Pentacoordinated Phosphorus Compounds Research Articles

Acceleration of the pseudorotation rates in pentacoordinated phosphorus compounds. Conformational transmission versus hexacoordinated zwitterionic intermediates

A variable-temperature 13C NMR study, accompanied by a high-resolution 1H NMR conformational analysis study, on a series of monocyclic oxyphosphoranes is reported. The selected compounds enabled us to study the acceleration of the rates of intramolecular ligand reorganization on pentacoordinated phosphorus. It allowed us to determine whether the enhancement of the reorganization rates was brought about by accelerated pseudorotation due to the conformational transmission effect or by the involvement of hexacoordinated zwitterionic phosphorus intermediates. The results of the study further substantiate the findings that the involvement of such hexacoordinated intermediates is of no importance in the type of oxyphosphoranes studied.

Pseudorotation in pentacoordinated phosphorus compounds. The influence of the conformational transmission effect on the barriers to pseudorotation in cyclic alkoxyphosphoranes

A variable-temp. 13C NMR study on a series of monocyclic oxyphosphoranes I (R1 = H, Me; R2 = Me, Ph; R3 = Me, OEt; R4 = Me, cyclopentylmethyl, etc.) is used to examine the influence of the conformational transmission effect on the barriers to pseudorotation in pentacoordinated P compds. The pseudorotation rates of monocyclic oxyphosphoranes exhibiting the conformational transmission effect is 2-4 times faster as compared to their counterparts in which the effect is absent. The conformational change in the basal ligands of the intermediate square planar structures, due to the conformational transmission effect, is responsible for the lowering of the activation barriers by 2-3 kJ mol-1.

ChemInform Abstract: New Tricoordinated and Pentacoordinated Phosphorus Compounds and a Boron Spirane Involving an Enolpyruvate Moiety. Synthesis of a Hydroxyphosphorane Model of Intermediate Phosphoranes in Nucleophilic Substitution Reactions on Phosphoric Esters of Enolpyruvic Acid.

AbstractPhenylpyruvic acid (I) reacts with tri‐ or pentacoordinated phosphorus compounds such as (II), (IV), or (VI) to form the corresponding spirophosphoranes (III), (V), or (VII).

ETUDE DE QUELQUES REACTIONS DE LA TRIS(TERT-BUTYL)PHENYLPHOSPHINE

Abstract The reaction of tris(tert-butyl)phenylphosphine with some hydrogen acceptors has been investigated. Triphenylcarbenium hexafluorophosphate allows to obtain a phosphonium salt: the possibility of preliminary formation of phosphenium with a P[sbnd]H bond during this reaction is discussed. With methyltrifluoromethanesulfonate, two pentacoordinated phosphorus compounds are isolated. Diethylazodicarboxylate gives rise to a σ3, λ5-phosphorane. The transient formation of phosphinidene and of 1,2-bis(ethylcarboxylate) 3-tris(tert-butyl)phenyldiazaphosphirine is discussed.

ChemInform Abstract: Sterically Hindered Pentacoordinated Phosphorus and Silicon Compounds

ChemInformVolume 18, Issue 40 Organoelement Compounds ChemInform Abstract: Sterically Hindered Pentacoordinated Phosphorus and Silicon Compounds R. R. HOLMES, R. R. HOLMES Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorV. CHANDRASEKHAR, V. CHANDRASEKHAR Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorR. O. DAY, R. O. DAY Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. J. HARLAND, J. J. HARLAND Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. S. PAYNE, J. S. PAYNE Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. M. HOLMES, J. M. HOLMES Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this author R. R. HOLMES, R. R. HOLMES Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorV. CHANDRASEKHAR, V. CHANDRASEKHAR Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorR. O. DAY, R. O. DAY Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. J. HARLAND, J. J. HARLAND Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. S. PAYNE, J. S. PAYNE Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this authorJ. M. HOLMES, J. M. HOLMES Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USASearch for more papers by this author First published: October 6, 1987 https://doi.org/10.1002/chin.198740238AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume18, Issue40October 6, 1987 RelatedInformation

Synthesis of Hexa- and Pentacoordinated Phosphorus Compounds from White Phosphorus

Abstract A new method is developed for the synthesis of phosphoranes (IIIa-d) and phosphorates (IVa-d) starting from substituted o-benzoquinones(Ia-d), catechols(IIa-d) and white phosphorus.

The reaction of thiophosphoryl dichloride with catechol

Phenyl thiophosphonyl dichloride reacted with catechol n the presence of triethylamine to yield a pentacoordinated phosphorus compound 3. The reactions of a number of phosphorodi-chloridothioates with catechol gave a hexacoordinated phosphorus compound 8. The mechanism of these reactions are discussed.

PREPARATION AND STRUCTURAL STUDIES OF A NUMBER OF HETEROCYCLIC PHOSPHORANES

Abstract A series of monocyclic five-membered ring containing trivalent phosphorus compounds with oxygen, nitrogen and sulfur bonded to phosphorus, in various combinations has been allowed to react with trifluoroethyl and 1,1,1,3,3,3-hexafluoroisopropyl benzenesulfenates. In some cases, pentacoordinated phosphorus compounds resulted. These materials have been studied by various NMR techniques. The same trivalent phosphorus compounds were allowed to react with 3,4-(bistrifluoromethyl)1,2,dithiete. In some cases phosphoranes were formed and they were also studied by NMR.

Zur Struktur des „Trichlor‐diphenoxyphosphorans”︁

The Structure of “;Trichloro‐diphenoxyphosphorane”The structure of ‘Trichloro‐diphenoxyphosphorane’ synthesized by well‐known and new methods is not a pentacoordinated phosphorus compound, but has the structure of tetraphen‐oxyphosphonium hexachlorophosphate 4.

THE THERMOLYSIS OF PENTA-COORDINATE PHOSPHORUS HETEROCYCLES

Abstract Small-ring heterocycles are an important class of penta-coordinate phosphorus compounds, whose properties—including thermolysis—have been extensively studied.1,2 It is noteworthy that these compounds display a wide range of thermal stability—certain examples decompose completely below -40°C, while others are stable indefinitely at > 300°C—yet any thermolysis reaction almost invariably takes place at the phosphorus centre. Diverse conditions have been employed: reactions have been carried out in the melt, in solution and in the gas phase, and ionic, radical and concerted mechanisms have been advanced to explain the results. In this article, we hope to rationalise this behaviour and to give a representative survey of the field. Unfortunately, a truly comprehensive review is literally not possible at this time, since in the older literature, P(v) intermediates are often written without evidence of their existence, or, betaine structures are assigned to species which are in fact phosphoranes. Two cla...

Synthesis and structure of BIS(Trifluoromethyl)BIS(Tri-methylsilyl)Amino dichloroarsorane, (CF 3) 2AsCl 2N(SiMe 3) 2

The synthesis of (CF 3) 2AsCl 2N(SiMe 3) 2 is reported. This compound has been characterized on the basis of an X-ray analysis. It has a trigonal bipyramidal geometry with axial chlorine atoms. Variable temperature 1H- and 19F-NMR data show no observable changes. In comparison to pentacoordinated phosphorus compounds the tendency to form tetracoordinated derivatives is strongly diminished in the case of arsenic compounds.

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.

Preparation and nuclear magnetic resonance studies of pentacoordinated phosphorus compounds containing hexafluoroisopropoxy groups

Preparation and nuclear magnetic resonance studies of pentacoordinated phosphorus compounds containing hexafluoroisopropoxy groups

Pentaco-ordinate phosphorus compounds by nucleophilic addition to activated alkenes

The reactions between a variety of trico-ordinate phosphorus compounds and acrylonitrile or ethyl acrylate provide a novel route to pentaco-ordinate phosphorus compounds.

A model for calculating conformational energies in pentacoordinate phosphorus compounds

Abstract A model is developed which allows the estimation of the relative stability of all trigonal bipyramidal (TP) and square pyramidal (SP) isomers of a given pentacoordinate phosphorus compound. It is based on the widely used pseudorotational hypothesis. The model makes use of activational energies governing fluxional behavior for simple acyclic derivatives of known structure and results of theoretical and spectroscopic studies defining TP-SP energy differences. Based on these criteria, apicophilicity scales are constructed for the TP and SP with the additional constraints that they have the same range and correlate linearly with each other as a function of ligand electronegativity. The resultant model which incorporates ring strain and steric terms has general applicability and should prove of considerable predictive value in quantifying pentacoordinate intermediates and transition states postulated in phosphorus reaction mechanisms. The model gives relative isomer energies in excellent agreement wit...

PREPARATION OF PHOSPHORANES FROM TRIVALENT PHOSPHORUS COMPOUNDS AND 1,2-DIOXANE

Abstract 1,2-Dioxane has been allowed to react with a variety of trivalent phosphorus compounds. In some cases pentacoordinate phosphorus compounds were formed, whereas in others tetrahydrofuran and the appropriate phosphoryl containing compound were produced. The mechanism of the reaction is discussed.

Interaction of lithium alkylamides or lithium dialkylamides with tetraphenylphosphonium chloride reaction course as a function of reaction conditions and dialkylamide structures

Reaction of Ph 4P +Cl − with LiNHR (where R = CH 3, C 2H 5, i-C 3H 7, n-C 4H 9, but not C(CH 3) 3) gives phosphineimines III, whereas the reaction with LiNR 2 proceeds via three routes depending on the size of R and the dialkylamide excess. With larger R groups, homolytic decomposition of pentacoordinate phosphorus compounds occurs. With smaller R groups, Ph 3P and PhNR 2 are formed. Higher excesses of lithium amide result, probably, in ligand exchange at the pentacoordinate phosphorus followed by decomposition of the exchange products. Charge transfer complex intermediates are assumed to be formed in all the reactions.

Reduction of nitro- and nitroso-compounds by tervalent phosphorus reagents. Part XII. Conversion of aryl 2-nitroaryl ethers into novel 3-aryl-2,3-dihydro-1,3,2-benzoxazaphosph(V)oles (oxazaphosphoranes) and their 2-oxo-derivatives

Reactions in cumene of aryl 2-nitroaryl ethers (2-NO2·C6H4·O·C6H2R32R4: R3= Me, R4= H; R3= R4= Me; R3= OMe, R4= H; R3= H, R4= OMe; R3= R4= H; R3= H, R4= Me; R3= Me, R4= CO2Me) with tervalent phosphorus reagents (4 mol. equiv.)(R2R12P: R1= R2= MeO, EtO, or PriO; R1= EtO, R2= Me; R1= MeO, R2= Ph; R1= Ph, R2= MeO; R12=–O·CH2·CH2·O–, R2= Ph) give novel pentaco-ordinate phosphorus compounds, the 3-aryl-2,3-dihydro-1,3,2-benzoxazaphosph(V)oles (8)(12–95%). These are very rapidly hydrolysed in water to give tetraco-ordinate phosphorus compounds, 2-alkoxy-3-aryl-, 2-hydroxy-3-aryl-, 2-alkyl-3-aryl-, or 2,3-diaryl-2,3-dihydro-2-oxo-1,3,2-benzoxazaphospholes (15)–(17), according to conditions and the phosphorus ligands in the original oxazaphosphole (8). Hydrolysis in acid leads to 2-hydroxydiarylamines (13). The reaction of 4-methoxyphenyl 2-nitrophenyl ether with diethyl methylphosphonite gave as a major by-product (19.5%) a spiro-oxazaphosphole (32), probably via ligand exchange of the first-formed oxazaphosphole (8) with its hydrolysis product, 2-hydroxy-4′-methoxydiphenylamine. The reaction of ethane-1,2-diol with 2,3-dihydro-2,2-dimethoxy-2-phenyl-3-(2,4,6-trimethylphenyl)-1,3,2-benzoxazaphosphole (34) similarly gave the spiro-oxazaphosphole (35).

Nonequivalence of axial fluorine atoms in pentacoordinate phosphorus compounds with P-N bonds

Nonequivalence of axial fluorine atoms in pentacoordinate phosphorus compounds with P-N bonds