Ramanspektroskopische Untersuchungen an PCl5 II. Das System PCl5—ZrCl4

Raman spectra of some solid and molten PCl₅–ZrCl₄ mixtures have been recorded. ZrCl₆ ^2– complex ions accompanied by at least one more chlorozirconate species are present in the solid as well as in the melt. The newRaman frequencies are attributed to ZrCl₅ ^–, which fundamentals are given and assignment is proposed to be analogous to TiCl₅ ^–. The presence of ZrCl₆ ^2– and ZrCl₅ ^– can be explained by the equilibrium ZrCl₆ ^2–+PCl₄ ⁺ZrCl₅ ^–+PCl₅.

     

Crystal and molecular structure of tetrachlorophosphorus(V) hexachlorouranate(V)

The crystal structure of tetrachlorophosphorus(V) hexachlorouranate(V), PCl⁺₄.UCl^?₆, has been solved with 2492 independent F(hkl) collected by necessity from one component of a bicrystal; all crystals prepared were twinned. The structure is triclinic, space group P$\text{1}$, with a = 7.038(4), b = 7.373(4), c = 13.706(8) Å, α = 89.38(3), β = 88.80(3), γ = 105.20(3)°, with Z = 2. The two components of the bicrystal, in the volume ratio of 2.5 to 1, had their reciprocal lattice spots sufficiently separated to allow collection of the data set from component 1 with AgKα radiation (λ = 0.5608 Å). A model was derived from the Patterson synthesis and refined by least squares to R = Σ(|Fo|-|F_C|)/Σ|Fo| = 0.146. The structure was confirmed by a final (ρ_o-ρ_c) synthesis. The structure is an assembly of octahedral U(1)Cl^?₆, U(2)Cl^?₆ and tetrahedral PCl⁺₄ groups. The chlorine atom array is hexagonal close-packed, while the polyhedra are regular within the experimental errors. The structure is isomorphous with the transition metal analogues PCl₅.NbCl₅ and PCl₅.TaCl₅.     

Bis­(tri­chloro­phosphine)­iminium salts, [Cl3P=N=PCl3]+, with transition metal halide counter‐ions

The structures of four bis­(tri­chloro­phosphine)­iminium {[Cl₃P=N=PCl₃]⁺; systematic name: tri­chloro­[(tri­chloro­phos­phor­an­yl­idene)im­in­io]phos­phor­us(V)} salts, namely bis(tri­chloro­phosphine)­iminium hexa­chloro­niobate, (Cl₆NP₂)[NbCl₆], (I), bis­(tri­chloro­phosphine)­iminium hexa­chloro­tantalate, (Cl₆NP₂)[TaCl₆], (II), bis­(tri­chloro­phosphine)­iminium tri‐μ‐chloro‐bis­[tri­chloro­titanium(IV)], (Cl₆NP₂)[Ti₂Cl₉], (III), and bis­[bis­(tri­chloro­phosphine)­iminium] di‐μ‐chloro‐bis­[tetrachloro­zirconium(IV)], (Cl₆NP₂)₂[Zr₂Cl₁₀], (IV), have been determined. The P=N distances in the discrete [Cl₃P=N=PCl₃]⁺ moieties in structures (I), (II) and (IV) range from 1.5460 (14) to 1.5554 (16) Å, and the P=N=P angles range from 136.8 (3) to 143.4 (4)°. The [Cl₃P=N=PCl₃]⁺ cation in (III) is disordered and the calculated geometries for the cation are therefore less reliable. Compounds (I) and (II) are isostructural and the metal anions have slightly distorted octahedral geometries. The anion in compound (III) consists of two distorted octahedral Ti centres linked by three μ₂‐Cl atoms, while in compound (IV), the dianion is derived from two distorted edge‐shared ZrCl₆ octahedra.     

Effects of organometallic cocatalysts on the polymerization of disubstituted acetylenes by TaCl5 and NbCl5

The effects of organometallic cocatalysts on the polymerization of disubstituted acetylenes were investigated. Diphenylacetylene did not polymerize with TaCl₅ alone, while it produced a polymer quantitatively in the presence of appropriate cocatalysts (Me₄Sn, Et₃SiH, etc.). The poly(diphenylacetylene) formed was an insoluble yellow solid. 1-Phenyl-1-alkynes (1-Phenyl-1-butyne and -1-octyne) polymerized with TaCl₅ and NbCl₅ alone to yield polymers whose weight-average molecular weights (M _w's) were ca. 5 × 10⁵. Use of cocatalysts (nBu₄Sn etc.) to the polymerization of these monomers accelerated the reaction, and increased the polymer molecular weights up to ca. 1.5 × 10⁶. The poly(1-phenyl-1-alkynes) were soluble white solids. Internal octynes (2-, 3-, and 4-octynes) gave mixtures of a polymer and cyclotrimers with TaCl₅ alone. In contrast, cyclotrimers formed virtually selectively by addition of cocatalysts. Thus, various effects of organometallic cocatalysts were observed depending on the kind of monomer.     

Reactions of Chalcogen Oxide Chlorides EOCl2 (E = S,Se) with Group 5 Metal Chlorides

The tantalum derivative TaCl₅(SOCl₂), thermally unstable above 290 K, was prepared from Ta₂Cl₁₀ and SOCl₂ and studied by X‐ray crystallography at 180 K. Tantalum atom is octahedrally coordinated by five chlorides at Ta–Cl distances comprised between 2.32 and 2.36 Å and by the oxygen atom of SOCl₂ at the Ta–O distance of 2.34 Å. No evidence for the existence of an analogous compound of niobium(V) has been obtained. The halides of Group 5, M₂Cl₁₀, M = Nb, Ta, react with SeOCl₂ to give the solid adducts MCl₅(SeOCl₂) stable at room temperature. The reaction of NbCl₅(SeOCl₂) with SOCl₂ affords [SeCl₃][NbCl₆] which contains trigonal‐pyramidal (SeCl₃)⁺ cations with Se–Cl distances of 2.13–2.16 Å and octahedral [NbCl₆]^– anions (Nb–Cl: 2.27–2.45 Å). A distorted octahedral coordination around the selenium atom is achieved by additional interactions [Se…Cl, 2.81–2.98 Å] between selenium and the [NbCl₆]^– anion.     

Kristallstruktur und Schwingungsspektrum von Tris-trichlorophosphazeno-carbenium-hexachloroantimont [C(N  PCl3)3]+SbCl6−

Crystal Structure and Vibrational Spectrum of Tris-trichlorophosphazeno-carbenium-hexachloroantimonate [C(N?PCl₃)₃]⁺SbCl₆^? [C(N?PCl₃)₃]SbCl₆ crystallizes in the space group P1 with the lattice constants a = 903 b = 1046, c = 1307 pm and α = 94.8, β = 88.3, γ = 103.8°. Using X- ray diffraction data, the crystal structure was determined and refined to a residual index of 0.027. The structure consists of octahedral SbCl₆^? ions and [C(N?PCl₃)₃]⁺ ions having approximately C_3h symmetry; the atoms C, N, P, and one Cl per PCl₃ group lie approximately in a plane. The i. R. and Raman spectrum was registered and assigned.     

Über Phosphorstickstoff-Verbindungen XXVIII. Über Reaktionen von Cyanamid,Dicyanimid und Dicyandiamid mit PCl5

Interaction between cyanamide and PCl₅ in the mole ratio 1:3 yields the phosphazenium salt [Cl₃P?N? C(Cl)?N? PCl₃] [PCl₆]. The reaction of sodium dicyanimide and PCl₅ gives 1. 1. 3. 5-tetrachloro-1-phospha-2. 4. 6-triazine (compound B in ?Inhaltsübersicht”?). Dicyandiamide and PCl₅ (1:2) give compound C and, at milder conditions the salt-like phosphatriazine D. Solvolysis of C with formic acid or of D with sulphur dioxide yields E.     

Nb and Ta Adducts: Connecting d0 Metal Chlorides and Phosphorus Sulfide Cages

Phosphorus sulfide cages α‐P₄S₄, α‐P₄S₅, β‐P₄S₅, and β‐P₄S₆ and transition‐metal chlorides TaCl₅ and NbCl₅ form molecular adducts in CS₂/n‐hexane. The crystal structures of the adducts (TaCl₅)(α‐P₄S₄), (TaCl₅)(α‐P₄S₅), (TaCl₅)(β‐P₄S₅), (NbCl₅)(β‐P₄S₅), and (TaCl₅)(β‐P₄S₆) are reported and their conformation and energetic stability are discussed on the basis of ab initio electronic structure calculations. Furthermore bond lengths of coordinated and noncoordinated phosphorus sulfide cages obtained from experiment and theory are compared, emphasizing the changes within the cages that emerge upon coordination.     

Metallchlorid-Graphitverbindungen aus nichtwäßrigen Lösungsmitteln Einlagerung aus Thionylchloridlösungen

Metal Chloride-Graphite Compounds from Nonaqueous Solvents. Intercalation from Thionylchloride Solutions The intercalation of UCl₅, AlCl₃, NbCl₅, TaCl₅, and MoOCl₄ from SOCl₂ solutions is investigated. From concentrated UCl₅ solutions, dependent on the temperature, two compounds are obtained: UCl₅-graphite and UCl₅–SOCl₂-graphite, both with the structure of a first intercalation stage. The other metal chlorides are intercalated without SOCl₂: AlCl₃ to a second stage; NbCl₅, TaCl₅ and MoOCl₄ to a third stage. Chlorine additionally bound in the AlCl₃, NbCl₅ and TaCl₅ compounds results from a decomposition reaction of the SOCl₂.     

Zur Bildung gasförmiger MCl2-Komplexe. Vergleichende Untersuchung zur Eignung von Al2Cl6, Ga2Cl6, In2Cl6, Fe2Cl6, SiCl4, TiCl4, PCl5, TaCl5 und U2Cl10 als Komplexbildner

Formation of Gaseous MCl₂ Complexes. Comparative Study on the Suitability of Al₂Cl₆, Ga₂Cl₆, In₂Cl₆, Fe₂Cl₆, SiCl₄, TiCl₄, PCl₅, TaCl₅, and U₂Cl₁₀ as Complex Former The thermodynamic data for reactions of the type MCl_2,s + L₂Cl_6,g = ML₂Cl_8,g are – as expected – nearly independent on L(Al, Ga, In, Fe). Transport rates e. g. of CoCl₂ something smaller with L ? Ga may be traced back on uncertainties concerning the Ga₂Cl₆ dissociation, and with L ? Fe they may be traced back on the incorporation of FeCl₂ into MCl_2,s. SiCl₄ and TiCl₄ cause no noticable transport of CoCl₂ or CuCl₂ in a temperature gradient, which leads to a short bond consideration. PCl₅ and TaCl₅ cause the transport of small amounts of CoCl₂. U₂Cl₁₀/UCl₅ are able to transport a remarkable amount of CaCl₂ and CoCl₂, respectively.     

Electrochemical Studies of Tantalum(V) Chlorides and Bromides in Acetonitrile. Electrochemical Generation of Tantalum(IV) Species

The electrochemical properties of tantalum halides, TaX₅ Et₄NTaCI₆ and Bu₄NTaBr₆ (X = Cl^? and Br^?) were investigated in rigorously dried acetonitrile using cyclic voltammetry and constant potential electrolysis. A special vacuum electrochemical cel1 equipped with a sample loading device and an AI₂O₃ column was used in order to prevent the hydrolysis of tantalum halides with the small amount of water present in “dry” acetonitrile. Two one-electron reduction waves were observed for al1 tantalum(V) species which correspond to consecutive Ta(V) → Ta(IV) and Ta(IV) → Ta(III) reduction. The E_1/2 values for the Ta(V) → Ta(IV) reduction process are criticalIy dependent on the number of CI^? ligands coordinated to the tantalum atom. As the number of Cl^? is increased from 4 to 5 and 6, it becomes more difficult, by 0.4 V, to reduce Ta(V) to Ta(IV). Constant potential electrolysis at –20°C generates Ta(IV) species; thus TaCl₆ ^2-. TaBr₆ ^2-, TaCl₅NCMe^?, TaBr₅NCMe^? and TaCI₄(NCMe)₂, are obtained in acetonitrile solution after electrolysis. It was found that the reduction product of TaCl₅NCMe depends upon the temperature. At a higher temperature (0°C) the initial electron transfer step is fol1owed by a chemical reaction in which some of the product, TaCI₅NCMe^?, reacts with the starting material, TaCI₅NCMe. to produce TaCl₆ ^? and TaCl₄(NCMe)₂. At lower temperatures (–20°C) the rate of the folIowing chemical reaction is much slower and the reduction product is almost exclusively TaCl₅NCMe^?.     

On Tetrachlorophosphonium Chlorometallates of Rhenium and Molybdenum: Syntheses,Crystal Structures,and Magnetism of [PCl4]2[Re2Cl10] and [PCl4]3[ReCl6]2, and the Magnetic Properties of [PCl4]2[Mo2Cl10]

MoCl₄, ReCl₄, and ReCl₅ react with PCl₅ in sealed glass ampoules at temperatures between 220° and 320° to [PCl₄]₂[Mo₂Cl₁₀] ( 1 ) [PCl₄]₂[Re₂Cl₁₀] ( 2 ), and [PCl₄]₃[ReCl₆]₂ ( 3 ). 2 crystallizes isotypically to the previously reported 1 and the respective titanium and tin containing analogues. The structure (triclinic, P1, Z = 1, a = 897.3(2), b = 946.0(2), c = 687.13(9) pm, α = 95.59(2)°, β = 95.80(2)°, γ = 101.07(2)°, V = 565.4(2) 10⁶ pm³) is built of tetrahedral [PCl₄]⁺ and edge sharing double octahedral [Re₂Cl₁₀]^2– ions and can be derived from a hexagonal closest packing of Cl^– ions with tetrahedral and octahedral holes partially filled by P(V) and Re(IV), respectively. 3 crystallizes isotypically to [PCl₄]₃[PCl₆][MCl₆] (M = Ti, Sn) (tetragonal, P 4₂/mbc, Z = 4, a = 1496.2(1), c = 1363.2(2) pm). Because no evidence was found for the presence of [PCl₆]^– ions, Re in 3 has to be of mixed valency with Re^IV and Re^V sharing the same crystallographic site. The structure can be derived from a cubic closest packing or alternatively from an only sparsely distorted body centered cubic arrangement of Cl^– ions which is rarely found for anion arrays. The tetrahedral and octahedral holes are partially filled by P^V and M^IV/V, respectively. Magnetic measurements show all three compounds to be paramagnetic and confirm the oxidation state IV for Mo and Re in 1 and 2 and the mixed valence (IV/V) for Re in 3 .     

Über Trichlorphosphazo-Verbindungen aus Nitrilen. III. Die Reaktion zwischen Acrylnitril und PCl3

On Trichlorophosphazo Compounds from Nitriles. III. The Reaction between Acrylonitrile and PCl₃. The reaction of PCl₃ with acrylonitrile at higher temperatures gives CH₂Cl? CCl₂? CCl₂? N? PCl₃ ( II ). On pyrolysis of (II), CH₂Cl? CCl₂? CN (IV) is form- ed. Treatment of (II) with SO, results in CHzCL? CCl₂? CCl?N-P(0)Cl₂ ( III ). At lower temperatures and/or in the presence of PCl₃, acrylonitrile reacts with PCl₃ to give the cis/ trans isomers VIa and VIb .     

Photoelektronenspektren von Verbindungen der V. Hauptgruppe. VIII. Die Stiborane Me3SbX2 (X = Me,Cl, Br,I) und SbCl5 – im Vergleich mit Nebengruppenanaloga TaMe5, TaCl5 und NbCl5

Photoelectron Spectra of Group V Compounds. VIII. Stiboranes Me₃SbX₂ (X = Me, Cl, Br, I) and SbCl₅ — Compared with Group Vb Analogs TaMe₅, TaCl₅, and NbCl₅ The gas phase HeI photoelectron spectra of Me₅Sb, Me₃SbCl₂, Me₃SbBr₂, Me₃SbI₂, and SbCl₅ are assigned on the basis of a qualitative D_3h m. o. model and by comparison with the p. e. data of Me₃Sb and SbCl₃. The type of the three-centre-four-electron bond of the model compound SbH₅ is discussed with respect to the axial bond of a typical sp³d molecule. The highest occupied m.o. of Me₅Sb has non-bonding character; d-orbital participation may be excluded PE-spectroscopically. The differences between iso(valence)-electronic analogs EX₅ of groups Va and Vb are investigated by means of the known p. e. ionisation potentials of TaMe₅, TaCl₅, as well as of NbCl₅; their p. e. spectra are correlated. EHMO calculations for SbH₃, H₃SbHal₂, SbH₅, and NbH₅ are performed to confirm the assignments and the interpretation.     

Synthesis,structure, and properties of poly[1‐(trimethylgermyl)‐1‐propyne]

Polymerization of 1‐(trimethylgermyl)‐1‐propyne (TMGP) with TaCl₅ and NbCl₅ produced a colorless polymer in high yields, whose molecular weight reached about 3 × 10⁵–14 × 10⁵. The molecular weight distribution of the poly(TMGP) with NbCl₅ in cyclohexane was somewhat narrow (M_w /M_n = ∼1.54). The TaCl₅‐based poly(TMGP) dissolved in toluene, chloroform, cyclohexane, carbon disulfide, carbon tetrachloride, tetrahydrofuran, hexane, and so forth; the NbCl₅‐based polymer was less soluble and did not dissolve in hexane, despite its lower molecular weight. The cis contents of the NbCl₅‐ and TaCl₅‐based poly(TMGP)s determined by ¹³C NMR were 67 ± 5 and 28 ± 3%, respectively. The onset temperature of the weight loss of poly(TMGP) in air was 350 °C, indicating fair thermal stability. The oxygen permeability coefficient (P) of poly(TMGP) at 25 °C was 7800 barrer after the methanol conditioning, and the permeability was fairly stable to aging. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2964–2969, 2000     

Polymerization of N-vinylcarbazole by transition metal salts

The polymerization of N-vinylcarbazole (NVC) in the presence of transition metal salts such as WCI₆, MoCI₅, TaCl₅ and NbCl₅ under different reaction conditions was studied. In general, aromatic solvents were found to be superior to aliphatic solvents in the polymerization of NVC, i. e., both conversion and molecular weight were higher in aromatic solvents. It was observed that the polymerization reaction proceeds rapidly and almost quantitatively, even at low monomer concentration (< 5 × 10^?2M) and at low catalyst to monomer mole ratio (10^?5) in aromatic solvents. The copolymerization of NVC with acenaphthylene (ACN) was also investigated in solution at room temperature. The resulting homo- and copolymer were characterized by IR, NMR, x-ray diffraction, and elemental analysis. Thermal and photophysical properties are also reported. From the spectral data, the polymerization solvent was found to have a strong influence upon the polymer stereoregularity.     

Umsetzungen von Cp*NbCl4 und Cp*TaCl4 mit Trimethylsilyl‐azid,Me3Si‐N3. Molekülstrukturen der bis(azido)‐oxo‐verbrückten Komplexe [Cp*NbCl(N3)(μ‐N3)]2(μ‐O) und [Cp*TaCl2(μ‐N3)]2(μ‐O) (Cp* = Pentamethylcyclopentadienyl)

Reactions of Cp*NbCl₄ and Cp*TaCl₄ with Trimethylsilyl‐azide, Me₃Si‐N₃. Molecular Structures of the Bis(azido)‐Oxo‐Bridged Complexes [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) and [Cp*TaCl₂(μ‐N₃)]₂(μ‐O) (Cp* = Pentamethylcyclopentadienyl) The chloro ligands in Cp*TaCl₄ (1c) can be stepwise substituted for azido ligands by reactions with trimethylsilyl azide, Me₃Si‐N₃ (A) , to generate the complete series of the bis(azido)‐bridged dimers [Cp*TaCl_3‐n(N₃)_n(μ‐N₃)]₂ ( n = 0 (2c) , n = 1 (3c) , n = 2 (4c) and n = 3 (5c) ). If the solvent CH₂Cl₂ contains traces of water, an additional oxo bridge is incorporated to give [Cp*‐TaCl₂(μ‐N₃)]₂(μ‐O) (6c) or [Cp*TaCl(N₃)(μ‐N₃)]₂(μ‐O) (7c) , respectively. Both 6c and 7c are also formed in stoichiometric reactions from [Cp*TaCl₂(μ‐OH)]₂(μ‐O) (8c) and A . Analogous reactions of Cp*NbCl₄ (1b) with A were used to prepare the azide‐rich dinuclear products [Cp*NbCl_3‐n(N₃)_n(μ‐N₃)]₂ (n = 2 (4b) , and n = 3 (5b) ), and [Cp*NbCl(N₃)(μ‐N₃)]₂(μ‐O) (7b) . The mononuclear complex Cp*Ta(N₃)Me₃ (10c) is obtained from Cp*Ta(Cl)Me₃ and A . All azido complexes were characterised by their IR as well as their ¹H and ¹³C NMR spectra; X‐ray crystal structure analyses are available for 6c and 7b .     

Über 2-(Dimethylaminomethyl)ferrocenyl-Verbindungen des Vanadiums,Niobs und Tantals

On 2-(Dimethylaminomethyl)ferrocenyl Compounds of Vanadium, Niobium, and Tantalum Former results, indicating the ability of (dimethylaminomethyl)ferrocenyl groups forming stable σ-organo transition-metal derivatives, were proved by the synthesis of heterobimetallic 2-(dimethylaminomethyl)ferrocenyl compounds of the three-valued vanadium as well as five valued niobium and tantalum from VCl₃, NbCl₅, TaCl₅, and (FcN)Li ( I ). The synthesis and properties of the compounds (FcN)₂VCl ( II ), (FcN)_nNbCl_5–n(THF)_x [n = 1, x = 1,3 ( III ); n = 2, x = 0 ( IV ); n = 3, x = 0 ( V )] as well as (FcN)TaCl₄(THF)_1.5 ( VI ) are reported. An intensive characterization, especially in respect of possible chelate structures was tried by i.r., ¹H-n.m.r., uv-vis, mass spectroscopy, and elementary analysis.     

Molecular and Electrooptical Characteristics of Poly(1-trimethylsilyl-1-propynes) with Varied Chain Regularity

Samples of a disubstituted polyacetylene, poly(1-trimethylsilyl-1-propyne), containing on the average 60% of cis-C=C bonds and prepared with NbCl₅ as catalyst were studied by means of Kerr effect measurements in solution and molecular hydrodynamics methods. The resulting data were correlated with the properties of the sample prepared with another catalytic system, TaCl₅/BuLi. Samples prepared under different catalytic conditions were found to have much different electrooptical properties. It was concluded that the TaCl_5/BuLi catalyst allows preparation of polymers with longer continuous sequences of monomeric units of the same isomeric structure as compared with those obtained with NbCl₅.     

Schwingungsspektroskopische Untersuchungen an Trimethylphosphonium-Kationen (CH3)3PX+ (X = H,D) und Kristallstrukturen von (CH3)3PD+SbCl6− und (CH3)3PCl+SbCl6−

Vibrational Spectra of Trimethylphosphonium Cations (CH₃)₃PX⁺ (X = H, D) and Crystal Structures of (CH₃)₃PD⁺SbCl₆^? and (CH₃)₃PCl⁺SbCl₆^? The trimethylphosphonium salts (CH₃)₃PX⁺SbCl₆^? (X = H, D) and (CH₃)₃PH⁺MF₆^? (M = As, Sb) are prepared and characterized by vibrational and NMR spectroscopy (¹H, ³¹P, ¹³C). In addition the crystal structures of (CH₃)₃PD⁺SbCl₆^? and (CH₃)₃PCl⁺SbCl₆^? are reported. (CH₃)₃PD⁺SbCl₆^? crystallizes in the orthorhombic space group Pnma with a = 1555(1) pm, b = 753.1(8) pm, c = 1166(1) pm Z = 4. (CH₃)₃PCl⁺SbCl₆^? crystallizes triclinic in the space group P1 with a = 704.6(4) pm, b = 729.5(3) pm, c = 1391.1(7) pm, α = 89.57(4)°, b? = 88.04(4)°, γ = 74.98(4)° and Z = 2.