Bis(tert-butyl­sulfonyl)ethyne and 1-tert-butyl­sulfinyl-2-tert-butyl­sulfonyl­ethyne

The title compounds are electron-poor ethynes. The structure determination of bis­(tert-butyl­sulfonyl)ethyne, C₁₀H₁₈O₄S₂, (I), is the first of a bis-sulfonyl-substituted ethyne. The mol­ecule is situated on a crystallographic inversion centre. The S-Csp bond [1.737 (2) Å] is the longest of this type reported to date. 1-tert-Butyl­sulfinyl-2-tert-butylsulfonyl­ethyne, C₁₀H₁₈O₃S₂, (II), which is basically the same as (I) minus one O atom, crystallizes isomorphous with (I). This results in a nearly equal distribution of the three O atoms over the four possible positions.