Phosphorus in Compounds

A near-Hartree-Fock wavefunction for HCP confirms the triple C=P bond and yields values for a number of electron properties which agree quite well with the limited available experimental data. N.m.r. parameters for this compound, obtained by passing PH3 through a carbon arc, have been obtained, the value of 211 Hz for —H) being rationalized on the basis of sp hybridization at 

The results of a microwave determination of the molecular structure of phos-phabenzene are summarized in (17), and in 2-phenyl-1-phosphanaphthalene (18) the condensed rings are almost planar.  

Coupling constants for MePH2 have been calculated by a simple LCAO—MO method, and agree qualitatively with experimental values. Ion cyclotron resonance spectroscopy on the methylphosphines Me PH3 , where n = 1—3, has been investigated, to define their gas-phase ion chemistry. The proton affinities obtained range from 187.9 kcal moP for PH3 to 228.0 kcal mol for Me3P, and these values can be fairly closely reproduced by CNDO/2 calculations. The calculated ionization potentials are, however, considerably higher than the experimental values. 

New secondary-primary diphosphines can be prepared by reduction of the products from the base-catalysed addition of a phosphine to a vinylphosphorus compound, as shown in equation (32). ° Methods for the preparation of 

Nardin, and L. Randacdo, Inorg. Chim. Acta, 1975, 12, 23. 

The optimum geometry of tri-t-butylphosphine has been determined by CNDO/2 calculations,234 and the CNDO/S method has been extended to include second-row elements.235 The results for phosphorin (15) satisfactorily explain the observed u.v. transitions, dipole moment, and ionization potentials. An X-ray structure of 1-benzylphosphole (16) points to the presence of a non-planar ring with a mean P—C(ring) distance of 1.783 A 236 the shortening of the latter over the sum of the single-bond radii is consistent with some delocalization of the phosphorus lone pair. A number of new cyclic phosphides of carboxylic acids such as (17) can be 

A novel route to aminomethyl-phosphines involves the insertion of N-t-butylmethyleneimine into a P—H bond as shown in equation (6).239 

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The configurations at phosphorus in compounds 73-76 were assigned on the basis of II-NMR data assuming that in phosphorus-containing heterocycles, the protons in a 1,3-m-relation to a P=0 group are deshielded. Thus, since H4 and H5 resonate at lower field in compounds 73a-76a than in compounds 73b-76b, the P=0 group must be cis to H4 and H5 in the a series [32]. These assignments were fully supported by the crystal structure studies of 75a, which showed that this... 

Preparation of Phosphoranes from Phosphorus(in) Compounds.—Benzoylphosphor-anes have been made from xenon difluoride, as shown for (80).76 The barrier to rotation of the benzoyl group in (80) is found to be below 8 kcal mol-1, although... 

That the three ordinary valencies of phosphorus in compounds of the type POX3 or PQR3 do not act in one plane, but are distributed in space symmetrically with respect to one another, was demonstrated by Caven,1 who replaced chlorine atoms in the trichloride one at a time taut in different succession by various groups such as RNH— or RO—, forming, for example, the anilino-, p-toluidino- and then the P toluidino-anilino chloride. 

B. Syntheses Through Modification at Phosphorus in Compounds with Carbon-Phosphorus Bonds... 

Herriott used the phosphorus epimers of 0-(-)-menthyl methylphenylphosphinoth-ioate to demonstrate the almost quantitative stereospecificity in the reaction with mCPBA by contrast, the use of trifluoroperoxyacetic acid was less successful, with a retention to inversion ratio of 21 79. A further feature in favour of mCPBA is the independence of its activity relative to solvent. Other extensive correlations were made by Inch and coworkers during investigations into the stereochemistry of displacement reactions at phosphorus in compounds based on a carbohydrate template 81 by means of structural assignments based on infrared absorption frequencies for the P=0 bond together with P NMR chemical shifts, they showed that mCPBA oxidation of thiophosphoryl or selenophosphoryl bonds (A or B = =S or =Se, B or A = Me or Ph) occurred highly stereoselectively with the formation of the phosphonate ester with retained stereochemistry ... 

Bonds to Oxygen.—Lower Oxidation States. Configuration interaction calculations have been carried out on the PO molecule using accurate SCF-LCAO-MO wavefunctions. E.s.r. spectra show that t-butoxyl radicals add to trialkyl phosphites - to produce phosphoranyl radicals Bu OP(OR)3, and that phosphorus(in) compounds and t-butylperoxyl radicals react by a simple bimolecular reaction. ... 

Bonds to Carbon —Phosphorus in) Compounds. A direct route to MezPCl from methyl chloride and red phosphorus has been achieved by modification of the method used for preparation of MePCl2 in which methyl chloride is passed over a mixture of phosphorus and copper powder packed in a glass tube. The inclusion of active carbon in the last part of the tube is the important modification. 

The unlikely looking claim has been made that hexafluorocyclopentadiene adds 1,4 to one double bond of hexafluorobutadiene. Hexafluorobuta-l,3-diene forms flve-membered heterocycles with phosphorus(in) compounds. ... 

Quin L D and Verkade J G (eds) 1994 Phosphorus-31 NMR Spectral Properties in Compound Characterization and Structural Analysis (New York VCH)... 

One of the principal classes of flame retardants used in plastics and textiles is that of phosphorus, phosphorus—nitrogen, and phosphorus—halogen compounds (see also Flame retardants for textiles). Detailed reviews of phosphoms flame retardants have been pubhshed (1—6) (see also Phosphorus compounds). 

Other Phosphorus—Nitrogen Compounds. Of the binary phosphoms—nitrogen compounds, only triphosphoms pentanitride [12136-91 -3] 3 5 been obtained in a pure state. It can be prepared by treatment of P S q with ammonia and subsequent heating of the intermediate... 

Phosphorus heterocyclic compounds, 1, 493-538 five-membered ring systems, 1, 513-523 nomenclature, 1, 496 six-membered ring systems, 1, 497-513 Photoaromatization oxirenes from, 7, 125-126 Photobleaching chromenes in, 3, 880 Photochemical reactions heterocyclic compound synthesis from, 5, 159 reviews, 1, 56 heterocyclic compounds reviews, 1, 71, 72... 

Phosphorus and Silicon in Waters, Effluents and Sludges [e.g. Phosphorus in Waters, Effluents and Sludges by Spectrophotometry-phosphomolybdenum blue method. Phosphorus in Waters and Acidic Digests by Spectrophotometry-phosphovanadomolybdate method. Ion Chromatographic Methods for the Determination of Phosphorus Compound, Pretreatment Methods for Phosphorus Determinations, Determination of silicon by Spectrophotometric Determination of Molybdate Reactive Silicon-1 -amino-2-naphthol-4, sulphonic acid (ANSA) or Metol reduction methods or ascorbic acid reduction method. Pretreatment Methods to Convert Other Eorms of Silicon to Soluble Molybdate Reactive Silicon, Determination of Phosphorus and Silicon Emission Spectrophotometry], 1992... 

Many reagents can be used to oxidatively fluorinate phosphorus(IIl) compounds, as shown in equation 14 [93, 94, 95, 96]... 

The recommended names for these compounds (phosphinic acid and phosphinates) have not yet gained wide acceptance for inorganic compounds but are generally used for organophosphorus derivatives. Hypophosphites can be made by healing white phosphorus in aqueous alkali ... 

As nitrogen compounds are known to improve the LOI values of phosphorus FR positively, the effect of a few nitrogen compounds such as urea, melamine, HMTA, etc. were studied. Table 11 shows that nitrogen gives a synergistic effect with phosphorus in cellulose. Similar results have also been observed for LDPE. 

As a result of different chemical surroundings the resonance frequency absorption will show definite peaks registered by Fourier transform technique. Compared to an internal standard the intensity of the signals is used for quantitative determination of different phosphorus-containing compounds in a given sample. 

The term phospho- is used for (H0)2P(0)- or ionized forms in a biochemical context (see recommendations for the nomenclature of phosphorus-containing compounds [24]). 

The diazaphosphane or aminoiminophosphane ligands with a NPN framework are another subclass of cyclophosphazenes. These compounds with both phosphorus in oxidation state (111) [104-110] and (V) [111-112] have been employed in the synthesis of four membered heterocycles and coordination chemistry with group 13 derivatives. Several complexes of trivalent phosphorus derivatives with both aluminum halide and alkyls are known as illustrated for 48 in Scheme 21 [113-119]. The structure determination of 48 confirms the formation of a four membered metallacycle [116, 117],... 

Just as in the case for the hydrosphere, the atmosphere participates in all of the major biogeochemical cycles (except for phosphorus). In turn, the chemical composition of the atmosphere dictates its physical and optical properties, the latter being of great importance for the heat balance of Earth and its climate. Both major constituents (O2, H2O) and minor ones (CO2, sulfur, nitrogen, and other carbon compounds) are involved in mediating the amounts and characteristics of both incoming solar and outgoing infrared radiation. 

A 2/1 blend of polycarbonate and polyethylene terephthalate (PC/PET) was flame retarded with bromine, phosphorus, a blend of bromine and phosphorus, and compounds containing both phosphorus and bromine in the same molecule. All compositions contained 0.5 % Teflon 6C as a drip inhibitor and where specified 5 % of an impact modifier. 

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