Metal Assisted Synthesis of Cationic Sulfidobismuth Cubanes in Ionic Liquids

Abstract

Invited for this month's cover is the group of Michael Ruck at the Technische Universität Dresden (Germany). The cover picture shows the spiro ‐dicubane Bi₇S₈ ⁵⁺ in the center, accompanied by two Bi₄S₄ ⁴⁺ hetero‐cubanes on both sides, which are shown along their threefold axis. These sulfidobismuth polycations were isolated in salts with [AlCl₄]^– and [S(AlCl₃)₃]^2– anions. The starting material was Bi₂S₃, which is generally hard to dissolve but can easily be activated under ionothermal conditions. Moreover, the presence of noble metal ions, such as Ag⁺, Au⁺ or Pt²⁺, played a crucial role for the formation of those compounds. This research was performed in the framework of the Priority Program SPP 1708 “Material Synthesis Near Room Temperature” of the German Research Council (DFG). Read the full text of their Full Paper at 10.1002/open.202000246.

“…This study emphasizes the importance of various reaction parameters on the outcome of syntheses in ionic liquids…” Find out more about the story behind the front cover research at 10.1002/open.202000246.

What is the most significant result of this study?

This study emphasizes the importance of various reaction parameters on the outcome of syntheses in ionic liquids. In particular, we demonstrate that traces of auxiliaries, here noble metal cations, can strongly influence the interactions in the solution and thereby the crystallization of specific products.

Who designed the cover?

The cover was designed by Maximilian Knies and Michael Ruck and realized by Maximilian Knies.

Did you expect a very different outcome? If so, what was your initial guess?

We originally targeted the formation of compounds containing Au⁺ or Pt²⁺ cations and were surprised that they acted as structure directing agents, even in almost catalytic concentrations.

What prompted you to investigate this topic/problem?

Ionic liquids have been gathering much attention in the past decades due to their unique solvent properties. They are able to dissolve otherwise nearly insoluble compounds at moderate temperatures and promote reactions, which need harsh conditions in conventional syntheses. This allows for an increase in resource efficiency, which is key in the effort towards a more sustainable chemistry.

Is your current research mainly curiosity driven (fundamental) or rather applied?

Our research on the use of ionic liquids (ILs) in inorganic material chemistry is rather fundamental in nature, while its application aspects are the motivation for this. ILs have promising properties in terms of efficient and sustainable synthesis at low temperature and under normal pressure. In addition, they usually ensure high purity of the product. Prior to any technological innovation, the knowledge base must be built up, but we are convinced that industrial applications are within reach.

M. Knies, M. F. Groh, T. Pietsch, M. Lê Anh, M. Ruck, ChemistryOpen 2021, 10, 59.