Triphosphine

Diphosphine under the correct conditions of thermolysis will decompose mainly according to (4.155) and the desired triphosphine can be concentrated by fractionation. Triphosphine is a spontaneously inflammable, colourless liquid, soluble in diphosphine, stable at -80°C, but turning yellow at room temperature giving eventually solid products. 

If liquid diphosphine and triphosphine are heated, tetraphosphine, P4H5, and cyclopentaphos-phine, P3H5 are among the products obtained. Triphosphine will disproportionate to diphosphine and tetraphosphine under the action of light and heat. 

Both n-(4.162a) and iso-(4.162b) forms of tetraphosphine are known. These, and many isomers of higher members of the various polyphosphine series, have now been characterised. In the case of n-P4Hg, the two inside P atoms are asymmetrical and this leads to three possible optical isomers [8,22-24] (Chapter 13.2). 

When white phosphorus reacts with various reagents to give phosphine, PH3, for example, (4.13), (4.15), all the original bonds in the P4 tetrahedron are broken. The simple butterfly hydrides P4H2 

The P4H anion is quick to react to form condensed varieties moreover, it is in rapid equilibrium. 

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Bardaji, M., Laguna, A., Orera, V.M. and Villacampa, M.D. (1998) Synthesis, Structural Characterization, and Luminescence Studies of Gold(l) and Gold(lll) Complexes with a Triphosphine Ligand. Inorganic Chemistry, 37(20), 5125-5130. 

Bardaji, M., Laguna, A., Vicente, J. and Jones, P.G. (2001) Synthesis of luminescent gold(I) and gold(III) complexes with a triphosphine ligand. Inorganic Chemistry, 40, 2675-2681. 

Related to these diphosphine dichalcogenides are the triphosphine trisulfides [R2P(S)]3CH (12) which can be prepared from lithiated methylene diphosphine disulfides upon treatment with thiophosphinic chlorides (Equation 9). Deprotonation of 12 with tBuLi gives a resonance-stabilised anion 13 containing a planar central carbanion whose charge is delocalised onto the three neighbouring phosphorus and sulfur atoms.32... 

Triphosphine reacted with carbon tetrabromide to form an organic salt [13]. This reactive species then reacted with alcohol to form the corresponding bromide. Kinetics results showed that there is no significant difference in reaction rate when resin beads of different sizes were used. This demonstrated that the diffusion of the organic salt into bead was not rate hmiting compared with the reaction rate. 

Triphosphine, P3H5, has been identified as a product from the hydrolysis of CaaPj or Mg3P2 in acidic media by mass spectroscopy In addition, using mass spectroscopic analysis Baudler and her co-workers 436.437) able to identify the following higher phosphines formed during the hydrolysis or the disproportionation of diphosphine ... 

Figure 2.35 Trinuclear gold compound with bridging thiolate and triphosphine ligands.

The use of both di- or triphosphines and chalcogenolates as building blocks in the same molecule leads to different species. The trinuclear derivative shown in Figure 2.35 is an example [167]. A more complicated structure is that of Au9(p.-p-tc)6(p.-dppm)4]3+ (p-tc = p-thiocresolate) which exhibits short gold-gold interactions. An emission at 540 nm is observed upon excitation at 450 nm in the solid state at room temperature that increases in intensity at 77 [168]. 

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