Reactions of aminophosphines with trifluormethanesulfonic acid: phosphenium ion (two-coordinate phosphorus ion) or tricovalent phosphorus products?

The title reaction is shown to give phosphenium ion products (1), mixtures of (10 and tricovalent substitution products (2), or other products, depending on the nature of the substituents on phosphorus.     

New functionalised ditertiary phosphines via phosphorus based Mannich condensation reactions

The one-step synthesis of a family of functionalised ditertiary aminophosphines are described including the X-ray crystal structure of 4-{(Ph₂PCH₂)₂N}C₆H₄CO₂H.     

Reactions of coordinated trimethylphosphite with binary fluorides

Fluorination of free trimethylphosphite by phosphorus pentafluoride or tungsten hexafluoride involves complex formation followed by rapid F-for-OCH₃ exchange and Michaelis-Arbusov rearrangement reactions (D.W.A. Sharp et al., $\text{J. Chem. Soc. A}$, 1969, 872; J.M. Winfield et al., $\text{ibid}$, 1970, 501). Reactions between WF₆ or PF₅ and P(OCH₃)₃, coordinated to Fe^II (low spin d⁶-inert) or Cu^I (d¹⁰ -labile) cations in CH₃CN, counter anions PF₆^? or AsF₆^?, are very different as evidenced by an n.m.r. study.Reactions between Fe^IIP(OCH₃)₃ and WF₆ are very slow at room temperature; the major products are CH₃PF₄ and WOF₄.NCCH₃. Reactions between Cu^IP(OCH₃)₃ and WF₆ or PF₅ are rapid, even below room temperature, and depend on the stoicheiometry. The major products are W₂O₂F₉^? and a PF₅X^? species, or OPF₃, minor products include CH₃OPF₂, (CH₃O)₂PF, and PF₃. When the mole ratio coordinated P(OCH₃)₃:WF₆ is 1:1, additional W₂O₂F₉ and PF₅X n.m.r. signals are observed.The reactions involve fluorination of free P(OCH₃)₃ whose concentration in solution is limited by the metal cation, and in the reaction between PF₅ and Cu^IP(OCH₃)₃ PF₅.P(OCH₃)₃ has been identified as the initial product. Conventional Michaelis-Arbusov rearrangements are of minor importance as CH₃CN acts as a sink for CH₃⁺, but the final step in the formation of CH₃PF₄ is of this type.     

Reactions of titanium dioxide with metal fluorides

TiO₂ with several condensed-phase metal fluorides at elevated temperatures to form TiF₄ and the metal oxide. Known mixed titanium metal oxides are usually observed as intermediates. FeOF is an intermediate from the system FeF₃ + TiO₂. With CaF₂ and BaF₂, the reaction did not proceed beyond the intermediates CaTiO₃ and BaTiO₃. Reactions usually start at approximately the temperatures predicted from thermochemical data.     

NMR investigation of stereochemical nonrigidity of five-coordinate phosphorus fluorides

Phenomena associated with stereochemical nonrigidity of five-coordinate phosphorus fluorides (Berry pseudorotation and restricted rotation of different functional groups about the bond with the central phosphorus atom) have been analyzed. The main cause of restricted rotation isp d bonding of unsharedp-electron pairs of substituents with vacantd-orbitals of the phosphorus. Additional stabilization of the molecule occurs when it is possible to form an H...F hydrogen bond between the liquid and an axial fluorine atom in the phosphorane. The relationship between pseudorotation and restricted rotation is considered.A. N. Nesmeyanov Institute of Organoelemental Compounds, Russian Academy of Sciences, 117813 Moscow. N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1784–1793, August, 1992.     

Unprecedented steric deformation of ortho-carborane

The reduction and subsequent oxidation of meta-carboranes containing bulky groups attached to the cage C atoms affords sterically-crowded ortho-carboranes with unprecedentedly long C-C connectivities.     

Effect of the substituent on the phosphorus atom on the reaction of aminophosphines with 1-alkylisatins

Depending on the substituent on the phosphorus(III) atom, reactions of tris(dialkylamino)phosphines, 2-diethylamino-1,3,2-benzodioxaphosphole, and benzene-1,4-diylbis(N,N,N′,N′-tetraethylphosphonous diamide) with 1-alkylisatins lead to the formation of isoindigo derivatives, spirophosphoranes, or spirooxiranes whose structure was determined by NMR spectroscopy and X-ray analysis.     

Reactions of phosphorus halides with urethane

By the reaction of phosphorus trichloride, thiophosphoryl chloride, phosphorus oxychloride and phosphorus pentachloride with urethane in stoichiometric ratio 1:1 or 1:2 in benzene, compounds of the type

and

(X = S, O or Cl; n = 1 or 2) have been synthesized. A probable mechanism for their formation has also been suggested.     

Nanocage encapsulation of two ortho-carborane molecules

Bowl-shaped C-methylcalix[4]resorcinarene forms a 1:1 ball-and-socket nanostructure with o-carborane through two endo-cavity BC-H...pi hydrogen bonds. In the presence of 4',2:6,4"-terpyridine, two of these nanostructures are held together by four terpyridines through sixteen OH...N hydrogen bonds, completely shrouding two carboranes.     

Reactions of alkenes with phosphorus pentachloride and trichlorosilane

Conclusions Alkenyldichlorophosphines are formed in high yields when alkenes are phosphorylated by treatment with PCl₅ in the presence of hydrosilanes under conditions that promote the formation of trimolecular complexes of alkene, PCl₅, and hydrosilane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.207–209, January, 1976.     

Fluoro-ketones. II Reactions of fluorocarbon grignards and copper compounds with perfluoroalkylacid fluorides

The reactions between C₆F₅MgBr (I), p-BrC₆F₄MgBr (X), C₆F₅Cu (XXI), p-HC₆F₄Cu (XXII) and p-BrC₆F₄Cu (XV) with primary and secondary perfluoroalkylether acid fluorides were studied. The Grignard compounds react very slowly with the secondary acid halides (R_fCF(CF₃C(O)F) whereby competing reactions cause undesirable by-products and reduction of ketone yields. Primary acid halides (R_fCF₂C(O)F) react much faster with C₆F₅MgBr to give the ketone in improved yields. The organocopper compound react with either primary or secondary acid halides to give the ketone in excellent yields with no by-product formation from competing secondary reactions. Solvent, type of organometallic reagent and primary versus secondary acid fluoride are variables that influence product yield and product distribution.     

Reactions of phosphorus trichloride with Schiff bases

The reactions of Schiff bases with phosphorus trichloride in the medium of acetone containing pyridine are facile and compounds of the types RC(PCl₂)NR′ and [RC(PCl₂)N]₂C₆H₄ have been prepared.     

Reactions of 2-aminopyridines with phosphorus pentachloride

The reaction of 2-aminopyridines with PCl₅ proceeds with the formation of 2-trichlorophosphazopyridines, which when treated with morpholine are converted to 2-dimorpholidochlorophosphazopyridines. By heating these last products with 96% ethanol, dimorpholido pyridyl-2-amidophosphoric acids are obtained.     

Reactions of dental enamel with superficially applied fluorides: electron spectroscopic investigations

Electron spectroscopy combined with argon ion etching was applied for studying reactions of fluoride with dental enamel. Using this assembly to alternately record the spectra and etch the surface, depth profiles of topmost surface enamel can be obtained. The hyperfine depth resolution of the technique provided new information on the distribution of fluoride and its reaction products in the outermost layers of dental enamel.