Tetramethyldiphosphane disulfide

The present procedure starts with tetramethyldiphosphane disulfide which is desulfurized with iron powder to tetramethyldiphosphane. The diphosphane is cleaved with sodium in liquid ammonia, followed by addition of 1,2-dichloroethane, to give ethylenebis-(dimethylphosphine). This procedure avoids the use of phosphine (PH3) and eliminates the need for high-pressure apparatus. Sections A and B for preparing tetramethyldiphosphane and the disulfide have been reported5,6 and are reproduced with some modifications. The total working time for Secs. A, B, and C is 3 days. 

Under a stream of nitrogen, a solution of 217 g. (1.28 moles) of freshly distilled phosphorus trichloride sulfidet in 300 ml. of ether is added to the dropping funnel. The Grignard solution is cooled to 

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Bis(0-salieylidenaminopropylaziridine)iron(III) perchlorate, 3853 Bis(tetramethyldiphosphane disulfide)cadmium perchlorate, 3102 Carbonyl-bis(triphenylphosphine)iridium-silver diperchlorate, 3898 5-/ -Chlorophcnyl-2.2-dimcthy 1-3-hcxanonc. 3664 Copper(II) perchlorate, Polyfimctional amines, 4057 Copper(II) perchlorate, /V-(2-Pyridyl)acylacctamidcs. 4057 2(5-Cyanotetrazole)pentaamminecobalt(III) perchlorate, 0974 1,5-Cyclooctadiene-bis(4-chloropyridine /V-oxidc)rhodium(I) perchlorate, 3761... 

It ignites in air [1], and unreacted tetramethyldiphosphane residues may also ignite [2], See Bis(tetramethyldiphosphane disulfide)cadmium perchlorate See other alkylphosphines... 

Bis(2-picrylhydrazino)-3,5-dinitropyridine, 3729 Bis(2-propyloxy)diazene, see Diisopropyl hyponitrite, 2533 Bis(propyloxy)diazene, see Dipropyl hyponitrite, 2534 Bispyridinesilver(l+) perchlorate, see Dipyridinesilver(I) perchlorate, 3261 Bis(<9-salicylidenaminopropylaziridine)iron(III) perchlorate, 3847 Bis(tetramethyldiphosphane disulfide)cadmium perchlorate, 3096... 

ETHYLENEBIS(DIMETHYLPHOSPHINE) [l,2-BIS(DIMETHYLPHOSPHINO)ETHANE], TETRAMETHYLDIPHOSPHANE DISULFIDE, AND TETRAMETHYLDIPHOSPHANE... 

The preparation of ethylenebis(dimethylphosphine) has been described by metallation of phosphine with sodium, followed by methylation of the resulting sodium phosphide with iodomethane. Two further metallation-methylation sequences using sodamide and iodomethane produce sodium dimethylphosphide, which is treated with 1,2-dichloroethane in liquid ammonia, to give the diphosphine.2 Other procedures involve heating tetramethyldiphosphane with ethylene,3 or tetramethyldiphosphane disulfide with ethylene, both... 

The synthesis of tetramethyldiphosphane disulfide from commercially available methyl-magnesium bromide solution has been described in detail.6 The disulfide is available from Strem Chemical Co., Danvers, Mass. 01923. 

Tetramethyldiphosphane disulfide is stable in air. The crystals are soluble in chloroform and acetone, moderately soluble in benzene and toluene, slightly soluble in alcohols, and insoluble in ether and pentane. In the solid state the preferred conformation is trans, as indicated by one strong P—S stretching absorption in the infrared spectrum (Nujol mull) at 567 cm.-1, and the absence of a P—P band, which is found only in the Raman spectrum at 445 cm.-1.9 Other principal absorption bands are at 733, 745, 860, 882, 939, and 1281 cm."1. 

Organic Syntheses411 includes directions for the preparation of tetramethyldiphosphane disulfide. 

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