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Published on: May 27, 2018
Realization of a four-step molecular switch in scanning tunneling microscope manipulation of single chlorophyll-a
1Quantitative Biology Institute, Nanoscale and Quantum Phenomena Institute, and Department of Physics and Astronomy, Ohio University, Athens, OH 45701, USA.
Abstract:
Single chlorophyll-a molecules, a vital resource for the sustenance of life on Earth, have been investigated by using scanning tunneling microscope manipulation and spectroscopy on a gold substrate at 4.6 K. Chlorophyll-a binds on Au(111) via its porphyrin unit while the phytyl-chain is elevated from the surface by the support of four CH(3) groups. By injecting tunneling electrons from the scanning tunneling microscope tip, we are able to bend the phytyl-chain, which enables the switching of four molecular conformations in a controlled manner. Statistical analyses and structural calculations reveal that all reversible switching mechanisms are initiated by a single tunneling-electron energy-transfer process, which induces bond rotation within the phytyl-chain.
