Realization of a four-step molecular switch in scanning tunneling microscope manipulation of single chlorophyll-a molecules

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 CH3 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.

[1]  Scanning tunneling microscopy single atom/molecule manipulation and its application to nanoscience and technology , 2005, cond-mat/0506038.

[2]  Kai-Felix Braun,et al.  Single-Atom Extraction by Scanning Tunneling Microscope Tip Crash and Nanoscale Surface Engineering , 2004 .

[3]  M. Crommie,et al.  Controlled Atomic Doping of a Single C60 Molecule , 2004, Science.

[4]  G. Dujardin,et al.  Picometer-Scale Electronic Control of Molecular Dynamics Inside a Single Molecule , 2005, Science.

[5]  Cees Otto,et al.  The native architecture of a photosynthetic membrane , 2004, Nature.

[6]  J. W. Gadzuk.  Resonance-assisted, hot-electron-induced desorption , 1995 .

[7]  J. Hollas.  Basic Atomic and Molecular Spectroscopy , 2002 .

[8]  J. Linnanto,et al.  Spectroscopic properties of Mg-chlorin, Mg-porphin and chlorophylls a, b, c1, c2, c3 and d studied by semi-empirical and ab initio MO/CI methods , 2000 .

[9]  D. Eigler,et al.  Positioning single atoms with a scanning tunnelling microscope , 1990, Nature.

[10]  K. Rieder,et al.  Selective bond breaking of single iodobenzene molecules with a scanning tunneling microscope tip , 2003 .

[11]  B. Lundqvist,et al.  Single-Molecule Dissociation by Tunneling Electrons , 1997 .

[12]  Nikolai Lebedev,et al.  Integration of Photosynthetic Protein Molecular Complexes in Solid-State Electronic Devices , 2004 .

[13]  R. Leblanc,et al.  Chlorophyll a dimer: a possible primary electron donor for the photosystem II. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[14]  Nathan Nelson,et al.  Crystal structure of plant photosystem I , 2003, Nature.

[15]  N. Isaacs,et al.  Crystal Structure of the RC-LH1 Core Complex from Rhodopseudomonas palustris , 2003, Science.

[16]  Jascha Repp,et al.  Controlling the Charge State of Individual Gold Adatoms , 2004, Science.

[17]  Zhenfeng Liu,et al.  Crystal structure of spinach major light-harvesting complex at 2.72 Å resolution , 2004, Nature.

[18]  G. Nazin,et al.  Mechanisms of reversible conformational transitions in a single molecule. , 2004, Physical review letters.

[19]  Larry A. Nagahara,et al.  A Bond-Fluctuation Mechanism for Stochastic Switching in Wired Molecules , 2003, Science.

[20]  Jason D. Monnell,et al.  Conductance Switching in Single Molecules Through Conformational Changes , 2001, Science.

[21]  C. Bauer,et al.  Molecular evidence for the early evolution of photosynthesis. , 2000, Science.

[22]  N. Lorente,et al.  Selectivity in vibrationally mediated single-molecule chemistry , 2003, Nature.

[23]  Francesca Moresco,et al.  Scanning tunneling microscopy experiments on single molecular landers. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[24]  W. Lee,et al.  Photoelectrical properties of molecular layer consisting of chlorophyll a∕ferredoxin heterostructure , 2004 .