Metal Phosphide Halides

Reactions of alkyl halides with alkaU metal phosphides [39-41], addition reactions of olefins with PHj [42] or the pyrolytic cleavage of P-0 bonds in RPO2H2 [43] are also reported for the preparation of alkyl/aryl functionalized primary... 

Phosphides and amides are closely related, as a synthetic route is based on metathesis of metal amides, especially the respective trimethylsilyl amides, with the appropriate free acidic phosphine or an anion derived therefrom. Reaction of metal halides and trisilylphosphines is an alternative for preparing metal phosphides. 

The reaction of alkali metal phosphides with appropriate halides, sultones or cyclic sulfates is a generd method for preparation of a variety of tertiary phosphines useful in aqueous organometallic catalysis. These... 

The observations made by the New Hampshire group concerning the variable reactivity of metal phosphides with alkyl halides and tosylates should be kept in mind when planning ligand syntheses by these routes. It appears that, for any particular halide or tosylate substrate, the best metal phosphide for displacement can be determined only by experiment. 

There are several different preparations of metal phosphides. Secondary phosphines can be metallated by strong bases such as butyl-lithium or alkali metals (Scheme 5). Primary phosphines can be doubly lithiated using LDA or BuLi.11 Both the anion and dianion metal phosphides can be generated in situ before adding the electrophile into the same pot.12,13 Phosphorus halides can be metallated using lithium metal. 

Further, elemental phosphorus can be converted by Grignard reagents or organolithium compounds into metal phosphides which afford primary phosphines on hydrolysis phenylphosphine was obtained in this way in yields of up to 40% from phenyllithium and white phosphorus.214 In some circumstances cyclophosphines are formed on reaction of alkyl halides with the phosphide solutions obtained from elemental phosphorus.215... 

Treatment of the appropriate polyfunctional halide with metal phosphides is almost the only method of obtaining di-, tri-, or tetra-tertiary phosphines. 

The different cations and anions of each molecule are covered in separate chapters. Most of the information on these ionic species results from gas-phase studies or quantum-chemical calculations. Only PHg and PHJ have been obtained to date as ions of salt-like compounds, either in solution or in the solid state PHg, e.g., in the alkali metal phosphides MPHg, where M = Li to Cs and PHJ, e.g., in the phosphonium halides PH4X, where X = Cl, Br, I. 

Thermal decomposition of some boron trihalide addition compounds will yield the monophosphide (4.334) and displacement from another metal phosphide may also be used (4.335,4.336). The compound can also be obtained directly from white P by the reaction (4.337) or by co-reduction of P halides [4]. 

Alkyl halides react with sodium (and other metal phosphides) to give phosphines (6.39-6.42). The metal phosphides can be prepared by the action of the metal on the appropriate phosphine in liquid ammonia (6.8-6.30). 

Some phosphines can be obtained from phosphonium halides by the action of metals or metal phosphides (6.401,6.402). 

A variety of substituted silyl phosphines, all based on Si-P linkages, can be made by reacting alkali metal phosphides with silicon halides as in (9.176) through (9.178). 

Monosnlfides of U, Gd, Th and other metals are obtained from a solution of the normal valent metal sulfide and chloride in an NaCl/KCl eutectic. LaB is prepared by taking La Og and B Og in an LiBO /LiF melt and by using gold electrodes. Crystalline transition metal phosphides are prepared from solutions of oxides with alkali metal phosphates and halides. 

Metal phosphides (M3P to MP3) are prepared by the direct union of elements. Certain phosphides have been prepared by electrolysis (e.g. FeP). Reaction of oxides or halides with PH3 also yields phosphides. 

Phosphoms shows a range of oxidation states from —3 to +5 by virtue of its electronic configuration. Elemental P is oxidized easily by nonmetals such as oxygen, sulfur, and halides to form compounds such as 2 5 2 5 reduced upon reaction with metals to generate phosphides. The... 

Low-temperature solvents are not readily available for many refractory compounds and semiconductors of interest. Molten salt electrolysis is utilized in many instances, as for the synthesis and deposition of elemental materials such as Al, Si, and also a wide variety of binary and ternary compounds such as borides, carbides, silicides, phosphides, arsenides, and sulfides, and the semiconductors SiC, GaAs, and GaP and InP [16], A few available reports regarding the metal chalcogenides examined in this chapter will be addressed in the respective sections. Let us note here that halide fluxes provide a good reaction medium for the crystal growth of refractory compounds. A wide spectrum of alkali and alkaline earth halides provides... 

No, the editor didn t know what this name meant either.) It means salts of the triva-lent anions of Group V, restricted in [1] to arsenides, antimonides and bismuthides and prepared by reaction of sodium pnictides with anhydrous halides of transition and lanthanide metals. This violently exothermic reaction may initiate as low as 25°C. Avoidance of hydrated halides is cautioned since these are likely to react uncontrollably on mixing. Another paper includes a similar reaction of phosphides, initiated by grinding [2], Nitrides are reported made from the thermally initiated reaction of sodium azide with metal halides, a very large sealed ampoule is counselled to contain the nitrogen [3],... 

These are usually reactions of anhydrous transition and B metal halides with dry alkali metal salts such as the sulphides, nitrides, phosphides, arsenides etc. to give exchange of anions. They tend to be very exothermic with higher valence halides and are frequently initiated by mild warming or grinding. Metathesis is... 

---