12185-09-0Relevant articles and documents
Practical aspects for the coupling of gas analytical methods with thermal-analysis instruments
Kaisersberger,Post
, p. 73 - 93 (1997)
The coupling of mass spectrometry, Fourier-transform infrared spectroscopy and gas chromatography with thermal-analysis methods is discussed from the practical point of view. The gas-flow conditions in thermobalances, the design of coupling interfaces, and the features of the gas analysers relevant to the coupling are shown. The high sensitivity of the Skimmer coupling as compared to the capillary coupling of mass spectrometers is explained by the perfect gas-flow conditions and elimination of condensation effects. Optimisation of transfer systems and gas cells contribute to a high sensitivity also for the FTIR coupling. The evaporation of zinc and phosphorus from a ZnGeP2 semiconductor is shown by the Skimmer coupling with MS and the HF evolution from a brick clay is measured by coupled FTIR.
Synthesis and molecular structure of fluoro(triphosphanyl)silane and attempts to synthesize a silylidyne-phosphane
Driess, Matthias,Monsé, Christian,Bl?ser, Dieter,Boese, Roland,Bornemann, Holger,Kuhn, Arvid,Sander, Wolfram
, p. 294 - 305 (2003)
The synthesis, isolation, spectroscopic characterization (IR, multi-nuclear NMR) and single-crystal X-ray diffraction analysis of FSi(PH2)3 (1a), the first isolable fluorophosphanylsilane, is reported along with the gas phase decomposition of 1a, MeSi(PH2)3 (1b) and EtSi(PH2)3 (1c) under flash vacuum or pulsed pyrolysis conditions and matrix isolation of the products. The title compound is formed quantitatively by PH2/F-ligand exchange reaction of tetraphosphanylsilane Si(PH2)4 with the difluorodiarylstannane Is2SnF2 (Is=2,4, 6-triisopropylphenyl) in the molar ratio of 1:1 in benzene as solvent. Since 1a cannot be separated from the solvent by fractional condensation its isolation was achieved by means of preparative GC. A single crystal of 1a (triclinic, Pl?) suitable for X-ray diffraction analysis was grown by in situ crystallization on a diffractometer at 175 K through miniaturized zone melting with focused infra-red radiation. Interestingly, the Si atom is remarkably distorted tetrahedral coordinated with F-Si-P angles of 120.4(7), 110.4(7), 106.3(1)° and normal Si-F (1.60(2) ?) and Si-P distances (av. 2.241(2) ?). According to ab initio (MP2/6-31G(d,p); MP2/6-311G(2d,p)) and DFT calculations (BLYP, B3LYP, B3PW91 functionals), the distortion is not an intrinsic property of the molecule but due to crystal packing forces. The best agreement between the experimental versus calculated geometrical and vibrational data is achieved at the B3PW91/6-311G(2d,p) level of theory. Since 1a-c appeared as potential precursors for the respective silylidyne-phosphanes ('silaphospha-acetylene') RSiP through stepwise extrusion of PH3, some thermodynamical data for the decomposition and the relative energies of linear RSiP versus bent :SiPR isomers (R=H, Me, Et, Pr, Ph, CF3, OMe, halogen and SiH3) were also calculated. The latter revealed that electronegative substituents R favor the Si-P triple bond in RSiP (except for R=CF3 which stabilizes the :SiPR form) while strong σ-donating substituents R (H, SiH3) favor the :SiPR isomer with Si-P double bond. Although elimination of PH3 and other fragmentation products could be detected by controlled thermal decomposition and matrix isolation, neither flash vacuum experiments of 1a, 1b and 1c (400-600 °C) nor pulsed pyrolyses of 1a at (1100 °C) did provide any direct evidence for the formation of the desired species with Si-P multiple bonds.
Kinetics of the Dissociation of InP under Vacuum
Gallagher, P. K.,Chu, S. N. G.
, p. 3246 - 3250 (1982)
Mass-spectrographic evolved-gas analysis is used to study the rate of decomposition of InP at various linear heating rates under vacuum.Because of the high sensitivity of the technique, it is possible to evaluate the Arrhenius parameters at very low values of fraction reacted (α), 0.10>/=α>/=0.0003, by using the Ozawa method of data analysis.Derived values of the activation energy and log preexponential are 70.5 kcal mol-1 and 13.85 s-1, respectively.These are consistent with the values calculated by using the Freeman and Carrol, Ozawa, and Kissinger methods in the more conventional range of 0.1A composite of all of all of the calculated values shows a nearly linear relationship between activation energy and log preexponential resulting from the mathematical ill-conditioning of the Arrhenius equation.Some extrapolations are made to low temperatures as guidelines for those interested in the thermal processing of InP.
Contributions to the Chemistry of Phosphorus. 235. On the Preparation ofLarger Amounts of Diphosphane(4) in the Laboratory
Baudler, M.,Staendeke, H.,Borgardt, M.,Strabel, H.,Dobbers, J.,et al.
, (2008/10/08)
The preparation of several hundred grammes of diphosphane(4) by hydrolysis of calcium phosphide in a semicontinuous process as well as the handling of larger amounts of this compound are reported. In comparison with earlier results [12], the yield has been raised by 37 percent with simultaneous increase of the accessible total amount. The white solid which is formed in the preparation and purification of diphosphane(4) is not, as was believed in earlier work [25,8], triphosphane(5) or another, novelphosphorus hydride but is rather a clathrate compound of diphosphane(4) or the phosphanes PnHn+2 (n=2-4) and water, respectively.
The First Hydrides of a Phosphorus Sulfide Cage: Nuclear Magnetic Resonance Evidence for α-Tetraphosphorus Trisulfide Hydride Compounds
Tattershall, Bruce W.,Kendall, Nigel L.
, p. 3163 - 3168 (2007/10/02)
The hydrides α-P4S4(H)R (R = H, I, NMePh or SPh) have been prepared in solution by the reaction of α-P4S3I2 or of the corresponding α-P4S3(I)R with Sn-n-Bu3H, and identified by 31P NMR spectroscopy.The compounds were unstable and not isolated.Ab initio molecular orbital calculations of geometry have been carried out for α-P4S3H2, α-P4S3(NMe2)2 and α-P4S3H(NMe2).
Gas-phase ion chemistry of HP2-, FP2-, and HP2+
O'Hair, Richard A. J.,Krempp, Michèle,Damrauer, Robert,DePuy, Charles H.
, p. 2092 - 2096 (2008/10/08)
The gas-phase ion-molecule chemistry of the mass-selected ions HP2-, FP2-, and HP2+ has been studied in a tandem flowing afterglow selected-ion flow tube (FA-SIFT). Both HP2- and HP2+ are formed by direct electron impact on phosphine, followed by subsequent ion-phosphine reactions in the first flow tube. The related ion, FP2-, is formed via an ion-molecule reaction between HP2- and hexafluorobenzene. We have observed a number of reactions of HP2-, including hydride transfer and proton abstraction, as well as fluoride transfer and proton abstraction for FP2-. Using bracketing techniques, the gas-phase proton affinity of P2 has been determined as 162 ± 3 kcal mol-1, in good agreement with Nguyen and Fitzpatrick's theoretically predicted value of 158 ± 3 kcal mol-1. The heats of formation of HP2-, HP2+, HPPH, FP2-, and FPPH have been estimated from the experimentally determined hydride, proton and fluoride affinities of P2 and from the gas-phase acidities of HPPH and FPPH.
