Beiträge zur Chemie des Phosphors. 142. P6(t-Bu)5H – das erste Cyclotetraphosphan mit P2-Seitenkette

Contributions to the Chemistry of Phosphorus. 142. P₆(t-Bu)₅H – the First Cyclotetraphosphane with a P₂ Side Chain The thermolysis of 1, 2-di-tert-butyldiphosphane, H(t-Bu)P? P(t-Bu)H, leads to formation of the hitherto unknown hexaphosphane P₆(t-Bu)₅H ( 1 ). In the first instance the iso-P₅H₅ derivative P₅(t-Bu)₄H [3] is formed, which reacts further with H₂(t-BuP)₂ or H₂(t-BuP)₃ yielding 1 . Compound 1 has been isolated in the pure state and structurally characterized as 1-(1,2-di-tert-butyldiphosphino)-2, 3, 4-tri-tert-butyl-cyclotetraphosphane, i. e. as a four-membered ring compound with a P₂ side chain. Due to the chirality of the P atoms in the side chain, 1 exists as a mixture of two configurational isomers, the threo-and the erythro-form.     

Beiträge zur Chemie des Phosphors, 45. Triphenyl-cyclotriphosphan - ein Derivat des P3H3

Contributions on the chemistry of phosphorus. 45. Triphenyl cyclotriphosphane - a derivative of P₃H₃ Triphenyl-cyclotriphosphane-dipotassium ( 2 ) can be prepared without solvent by metallation of pentaphenyl-cyclopentaphosphane ( 3 ) with the stoichiometric amount of potassium in benzene, moreover by precipitation of the corresponding reaction solution in tetrahydrofuran with toluene or petroleum ether. However, 2 · THF is formed when the solvent is removed completely, 2 or 2 · THF react with iodine at - 78°C to give the compounds K₂(C₆H₅P)₃ (4) or 4 · THF. These decompose in solution under formation of potassium iodide and triphenyl-cyclotriphosphane ( 1 ), not described before. 1 could be isolated in a pure state. It differs from 3 by its characteristic melting behaviour and the osmometric molecular weight, but especially by the i.r. and mass spectrum. 1 is stable at ? 20 °C for several weeks, but rearranges easily to give the more stable 3 , especially at somewhat higher temperatures.     

Beiträge zur Chemie des Phosphors. 128. Synthese des Diphosphastanna-cyclopropans (t-BuP)2Sn(t-Bu)2

Contributions to the Chemistry of Phosphorus. 128. Synthesis of the Diphosphastanna-cyclopropane (t-BuP)₂Sn(t-Bu)₂ The first three-membered P₂Sn heterocycle, 1,2,3,3-tetra-tert-butyl-1,2,3-diphosphastanna-cyclopropane (1,2,3,3-tetra-tert-butyl-1,2,3-diphosphastannirane) ( 1 ), has been synthesized by [2+1] cyclocondensation of K(t-Bu)P—P(t-Bu)K with (t-Bu)₂SnCl₂. 1 is stable at room temperature. Besides, (t-BuP)₂[Sn(t-Bu)₂]₂ ( 2 ), (t-BuP)₄Sn(t-Bu)₂ ( 3 ), and (t-BuP)₄ are formed. In the reaction with Et₂SnCl₂, the six-membered ring compound [(t-BuP)₂SnEt₂]₂ ( 4 ) is the main-product; the four- and five-membered cyclostannaphosphanes (t-BuP)₃SnEt₂ ( 5 ) and (t-BuP)₃(SnEt₂)₂ ( 6 ) are also formed. 1 could be isolated in the pure state and has been unambiguously characterized as a three-membered heterocycle with a P₂Sn skeleton. The ³¹P-NMR parameters of the other new cyclostannaphosphanes 2–6 are reported.     

Beiträge zur Chemie des Phosphors. 140. Dilithium-hydrogenheptaphosphid,Li2HP7 – ein teilmetalliertes Derivat von P7H3: Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 140. Dilithium Hydrogen Heptaphosphide, Li₂HP₇ — a Partially Metallated Derivative of P₇H₃: Preparation and Structural. Characterization Dilithium hydrogen heptaphosphide, Li₂HP₇ ( 2 ), is purely obtained as an orange-red solvent adduct by reacting P₂H₄ with n-BuLi or Li₃P₇ ( 1 ) under suitable conditions. 2 is also formed in the metalation of LiH₂P₇ ( 3 ) or P₇H₃, in the disproportionation of LiH₄P₅, in thepartial protolysis of 1 , and in the nucleophilic cleavage of P₄. The composition and the structure of 2 could be elucidated by a complete analysis of its low-temperature ³¹P{¹H}-NMR spectrum. As shown by the δ(³¹P) values, the P₇ cage in 2 is clearly distorted compared with 1 . The P₇H^2? ion has fluctuating bonds in analogy to dihydrobullvalene and can be described by two valence-tautomeric forms with identical structures. At room temperature 2 disproportionates yielding lithium polyphosphides with a greater number of phosphorus atoms.     

Beiträge zur Chemie des Phosphors. 43. Gaschromatographische Trennung von Phosphanen

Monophosphane (PH₃), diphosphane (P₂H₄), and triphosphane-5 (P₃H₅) could be separated in mixtures by isothermal gas chromatography. On the basis of the experiences hereby obtained, further gas chromatographic separations were carried out with a programmed temperature mode. For the identification of the chromatographic peaks a mass spectrometer as a second detector was applied. In the temperature range from ?60°C to +60°C, it was possible for the first time to separate mixtures of diphosphane and higher phosphanes without any decomposition in the gas chromatographic column. Besides monophosphane and diphosphane, triphosphane-3 (P₃H₃), triphosphane-5 (P₃H₅), and tetraphosphane-6 (P₄H₆) could be eluated as undecomposed components. By this, a fundamental basis for the application of gas chromatography to the quantitative analysis of mixtures of phosphanes and to the development of a gas chromatographic method for the preparative isolation of individual higher phosphanes has been established.     

Beiträge zur Chemie des Phosphors. 203 [1].(t- BuSi)4P3Cl3, das erste Silaphosphan mit Norcuban-Struktur

Contributions to the Chemistry of Phosphorus. 203. (t-BuSi)₄P₃Cl₃ – The First Silaphosphane with a Structure Analogous to Norcubane The reaction of t-BuSiCl₃ with LiAl(PH₂)₄ yields the compound (t-BuSi)₄P₃Cl₃ ( 1 ), which has been isolated in pure form. According to NMR spectroscopic investigations and an X-ray single-crystal analysis, 1 is 2,4,6,7-tetra-tert-butyl-2,4,7-trichloro-1,3,5-triphospha-2,4,6,7-tetrasilatricyclo[3.1.1.0^3,6]heptane and thus the first silaphosphane with a structure analogous to norcubane. The compound crystallizes monoclinically in the space group P2₁/n with a = 1102.1 pm, b = 1609.2 pm, c = 1612.8 pm, β = 90.90° and Z = 4. The main structural feature is a cube alternately composed of Si and P, from which one phosphorus atom has been removed. The Si atoms are each substituted by t-Bu groups, the three adjacent to the missing corner additionally by Cl atoms.     

Beiträge zur Chemie des Phosphors. 170. Konstitutions- und Konfigurationsisomere von Hexaphosphan(8), P6H8

Contributions to the Chemistry of Phosphorus. 170. Constitutional and Configurational Isomers of Hexaphosphane(8), P₆H₈ Phosphane mixtures containing 5–10 P-% of hexaphosphane(8), P₆H₈, are obtained by thermolysis of diphosphane, P₂H₄, or as residue from distillation of crude diphosphane [3]. By complete analysis of the ³¹P{¹H}-NMR spectrum on the basis of selective population transfer experiments, the following P₆H₈-isomers with a branched phosphorus skeleton have been identified and structurally characterized: the two diastereomers of 2-phosphinopentaphosphane ( 1a : erythro; 1b : threo), two of the three diastereomers of 3-phosphinopentaphosphane ( 2a : erythro, erythro; 2b : erythro, threo), and the highly symmetric 2,3-diphosphinotetraphosphane ( 3 ). The correlation between the diastereomers and the observed spin systems results from the preferred gauche orientation of neighboring free electron pairs, the dependence of ¹J(PP) on dihedral angles as well as the ³J(PP) and ⁴J(PP) long range couplings. Any indications of the diastereomers of n-P₆H₈ with an unbranched chain of phosphorus atoms have not been found.     

Beiträge zur Chemie des Phosphors. 200. Tetraisopropyl-tetradecaphosphan(4), P14(i-Pr)4 – Darstellung und strukturelle Charakterisierung

Contributions to the Chemistry of Phosphorus. 200. Tetraisopropyl-tetradecaphosphane(4), P₁₄(i-Pr)₄ – Preparation and Structural Characterization Tetraisopropyl-tetradecaphosphane(4) ( 1 ) has been obtained by reacting i-PrPCl₂, P₄, and magnesium and subsequently thermolysing the crude reaction product, and has been isolated in pure form. Whereas the ³¹P{¹H}-NMR spectrum provides only limited structural information, the ¹³C{¹H, ³¹P}-DEPT-NMR and the ¹H{³¹P}-NMR spectrum of 1 reveals the presence of two symmetrical configurational isomers 1a and 1c and one asymmetrical diastereomer 1b . This would only be possible, if 1 is 3,4,10,11-tetraisopropyl-hexacyclo[6.6.0.0^2,6.0^5,14.0^7,12.0^9,13]tetradecaphosphane. When crystallizing 1 pure 1a precipitates, which at +10°C in solution is retransformed into the isomeric mixture 1a , 1b , 1c by inversion of the configuration.     

Beiträge zur Chemie des Phosphors. XXXIX. Zur Hydrolyse des Diphosphor-tetrajodids

In the preparation of Ba₂H₂(H₂P₂O₄)₃ by P₂I₄ hydrolysis in barium acetate/acetic acid buffer solution P(II)—P(IV), P(IV)—P(IV), P(III), and P(V) acid are formed in addition to about 17% of the starting phosphorus as P(II)—P(II) acid after separating the Ba₂H₂(H₂P₂O₄)₃. Thus in this reaction a total of 64% of P₂I₄ Phosphorus can be detected as hypodiphosphorous acid H₄P₂O₄. The precipitated yellow reaction product, obtained by water hydrolysis of P₂I₄, contains no solid phosphorus hydride — as believed previously — but as a result of elementary analysis, iodometry, and chromatography, a high molecular-weight phosphorus, hydrogen and oxygen containing substance of statistical stoichiometry with oxydation number ～0 for phosphorus. P? H, P?O, and P? O? P groups could be detected by IR-spectroscopy, but not P? OH groups. The P₂I₄ hydrolysis probably proceeds via a yellow coloured initial product with trivalent phosphorus, and yields a very complex reaction mixture in which also the intermediates partially still react further.     

Beiträge zur Chemie des Phosphors. 183. Lithium-tetrahydrogenheptaphosphid und Lithium-octa-hydrogenheptaphosphid

Contributions to the Chemistry of Phosphorus. 183. Lithium Tetrahydrogen Heptaphosphide and Lithium Octahydrogen Heptaphosphide Lithium tetrahydrogen heptaphosphide, LiH₄P₇ ( 1 ), and lithium octahydrogen heptaphosphide, LiH₈P₇ ( 2 ), belong to the first reaction products of the metalation of P₂H₄ with n-butyllithium that can be identified. Both compounds are also formed on reaction of Li₃P₇ with excess P₂H₄. 1 also results from the reaction of LiH₄P₅ with P₂H₄. Whereas 1 can be isolated as an orange-red crystalline solvent adduct in a purity of 60-70 per cent, 2 cannot be enriched further due to its extreme reactivity. The composition and the structure of 1 and 2 have been elucidated from their ³¹P-NMR spectra. Hence, 1 has a P₇ skeleton analogous to that of norbornane, whereas 2 as a precursor in the formation of 1 from P₂H₄ and n-BuLi is an open-chain doubly branched heptaphosphide.     

Beiträge zur Chemie des Phosphors. 169. 31P-NMR-spektroskopischer Nachweis und Struktur von Hexaphosphan(6), P6H6

Contributions to the Chemistry of Phosphorus. 169. ³¹P-NMR Spectroscopic Detection and Structure of Hexaphosphane(6), P₆H₆ Phosphane mixtures containing 5–10 P-% of hexaphosphane(6), P₆H₆, are obtained by thermolysis of a mixture of chain-type phosphorus hydrides P_nH_n+2 (n = 2–7) at 25–35°C. According to the complete analysis of the ³¹P{¹H}-NMR spectrum on the basis of selective population transfer experiments, P₆H₆ has the constitution of 1-phosphino-cyclopentaphosphane. An indication of the constitutional isomer with a six-membered phosphorus-ring and all trans orientation of the hydrogen atoms and the free electron pairs, respectively, has not been found. From the δ(³¹P) data of the phosphanes with five-membered rings P_nH_n (n = 5, 6) a relationship for the chemical shifts of this class of compounds as a function of their structural parameters is derived.     

Beiträge zur Chemie des Phosphors. 167 [1, 2]. Konstitutions- und Konfigurationsisomere von Pentaphosphan(7), P5H7

Contributions to the Chemistry of Phosphorus. 167. Constitutional and Configurational Isomers of Pentaphosphane(7), P₅H₇ Phosphane mixtures containing 10—15 P-% of pentaphosphane(7), P₅H₇, are obtained by thermolysis of diphosphane, P₂H₄, or as residue from distillation of crude diphosphane [3]. According to the complete analysis of the ³¹P{¹H}-NMR spectrum on the basis of selective population transfer experiments, P₅H₇ exists as a mixture of three diastereomers of n-P₅H₇ — 1a (erythro, erythro), 1b (erythro, threo), 1c (threo, threo) — and of the constitutional isomer 2-phosphinotetraphosphane 2 (iso-P₅H₇, largest relative isomeric abundance). The correlation between the diastereomers and the observed spin systems results from the preferred gauche orientation of neighboring free electron pairs, the dependence of ¹J(PP) on dihedral angles, and the ³J(PP) long range couplings. From the ³¹P-NMR data of the phosphane molecules P_nH_n+2 with n = 1—5 general relationships for the δ(³¹P) values and the ¹J(PP) coupling constants of chain-type phosphorus hydrides as a function of their structural parameters are derived.     

Beiträge zur Chemie des Phosphors. 111. 1,2-Dichlor-1,2-di-tert-butyldiphosphan

Contributions to the Chemistry of Phosphorus. 111. 1,2-Dichloro-1,2-di-tert-butyl-diphosphane The reaction of tri-tert-butyl-cyclotriphosphane, (t-BuP)₃, with phosphorus(V) chloride (molar ratio 1:2) leads to the title compound Cl(t-Bu)P? P(t-Bu)Cl ( 1 ), which is remarkably stable against disproportionation reactions. As the first 1,2-dichloro-1,2-diorganyldiphosphane, 1 has been isolated in a pure state and was thoroughly characterized. At room temperature, 1 exists in a mixture of the d,l and meso form (about 20:80). The mutual repulsion of the negative polarized Cl atoms and their preferred gauche arrangement to the free electron pairs of neighboured P atoms leads to a gauche-conformation of the lone electron pairs in the d,l- and to a trans-conformation in the meso-configuration.     

Beiträge zur Chemie des Phosphors. 212. Tetraisopropyl-dodecaphosphan(4), P12i-Pr4 – Darstellung,Eigenschaften und Moleküldynamik

Contributions to the Chemistry of Phosphorus. 212. Tetraisopropyldodecaphosphane(4), P₁₂i-Pr₄ – Preparation, Properties, and Molecular Dynamics According to an earlier crystal structure analysis, tetraisopropyldodecaphosphane(4) ( 1 ) exhibits the symmetry C₂, and the substituents are arranged in all-trans position [3]. We have now found by NMR spectroscopic studies that in solution a second configurational isomer of the symmetry C_S ( 1b ) exists in addition to the molecule present in the crystal ( 1a ). The transformation of 1a into 1b , which can only occur through a quasi synchronous inversion at the atoms P³ and P⁴ or P⁹ and P¹⁰, takes place at a noticeable rate already below room temperature.     

Beiträge zur Chemie des Phosphors. 222. Pentaisopropyl-tridecaphosphan(5), P13i-Pr5– Struktur in Lösung und im Kristall

Contributions to the Chemistry of Phosphorus. 222. Pentaisopropyltridecaphosphane(5), P₁₃iPr₅ – Structure in Solution and in the Crystal In an earlier investigation [3] pentaisopropyltridecaphosphane(5) ( 1 ) had been obtained by reacting i-PrPCl₂, P₄ and magnesium and subsequently thermolysing the crude reaction product, but had been structurally characterized only incompletely. We have now corroborated the earlier postulated constitution by NMR spectroscopic studies and an X-ray structural analysis. Thus 1 is 3,4,7,10,11-pentaisopropyl-pentacyclo[7.4.0.0^2,6.0^5,13.0^8,12]tridecaphosphane. In solution two configurational isomers 1 a and 1 b exist in the relative abundance of about 2 : 1, which have the symmetry C₁ and C_s, respectively. When crystallizing pure 1 b precipitates, which at room temperature in solution is retransformed into the isomeric mixture 1 a , 1 b by inversion of the configuration. Any indications of an additional symmetric diastereomer have not been found. Obviously, in isomer 1 b the inversion barrier of the atom P⁷ is markedly higher than for the atoms of the two-atom bridges P³? P⁴ and P¹⁰? P¹¹, respectively.     

Beiträge zur Chemie des Phosphors. 168 [1]. Zur Kenntnis der Isomere von Tetraphosphan(6), P4H6

Contributions to the Chemistry of Phosphorus. 168. About the Isomers of Tetraphosphane(6), P₄H₆ Additional informations about the ³¹P-NMR parameters of d,l- and meso-n-P₄H₆ as well as of iso-P₄H₆ have been obtained by ³¹P-NMR spectroscopic investigations of mixtures of phosphanes containing 26—48 P-% of tetraphosphane(6). On the basis of the differences in the ³J(PP)-coupling constants the observed AA′BB′-spin systems have been reassigned to the various diastereomers of n-P₄H₆.     

Beiträge zur Chemie des Arsens. 5. Zur Existenz von Penta-tert-butyl-cyclopentaarsan, (t-BuAs)5

Contributions to the Chemistry of Arsenic. 5. On the Existence of Penta-tert-butyl-cyclo-pentaarsane, (t-BuAs)₅ The reaction of tert-butyldichlorarsane with magnesium in tetrahydrofurane or diethylether yields the hitherto unknown penta-tert-butyl-cyclopentaarsane, (t-BuAs)₅ ( 1 ), in addition to the cycloarsanes (t-BuAs)₄ and t-Bu₆As₈. Compound 1 was preparatively concentrated to ? 80 mole-% and characterized by its ¹H-NMR and mass spectrum. The thermodynamic stability of the tert-butyl substituted monocyclic arsanes decreases in the order (t-BuAs)₄ > (t-BuAs)₅ > (t-BuAs)₃. By thermolysis of 1 t-Bu₆As₈ and other polycyclic arsanes are formed.     

Beiträge zur Chemie des Phosphors. 219 [1]. Tetraisopropyl-octadecaphosphan(4), P18i-Pr4 – Darstellung und kernresonanzspektroskopische Strukturbestimmung

Contributions to the Chemistry of Phosphorus. 219. Tetraisopropyloctadecaphosphane(4), P₁₈i-Pr₄ — Preparation and Structure Determination by Nuclear Magnetic Resonance Tetraisopropyloctadecaphosphane(4) ( 1 ) has been obtained by reaction of i-PrPCl₂ with P₄ and magnesium and subsequent thermolysis of the crude reaction product, and has been isolated in 95% purity. According to NMR-spectroscopic investigations, 1 contains a conjuncto-phosphane skeleton consisting of a P₁₁(5)- and a P₉(3)-structural element analogous to that of deltacyclane, joined through a common P₂-bridge. Thus, 1 is 8,14,16, 18-tetraisopropyloctacyclo[13.2.1.0^2,13.0^3,11.0^4,9.0^5,7.0^6,10.0^12,17]octadecaphosphane. Compound 1 is formed as a mixture of two configurational isomers 1 a and 1 b , which differ from each other in their spatial arrangements of the isopropyl group at P₈.     

Beiträge zur Chemie des Phosphors. 99. Ein Heterocyclophosphan mit P4N-Ringgerüst: Synthese und Eigenschaften von (PC6H5)4N(c-C6H11)

Contributions to the Chemistry of Phosphorus. 99. A Heterocyclophosphane with a P₄N Ring Skeleton: Synthesis and Properties of (PC₆H₅)₄N(c-C₆H₁₁) The first cycloazaphosphane, (PC₆H₅)₄N(c-C₆H₁₁) ( 1 ), is obtained by the reaction of N, N-dichlorocyclohexylamine with an excess of dipotassium phenylphosphide K—(PC₆H₅)_n—K (n = 3, 4). Besides, considerable amounts of (PC₆H₅)₅ are formed and occasionally some (PC₆H₅)₄ and (PC₆H₅)₆ can be found. 1 could be purely isolated in 12% yield. The compound is relatively stable against heating but light sensitive. It was characterized by elemental analysis, mass-, NMR, and vibrational spectra. The phenyl substituents at adjacent phosphorus atoms are arranged in trans position. After the reaction of K(R)P—P(R)K with N, N-dihalogenamines no clear indications for the formation of azadiphosphiranes with a P₂N three-membered ring skeleton could be found.     

Beiträge zur Chemie des Phosphors. 236. Über einige physikalische und chemische Eigenschaften von Diphosphan(4)

Contributions to the Chemistry of Phosphorus. 236. On Several Physical and Chemical Properties of Diphosphane(4) The density of diphosphane(4) has been measured between ?78°C and +18°C and the value d₄²⁰ = 1.014 · 0.002 extrapolated. The refractive index of P₂H₄ was determined to be n²⁰ = 1.66 ± 0.01. The surface tension at 0°C and ?50°C was measured to be σ = 34 and 42 dyn · cm^?1, respectively. In the UV absorption spectrum, gaseous P₂H₄ exhibits a broad absorption band at λ_max = 2 220 Å, in n-hexane solution, this band is shifted somewhat to shorter wave-lengths. The molar extinction coefficient was determined to be ? ≈? 900 1 · mol^?1 · cm^?1. As a result of photolytic decomposition, absorptions for PH₃ and more phosphorus-rich hydrides also occur. The solubility behavior of P₂H₄ in various organic solvents and the stabilities of the resultant solutions have been investigated. At 0°C, the solubility of diphosphane(4) in water was found to be ± 035 ± 0.003 g P₂H₄/100 g solution and that of water in diphosphane(4) to be 43.2 ± 1.6 g H₂O/100 g solution. The system diphosphane(4)/methanol also exhibits a miscibility anomaly. The IR spectra of liquid P₂H₄ and of its solutions in various solvents revealed, in accord with the results of nuclear magnetic resonance spectroscopy [7], that diphosphane(4) is practically not associated. Weak interactions through hydrogen bridging bonds occur with pyridine and methanol in which P₂H₄ serves as the proton donor and, in the latter case, also as proton acceptor. For the thermolysis of diphosphane(4), it has been found that the primary step comprises a disproportionation with inter-molecular elimination of PH₃ and formation of triphosphane(5). With further progress of the thermolysis, in dependence on the reaction conditions, mixtures of various phosphanes of differing composition are formed. Photolysis gives rise to phosphane mixtures having similar compositions. With aqueous silver salt and iodine solutions, diphosphane(4) reacts as a reducing agent; with sodium hydroxide solution, it reacts by a slow disproportionation as well as by formation and degradation of the subsequently formed polyphosphides. On reaction with triphenylmethyl, triphenylmethane and a yellow solid of varying composition are formed. The reaction of diazomethane with diphosphane(4) leads to the preferential insertion of the carbene in the P? P bond and formation of methylenebis(phosphane).