With tetramethyldiphosphane

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. 

Roschenthaler and co-workers 120,122) have investigated the action of excess HFA on tetramethyldiphosphane. The resulting 1,2-oxaphosphetanes 58c,o,w and their relative conformations have been studied with NMR. 

With the sterically demanding terl-butyldiphosphane, the tellurium-phosphorus compound was quantitatively formed and disproportionation to ditellurium and diphosphane was not observed. After distillation of di-isopropylphosphano 4-methylphenyl tellurium, some tetraisopropyldiphosphane was observed. The diphosphane was observed spectroscopically after storage of the pure yellow-orange oil for a few days at 20°. Dimethylphosphano methyl tellurium cannot be isolated because the compound is in equilibrium with dimethyl ditellurium 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... 

Caution. In common with other alkyl diphosphanes, tetramethyldiphosphane presents some hazard because of its toxicity and extreme susceptibility to air oxidation. Therefore, all operations must... 

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