CARBODIPHOSPHAN (2.4.6-tBu3C6H2[sbnd]P[dbnd]2)C: REAKTION MIT ELEKTROPHILEN

Abstract

The reaction of Ar[sbnd]P[dbnd]C[dbnd]P[sbnd]Ar (Ar=2.4.6-^tBu₃C₆H₂) with electrophiles (H⁺, S₈) proceeds at the phosphorus atom with subsequent cyclisation of an o-^tbutyl group.     

ESCA STUDIES OF A DIPHOSPHENE

Abstract

The nature of the P[dbnd]P bond in E-bis(2,4,6-tri-tert-butylphenyl)diphosphene was studied by means of ESCA, indicating that the phosphorus 2p binding energy is the lowest among those for common organophosphorus compounds.     

Synthesis and investigation of new types of dicoordinated phosphorus compounds

Abstract

New synthetic methods for the preparation of stable compounds with P[dbnd]N, P[dbnd]C and P[dbnd]P -linkages have been developed.     

Phosphorus-Nitrogen Compounds as Complex Ligands

Abstract

Amino(imino)phosphanes(σ²-phosphazenes) of the type N[sbnd]P[dbnd]N- are useful complex ligands.     

New Stable Diphosphenes

Abstract

Since the isolation of the first stable diphosphene by YOSHIFUJI, some other diphosphenes have been prepared and stabilized by very bulky substituents. We have recently described the synthesis, via a germylated way, of the bis [bis (trimethylsilyl)methyl]diphosphene 1, one of the least crowded stable diphosphenes:     

UNUSUAL DIRECTION OF THE ARBUZOV REACTION OF DIALKOXYMETHYLPHOSPHONITES AND THEIR ANALOGUES

Abstract

The alkylation and acylation reactions of dialkoxymethylphosphonites and their analogues have been studied. The Arbuzov rearrangement of these compounds was accompanied by the P[sbnd]C bond cleavage with retention of three-coordinate phosphorus atom.     

CYCLIC ORGANOPHOSPHORUS COMPOUNDS. PART XVI1. MASS SPECTROMETRIC FRAGMENTATION OF SOME 5,5-DIMETHYL-1,3,2-DIOXAPHOSPHORINAN 2-OXIDES AND 2-SULPHIDES

Abstract

The mass spectra of seventeen 5,5-dimethyl-1,3,2-dioxaphosphorinan 2-oxides and nineteen 5,5-dimethyl-1,3,2-dioxa-phosphorinan 2-sulphides, mostly with amino substituents on phosphorus, have been determined. In some cases, interpretation of the spectra was aided by accurate mass measurements and by the examination of deuterated compounds. For the 2-sulphides, sulphur is lost either as such or as the thiol radical, both processes often being of weak intensity, and the thiol hydrogen appears to be derivable from either a ring methylene group or a C-5 methyl group. Loss of S or HS occurs more strongly for the phosphoramidothionates which, together with the phosphoramidates, also fragment to an important extent in the amido substituent with retention of the dioxaphosphorinan ring; P[sbnd]N bond cleavage is also observed. For the 2-thiones, the ions at m/e 165 (14; R[dbnd]H) and 133 (15; R[dbnd]H) are characteristic.     

High-Field 1H-NMR Study of Poly(Vinyl Chloride) Defects

Radical poly(vinyl chlorides), (PVC), obtained in bulk and in suspension polymerizations, and their low molecular weight extracts have been thoroughly studied by high-field NMR to obtain better qualitative and quantitative analyses of their structural defects. Assignments have been achieved by ¹H-¹H decoupling experiments and hyperfine spectral structure analysis of model compounds and low molecular weight extracts. Strong effects of the nature of the solvents used in ¹H-NMR analysis were observed. Most of the defects of these radical PVC's have been quantitatively estimated in terms of average number values in correlation with their [Mbar]_n. End-groups of type [I'] (= ?CH₂?CH[dbnd]CH[sbnd]CH₂C1) are about 0.5 per chain; internal double bonds can only be estimated by difference, and their amount increases with increasing conversion. A very low quantity of vinyl chain end [I'] ([dbnd] [sbnd]CHC1[sbnd]CH[dbnd]CH₂) has been found only in low molecular weight extracts. For the three probable saturated chloromethyl ends [II] ([dbnd][sbnd]CHCl[sbnd]CH₂Cl), [III] ([dbnd] [sbnd]CH₂[sbnd]CH₂Cl), and [IV] ([dbnd] >CH[sbnd]CH₂C1), only [II] and [III] were definitely identified. Finally, in taking into account all the endgroups, it has been concluded that branches would be grafted throughout the process. On the average, 4 to 5 branches have been found per chain of high molecular weight PVC.     

Generation, isolation, and reactivity of a kinetically stabilized diphosphene anion radical

The stable lithium diphosphene anion radical, [Li(dme)₃]⁺[TbtPPTbt]⁻ (dme: 1,2-dimethoxyethane, Tbt: 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl), was readily synthesized by the one-electron reduction of the corresponding neutral diphosphene (TbtPPTbt). The molecular structure of the diphosphene anion radical was discussed in detail on the basis of its ESR, UV-Vis and Raman spectra, and theoretical calculations. The diphosphene anion radical was found to undergo ready chalcogenation reactions using elemental sulfur and selenium to afford the corresponding thiadiphosphirane and selenadiphosphirane, respectively.     

CRYSTAL STRUCTURE OF THE NOVEL COMPOUND (1α, 3bT, 5α)-1,3-DIPHENYL-5-HYDRIDO-5-ISOPROPOXY-1λ6, 3λ6,2,4,6,5λ5-DITHIATRIAZAPHOSPHORINE-1,3-DIOXIDE. A COMPARISON WITH RELATED STRUCTURES

Abstract

The title compound (1α, 3β, 5α)-(NSOPh)₂NP(H)O-i-Pr crystallizes in the spacegroup P2₁/n with cell dimensions: a = 12. 150(2), b = 8.911(1), c = 17.614(3) Å, β = 107.52(1)^o; Z = 4. The structure was solved by direct methods and refined by least-squares techniques to an R value of 0.048 for 2420 independent reflections (collected at room temperature) with I > 2.5 σ(I). The unit cell contains dimeric units which are formed by unprecedented P[sbnd]H…O[dbnd]S bridges. The conformation of the inorganic ring skeleton can be described as a boat; phosphorus and sulfur atoms show a distorted tetrahedral geometry. The S[sbnd]N bond lengths differ slightly, ranging from 1.547(3) to 1.588(2) Å. The exocyclic bond lengths are P[sbnd]H = 1.34(2), P[sbnd]O = 1.553(2), S[sbnd]O = 1.439(2) (mean value), and S[sbnd]C = 1.767(4) (mean value) Å. From a comparison with analogous structures the degree of asymmetry (ΔI = {[P[sbnd]N]-[S[sbnd]N]}Å) in the SNP unit is related to the difference in electronegativity between the sulfur and phosphorus centres.     

REACTION OF SCHIFF BASE OF THIOHYDRAZIDES WITH P(NR2)3

Abstract

Three pathways were observed in the reactions of Schiff bases of Thiohydrazides with P(NR₂)₃. (a) MeS-R₂N exchange: MeS-C([dbnd]S)-NHN[dbnd]CHPh (1) reacted with P(NR₂)₃ led to new Schiff bases, R₂N-C([dbnd]S)-NHN[dbnd]CH = Ph (2). (b) Cleavage of C[dbnd]S bond and the formation of P[dbnd]S bond: H₂N-C([dbnd]S)-NHN[dbnd]CH = Ph (3) reacted with P(NR₂)₃ gave rise to the thiophosphoric amide. (Et₂N)₂P([dbnd]S)-NH-CH = N-N[dbnd]CH-Ph (4). (c) Formation of thiadiazole and triazole: Schiff bases 2a and H₂N(MeS)C = N-N[dbnd]CH-Ph (6) reacted with P(NR₂)₃ respectively and produced 5-dimethylamino-2-phenyl-2,3-(2H)-1,3,4-thiadiazole (5) and 5-methylthio-2-phenyl-2,3-(2H)-1,3,4-triazole (7).     

THE PREPARATION AND CHARACTERIZATION OF Cd(XCN)4M TYPE COMPOUNDS

Abstract

A series of compounds of the type Cd(XCN)₄M (X=S and Se; M=Mn, Fe, Co and Zn) have been prepared and characterized. These compounds crystallize in the tetragonal system: space group I4[sbnd]S₄ ². The bidentate thiocynate and selenocyanate ligands coordinate to the “hard” M(II) ions through the nitrogen atom and the “soft” Cd(II) ion through the sulfur or selenium atom. The Cd[sbnd]Se bond in Cd(XCN)₄ M is slightly stronger than the Cd[sbnd]S bond while the M[sbnd]NCSe bond is slightly weaker than the M[sbnd]NCS bond. The M(II) ions tetrahedrally coordinated by the nitrogen end of XCN^? are in the high spin state. The [sbnd]NCS and [sbnd]NCSe ligands are located at about the same place in the spectrochemical series.     

SULFENAMIDES AND SULFINAMIDES II1 INTERCHANGE REACTIONS OF AROMATIC SULFENAMIDES

Abstract

A study has been made of photocatalyzed interchange reactions of aromatic sulfenamides. The significance of the results in relation to the relative ease of S[sbnd]N and S[sbnd]S bond fission is discussed, together with possible mechanisms of interchange. Relevance to industrial processes is noted.     

REACTIONS IN THE CHLOROSILANE-SILANOL-SILOXANE SYSTEM

Abstract

We obtained the first σ?-values and E_s -values for siloxy groups by spectroscopic and kinetic methods. Detailed mechanistic investigations are performed on the hydrolysis of chlorosiloxanes, the cleavage of Si[sbnd]O[sbnd]Si bonds by HCl, and the substituent exchange reaction between silanols and chlorosilanes.     

PENTACO-ORDINATE PHOSPHORUS COMPOUNDS BY NUCLEOPHILIC ADDITION TO ACTIVATED ALKENES AND ALKYNES IN THE PRESENCE OF ALCOHOLS AND PHENOLS

Abstract

The reactions of a variety of trico-ordinate phosphorus compounds, Ar _n P(OR)_3-n (n = 1 or 2), and cyclic analogues, with acrylonitrile, ethyl acrylate or ethyl phenylpropiolate and alcohols or phenols in low polarity media gives rise to a wide range of pentaco-ordinate phosphorus compounds. Attempts to extend this synthetic route to phosphoranes containing P[sbnd]N or P[sbnd]S bonds met with no success.     

SYNTHESIS AND NMR CHARACTERIZATION OF P-VINYL SUBSTITUTED PHOSPHAZENE PRECURSORS1

Abstract

The reactions of either PhPCl₂ or PCl₃ with (Me₃Si)₂NLi followed by H₂C[dbnd]CHMgBr were used to prepare the new P-vinyl substituted [bis(trimethylsilyl)amino]phosphines, (Me₃Si)₂NP(R)CH[dbnd]CH₂ [1: R=Ph, 2: CH[dbnd]CH₂, 3: R=Me, and 4: R=N(SiMe₃)₂]. Oxidative bromination of phosphines 3–1 afforded the P-bromo-P-vinyl-N-(trimethylsilyl)phosphoranimines, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)Br [5: R=Ph, 6: R=CH[dbnd]CH₂, 7: R=Me], which, upon treatment with CF₃CH₂OH/Et₃N, were subsequently converted to the P-trifluoroethoxy derivatives, Me₃SiN[dbnd]P(CH[dbnd]CH₂)(R)OCH₂CF₃ [8: R=Ph, 9: R=CH[dbnd]CH₂, 10: R=Me]. Compounds 1–10, which are of interest as potential precursors to P-vinyl substituted poly(phosphazenes), were fully characterized by elemental analyses (except for the thermally unstable P-Br derivatives 5–7) and NMR spectroscopy (¹H, ¹³C, and ³¹P) including complete analysis of the vinylic proton splitting patterns via HOM2DJ experiments.     

REACTIONS OF A PHOSPHORANIMINE ANION WITH SOME ORGANIC ELECTROPHILES

Abstract

The reactions of a variety of electrophiles with the N-silyl-P-trifluoroethoxyphosphoranimine anion Me₃Sin°P(Me)(OCH₂CF₃)CH^? ₂ (1a), prepared by the deprotonation of the dimethyl precursor Me₃SiN[dbnd]P(OCH₂CF₃)Me₂ (1) with n-BuLi in Et₂O at-78°C, were studied. Thus, treatment of 1a with alkyl halides, ethyl chloroformate, or bromine afforded the new N-silylphosphoranimine derivatives Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂R [2: R = Me, 3: R = CH₂Ph, 4: R = CH[sbnd]CH₂, 5: R = C(O)OEt, and 6: R = Br]. In another series, when 1a was allowed to react with various carbonyl compounds, 1,2-addition of the anion to the carbonyl group was observed. Quenching with Me₃SiCl gave the O-silylated products Me₃SiN[dbnd]P(Me)(OCH₂CF₃)CH₂°C(OSiMe₃)R¹R² [7: R ¹ = R ² = Me; 8: R ¹ = Me, R ² = Ph; 9: R¹ = Me, R ² = CH[sbnd]CH₂; and 10: R ¹ = H, R ² = Ph]. Compounds 2–10 were obtained as distillable, thermally stable liquids and were characterized by NMR spectroscopy (¹H, ¹³C, and ³¹P) and elemental analysis.     

Preparation,structures, and reactivities of compounds with double bonding between the heavier group 5A elements

Abstract

The synthesis of diphosphenes (RP[dbnd]PR′), phosphaarsenes (RPxydAsR′), phosphastibenes (RP[dbnd]SbR′), and diarsenes (RAs[dbnd]AsR′) is discussed. X-ray crystallographic studies have been performed on representative double-bonded compounds. The reactivities and coordination chemistry of selected compounds have been explored.