Diphosphine disulfides

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... 

Other related compounds are the diphosphine disulfides R2P(S)P(S)R2 14, which contain a direct phosphorus-phosphorus bond, and polysulfur fe(dior-ganophosphine sulfides) R2P(S)-S -P(S)R2 in which the two phosphorus centres are connected by a chain of one of more sulfur atoms. R2P(S)P(S)R2 compounds are accessible from heating secondary phosphine sulfides with thiophosphinic chlorides (Equation 10) or by reaction of fephosphines with... 

The metal and ammonium salts of dithiophosphinic acids tend to exhibit far greater stability with respect to this thermal decomposition reaction, and consequently these acids are often prepared directly in their salt form for convenience and ease of handling. Alkali-metal dithiophosphinates are accessible from the reaction of diphosphine disulfides with alkali-metal sulfides (Equation 22) or from the reaction of alkali-metal diorganophosphides with two equivalents of elemental sulfur (Equation 23). Alternatively, they can be prepared directly from the parent dithiophosphinic acid on treatment with an alkali-metal hydroxide or alkali-metal organo reagent. Reaction of secondary phosphines with elemental sulfur in dilute ammonia solution gives the dithiophosphinic acid ammonium salts (Equation 24). 

Although diphosphine disulfides of formula R2P(S)P(S)R2 take up a trans conformation in the solid state (see Section 5.2.3), upon coordination to a metal centre they can rearrange to adopt a cis conformation, hence facilitating bidentate chelation of the metal (e.g., Equation 78).117 In addition, a cis-bridging mode has also been proposed for these ligands in bi-metallic complexes.117... 

Cleavage of diphosphines with LiAIH, can be a route to secondary phosphines, e.g., diphosphine disulfides react ... 

The drying of impure ethers can produce a violent explosion. Further information about this hazard may be found in Inorganic Syntheses, Volume 12, p. 317. A hazard associated with the synthesis of tetramethyl-diphosphine disulfide [ Inorg. Synth., 15, 186 (1974)] is cited in Inorganic Syntheses, Volume 23, p. 199. 

Tertiary phosphine sulfides were reported as products from the reaction of thiophosphoryl chloride with Grignard reagents in a ratio greater than 1 3 (183,188). However, Kabachnik and Shepeleva discovered in 1949 that diphosphine disulfides can result from this condensation (101). 

To obtain a measure of the versatility of the method, a series of alkyl Grignard reagents were examined (32,90). The isopropyl and sec-butyl reagents failed to generate the corresponding diphosphine disulfide with... 

In a striking piece of research Maier successfully prepared mixed tetra-substituted diphosphine disulfides and separated the meso form from the d,Z-isomers through solubility differences (130,131). Pollart and Harwood also found that phenylphosphonothioic dichloride and ethyl Gri-gnard reagent gave a mixed diphosphine disulfide (161). Treatment of... 

However, the information on fluorine-containing derivatives of these materials is very limited. P-F Phosphoranes 193 and 194, resulted from the fluorination of diphosphine disulfide 192 or from the reaction of 1-methyl-methylenephosphorane 191 with hydrogen fluoride, were among the first representatives of the fluorine-containing phospholanes. ... 

The same reactant, diphosphine disulfide was used in reaction with aldehydes and ketones to provide (dimethylthiophosphinoyloxymethyl-) dimethylphosphine sulfide derivatives in the presence of RhH(PPh3)4 and l,2-bis(diphenylphosphino)ethane (Scheme 20) ... 

Thionyl chloride Phosphinic acid chlorides from diphosphine disulfides... 

Without additional reagents Thiophosphinic acid bromides from diphosphine disulfides s. 19, 590 Thionyl chloride Phosphinic acid chlorides from diphosphine disulfides s. 19, 591... 

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