Phosphorus Selenide Anions

Characterised anions now include all those shown in Table 9.9 [16-18]. 

Numerous mixed-metal phosphorus selenides have been reported, for example, K2ThP3Se9, Cs4Th2P5Se,7, Rb2Au2P2Seg Cs3AuP2Seg and so forth [19-21]. 

Long chains of type [P3Se4 ] exist in KjRuPgSeio (9.661) [16-23]. Alkali metal salts such as KPScg contain continuous chain anions of type [PSeg ] [24-26] (Table 9.9). 

Presently known complexes include those with 4-, 5- and 6-membered rings (9.683) as well as larger arrangements such as Equation 9.684 [27,28]. Compounds of type (9.683) are at present of interest as electronic materials (Chapter 12.20). 

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Konstantin Karaghiosoff received his PhD in 1986 from Munich University under the supervision of Alfred Schmidpeter. In his Thesis he developed the synthesis of many new heterophospholes. Further interests of him include phosphorus selenide derived anions and cations, as well as the analysis of NMR spectra of high order. He is Professor of Chemistry at the University of Munich. 

Phosphorus/sulphur anions and corresponding selenides and their anions are dealt with in Chapter 9.11. 

Diselenophosphates have been much less investigated than the analogous dithiophosphates, but some interesting chemistry was revealed. The reactions of phosphorus(V) selenide, P2Se5, with alcohols and phenols produce diseleno-phosphoric acid diesters, (RO)2P(Se)SeH, the parent compounds of di-selenophosphato anionic ligands. The free acids are not stable and should be immediately converted to metal salts or complexes. 

Treatment of diphenyl diselenide with tributylphosphine in an alkaline medium generates a benzeneselenolate anion [24], which reacts with various electrophiles, such as halides, epoxides, a, -unsaturated ketones, to generate various selenides [24,25]. The mechanism for the generation of the benzeneselenolate is proposed as shown in Scheme 17 [25]. A selenophosphonium ion and/or a pentavalent phosphorus species are initially formed in the reaction of diphenyl diselenide and tributylphosphine, and then the addition of sodium hydroxide liberates the benzeneselenolate and phosphine oxide. 

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