Phosphines compounds

Phosphorus NMR spectroscopy serves as a valuable diagnostic tool in the characterization and structural elucidation of primary phosphine compounds. As shown in Table 1, RPH groups resonate in the -125 ppm to -150 ppm range with direct one bond P- H coupling constants of 193-197 Hz. 

There now are available a number of alkyl azide compounds that may be used in click chemistry reactions and the Staudinger ligation processes. It is not recommended, however, to use aryl azide compounds, as these are light sensitive and photoreactive as well as highly susceptible to reduction in the presence of thiols. Unfortunately, at the time of this writing there are fewer choices in aryl phosphine compounds to participate in this reaction, as commercial sources of labeling reagents are limited. 

The methods used for in vivo incorporation of azido-monomers and performing a labeling reaction with live cells are relatively simple. The following protocol is based on the methods of Saxon and Bertozzi (2000), which uses acetylated azidoacetylmannosamine as the azido-monomer source and a biotin-PEG-phosphine compound to biotinylate cell surface glycoproteins at the specific azide-sialic acid incorporation sites (Figure 17.19). 

Basicity of some organic molecules Amine compounds Arsine compounds Phosphine compounds... 

In this paper, only the original triphenyl phosphine compound Au55(PPh3)i2Cl6 will be examined. In order to simplify reading, we will use the abbreviation AU55 to mean this version. For an occasional reference to the... 

The counter-ions of some of the quaternary onium groups were exchanged with an anionic phosphine compound, which was then used to complex palladium. Thus, a polymer material containing phase transfer catalyst and transition-metal catalyst groups was obtained (Fig. 20). The Heck-type vinyla-tion reaction [137] was used to examine the catalytic activity of the heterogeneous system. The polymer-supported catalyst was found to compare favourably with the homogeneous system (Fig. 21). 

Treatment of the 1 2 adduct 62 with one equiv. of hydrogen peroxide in methanol gave mainly a pure, crystalline compound (m.p. 209-210.5°) whose structure was presumed to be bis(3-0-acetyl-5,6-dideoxy -1,2-0 - isopropylidene - 6-C-nitro - / -L-idofuranose-5-yl)phenyl-phosphine oxide (69) therefore, the original 1 2 adduct 62 was assumed to be a mixture consisting mainly of the corresponding phosphine compound. 

Because arsenic(V) (as arsonic or arsinic acids) is readily reduced to arsenic(III) by sulfur dioxide in concentrated HX,102,103 this makes chloroarsines much more readily accessible than the corresponding phosphine compounds. This is shown in equation (31),104... 

R)-(o-Methoxy phenyl)methyl(N, N-dimethylsulfonylmethyl) phosphine (Compound 16). This compound is not crystalline it formed a crystalline derivative of the type L2Rh AcAc, which was used for the catalyst. 

The first two examples in Figure 1.20 illustrate that the structural formulas of alkyl and aromatic phosphine compounds may be derived by substituting organic groups for the H atoms in phosphine (PH3), the hydride of phosphorus, discussed as a toxic inorganic compound in Section 12.10. Methylphosphine is a colorless, reactive gas. Crystalline, solid triphenylphosphine has a low reactivity and moderate toxicity when inhaled or ingested. 

To which kinds of nitrogen and sulfur compounds are alkyl and aryl phosphine compounds analogous ... 

Unlike phosphines, the coordination of NHCs to metal centers usually requires the activation of a precursor, which makes NHC-based complexes relatively less accessible than the analogous phosphine compounds. There is a variety of methods for forming carbenes, most of them from the corresponding azolium salts, and these have been reviewed [10-14], The methods for preparing NHC-metal complexes can be classified according to the nature of the NHC precursor and to the activation method employed. In this sense, the most widely used strategies are ... 

The early work on bidentate phosphine compounds of manganese was reviewed in 1972.186 More recent preparations of the compounds [MnX2(diars)2], and preparations of similar compounds with the ligand o-phenylene(dimethylarsine) (dimethylstibine), have indicated that if care is taken in... 

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