Phosphorus trichloride complexes

At the time of our investigation the only known coordination compounds of chlorophosphines (aside from phosphorus trichloride complexes) were the nickel-(0) compounds, tetrakis(methyldichlorophosphine)nickel-(0) (20) and tetrakis-phenyldichlorophosphine) nickel- (0) (17). Tetrakis (methyldichlorophosphine) -nickel-(0) is noteworthy in that it represents a still rare example of the direct reaction of a ligand with an elemental transition metal to give a complex, while tetrakis (phenyldichlorophosphine) nickel- (0), like tetrakis (trichlorophosphine) -nickel-(0), was obtained readily via the carbonyl. AD chlorophosphine-nickel-(O) complexes, including the phosphorus trichloride complex, Ni(PCl3)4, are compounds relatively stable in the atmosphere, but show poor stability in almost any organic solvent, even under strictly anaerobic conditions. 

A general inspection of the Tables of published phosphorus chemical-shift data on co-ordination complexes (in Section VII) indicates the difficulties in any quantitative understanding. In general it appears that the majority of transition metal— phosphine complexes (particularly those containing the metal in its zerovalent state) have resonances at lower field than the corresponding unco-ordinated phosphine. On the other hand the chemical shifts of all phosphorus trichloride complexes occur at higher field than the free ligand, while the behaviour of phosphite complexes is rather more variable. Phosphine... 

The donor-acceptor formation can be considered by transfer of electrons from the donor to the acceptor. In principle one can assume donor-acceptor interaction from A (donor) to B (acceptor) or alternatively, since B (A) has also occupied (unoccupied) orbitals, the opposite charge transfer, from B to A. Such a view refers to mutual electron transfer and has been commonly estabUshed for the analysis of charge transfer spectra of n-complexes [12]. A classical example for a donor-acceptor complex, 2, involving a cationic phosphorus species has been reported by Parry et al. [13]. It is considered that the triaminophosphines act as donor as well as an acceptor towards the phosphenium cation. While 2 refers to a P-donor, M-donors are in general more common, as for example amines, 3a, pyridines, 3b, or the very nucleophilic dimethylaminopyridine (DMAP) [ 14], 3c. It is even a strong donor towards phosphorus trichloride [15]. 

A comprehensive review of the preparation, reactions, and n.m.r. spectra of phosphorus-fluorine compounds has appeared. This year s literature has been notable for the first detailed applications of ab initio SCF-MO calculations to the problems of bonding in halogenophosphines and their derivatives. - Comparison of the results of such theoretical calculations with experimental data obtained from photoelectron spectra shows a good correlation in the case of phosphorus trichloride and phosphoryl chloride, and of phosphorus trifluoride and its borane complex. ... 

Two papers have appeared on the reactions of halogenophosphines with tervalent phosphorus compounds. In a detailed study of the reactions at 20 °C of a range of tertiary phosphines with phosphorus trichloride, dichlorophenylphosphine, and chlorodiphenylphosphine, it has been shown that, in general, 1 1 adducts are formed, provided that the tertiary phosphine is a good nucleophile. With diphenylchlorophosphine, for example, an adduct (18) is formed with dimethylphenylphosphine, but not with diphenylmethylphosphine, although the relative importance of steric and electronic factors remains to be established. The related reactions of phosphorus trichloride and of dichlorophenylphosphine are much more complex, and the initial crystalline products are not amenable to analysis. The reactions at 280 °C of a similar system have been shown to lead to halogen exchange, e.g. the conversion of (19) to (20). 

With phosphorus trichloride, a rather complex reaction results partly in the formation of [PhaP N uPPha PPhCl]+ Cl. The reactivity of the phosphorus(iii) atom is also demonstrated by its ability to desulphurize thiophosphoryl chloride, and its ready reactions with Group VI elements, diborane, and carbon disulphide ... 

The controlled occurrence of two electrophilic aromatic substitution reactions at a single phosphorus center using phosphorus trichloride has been accomplished using aluminum chloride as the catalyst, but with tris(2-chloroethyl) phosphite as the agent for the decomposition of the adduct-Lewis acid complex (Figure 6.13).60... 

Phosphorus trichloride forms a tetracoordinated nickel complex by action with nickel tetracarbonyl ... 

In our study of the fluorination of coordinated chlorophosphine ligands (23), we started out with tetrakis(trichlorophosphine)nickel-(0), which could previously be converted into tetrakis(trifluorophosphine)nickel-(0) by displacement of the coordinated phosphorus trichloride with excess phosphorus trifluoride in a sealed tube (32). The limitations of this method, requiring the use of phosphorus trifluoride, a low boiling gas, under pressure, and involving the mechanical separation of the fluorophosphine complex from phosphorus trichloride, are obvious, and the yield was low. A straightforward method for the synthesis of this interesting compound was found in the fluorination of the coordinated phosphorus trichloride with potassium fluorosulfinate ... 

Both compounds being colorless and volatile, the liquid methyl derivative could be distilled in vacuo (b.p. 66-68° at 3.5 mm.), while the phenyl compound is a crystalline solid melting at 66°, which is sublimable in vacuo. The fluorination reactions occur somewhat less vigorously than in the case of the phosphorus trichloride nickel-(0) complex, and gentle heating was normally required to initiate the reaction. Benzene was used as a solvent. 

Numerous adducts of MX4 with nitrogen, phosphorus, arsenic, oxygen and sulfur donors have been obtained, mainly for niobium with X = CI or Br7 (Tables 29-33). The absence of MF4 adducts, except for [NbF4(py)2],511 may be due less to their instability than to a lack of investigations. An ill-defined fluoro trichloride complex, [NbCl3F(MeCN)2.65], has also been reported.512... 

The halides, GaQs, AlBrs, A1C13, and FeCl3, very probably also exist in dimeric form. With these halides, however, the complexation reaction with the azide is the fast step so that no square-root term is found in the kinetic equation. Arsenic trichloride, arsenic tribromide, phosphorus trichloride, and phosphorus pentachloride were without effect on the rate of decomposition of benzoyl azide. Finally, the authors have observed that the catalytic influence of boron tribromide was much higher than all the other halides. Its rate constant was estimated to be about 18 times larger than that for gallium chloride. 

Platinum(II)15 and palladium(II)16 complexes of phosphorus trichloride undergo solvolysis in water and alcohols to form complexes with orthophosphorous acid or orthophosphite ligands (equation 6). Similar reactions occur between the palladium(II) phenyldichlorophosphine complex (8) and the diols ethyleneglycol and catechol, but new chelate rings are not formed (Scheme 2). Solvolysis also occurs with attack of diphenylphosphinic acid or a similar diphenylchlorophosphine complex (9) (equation 7). The palladium complexes (8) and (9) are unstable to excess methanol, water or base and undergo reduction. Similarly, the phosphorus trichloride gold(I) complex (10) is reduced by water, but forms stable products on reaction with alcohols (equation 8).15 During the above reactions, the phosphorus—metal bond remains intact and the overall process is one of substitution at phosphorus. 

In the preparation of phosphorus tetritoxide by exposing to air for 24 hrs. yellow phosphorus under a layer of phosphorus trichloride, a thick white crust is formed on the surface of the phosphorus and above and below this a yellow layer of a complex with the composition 4P40.3PS05. The phosphorus trichloride is decanted off, the pieces of phosphorus to which the complex adheres are separated from one another and put into water. The complex dissolves in water, forming a yellow soln. which is poured off from the phosphorus. At 80°, the product decomposes into phosphorio acid, and yellow flakes of a hydrated phosphorus suboxide of unknown composition. 

E. D. Chattaway and H. P. Stevens found that phosphoric acid decomposes nitrogen iodide, producing ammonia. According to A. Geuther, when phosphoric acid is treated with phosphorus pentachloride at ordinary temp., phosphoryl chloride and hydrogen chloride are formed phosphorus trichloride furnishes meta-phosphoric and phosphorous acids and phosphoryl chloride is without action in the cold, but when hot, metaphosphoric acid is formed if the phosphoryl chloride be in excess, and phosphorous acid if only a little be present. G. Meyer, and A. Vogel prepared a complex with boric oxide or boric acid—vide boron phosphate, 5. 32, 27. 

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