Pentavalent phosphorus

Ihese reactions (and those of the irichloride) indicate the great tendency of (pentavalent) phosphorus to unite with oxygen (cf. silicon). 

Pentavalent phosphorus derivatives can be converted to phosphonyl halides or phosphine oxides by partial hydrolysis or by other oxygen donors. 

Compounds of tnvalent phosphorus are generally oxidized to pentavalent phosphorus denvaPves bis(fluoroalkyl) and tns(fluoroalkyl) phosphites are oxi dized to the corresponding[106, lOI] (equation 92)... 

Organophosphates are a group of pentavalent phosphorus compounds, which contain an organic group (e.g. parathion, malathion, tabun, sarin, soman). 

Although the phosphorous acid esters are often referred to as such, they are not true phosphites [72]. To be more precise, they exist almost exclusively in the phosphonate form of pentavalent phosphorus, as shown in structures (5) and (6) ... 

There have apparently been no recent developments in reagents for desulphurizing sulphoxides that use pentavalent phosphorus compounds. Reagents that were reviewed in 1984 include phosphorus pentasulphide, thiophosphoryl bromide, Lawesson s reagent (1), and phosphorus pentachloride in the presence of a trap for CD ions. The traps used included an enamine or an N, JV-dialkylaniline. Presumably, the net effect of this reaction is to generate phosphorus trichloride in situ. The three thiophosphorus reagents obviously function because the P=S bond is some 150 kJ moD weaker than the P=0 bond . 

Two types of OPIDN have been described in animals (Abou-Donia and Lapadula 1990). Type I is produced by compounds with a pentavalent phosphorus (like TOCP), and Type II is produced by compounds with a trivalent phosphorus. Characteristics used to differentiate between the types of OPIDN include species selectivity, age sensitivity, length of latent period, and morphology of neuropathologic lesions. Thus, at doses that did not produce death due to acetylcholinesterase inhibition, TOCP (a Type I compound) produced lesions in the spinal cord of rats without producing ataxia. In contrast, triphenyl phosphite (a Type II compound) produced delayed (1 week) ataxia in the rat and a distribution of spinal cord lesions distinct from those produced by TOCP (Abou-Donia and Lapadula 1990). 

All these drawbacks can be avoided by using a simple and general strategy for the synthesis of neutral phosphorus dendrimers elaborated up to generation 12, in which the core and subsequent branching points are pentavalent phosphorus atoms. 

Data from this laboratory and others8,9,10 indicate that the general procedure outlined for the synthesis of F2PX compounds may be extended to the synthesis of the oxy derivatives of pentavalent phosphorus such as F2C1P0 and Cl2FPO, but the detailed directions are not given here. The mixed oxyhalides of phosphorus, like the corresponding mixed halophosphines, have not been obtained easily in pure form from complex reaction mixtures.11,12... 

Ionic dissociation of carbon-carbon a-bonds in hydrocarbons and the formation of authentic hydrocarbon salts, 30, 173 Ionization potentials, 4, 31 Ion-pairing effects in carbanion reactions, 15, 153 Ions, organic, charge density-NMR chemical shift correlations, 11,125 Isomerization, permutational, of pentavalent phosphorus compounds, 9, 25 Isotope effects, hydrogen, in aromatic substitution reactions, 2,163... 

Partitioning of carbocations between addition of nucleophiles and deprotonation, 35, 67 Perchloro-organic chemistry structure, spectroscopy and reaction pathways, 25, 267 Permutational isomerization of pentavalent phosphorus compounds, 9, 25 Phase-transfer catalysis by quaternary ammonium salts, 15, 267 Phosphate esters, mechanism and catalysis of nucleophilic substitution in, 25, 99 Phosphorus compounds, pentavalent, turnstile rearrangement and pseudoration in permutational isomerization, 9, 25... 

Protonation and solvation in strong aqueous acids, 13, 83 Protonation sites in ambident conjugated systems, 11, 267 Pseudorotation in isomerization of pentavalent phosphorus compounds, 9, 25 Pyrolysis, gas-phase, of small-ring hydrocarbons, 4, 147... 

Turnstile rearrangements in isomerization of pentavalent phosphorus compounds, 9, 25... 

The solids considered in this section are phosphorus oxynitrides and nitridooxophosphates. They are pentavalent phosphorus(V) compounds and correspond to a partial substitution of nitrogen, under the nitride form N3, for oxygen 02 within P04 tetrahedra, resulting in the formation of mixed P(0, N)4 tetrahedra. 

Martin, D.J., Catalyzed Process for Producing Pentavalent Phosphorus Derivatives, U.S. Patent 3,705,214, 1972. 

Halogen on both trivalent and pentavalent phosphorus is susceptible to such displacement. Control of the reaction to provide synthetic utility will be noted. Both isolable organometallics and transient species generated and used in situ will be surveyed. 

Figure 10.5 Stereoview of the reaction running through a bipyramidal pentavalent phosphorus atom. The y-phosphoryl group before and after the transfer is in a transparent mode. A putative Mg2+ was placed at the expected position between AsplO and the (3- and y-phosphoryl groups. (From Grueninger and Schultz, 2006. Copyright 2006, with permission from Elsevier.)...

Structure C is usually written with a pentavalent phosphorus this description, however, should merely denote that the phosphorus lone pair is delocalized and no allenic bond with two perpendicular jr-systems has been formed. H2C=P(H)=CH2, a typical representative of structure C phosphorus, can be described by an allyl-like r-system, ° with the p -type lone pair of a planar tricoordinate phosphorus participating in the 4-electron-3-center jT-bonding, without invoking d-orbital participation. " Thus, the C -type bonding of phosphorus involves tricoordination, with a planar bonding environment, whereby the lone pair is available for jT-bonding. 

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