Molecular swarm rearranges surface structures atom by atom
New study: Nano-scientists develop a molecular tool to change the
structure of a metal surface

Date:
October 7, 2020
Source:
University of Mu"nster
Summary:
Researchers have now developed a molecular tool which makes it
possible, at the atomic level, to change the structure of a metal
surface. The restructuring of the surface by individual molecules
- so-called N- heterocyclic carbenes - takes place similar to
a zipper.



FULL STORY ==========================================================================
The surface of metals plays a key role in many technologically relevant
areas, such as catalysis, sensor technology and battery research. For
example, the large-scale production of many chemical compounds takes place
on metal surfaces, whose atomic structure determines if and how molecules
react with one another. At the same time, the surface structure of a metal influences its electronic properties. This is particularly important
for the efficiency of electronic components in batteries. Researchers
worldwide are therefore working intensively on developing new kinds of
methods to tailor the structure of metal surfaces at the atomic level.


==========================================================================
A team of researchers at the University of Mu"nster, consisting of
physicists and chemists and led by Dr. Saeed Amirjalayer, has now
developed a molecular tool which makes it possible, at the atomic level,
to change the structure of a metal surface. Using computer simulations,
it was possible to predict that the restructuring of the surface by
individual molecules -- so-called N- heterocyclic carbenes -- takes place similar to a zipper. During the process, at least two carbene molecules cooperate to rearrange the structure of the surface atom by atom. The researchers could experimentally confirm, as part of the study, this "zipper-type" mechanism in which the carbene molecules work together
on the gold surface to join two rows of gold atoms into one row. The
results of the work have been published in the journal Angewandte Chemie International Edition.

In earlier studies the researchers from Mu"nster had shown the high
stability and mobility of carbene molecules at the gold surface. However,
no specific change of the surface structure induced by the molecules could previously be demonstrated. In their latest study, the researchers proved
for the first time that the structure of a gold surface is modified very precisely as a result of cooperation between the carbene molecules. "The carbene molecules behave like a molecular swarm -- in other words,
they work together as a group to change the long-range structure of the surface," Saeed Amirjalayer explains. "Based on the 'zipper' principle,
the surface atoms are systematically rearranged, and, after this
process, the molecules can be removed from the surface." The new method
makes it possible to develop new materials with specific chemical and
physical properties -- entirely without macroscopic tools. "In industrial applications often macroscopic tools, such presses or rollers, are used," Amirjalayer continues. "In biology, these tasks are undertaken by certain molecules. Our work shows a promising class of synthesized molecules which
uses a similar approach to modify the surface." The team of researchers
hopes that their method will be used in future to develop for examples
new types of electrode or to optimize chemical reactions on surfaces.


========================================================================== Story Source: Materials provided by University_of_Mu"nster. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Saeed Amirjalayer, Anne Bakker, Matthias Freitag, Frank Glorius,
Harald
Fuchs. Cooperation of N‐Heterocyclic Carbenes on a Gold
Surface.

Angewandte Chemie International Edition, 2020; DOI: 10.1002/
anie.202010634 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201007123048.htm

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