Eigenschaften von Chalkogen–Chalkogen‐Bindungen, XVII. Di‐und Trisulfane mit sterisch anspruchsvollen Alkyl‐Substituenten: Das erste trans1‐Dialkyldisulfan

Abstract

Properties of Chalcogen–Chalcogen Bonds, XVII[1]. – Di‐and Trisulfanes with Sterically Congested Alkyl Substituents: The First trans1‐DialkyldisulfaneBis[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) CS–SS–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 trans1‐CS–SC moiety with an unusually long SS bond (210–211 pm). The less crowded bis(triphenylmethyl)disulfane (4) contains a “normal” CS–SC moiety with anticlinal conformation (torsion angle – 110°).