Hydrogen bonds directly detected for the first time

May 12, 2017, University of Basel
A hydrogen bond forms between a propellane (lower molecule) and the carbon monoxide functionalized tip of an atomic force microscope. The measured forces and the distance between the oxygen atom at the AFM tip and the propellane's hydrogen atoms correspond precisely to the calculations. Credit: University of Basel, Department of Physics

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel's Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are connected to one another via , an interaction known as hydrogen bonding. These interactions play an important role in nature, because they are responsible for specific properties of proteins or nucleic acids and, for example, also ensure that water has a high boiling temperature.

To date, it has not been possible to conduct a spectroscopic or electron microscopic analysis of hydrogen and the in single molecules, and investigations using have also not yielded any clear results.

Dr. Shigeki Kawai, from Professor Ernst Meyer's team at the Swiss Nanoscience Institute and the Department of Physics at the University of Basel, has now succeeded in using a high-resolution atomic force microscope to study hydrogen atoms in individual cyclic hydrocarbon compounds.

Choosing the right molecules for a clear view

In close collaboration with colleagues from Japan, the researchers selected compounds whose configuration resembles that of a propeller. These propellanes arrange themselves on a surface in such a way that two hydrogen atoms always point upwards. If the tip of the atomic force microscope, which is functionalized with carbon monoxide, is brought close enough to these hydrogen atoms, hydrogen bonds are formed that can then be examined.

Hydrogen bonds are much weaker than chemical bonds, but stronger than intermolecular van der Waals interactions. The measured forces and distances between the oxygen atoms at the tip of the and the propellane's hydrogen atoms correspond very well to the calculations performed by Prof. Adam S. Foster from Aalto University in Finland. They show that the interaction clearly involves hydrogen bonds. The measurements mean that the much weaker van der Waals forces and the stronger ionic bonds can be excluded.

With this study, the researchers from the University of Basel's Swiss Nanoscience Institute network have opened up new ways to identify three-dimensional molecules such as or polymers via observation of .

Explore further: On-surface chemistry leads to novel products

More information: "Direct quantitative measurement of the C=O⋅⋅⋅H–C bond by atomic force microscopy" Science Advances (2017). DOI: 10.1126/sciadv.1603258 , http://advances.sciencemag.org/content/3/5/e1603258

Related Stories

On-surface chemistry leads to novel products

September 13, 2016

On-surface chemical reactions can lead to novel chemical compounds not yet synthesized by solution chemistry. The first-step, second-step, and third-step products can be analyzed in detail using a high-resolution atomic force ...

Argon is not the 'dope' for metallic hydrogen

March 23, 2017

Hydrogen is both the simplest and the most-abundant element in the universe, so studying it can teach scientists about the essence of matter. And yet there are still many hydrogen secrets to unlock, including how best to ...

Researchers create image of weak hydrogen bond using AFM

October 1, 2013

(Phys.org) —Researchers at China's National Center for Nanoscience and Technology and Renmin University have used Atomic Force Microscopy (AFM) to create an image of the weak hydrogen bonds present in a molecule. In their ...

Recommended for you

How the building blocks of life may form in space

April 25, 2018

In a laboratory experiment that mimics astrophysical conditions, with cryogenic temperatures in an ultrahigh vacuum, scientists used an electron gun to irradiate thin sheets of ice covered in basic molecules of methane, ammonia ...

Why we need erasable MRI scans

April 25, 2018

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is through the use of contrast agents—magnetic dyes injected into ...

Research gives new ray of hope for solar fuel

April 24, 2018

A team of Renewable Energy experts from the University of Exeter has pioneered a new technique to produce hydrogen from sunlight to create a clean, cheap and widely-available fuel.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

swordsman
not rated yet May 16, 2017
So what is it? What is the force level, and how does it vary from Van der Waal force??

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.