Boranes elemental sulfur

Reacting the two isomers of the macropolyhedral borane B18H22 [anti-B18H22l or [syn-BlgH22] with elemental sulfur, two dithiaboranes were isolated in 48% yield each and structurally characterized [S2B, 711,H 41 from the anti-... 

The white disulfide, only slightly soluble in toluene or mesitylene, is a useful reagent for the sulfurization of phosphines. The range of applicability for the sulfur transfer reagent has not yet been tested. In comparison with the known R2BS2BR2 boranes, the (9-BBN)2S2 compound is more readily available and can be synthesized in a pure form, free of monosulfide and thiol. The disulfide can be prepared in two different ways from (9-H-9-BBN)2 or 9-1-9-BBN, respectively, with elemental sulfur (methods A and B). 

The procedure described for the preparation of ethylenediamine-bisborane is general for the synthesis of amine-boranes and of borane adducts of other electron donors in which elements such as phosphorus and sulfur serve as the donor atom. In addition to the procedure used here for triphenylphosphine-borane, borane adducts of phosphines have been prepared by Analytical reagent grade (Mallinckrodt). 

---