Über die Umsetzung von P4E3I2 (E = S,Se) mit einigen Carbonsäuren und Dithiocarbonsäuren

On the Reaction of P₄E₃I₂ (E = S, Se) with some Carboxylic Acids and Dithiocarbamic Acids By the reaction of α-P₄E₃I₂ (E = S, Se) with carboxylic acids, dithiobenzoic acid or dithiocarbamic acids in the presence of triethylamin or with (C₆H₅)₃SnR, or of β-P₄E₃I₂ with tin-organic compounds α-P₄E₃(I)R, α(β)-P₄E₃R₂ [R = ? OC(O)C₆H₅, ? OC(O)CH₃, ? SC(S)NC₅H₁₀, ? SC(S)N(C₂H₅)₂], α-P₄S₃(I)SC(S)C₆H₅, α-P₄S₃(SC(S)C₆H₅)₂ and β-P₄E₃(I)R (R = ? OC(O)C₆H₅, ? OC(O)CH₃) were prepared in solution and identified by ³¹P NMR spectroscopy. In addition α-P₄S₃(NC₅H₁₀)(SC(S)NC₅H₁₀) was detected. The β-isomers could be obtained also with lesser yields by the reaction with the dithiocarbamic acids, too. The substitution of the second iodine ligand in β-P₄E₃I₂ resulted mainly in β-P₄S₃(R_exo)₂ and by inversion of the configuration at a phosphorus atom, in β-P₄E₃R_exoR_endo. α-P₄S₃I₂ reacted with methanol in CS₂ to α-P₄S₃(OCH₃)(SC(S)OCH₃) and α-P₄S₃(SC(S)OCH₃)₂. The ³¹P NMR data of the compounds are discussed. The ³¹P NMR spectra of the α(β)-P₄E₃ dithiocarbamates indicate dynamic processes in the solution, e. g. α-P₄S₃(I)(SC(S)NR₂) showed an intramolecular conversion, due to the anisobidentate dithiocarbamate ligand. This behaviour had not previously been noticed for compounds with a P₄S₃-skeleton.     

Reaktionen von Alkoholen und Mercaptanen mit Tetraphosphatrichalkogenadiiodiden

Reactions of Alcohols and Mercaptans with Tetraphosphorus Trichalcogenide Diiodides α-P₄E₃(I)R and α-P₄E₃R₂ (R = -OCH₃, -OC₂H₅, -OCH(CH₃)₂, -OC(CH₃)₃ and -OC₆H₅) have been detected in the reaction solutions of α-P₄E₃I₂ (E = S, Se) with alcohols in the presence of triethylamine, or with trimethyltin alkoxides in CS₂. β-P₄S₃I₂ reacted with methanol at 243 K in CS₂ to yield β-P₄S₃(I)OCH₃, β-P₄S₃(OCH₃)_exo(OCH₃)_endo, and β-P₄S₃[(OCH₃)_exo]₂. The thiolates α-P₄Se₃R₂′ (R′ = -SC₂H₅, -n-SC₅H₁₁, -n-SC₇H₁₅, -SC(CH₃)₃ and -SC₆H₅) were found in reaction solutions of α-P₄Se₃I₂ with thiols HR′. The ³¹P NMR data of these compounds are given.     

Reaktionen von P4S3I2 mit bifunktionellen Liganden

Reactions of P₄S₃I₂ with Bifunctional Ligands Nitrogen, oxygen, selenium or carbon atoms were introduced as bridges into the P₄S₃ skeleton by the reaction of α- or β-P₄S₃I₂ with bifunctional ligands. Among compounds in the series α-P₄S₃-α-E, the oxide μ-P₄SO was made for the first time. High concentrations of α-P₄S₄Se, made by a new route, allowed observation of ⁷⁷Se satellites in its ³¹P NMR spectrum and hence the assignment of ³¹P chemical shifts. Polymeric species were more stable than these monomers, leading to low yields in both reactions. α- and β-isomers of P₄S₃I₂ reacted with diethyl malonate. While β-P₄S₃I₂ gave traces of β-P₄S₃(CR₂)(R = C₂H₅CO₂) and of β-P₄S₃(CHR₂)_exo(CHR₂)_endo, along with insoluble products, α-P₄S₃I₂ yielded α-P₄S₃(CR₂), which could be isolated. P₄S₂(CR₂), a new skeleton similar to that of P₄S₃, was formed on storage of CS₂ solutions of a-P₄S₃(CR₂) for two days. The ³¹P NMR data of the molecules are given.     

Die ersten Fluorotrithiatetraphosphaheptane

The First Fluoro-trithiatetraphospha-heptanes Fluorinated α- and β-tetraphosphorus-trisulfur molecules were prepared by the reaction of α- or β-P₄S₃X₂ (X = Cl, Br, I) with (n-butyl)₃SnF. The substitution reaction of the α-isomers yields under retention of the configuration at the phosphorus atoms α-P₄S₃XF and α-P₄S₃F₂. In the reaction of the β-isomers more products were observed, because the configuration of the phosphorus atom can be retained or inversed in the first step of the substitution which yields β-P₄S₃X_exoF_exo or β-P₄S₃X_exoF_endo. The mass relation of the products depends on the halogen ligand. In the second substitution β-P₄S₃(F_exo)₂ or β-P₄S₃F_exoF_endo are formed. β-P₄S₃(F_endo)₂ was not observed. By the reaction of β-P₄S₃I₂ with BiX₃ (X = Cl, Br, I) we also were able to prepare small amounts of β-P₄S₃X_endoX_exo-molecules (X = I, Cl, Br) with an inversed configuration at one phosphorus atom. The ³¹P- and ¹⁹F-NMR parameter of all compounds are discussed.     

Derivate von arsensubstituierten Phosphorchalkogeniden

Derivatives of Arsenic Substituted Phosphorus Chalcogenides α-AsP₃S₃I₂, α-AsP₃Se₃I₂, and three isomers of β-AsP₃S₃I₂ were observed besides several phosphorus sulfides by ³¹P NMR spectroscopy after the reaction of As_nP_4–nE₃ (E ? S; Se; n = 0–4) with I₂ in the melt or with I₂, PI₃, and N-iodosuccinimid in CS₂ solutions. The reaction of As_nP_4–nS₃ with CHI₃ in CS₂ solution yielded two isomers of β-AsP₃S₃(CHI₂)I.     

Bicyclische Diiodtrichalcogenatetraphosphaheptane

Bicyclic Diiodine Trichalcogenatetetraphosphaheptanes Two isomers of each of β-P₄S₂SeI₂ and β-P₄SSe₂I₂ have been identified by ³¹P-NMR spectroscopy. They were prepared by the reaction of P₄S_3–nSe_n with I₂ in CS₂. Systematic changes in chemical shifts and in coupling constants with the alterations in molecular geometry, as sulfur was replaced by selenium, are reported.     

Zwei neue Phosphorsulfide

Two New Phosphorus Sulfides Jason [1] prepared by the reaction of triphenylantimony sulfide with α-P₄S₅ and α-P₄S₇ new phosphorus sulfides. The application of this method on α-P₄S₄ yielded the main product γ-P₄S₅ which was assumed to appear in low concentration in phosphorus-sulfur melts by Bjorholm and Jakobsen [2]. In addition the new isomers δ-P₄S₆ and ϵ-P₄S₆ were identified by ³¹P-NMR spectroscopy. Furtheron the sulfurization of α-P₄S₅ and β-P₄S₅ was studied. Reaction paths are suggested. In all cases the primary reaction is an exocyclic addition of phosphorus, followed by insertion or further addition.     

Sulfurisation of Amino Tetraphosphorus Trichalcogenide Compounds

Amino tetraphosphorus trisulfides α-P₄S₃(NR¹R²)₂ reacted with S₈ under photolysis using visible light, in moderate or low conversion, to give α-P₄S₃(S)(NR¹R²)₂, in which the added sulfur atom was exocyclic. For NR¹R² = NPr₂ⁱ, three isomers were found: a pair of diastereomers corresponding to attachment of the sulfur atom to a nitrogen-carrying phosphorus atom either with retention or with inversion of its configuration, and an isomer containing a sulfurised bridgehead phosphorus atom. For NR¹R² = NMePh, only the two diastereomers were seen. Photolysis of a mixture of α-P₄Se₃(NMePh)₂ and α-P₄Se₃(NMePh)I with S₈ gave as major products α-P₄SSe₂(NMePh)₂ and α-P₄SSe₂(NMePh)I, in which sulfur had replaced the bridging selenium atom in the starting compounds. This provides a synthesis of compounds α-P₄SSe₂XY in which sulfur occupies a specific skeletal position, rather than being randomly distributed. All products were characterised by ³¹P NMR in unseparated solutions. Ab initio MO calculations of geometry and of GIAO NMR chemical shifts at the 3-21G* level for three isomers of the unknown model compound α-P₄S₃(S)(NH₂)₂, and two isomers of α-P₄S₃(NH₂)₂, allowed identification of the observed isomer of α-P₄S₃(S)(NPr₂ⁱ)₂ with a sulfurised bridgehead, but relative assignment of the two diastereomers to their NMR parameters remains a hypothesis.     

Neues vom P4Se4

New Results on P₄Se₄ Preparation of P₄Se₄ from the elements yields always the β-modification of P₄Se₄. α-P₄Se₄ is obtained only with selenium deficient samples. However, it is also observed, when P₄Se₃ is annealed and then extracted with CS₂. The insoluble part has the X-ray pattern of α-P₄Se₄. A reversible α-β transition is not observed. MAS-³¹P-NMR investigations on solid P₄Se₄ by Eckert et al. [2] reveal P₂Se_4/2 building units, which are, in view of our results, not dimer but linked to a polymeric network. Well-crystallized samples of β-P₄Se₄ are obtained only at measuring temperatures above 573 K. The structure is of monoclinic symmetry with the space group P2₁/n (a = 114.9, b = 729.0, c = 1211.0 pm, β = 120.80°). The reaction of α-P₄Se₃I₂ with bis-(trimethyltin)selenide in CS₂ at low temperature yields molecular α-P₄Se₄, which can be detected in solution by ³¹P-NMR spectroscopy. α-P₄Se₄ has D_2d-symmetry like α-P₄S₄. It polymerizes at higher temperature. α-P₄Se₃I(SeSnMe₃) and α-P₄Se₃(SeSnMe₃)₂ were observed in the course of this reaction, too. The analogous reaction of α-P₄Se₃I₂ with bis-(trimethyltin)sulfide leads to comparable results.     

Aminoderivate von α‐P4S3, α‐P4Se3 und P3Se4 – Daten und Analyse der 31P‐NMR‐Spektren in Lösungen

Amino Derivatives of α‐P₄S₃, α‐P₄Se₃, and P₃Se₄; Data and Analyses of their ³¹P NMR Spectra in Solution α‐P₄S₃I₂, α‐P₄Se₃I₂, and P₃Se₄I were reacted with primary and secondary amines in CS₂. The reaction yields exo‐exo isomeres of α‐P₄S₃L₂ and α‐P₄Se₃L₂, the N‐bridged compounds α‐P₄S₃L′ and P₃Se₄L, with L = NHR¹, NPhR², THC (R¹ = ^tBu, Ad, Ph, Flu, TPMP; R² = Me, Et, ⁱPr), and L′ = NR¹. The ³¹P NMR data of the compounds in CS₂ solution were measured. By the reaction of α‐P₄Se₃I₂ with primary amines NH₂^tBu and NH₂Ad in CS₂ an asymmetric isomer α‐P₄Se₃I_endo(NHR¹)_exo was observed for the first time in the ³¹P NMR spectra. The influence of the ligands L on the ³¹P NMR parameter of α‐P₄S₃L₂, α‐P₄Se₃L₂, and P₃Se₄L is discussed.     

Schwingungsspektren von β-P4S5 und P4S7

Vibrational Spectra of β-P₄S₅ and P₄S₇ The vibrational spectra of the solid and liquid cage compounds β-P₄S₅ and P₄S₇ have been recorded. The assignments of the frequencies are proposed mainly based on polarization data. β-P₄S₅ decomposes during melting into P₄S₃ α-P₄S₇ and β-P₄S₆. Molten α-P₄S₇ dissociates to some extent into β-P₄S₆ and sulphur. An association of β-P₄S₆ with α-P₄S₇ is discussed for the molten state. All reactions in molten P₄S₇ are reversible.     

Versatile Stereoselective Synthesis of Completely Protected Trifunctional α-Methylated α-Amino Acids Starting from Alanine

A new route to completely protected α-methylated α-amino acids starting from alanine is described (see Scheme). These derivatives, which are obtained via base-catalyzed opening of the oxazolidinones (2S,4R)- and (2R,4S)- 2 , can be directly employed in peptide synthesis. The synthesis of both enantiomers of Z-protected α-methylaspartic acid β-(tert-butyl)ester (O⁴-(tert-butyl) hydrogen 2-methylaspartates (R) or (S)- 4a ), α-methyl-glutamic acid γ-(tert-butyl) ester (O⁵-(tert-butyl) hydrogen 2-methylglutamate (R)- or (S)- 4b ), and of N^ε-bis-Boc-protected α-methyllysine (N⁶,N⁶-bis[(tert-butyloxy)carbonyl]-2-methyllysine (R)- or (S)- 4c ) is described in full detail.     

Phosphorus NMR Characterisation of P–N Bond Rotamers of a α‐P4S3 Amide with a Conformationally Constrained Chiral Substituent

Reactions of bicyclic α‐P₄S₃I₂ with Hpthiq gave solutions containing α‐P₄S₃(pthiq)I and α‐P₄S₃(pthiq)₂, where Hpthiq is the conformationally constrained chiral secondary amine 1‐phenyl‐1,2,3,4‐tetrahydroisoquinoline. The expected diastereomers have been characterised by complete analysis of their ³¹P{¹H} NMR spectra. Hindered P–N bond rotation in the amide iodide α‐P₄S₃(pthiq)I caused greater broadening of peaks in the room‐temperature spectrum of one diastereomer than in that of the other. At 183 K, spectra of two P–N bond rotamers for each diastereomer were observed and analysed. The minor rotamers showed strong evidence for steric crowding, having large diastereomeric differences in ¹J(P–P) and ²J(P–S–P) couplings (49 Hz, 16 % of value, and 4.4 Hz, 19 % of value, respectively).     

Phases of tetraphosphorus triselenide analysed by magic angle spinning 31P NMR and Raman spectroscopy,and the Raman spectrum of tetraphosphorus tetraselenide

The local environments of the cage molecules in the phases of P₄Se₃ are analysed with ³¹P MAS-NMR and Raman spectroscopy.The ³¹P MAS-NMR spectra of the orientationally ordered α and α′,-phases have different chemical shifts for the apical P atom (α: 68.0, 86 and 88.0 ppm; α′: 75.8 ppm), but similar chemical shifts for the basal P atoms (α: −58.8 ppm, α′: −60.0 ppm).When either α or α′-P₄Se₃ is heated above 358 K, the resulting β-P₄Se₃ has a well-resolved, liquid-like spectrum, indicating extensive molecular re-orientation. The slowly quenched β-phase shows a remnant β-phase mixed with the α-phase as well as P₄Se₄. A rapidly quenched sample of β-P₄Se₃ also shows a small remnant β-phase in the α-phase, but also a new phase with sharp resonances at 12.5, 3.6, 0.1 and −12 ppm. These are probably due to a P₄Se₄ phase which may be orientationally disordered.The Raman spectrum of P₄Se₃ heated above the α-β phase transition temperature shows a disappearance of the lattice modes and the 373 cm⁻¹ mode as previously reported, but also shows some decomposition to P₄Se₄. The β-phase reverts into the α-phase on quenching, with only weak remnant bands attributable to P₄Se₄. The bands of P₄Se₄ become more prominent as the temperature of the β-phase is raised, but above the β-∂ phase transition they are less prominent.The Raman spectrum of P₄Se₄ is reported. The strongest band is at 350 cm⁻¹, with the next strongest band at 185 cm⁻¹. The spectra indicate that the dominant isomer is the selenium analogue of α-P₄S₄ (D_2h), confirming previous ³¹P MAS-NMR studies.     

Molybdenum(0) and Tungsten(0) Complexes with P,S and P,Se Monooxidized Bis(phosphanyl)amine Ligands

Reactions of monooxidized thioyl and selenoyl bis(phosphanyl)amine ligands C₁₀H₇‐1‐N(P(E)Ph₂)(PPh₂) [E = S ( 1 ), Se ( 2 )] with Mo(CO)₄(pip)₂ and W(CO)₄(cod) afforded the complexes [M(CO)₄{ 1 ‐κ²P,S}] [M = Mo ( 3 ), W ( 4 )] and [M(CO)₄{ 2 ‐κ²P,Se}] [M = Mo ( 5 ), W ( 6 )]. Complexes 3 – 6 were characterized by multinuclear NMR (¹H, ¹³C, ³¹P, and ⁷⁷Se NMR) and IR spectroscopy. Crystal‐structure determinations were carried out on 3 , 5 , and 6 , which represent the first examples of structurally characterized complexes of such ligands with group‐6 metal carbonyls.     

Tetraphosphor-trithio-dihalogenide und -pseudohalogenide

Tetraphosphorus Trithio Dihalides and Pseudohalides P₄S₃Cl₂, P₄S₃Br₂, P₄S₃(CN)₂ and P₄S₃(NCS)₂ were prepared by reacting α-P₄S₃I₂ with the corresponding silver halides and pseudohalides, respectively. The ³¹P n.m.r. data of the compounds are reported.     

Polycyclic Phosphorus Sulfide Compounds containing Chiral Amido or Imido Substituents

Reactions of α‐P₄S₃I₂ with (S)‐ or racemic‐RNH₂ (R = CH(Me)Ph) have given solutions containing exo, exo‐ or endo, exo‐α‐P₄S₃(NHR)₂, α‐ or β‐P₄S₃(μ‐NR), or P₄S₂(μ‐NR), as the first compounds with polycyclic phosphorus sulfide skeletons to contain chiral substituents. The expected diastereomers have been characterised by complete analysis of their ³¹P{¹H} NMR spectra, and relative configuration has been assigned in most cases. Considerable diastereomeric differences in coupling constants and chemical shifts were found.     

Neue Rheniumkomplexe mit Trichalkogenido- und Tetrachalkogenido-Chelatliganden

New Rhenium Complexes Containing Trichalcogenido and Tetrachalcogenido Chelate Ligands The reactions of Cp*ReCl₄ with polychalcogenide salts such as Na₂S₄ or (NEt₄)₂Se₆ lead initially to the violet trichalcogenido chelate complexes Cp*ReCl₂(E₃) (E = S ( 3a ), Se ( 3b )) which, due to their functional chloro ligands, can be used as intermediates for further reactions. Upon hydrolysis in moist solvents or aminolysis with tert. butylamine 3a, b are converted into the tetrachalcogenido chelate complexes Cp*Re(O)(E₄) (E = S ( 4a ), Se ( 4b )) and Cp*Re(N^tBu)(E₄) (E = S ( 5a ), Se ( 5b )), respectively. X-Ray structure analyses were carried out for the three mononuclear cyclo-oligoselenido compounds 3b–5b . It appears that the size of the Se^2?_n chelate ring (n = 3 or 4) essentially depends on steric factors within the coordination sphere of rhenium.     

Zur Reaktion von tert-Butyl-phosphaalkin mit Molybdänkomplexen

Reaction of tert -Butyl-phosphaalkyne with Molybdenum Complexes The reaction of tBuC≡P with [(CH₃CN)₃Mo(CO)₃] leads to the complex [Mo(CO)₄〈Mo(CO)₂(η⁴-P₃CtBu){η⁴-P₂(CtBu)₂}〉] 1 as well as to the alkyne complexes [Mo(CO)₄〈{P₃(CtBu)₂}{Mo(CO)₂(CtBu)}{η³-P₂(CtBu)₂}〉] 2 and [Mo(CtBu){η⁴-P₂(CtBu)₂(CO)}{η⁵-P₃(CtBu)₂}] 3 . All compounds are characterized by X-ray structural analysis, by NMR- and IR spectroscopy and by mass spectrometry. In complex 1 a 1,3-diphosphacyclobutadiene and a 1,2,4-triphosphacyclobutadiene are connected by two molybdenum carbonyl centres. In 2 a 1,3-diphosphacyclobutadiene is π- and a novel 1,2,4-triphospholyl ligand is σ-bonded at two Mo centres. A characteristic feature of 3 besides a π co-ordinated 1,2,4-triphospholyl ligand is a 3,4-diphosphacyclopentadienone as ligand, formed via CO insertion during the cyclodimerisation of two phosphaalkynes.     

Expected and unexpected photochemical reactions of acyl iodides

Photolysis of acyl iodides RCOI (R = Me, Me₂CH, Ph) under UV irradiation in toluene environment for 20–55 h proved to be a simple and efficient method of preparation of symmetrical α-diketones RCOCOR. In contrast, the photolysis under the same conditions of acyl iodides RCOI [R = Me(CH₂)₃, Me₃C] did not lead to the formation of the corresponding diacyls, and the reaction products were unexpected 1,1-bis(4-methylphenyl)pentane and a mixture of isomeric 3- and 4-methyl(tert-butyl)benzenes respectively. The most probable mechanism of their formation is the primary photochemical acylation of toluene in the aromatic ring followed by the photochemical reduction of the arising butyl 4-methylphenyl ketone in the case of the valeroyl iodide or the photochemical Norrish type I cleavage of isomeric 3- and 4-methylphenyl (tert-butyl) ketones in event of the pivaloyl iodide. In the photolysis of acetyl iodide (R = Me) in benzene or toluene alongside the diacetyl formation polyarylation process was observed of acylated and iodinated into the aromatic ring solvents with the formation of polymeric products with semiconductor and paramagnetic properties.