New analytical method reveals what happens inside tiny molecular frameworks

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Tiny magnetic probes can be used to investigate the chemical forces at work inside the pores of molecular framework compounds, but until now, this had only been possible to a limited degree. A new method developed by a team at Martin Luther University Halle-Wittenberg (MLU) could help to better understand the properties of these materials and control these properties in the future.

The study is published in the journal Small. Covalent organic frameworks (COFs) are regarded as promising materials for a range of applications. Essentially, they are porous, crystalline compounds.

Their regular, tiny pores are what make them special. "These pores make COFs suitable for a range of applications. They could be used to filter pollutants out of water or as catalysts for chemical reactions," says Simona Bassoli from the Institute of Chemistry at MLU.

A prerequisite for their application is that the chemical environment inside the pores can be specifically fine-tuned. And to do that, one must first be able to measure it precisely. However, doing exact measurements is a problem: Because the pores are only a few nanometers in size, optical methods fall short.

And there is a limit to what other direct measurement methods can achieve. The standard method currently being used measures how many nitrogen molecules become adsorbed in the pores at about -196°C. "At these temperatures, all molecular motion freezes.

You get a snapshot without any information about chemical interactions or important characterization of the pores' properties," adds Sebastian Michler from the Institute of Chemistry at MLU. The idea for the new research project emerged from the incubator program of the "BEAM" Research Training Group, where Bassoli and Michler are pursuing their doctorates. As part of this program, doctoral students learn how to apply for, plan and carry out their own research projects independently.