Eigenschaften von Chalkogen–Chalkogen‐Bindungen, XVII. Di‐und Trisulfane mit sterisch anspruchsvollen Alkyl‐Substituenten: Das erste trans 1‐Dialkyldisulfan

Properties of Chalcogen–Chalcogen Bonds, XVII [1] . – Di‐and Trisulfanes with Sterically Congested Alkyl Substituents: The First trans 1‐Dialkyldisulfane Bis[tris(trimethylsilyl)methyl]trisulfane ( 1 ) is obtained from tris(trimethylsilyl)methyllithium and sulfur with subsequent oxidation by oxygen or from tris(trimethylsily)methanethiol with sulfur dichloride. The solid trisulfane contains a transoid (helical) CS–SS–C backbone without severe distortion from steric strain. Desulfuration of the byproduct bis[tris(trimethylsilyl)methyl]tetrasulfane ( 2 ) with mercury provides 1 , but further desulfuration of 1 to bis[tris(trimethylsilyl)1‐methyl]disulfane ( 3 ) has not been achieved. 3 was isolated after oxidation of lithium tris(trimethylsilyl)methanethiolate with bromine. 3 contains a trans 1‐CS–SC moiety with an unusually long SS bond (210–211 pm). The less crowded bis(triphenylmethyl)disulfane ( 4 ) contains a “normal” CS–SC moiety with anticlinal conformation (torsion angle – 110°).