Chemists change the bonds between atoms in a single molecule for the first time

Chemists change the bonds between atoms in a single molecule for the first time

Images of individual molecules obtained by high-resolution atomic force microscopy. Voltage pulses applied from the tip of a scanning probe microscope can selectively and reversibly transform the molecular structure in the center into the structure on the right or left. Credit: Leo Gross/IBM

A research team from IBM Research Europe, the Universidade de Santiago de Compostela and the University of Regensburg has changed the bonds between the atoms in a single molecule for the first time. In her article published in the journal Science, the group describes their method and possible applications for it. Igor Alabugin and Chaowei Hu published a Perspective article in the same issue of the magazine, outlining the team’s work.

The current method of making complex molecules, or molecular devices, is generally quite challenging, Alagugin and Chaowei note – they liken it to tossing a box of Legos into a washing machine and hoping some useful compounds are made. In this new attempt, the research team greatly simplified this work by using a scanning tunneling microscope (STM) to break the bonds in a molecule and then adapting the molecule by creating new bonds — one chemistry first.

Schematic representation of the tip-induced reactions. Various molecular transformations are triggered in a targeted manner by voltage pulses at the tip of a scanning probe microscope. The color of the arrows indicates the value of the voltage pulses used to selectively trigger the various transformations. Source: Florian Albrecht/IBM

The team’s work consisted of placing a sample material in a scanning tunneling microscope and then using a very small amount of current to break certain bonds. More specifically, they started by pulling four chlorine atoms from the core of a tetracycle to use as their parent molecule. They then moved the tip of the STM to a C-CI connection and then electrocuted the connection. This with the other C-CI and CC pairs resulted in the formation of a diradical, leaving six electrons free for other bond formation. In an attempt to create a new molecule, the team then used the free electrons (and a dose of high voltage) to form diagonal C-C bonds, resulting in the creation of a bent alkyne. In another example, they applied a low voltage dose to create a cyclobutadiene ring.

The researchers note that their work was made possible by the development of ultra-high-precision tunneling technology developed by a team led by Gerd Binnig and Heinrich Rohrer, both at IBM’s Zurich lab. They suggest their technique could be used to better understand redox chemistry and create new types of molecules.

Bond-selective reactions observed in molecular collisions

More information:
Florian Albrecht et al, Selectivity in Single Molecule Reactions by Tip-Induced Redox Chemistry, Science (2022). DOI: 10.1126/science.abo6471

Igor Alabugin et al, A Swiss army knife for surface chemistry, Science (2022). DOI: 10.1126/science.abq2622

© 2022 Science X Network

Citation: Chemists Change Bonds Between Atoms in a Single Molecule for the First Time (2022 July 15) Retrieved July 17, 2022 from

This document is protected by copyright. Except for fair trade for the purpose of private study or research, no part may be reproduced without written permission. The content is for informational purposes only.

Leave a Comment

%d bloggers like this: