the title salts were crystallized. The [XeF₅][CrOF₅] and [Xe₂F₁₁][CrOF₅] salts could not be formed from mixtures of CrOF₄ and XeF₆ in aHF at low temperature (LT) owing to the low fluoride-ion affinity of CrOF₄, but yielded [XeF₅][HF₂]⋅CrOF₄ instead. In contrast, MoOF₄ and WOF₄ are sufficiently Lewis acidic to abstract F⁻ ion from [(HF)_nF]⁻ in aHF to give the [MOF₅]⁻ and [M₂O₂F₉]⁻ salts of [XeF₅]⁺ and [Xe₂F₁₁]⁺. To circumvent [(HF)_nF]⁻ formation, [Xe₂F₁₁][CrOF₅] was synthesized at LT in CF₂ClCF₂Cl solvent. The salts were characterized by LT Raman spectroscopy and LT single-crystal X-ray diffraction, which provided the first X-ray crystal structure of the [CrOF₅]⁻ anion and high-precision geometric parameters for [MOF₅]⁻ and [M₂O₂F₉]⁻. Hydrolysis of [Xe₂F₁₁][WOF₅] by water contaminant in HF solvent yielded [XeF₅][WOF₅]⋅XeOF₄. Quantum-chemical calculations were carried out for M′OF₄, [M′OF₅]⁻, [M′₂O₂F₉]⁻, {[Xe₂F₁₁][CrOF₅]}₂, [Xe₂F₁₁][MOF₅], and {[XeF₅][M₂O₂F₉]}₂ to obtain their gas-phase geometries and vibrational frequencies to aid in their vibrational mode assignments and to assess chemical bonding.     

Reactivity in the solid state between CoWO4 and RE2WO6 where RE = Sm, Eu, Gd

Reactivity in the solid state between CoWO₄ and some rare-earth metal tungstates RE₂WO₆ (RE = Sm, Eu, Gd) was investigated by the XRD method. Two families of new isostructural cobalt and rare-earth metal tungstates, Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆, were synthesized. The Co₂RE₂W₃O₁₄ phases are formed by heating in air the CoWO₄ and RE₂WO₆ compounds mixed at the molar ratio 2:1, while the CoRE₄W₃O₁₆ phases are synthesized at the molar ratio of CoWO₄/RE₂WO₆ equals to 1:2. The Co₂RE₂W₃O₁₄ phases as well as the CoRE₄W₃O₁₆ compounds crystallize in the orthorhombic system. The Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆ compound melt above 1150 °C. A melting manner of the Co₂RE₂W₃O₁₄ and CoRE₄W₃O₁₆ compounds was determined in an inert atmosphere. The formation of CoWO_4−x phase was observed during heating in an inert atmosphere.     

Neutral and ion chemistry in a C2H4-SiH4 discharge

This paper reports on a mass spectrometric study of the neutral and ionic species in a low-pressure rf discharge sustained in a C₂H₄-SiH₄ mixture diluted in helium. It is shown that C₂H₄ is readily decomposed into C₂H ₂ ^* and C₂H₃. The formation of secondary products such as C₄H₂, C₄H₄, and C₄H₆ is observed and confirms the presence of C₂H₂ in the discharge. Methylsilane (CH₃SiH₃) and ethylsilane (C₂H₅SiH₃) are also synthesized in this discharge. It is also observed that the major ions C₂H ₄ ⁺ , C₃H ₅ ⁺ , SiH ₃ ⁺ , Si₂H ₄ ⁺ , SiCH ₃ ⁺ , SiC₂H ₃ ⁺ , and SiC₂H ₇ ⁺ are not representative of the direct ionization of neutral species. Their formation is thus interpreted on the basis of ion-molecule reactions.     

Synthesen und Eigenschaften von Tris(perfluoralkyl)arsen- und -antimon(III,V)-Verbindungen

Preparations and Properties of Tris(perfluoroalkyl) Arsenic and Antimony(III, V) Compounds As(R_f)₃ and Sb(R_f)₃ (R_f?C₂F₅, C₄F₉, C₆F₁₃) are prepared in good yields by the polar reactions of AsCl₃ and SbCl₃ with bis(perfluoroalkyl) cadmium compounds as colourless liquids or solids. The oxidation of As(C₂F₅)₃ and Sb(C₂F₅)₃ with XeF₂ gives the difluorides M(C₂F₅)₃F₂ (M?As, Sb). As(C₂F₅)₃Cl₂ is prepared by chlorination of As(C₂F₅)₃ in the presence of AlCl₃, while Sb(C₂F₅)₃Cl₂ is formed in the reaction of Sb(C₂F₅)₃F₂ with (CH₃)₃SiCl. During the reaction of M(C₂F₅)₃F₂ with (CH₃)₃SiBr ¹⁹F-NMR spectroscopic evidence is found for M(C₂F₅)₃ Br₂. The thermal decompositions of M(C₂F₅)₃F₂ mainly yield C₄F₁₀ and M(C₂F₅)F₂, while the thermal decompositions of M(C₂F₅)₃Cl₂ yield M(C₂F₅)₂Cl and C₂F₅Cl. The properties and spectroscopic data of the new compounds are described.     

Azidokomplexe des Zirkoniums: ZrCl3N3, [ZrCl4N3]22⊝, [ZrCl4(N3)2]2⊝; die Kristallstruktur von (PPh4)2[ZrCl4N3]2

Azido Complexes of Zirconium: ZrCl₃N₃, [ZrCl₄N₃]₂^2?, [ZrCl₄(N₃)₂]^2?; Crystal Structure of (PPh₄)₂ [ZrCl₄N₃]₂ Highly explosive ZrCl₃N₃ is formed by the reaction of ZrCl₄ with iodine azide in dichloromethane suspension. According to the i.r. spectra, the compound is polymeric by azide and chlorine bridges. Zirconium tetrachloride reacts with one and two moles of tetraphenylphosphonium azide respectively, forming the thermally and mechanically stable complexes (PPh₄)₂[ZrCl₄N₃]₂ and (PPh₄)₂[ZrCl₄(N₃)₂]. The crystal structure of (PPh₄)₂[ZrCl₄N₃]₂ was determined by X-ray methods (1942 reflexions, R = 6.5%). The complex crystallizes in the monoclinic space group P2₁/n with two formula units per unit cell. The structure consists of tetraphenylphosphonium cations and dimeric anions [ZrCl₄N₃]₂^2?, in which the Zr atoms are linked by the α-N atoms of the azide groups, forming a centrosymmetric Zr₂N₂ ring with symmetry D_2h. According to the i.r. spectra, the azide groups in the complex (PPh₄)₂[ZrCl₄(N₃)₂] are covalently bonded at the Zr atom in trans positions.     

Co1−xFe2+xO4 (x = 0.1, 0.2) anode materials for rechargeable lithium-ion batteries

A cobalt-poor or iron rich bicomponent mixture of Co_0.9Fe_2.1O₄/Fe₂O₃ and Co_0.8Fe_2.2O₄/Fe₂O₃ anode materials have been successfully prepared using simple, cost-effective, and scalable urea-assisted auto-combustion synthesis. The threshold limit of lower cobalt stoichiometry in CoFe₂O₄ that leads to impressive electrochemical performance was identified. The electrochemical performance shows that the Co_0.9Fe_2.1O₄/Fe₂O₃ electrode exhibits high capacity and rate capability in comparison to a Co_0.8Fe_2.2O₄/Fe₂O₃ electrode, and the obtained data is comparable with that reported for cobalt-rich CoFe₂O₄. The better rate performance of the Co_0.9Fe_2.1O₄/Fe₂O₃ electrode is ascribed to its unique stoichiometry, which intimately prefers the combination of Fe₂O₃ with Co_1−xFe_2+xO₄ and the high electrical conductivity. Further, the high reversible capacity in Co_0.9Fe_2.1O₄/Fe₂O₃ and Co_0.8Fe_2.2O₄/Fe₂O₃ electrodes is most likely attributed to the synergistic electrochemical activity of both the nanostructured materials (Co_1−xFe_2+xO₄ and Fe₂O₃), reaching beyond the well-established mechanisms of charge storage in these two phases.     

Reactions of DI-η5-cyclopentadienyltricarbonyltriphenylphosphinediiron; an improved synthesis of the cyclopentadienylcarbonyliron tetramer

The compound (C₅H₅)₂Fe₂(CO)₃PPh₃, previously obtained by the photolysis of (C₅H₅)₂Fe₂(CO)₄ with PPh₃, may also be obtained by reflluxing these same reactants in benzene. The compound was isolated in pure form by means of low temperature column chromatography. It is unstable in solution in the absence of added PPh₃. Solid samples also are unstable over long periods of time. Decomposition in solution is complete within one hour at 80° yielding a mixture of (C₅H₅)₂Fe₂(CO)₄ and (C₅H₅)₄Fe₄(CO)₄. This reaction is suppressed by excess PPh₃. Heating a mixture of (C₅H₅)₂Fe₂(CO)₃PPh₃ and P(OEt)₃ gives a nearly quantitative yield of (C₅H₅)₂Fe₂(CO)₃P(OEt)₃. Refluxing a xylene solution of (C₅H₅)₂Fe₂(CO)₄ containing a slight molarr excess of PPh₃ for 7 h results in the isolation of (C₅H₅)₄Fe₄(CO)₄ in 56% yield, making this reaction by far the most convenient method for the preparation, in gram quantities, of this transition metal cluster.     

Preparation, crystal structure, and photoluminescence of Ca2SnO4:Eu, Y

Eu³⁺-doped Ca₂SnO₄ (solid solutions of Ca_2−xEu_2xSn_1−xO₄, 0?x?0.3) and Eu³⁺ and Y³⁺-codoped Ca₂SnO₄ (Ca_1.8Y_0.2Eu_0.2Sn_0.8O₄) were prepared by solid-state reaction at 1400 °C in air. Rietveld analysis of the X-ray powder diffraction patterns revealed that Eu³⁺ replaced Ca²⁺ and Sn⁴⁺ in Eu³⁺-doped Ca₂SnO₄, and that Eu³⁺ replaced Ca²⁺ and Y³⁺ replaced Sn⁴⁺ in Ca_1.8Y_0.2Eu_0.2Sn_0.8O₄. Red luminescence at 616 nm due to the electric dipole transition ⁵D_o→⁷F₂ was observed in the photoluminescence (PL) spectra of Ca_2−xEu_2xSn_1−xO₄ and Ca_1.8Y_0.2Eu_0.2Sn_0.8O₄ at room temperature. The maximum PL intensity in the solid solutions of Ca_2−xEu_2xSn_1−xO₄ was obtained for x=0.1. The PL intensity of Ca_1.8Y_0.2Eu_0.2Sn_0.8O₄ was 1.26 times greater than that of Ca_2−xEu_2xSn_1−xO₄ with x=0.1.     

Electrospray Mass Spectrometry Study on Polynuclear Pd(II) and Ni (II) Complexes of 3, 6, 9, 16, 19, 22‐Hexaazatricyclo [22. 2.2.211,14] triaconta‐11, 13, 24, 26 (1), 27, 29‐Hexaene

Polynuclear Pd(II) and Ni(II) complexes of macrocyclic polyamine 3,6,9,16,19,22‐hexaazatricyclo[22.2.2.2^11,14]‐triaconta 11,13,24,26(l),27,29‐hexaene (L) in solution were investigated by electrospray ionization mass spectrometry (ESIMS). For methanol solution of complexes M₂LX₄ (M = Pd(II) and Ni(II), X= Cl and I), two main clusters of peaks were observed which can be assigned to [M₂LX₃]⁺ and [M₂LX₂]²⁺. When Pd₂LCl₄ was treated with 2 or 4 mol of AgNO₃, it gave rise formation of Pd₂LCl₂ (NO₃)₂ · H₂O and [Pd₂L(H₂O)_m(NO₃)_n]^(4‐n)+, respectively. ESMS spectra show that the dissociation of the former in the ionization process gave peaks of [Pd₂LCl₂]²⁺ and [(Pd₂LCl₂)NO₃]⁺, while dissociation of the later gave the peaks of [Pd₂L(CH₃CO₂)₂]²⁺ and [Pd₂L(CH₃CO₂)₂](NO₃) ⁺ in the presence of acetic acid. Similar species were observed for Pd₂LI₄ when treated with 4 mol of AgNO₃. When [Pd₂L · (H₂O)_m(NO₃)_n]^(4‐n)+ reacted with 2 mol of oxalate anions at 40°C, [Pd₄L₂(C₂O₄)₂(NO₃)₂]²⁺ and [Pd₄L₂(C₂O₄)₂ (NO₃)]³⁺ were detected. This implies the formation of square‐planar molecular box Pd₄L₂(C₂O₄)₂(NO₃)₄ in which C₂O₄^? may act as bridging ligands as confirmed by crystal structure analysis. The dissociation form and the stability of complex cations in gaseous state are also discussed. This work provides an excellent example of the usefulness of ESIMS in the identification of metal complexes in solution.     

Redox and oxo-abstraction Reactions of Silylamine with MoOCl4

Trimethylsilyldiethylamine Me₃SiNEt₂ and MoOCl₄ (1:1) undergo a free radical redox reaction in CH₂Cl₂ or Et₂O to form MoCl₃O(HNEt₂). Reduction occurs even in aprotic media like CCl₄ and CS₂ to give Mo^V complexes Mo₂Cl₆O₂(N₂Et₄) and Mo₂Cl₆O₂[(SCNEt₂)₂S₂], respectively. A 2:1 reaction in nonionizing protic solvents undergoes redox cum cleavage to provide MoCl₂O(NEt₂) (HNEt₂) but a reaction at reflux temperature in 1,2-dichloroethane leads to diethylammonium salt, [Et₂NH₂][MoCl₄O(HNEt₂)]. Higher molar reactions (3:1, 4:1) in CH₂Cl₂ or Et₂O are associated with redox reaction as well as oxygen atom abstraction to form de-oxo Mo^IV complex MoCl₃(NEt₂)(HNEt₂)₂, whereas, a 3:1 reaction in CS₂ forms Mo₂Cl₄O(S₂CNEt₂)₄. Compounds have been characterized by elemental analyses, redox titration, magnetic moment, conductance, infrared, electronic absorption and ¹H-NMR measurements.