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1.
The large number of known stable compounds in which phosphorus has a low coordination number makes it clear that such compounds can no longer be regarded as “exotic” in main group chemistry. While the rich chemistry of P? C multiply bonded systems makes clear their affinity to their organic congeners, iminophosphanes in particular are also of increasing importance. The linkage of a phosphinidine fragment with an imine fragment via a multiple bond gives rise to a class of compounds with an unusually wide range of structural types. This in turn leads to a broad spectrum of chemical behavior which makes iminophosphanes extremely useful synthetic building blocks in organoelement chemistry. 相似文献
2.
Substituted μ3-carbido-capped tricobalt carbonyl clusters have been synthesised by reaction of [Co3(μ3-C(O)OCH2CHCH2)(CO)9] with a range of monodentate and chelating phosphane ligands. The products have been characterised by microanalysis, IR and NMR spectroscopy, mass spectrometry and, in the case of [Co3(μ3-CR)(CO)7(dppe)], [Co3(μ3-CR)(CO)7(dppm)], [Co3(μ3-CR)(CO)7(PPh3)2], [Co3(μ3-CR)(CO)7(PMe3)2] and [Co3(μ3-CR)(CO)6(PEt3)3] (R=C(O)OCH2CHCH2), single crystal X-ray diffraction. 相似文献
3.
Nina K. GusarovaAlexander V. Artem’ev Svetlana F. MalyshevaOl’ga A. Tarasova Boris A. Trofimov 《Tetrahedron letters》2011,52(51):6985-6987
A novel, convenient, atom-economic approach toward the synthesis of diselenophosphinic esters has been developed via the three-component reaction between aryl- or hetarylalkenes secondary phosphanes, and elemental selenium. The reaction proceeds without a catalyst (85 °C, 3 h, 1,4-dioxane) to afford the target compounds in good to high yields. 相似文献
4.
Contributions to the Chemistry of Phosphorus. 243 On the Oxocyclotetraphosphanes (PBut)4O1–4 Under suitable conditions, the reaction of tetra‐tert‐butylcyclotetraphosphane, (PBut)4, with dry atmospheric oxygen gives rise to the corresponding monoxide (PBut)4O ( 1 ) which has been isolated by column chromatography. The reaction with hydrogen peroxide furnishes a mixture of oxocyclotetraphosphanes (PBut)4O1–4 consisting of two constitutionally isomeric dioxides (PBut)4O2 ( 2 a , 2 b ), the trioxide (PBut)4O3 ( 3 ), and the tetraoxide (PBut)4O4 ( 4 ), in addition to 1 . According to the 31P NMR parameters the oxygen atoms are exclusively exocyclically bonded to the phosphorus four‐membered ring. Which of the P atoms are present as λ5‐phosphorus follows from the different low‐field shifts of the individual P nuclei compared with the starting compound. Accordingly, 1 is 1,2,3,4‐Tetra‐tert‐butyl‐1‐oxocyclotetraphosphane, 2 a and 2 b are 1,2,3,4‐Tetra‐tert‐butyl‐1,2‐dioxo‐ and ‐1,3‐dioxocyclotetraphosphane, respectively, 3 is 1,2,3,4‐Tetra‐tert‐butyl‐1,2,3‐trioxocyclotetraphosphane, and 4 is 1,2,3,4‐Tetra‐tert‐butyl‐1,2,3,4‐tetraoxocyclotetraphosphane. When the oxidation reaction proceeds a fission of the P4 ring takes place. 相似文献
5.
The title compound ( 1 ) was obtained by salt‐metathesis reaction of iPr3SiPLi2 with two molar equiv. of iPr3SiOTf (OTf = OSO2CF3) in 34% yield. Surprisingly, ( 1 ) consists of an 4 : 1 mixture of the two diastereomers ( 1 a ) and ( 1 b ), which do not interconvert to each other even at their decomposition temperature (> 70 °C). They represent different iPr‐rotational isomers which are separated by an unusual high rotational barrier (> 25 kcal mol–1), resulting from hindered rotations around the Si–C and C–C bonds. The unexpectedly small magnitude of the 1J(Si, P) coupling constant of ( 1 a ) (9.4 Hz) and ( 1 b ) (9.0 Hz) reflects unusual electronic properties of the Si3P skeleton. Hitherto only ( 1 a ) could be isolated in the form of single‐crystals and its structure was determined by X‐ray diffraction analysis. The P‐atom in ( 1 a ) is almost planar coordinated (sum of bond angles = 359.789(3)°), but the Si–P‐distance (2.264(7) Å) resembles those values of related silylphosphanes with pyramidally coordinated P atoms. Although MNDO calculations revealed two other iPr‐rotational isomers with similar energy, they prove that the Si3P skeleton prefers the trigonal‐planar arrangement due to steric congestion. 相似文献
6.
Walter Bauer Jochen Ellermann Martina Dotzler Diana Pohl Frank W. Heinemann Matthias Moll 《无机化学与普通化学杂志》2000,626(2):574-587
Chemistry of Polyfunctional Molecules. 133. X‐Ray Crystal Structural, Solid‐state 31P CP/MAS NMR, TOSS, 31P COSY NMR, and Mechanistic Contributions to the Co‐ordination Chemistry of Octacarbonyldicobalt with the Ligands Bis(diphenylphosphanyl)amine, Bis(diphenylphosphanyl)methane, and 1,1,1‐Tris(diphenylphosphanyl)ethane Co2(CO)8 reacts with bis(diphenylphosphanyl)amine, HN(PPh2)2 (Hdppa, 1 ), in two steps to afford the known compound [Co(CO)(Hdppa‐κ2P)2][Co(CO)4] · 2 THF ( 6 a · 2 THF). The intermediate [Co(CO)2(Hdppa‐κ2P) · (Hdppa‐κP)][Co(CO)4] · dioxane · n‐pentane ( 5 · dioxane · n‐pentane) was isolated for the first time and was characterized by X‐ray analysis. The cation 5 + exhibits a slightly distorted trigonal‐bipyramidal geometry. Detailed 31P‐NMR investigations (solid‐state CP/MAS NMR, TOSS, 31P‐COSY, 31P‐EXSY) showed that the additional tautomer [Co(CO)2(Hdppa‐κ2P)(Ph2P–N=P(H)Ph2‐κP)]+ ( 5 ′+) is present in solution. The tautomer equilibrium is slow in the NMR time scale. In contrast to the solid state only tetragonal pyramidal species of 5 are found in solution. At –90 °C there is slow exchange between the three diastereomeric species 5 a +– 5 c +. Compound 5 forms [Co(CO) · (Hdppa‐κ2P)2]BPh4 · THF ( 6 b · THF) in THF with NaBPh4 under CO‐Elimination. A X‐ray diffraction investigation shows that the cation 6 + consists of a slightly distorted trigonal‐bipyramidal co‐ordination polyeder. However, a distorted tetragonal‐pyramidal structure has been found for the cation 7 + of the related compound [Co(CO)(dppm)2][Co(CO)4] · 2 THF ( 7 · 2 THF; dppm = bis(diphenylphosphanyl)methane, Ph2PCH2PPh2). A comparison with the known [8] trigonal‐bipyramidal stereoisomer, ascertained for 7 + of the solvent‐free 7 , is described. In solutions of 6 a · 2 THF and 7 · 2 THF 13C{1H}‐ and 31P{1H}‐NMR spectra indicate an exchange of all CO and organophosphane molecules between cobalt(I) cation and cobalt(–I) anion. A concerted mechanism for the exchange process is discussed. CO elimination leads to discontinuance of the cyclic mechanism by forming binuclear substitution products such as the isolated Co2(CO)2 · (μ‐CO)2(μ‐dppm)2 · 0.83 THF ( 8 · 0.83 THF), which was characterized by spectroscopy and X‐ray analysis. For the dissolved [Co(CO)2CH3C(CH2PPh2)3][Co(CO)4] · 0.83 n‐pentane ( 9 a · 0.83 n‐pentane) no CO and triphos exchange processes between the cation and the anion are observed. Metathesis of 9 a · 0.83 n‐pentane with NaBPh4 yields [Co(CO)2CH3C(CH2PPh2)3]BPh4 ( 9 b ) which has been characterized by single‐crystal X‐ray analysis. The cation shows a small distorted tetragonal‐pyramidal structure. 相似文献
7.
Leonid I. Goryunov Vitalij D. Shteingarts Joseph Grobe Bernt Krebs Michael U. Triller 《无机化学与普通化学杂志》2002,628(8):1770-1779
Trimethylsilyldimethylarsane Me3SiAsMe2 was used as a reagent for the substitution of fluorine in polyfluoroarenes C6F5X (X = F, H, Cl) and C5NF5 by the Me2As group. The reactions occur between 50 — 180 °C, either in benzene or without solvent, to give as a rule 4‐X‐1‐(dimethylarsano)tetrafluorobenzenes XC6F4AsMe2, ( 1—3 ) and 4‐dimethylarsano‐tetrafluoropyridine C5NF4AsMe2 ( 4 ), respectively, in yields between 43 and 94 %. In the case of C6F6, also double substitution is observed affording 1, 4‐bis(dimethylarsano)tetrafluorobenzene 5 in addition to the monosubstituted derivative. The time and temperature dependencies of the reactions increase in the sequence: C6F6< C6F5H < C6F5Cl < C5NF5. The arsanes 1 and 4 were transformed to the potentially valuable bidentate ligands 1‐(dimethylarsano)‐4‐(dimethylphosphano)tetrafluorobenzene 6 and 4‐(dimethylarsano)‐2‐(dimethylphosphano)trifluoropyridine 8 by reaction with trimethylsilyl‐dimethylphosphane Me3SiPMe2. 6 reacts with oxygen to yield the corresponding phosphane oxide 7 . Trimethylsilyl‐dimethylamine Me3SiNMe2 also was successfully tested as a reagent for the dimethylamination of polyfluoroarenes C6F5X [X = F, H, Cl, CF3, P(S)Me2], 1‐P(S)Me2‐4‐H‐C6F4 and 4‐X‐C5NF4 [X = F, PMe2, P(S)Me2]. Sulfuration of the new Me2P derivatives 8 and 20 leads to the corresponding thiophosphanes 9 and 21 (Schemes 2 and 3). Furthermore, the recently reported very efficient one‐pot synthesis of Me2P substituted polyfluoroarenes (e.g. XC6F4PMe2 with X = F, Me2PC6F4) was extended to the preparation of Me2As and MeS derivatives of pentafluoropyridine using a mixture of Me3SnH, As2Me4 (or S2Me2) and C5NF5 as precursors for the one‐pot reaction. The expected products 4‐(dimethylarsano)tetrafluoropyridine 4 and 4‐(methylthio)tetrafluoropyridine 22 , respectively, were obtained in 84 and 82 % isolated yields. The novel compounds were characterized by spectroscopic (NMR, MS) and analytical data. Compounds 5 , 7 , 9 and 21 could be isolated in form of single crystals and their structures have been studied by X‐ray diffraction. 相似文献
8.
Unusual Reactivity of the Silicon-Phosphorus Double Bond in a Silylidene(fluorosilyl)phosphane: Intramolecular C, H Insertion and its Conversion in a New Silylidene(silyl)phosphane Thermolysis of the (fluoro-tert.butyl-2,4,6-triisopropylphenylsilyl)-tert.butyl-2,4,6-triisopropylphenylsilylidenephosphane (“Phosphasilene”) ( 1 ) in toluene at 130 °C leads, under C,H-activation of a methyl group of a ortho-isopropyl group, to the constitutional isomeric silyl(fluorosilyl)phosphane ( 2 ), whose structure has been crystallographically established. It crystallizes racemically and possesses a benzosilacyclopent-2-ene moiety as major structural motif. Lithiation of 2 leads to the corresponding lithium phosphanide ( 3 ), which eliminates LiF at 80 °C in toluene and, concomitantly, furnishes the colorless new silylidene(silyl)phosphane ( 4 ) in the form of its two diasteromers (Z : E ca. 1 : 2). The 31P NMR chemical shifts of δ = –29.95 and –31.75 are practically identical with the value of 1 , and the 29Si NMR spectrum shows resonance signals at characteristically low field (δ = 222.5 (1J(Si, P) = 160 Hz), 221.8 (1J(Si, P) = 161 Hz)). An single-crystal X-ray diffraction analysis of an enantiomeric form of the E-isomer reveals a Si=P distance of 2.063(2) Å, whereas the Si–P single bond distance of 2.246(2) Å is ca. 8% longer. The low coordinated silicon center is trigonal planar surrounded and the Si–P–Si angle is 108.09(8)°. 相似文献
9.
Benson M. Kariuki Patrizia Calcagno Kenneth D. M. Harris Douglas Philp Roy L. Johnston 《Angewandte Chemie (International ed. in English)》1999,38(6):831-835
The genetic algorithm approach , in which a population of trial structures is allowed to evolve subject to well-defined procedures for mating, mutation, and natural selection, was employed to solve the complex molecular crystal structure of Ph2P(O)(CH2)7P(O)Ph2 directly from powder diffraction data. The structure solution reveals an interesting (perhaps unexpected) molecular conformation (see picture), which emphasizes the importance of allowing complete conformational flexibility of the molecule in the structure solution calculation. 相似文献
10.
Analytical and Preparative Separation of Functional Carbosilanes and Phosphanes by Means of SFC (Supercritical Fluid Chromatography) Analytical and preparative separations of functional silanes, carbosilanes and phosphanes by means of SFC (supercritical fluid chromatography) using CO2 or CF3Cl as mobile phases are reported. The detecting system (an IR high pressure cell) of the apparatus which was developed by us is depicted. The separation of mixtures containing silanes with strongly polarizing groups proceeds successfully with Nucleosil-C18 and CO2 according to the molecular weights. Large differences in the polarity of the compounds give rise to a separation according to molecular weights, smaller ones to the types of compounds. The advantages of a separation by SFC are demonstrated using a mixture of 1,3,5-trisilacyclohexanes with SiH, CCl2 and SiF groups. The preparative separation is demonstrated using a mixture of 4 different groups of a toral 22 carbosilanes. Eight fractions were obtained each of which containing the compounds with the same number of Si atoms. The final separation was achieved by means of a pressure program (Nucleosil-C18, CO2). The preparative isolation of a cyclic phosphinoborane from a mixture of three components of the same type as well as the isolation of (Me3Si)3P from a mixture of P-rich silylphosphanes is reported. 相似文献