Phosphine Chalcogenides

The coordination chemistry of secondary phosphine chalcogenides and their conjugate bases. B. Walther, Coord. Chem. Rev., 1984, 60, 67 (110). 

The chromatographic behaviour of condensed phosphates was found to be strongly influenced by water content and pH. The Ry of tris(dimethyl-amino)phosphine chalcogenides is generally lower than those of the trialkyl-phosphine chalcogenides but the difference is greatest for the P " compounds, and whereas the trialkylphosphines have the highest Ry values in the whole series, tris(dimethylamino)phosphine has the lowest. ... 

Tertiary phosphine chalcogenide Diphosphine dichalcogenide Diphosphine monochalcogenide... 

Secondary phosphine chalcogenide (chalcogenophosphinite) Trichalcogenophosphonic acid (trichalcogenophosphonate) Chalcogenoamidophosphinic acid (chalcogenoimidophosphinate)... 

Studies on the solid-state structures, vibrational frequencies and dipole moments of tertiary phosphine chalcogenides have shown the phosphorus to be in an approximately tetrahedral environment with phosphorus-chalcogen bond lengths in-between those expected for single and double bonds.21 There has been much debate on the nature of the phosphorus-chalcogen bond in these... 

Secondary phosphine chalcogenides (15a) can be readily prepared from oxidation of secondary phosphines (R2PH) with elemental sulfur, selenium or tellurium, although care must be taken to avoid over-oxidation to give the dichalcogenophosphinic acids (see Section 5.2.5). 

Secondary phosphine chalcogenides (15a) exist in equilibrium with their chalcogenophosphinous acid tautomers (15b). This equilibrium sits far on the side of the chalcogenide tautomer 15a for virtually all organo R groups, to such an extent that it is difficult to even detect the presence of the acid tautomer 15b... 

Imino-fe(diorganophosphine chalcogenide)s and imino-fe(dialkoxy-/diary-loxy-phosphine chalcogenide)s, R2P(E)NHP(E)R2 (R = alkyl, aryl, alkoxy, aryloxy E = S, Se, Te) and their N-H deprotonated anionic forms, the dichalcogenoimidodiphosph(in)ates [R2P(E)NP(E)R2], have been extensively studied in the literature, mainly due to their wide-ranging coordination chemistry which has spanned almost all the metallic and semi-metallic members of the periodic table (see Section 5.3.8).72 78... 

Imino-fe(phosphine chalcogenide)s can in theory exist in two different tautomeric states an N-H tautomer 41a and a E-H tautomer 41b. However, extensive studies in both solution and the solid state have shown that in all cases (with the exception of some dioxo E = O species) the N-H tautomer predominates.75 Structural studies have revealed the N(PE)2 group in 41a to be planar or close to planar, with P-N-P bond angles in the range 122-133°, indicative of substantial sp2 character at the nitrogen centre. Planarity of the nitrogen is also observed in the anionic dichalcogenoimidodiphosph(in)ates 42. 

Figure 6 Coordination modes for secondary phosphine chalcogenides and chalcogenopho-sphinites...

Figure 2 Directionality parameters describing the E-XY interaction (a and b) for phosphine-chalcogenide donors in the case of a one a-bond, and three n back-bonds description of the P-E bond (c). For an alternative description of the P-E bond (see Chapter 5)...

The chemistry of phosphonium salts and phosphine chalcogenides has also continued to develop, although no major advances have appeared, doubtless reflecting the maturity of the area. 

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