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Measuring the mechanical properties of molecular conformers
S P Jarvis1, S Taylor1, J D Baran2
1School of Physics &Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
Nature Communications
|September 22, 2015
Summary
Molecular conformation significantly impacts manipulation forces. Differences in potential energy surfaces affect single molecule positioning, demonstrating how flexibility influences mechanical responses in porphyrins and other molecules.
Area of Science:
- Surface science
- Chemical physics
- Nanotechnology
Background:
- Scanning probe microscopy enables atomic-scale manipulation of single molecules.
- The influence of molecular conformation on manipulation forces remains largely unexplored.
Purpose of the Study:
- To investigate how molecular conformation affects the forces required for single molecule manipulation.
- To compare the mechanochemical response of different conformers of tetra(4-bromophenyl)porphyrin.
Main Methods:
- Non-contact atomic force microscopy (nc-AFM) was employed for single molecule manipulation.
- Dispersion-corrected density functional theory (DFT) calculations were used to interpret experimental findings.
Main Results:
- A significant difference in lateral manipulation forces was observed between two tetra(4-bromophenyl)porphyrin conformers.
- Despite similar adsorption properties, one conformer's positioning was prohibited while the other was successfully manipulated.
- DFT calculations revealed distinct diffusion barriers for each conformer, explaining the observed manipulation differences.
Conclusions:
- Conformational variations critically alter the mechanical response of molecules during scanning probe manipulation.
- These findings have implications for understanding and controlling the behavior of flexible molecules at the nanoscale.
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