Heteroboranes are an interesting area of main-group-element chemistry. Their intrinsic electron deficiency results in unique structures, properties, and electron distributions. Carbaboranes have so far drawn most of the research attention in this class of materials, while thiaboranes are less well understood.

Drahomír Hnyk, Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež, Jindřich Fanfrlík, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, and colleagues have investigated thiaboranes more closely. The team tried to react thiaboranes with various compounds, such as carbenes, amines, or methyl iodide, analogous to the area of carbaboranes. They also used density functional theory (DFT) calculations to compute the heat of formation of both known and hypothetical thiaboranes.

The researchers found that icosahedral closo‐1‐SB₁₁H₁₁ reacts with methyl iodide, giving a hexamethylated thiaborane. This type of methylation had so far been unknown in thiaborane chemistry. Based on the calculations, the team also proposes two so far unknown 13‐vertex nido-thiaboranes as promising targets for synthesis.

• Thiaboranes on Both Sides of the Icosahedral Barrier: Retaining and Breaking the Barrier with Carbon Functionalities,
  Josef Holub, Jan Vrána, Aleš Růžička, Zdeňka Růžičková, Jindřich Fanfrlík, Drahomír Hnyk,
  ChemPlusChem 2019.
  https://doi.org/10.1002/cplu.201900115