The structures of two carbonylphosphine complexes of chromium were determined by X-ray analysis. cis-Tricarbonyltriphosphinechromium(0), [(CO)3(PH3)3Cr], crystallizes in space group P21/m with a = 6.90± 0.01, b = 11.29±0.02, c = 6.41±0.01 Å, β = 93.80±0.08°, Z=2. The structure was solved by conventional methods and refined by least squares (R1 = 0.056). The idealized octahedral molecule shows approximate C3v, symmetry. The mean CrP-distance is 2.346±40.003 Å. Pentacarbonylphosphinechromium, [(CO)5(PH3)Cr], crystallizes in spacegroup Pnma with a = 12.23±0.02, b = 11.33±0.02, c = 6.61 ±0.01 Å, Z = 4. Cell dimensions and structural parameters are very similar to those of hexacarbonylchromium(0). In the crystal the PH3 group is disordered over three mutually cis-positions of the coordination octahedron. 相似文献
Chemistry of Polyfunctional Molecules. 118. Syntheses and Crystal Structures of Bicyclic Metallaphosphazenes with Four and Six Membered Rings Anhydrous MCl2 (M = Pt, Fe) react with LiN(PPh2)2 ( 1 ) in the molar ratio of 1:2 in boiling toluene within 25 hours under partially oxidative scrambling of the PNP chain in 1 yielding the bicyclic metallaphosphazenes 5 a, b . While compound 5 a can be isolated in substance, the intermediate 5 b proves to be highly reactive but can be stabilized in the presence of CO, forming the 18-valence-electron coordination compound as an isomeric trans( 6 a )/cis( 6 b ) mixture in the molar ratio of 99:1. Also treatment of anhydrous PtCl4 with four equivalents of 1 in boiling toluene during 60 hours yields 5 a . Alkylation of 5 a with CH3I leads to the formation of the ionic species [Pt2+{Ph2P? N(CH3)? PPh2}(Ph2P? N = PPh2 = N? PPh2?)]I? ( 9 ). The X-ray crystal structures of 5 a × 1 CH2Cl2 and 6 a reveal, that the metal centres have a planar P-coordination polyhedron in the solid state. In the complex 9 × 2,5 CH2Cl2 however the torsion angle between the P? Pt? P planes of the four and six membered rings shows to be 15°. The six membered metallacycles in 5 a × 1 CH2Cl2, 6 a and 9 × 2,5 CH2Cl2 differ in their geometrical arrangement. All the new compounds have also been characterized by their 1H, 31P{1H}, 13C{1H} NMR, IR, Raman and mass spectra. 相似文献
Chemistry of Polyfunctional Molecules. 116 Hydrido-, Deuterido-, Thiolato-, and Chlororuthenium(II) Complexes of Bis(diphenylphosphino)amine Bis(diphenylphosphino)amine, [(C6H5)2P]2NH (dppa, 1 ), reacts with [Ru(cod)(cot)] (cod = η-1,5-cyclooctadiene, cot = η-1,3,5-cyclooctatriene) ( 2 ) in a molar ratio of 2 : 1 both in a hydrogen or deuterium atmosphere at room temperature to yield cis-[Ru(H)2(dppa)2] ( 3 ) and cis-[Ru(D)2(dppa)2] ( 3 a ), respectively. The dihydride complex 3 is very sensitive towards halogenated solvents: dissolution of 3 in CHCl3 or CH2Cl2 produces the monohydride compound trans-[RuCl(H)(dppa)2] ( 4 ). Treatment of 3 with a threefold excess of tert-butyl mercaptane, Me3CSH, at room temperature results in the formation of cis-[Ru(H)(SCMe3)(dppa)2] ( 5 ). Trans-[RuCl2(dppa)2] ( 7 ) can be synthesized by the interaction of [RuCl2(PPh3)3] ( 6 ) with one or two equivalents of 1 in CH2Cl2 solution. The NMR spectra of 3, 3 a, 4, 5 and 7 are discussed with respect to molecular stereochemistry and hydrogen-halogen exchange under simultaneous cis-trans rearrangement. In addition to 1H, 2H, 31P{1H}, and 31P NMR, the structures of the different complexes were also derived from 1R, Raman, and mass spectra. The NMR spectra simulation of 3 permits detailed assignments of spin-spin coupling constants. Crystals of cis-[Ru(H)(SCMe3)(dppa)2] ( 5 ) are monoclinic, space group P21/c, with a = 1 179.9(3), b = 2 228.0(4), c = 1 854.8(6) pm, β = 96.23(2)°, Z = 4, and Rw = 0.062. The structural analysis shows that ruthenium is coordinated by two bidentate organophosphine ligands and by one tert-butyl thiolate molecule. The metal bound hydrogen atom was not located. However, in agreement with 1H NMR, its position is trans to a phosphorus nucleus. 相似文献
CF4-plasma etching of niobium and SiOx layers has been investigated in a r.f. diode reactor. Etch rates increase linearly with increasing power density and also increase with pressure. The etch rate ratio can be changed using different etch gases or operating in different plasma modes (PE or IEPE). Changing from the ion enhanced plasma etching mode (IEPE) to plasma etching mode (PE) the etch rate ratio is changing by an factor of ten. On the basis of etch rate dependences on process parameters and thermodynamic data it has been suggested the generation of flourine radicals as the rate limiting step. A general etching model has been proposed, which explains qualitavelty and quantitatively (on account of data from literature) the measured results. 相似文献
The redeposition of electrode material (Ni, Cr, Al) and material of a Nb layer on silicon surface during plasma etching of Nb, SiO2 and Si by a CF4 plasma has been investigated by Rutherford Back Scattering spectrometry. It is shown that a steady state exists, what causes a Nb contamination of etched Si surfaces. Obviously this steady state concentration (Nb)ads is influenced by additional redeposition of non-etchable electrode material as Ni, Cr and Al. 相似文献
The DSC-investigation of different concentrated sulphuric acid solutions shows that the results of this dynamic measurement method are in good agreement with those of steady state methods [1]. The diverse DSC-melting peaks can be interpreted by using the known behaviour of the system SO3/H2O [1] as the melting of different congruent melting phases or eutectics, respectively. The observed melting enthalpies are in the correct order.
Zusammenfassung DSC-Untersuchungen an Schwefelsäurelösungen verschiedener Konzentration zeigten, daß die Ergebnisse dieses dynamischen Meßverfahrens mit den Ergebnissen von Gleichgewichtsverfahren in guter Übereinstimmung stehen. Die verschiedenen DSC-Schmelzpeaks können unter Zuhilfenahme des bekannten Verhaltens des Systemes SO3/H2O, nämlich mit dem Schmelzen unterschiedlicher kongruenter Schmelzphasen bzw. Eutektika erklärt werden. Die ermittelten Schmelzenthalpien liegen in der richtigen Größenordnung.
Summary This synthetic and structural work describes a series of half-sandwich cyclopentadienylruthenium(II) complexes containing the diphosphazane ligands [(C6H5)2P]2NR (R=H:Hdppa,1a;R=CH3:dppma,1b;R=C2H5:dppea,1c;R=Li:Lidppa,1d). Treatment of1a, d with CpRuCl(PPh3)2 (Cp=5-C5H5, Ph=C6H5,2) in a molar ratio of 1:1 in boiling aromatic hydrocarbons affords the neutral complexes CpRuCl(Hdppa) (3) and CpRu(dppa)PPh3 (6). The ionic complexes [CpRu(Ph2P-NR-(PPh2)PPh3)Cl (R=CH3:4a;R=C2H5:4b) are formed by the reaction of1b,c with2. One pot reactions of1a–c with2 in the presence of NH4PF6 in boiling CH3OH give only the ionic compounds [CpRu(Ph2P-NR-PPh2)(PPh3)]PF6 (R=H, CH3, C2H5;5a–c). The sulfur dioxide and hydride complexes [CpRu(Hdppa)1-SO2]Cl (7) and CpRu(H)Hdppa (8) are obtained by the interaction of3 with SO2 or NaOCH3. All compounds are characterized as far as possible by IR, Raman,31P{1H} NMR,1H NMR,13C{1H} NMR, FD mass spectra, and their conductivity in CH2Cl2 solution. The X-ray crystal structures of3 and5a reveal that the P(1)-N(1)-P(2) angle of the coordinated ligand1a in both complexes is reduced to about 100° in comparison to free uncoordinated1a (119°). This small angle leads to a short P(1)–P(2) bond distance of 259.4 pm in3 and 254.3 pm in5a. The molecules of3 are connected by intermolecular (NH...Cl) hydrogen bridging bonds forming chains along thez axis of the unit cell. The crystals of5a contain two independent pairs of ions in the unit cell (Z=8). In5a no hydrogen bonds exist between the NH-groups and the PF
6–
anions. 相似文献
