Direct Imaging of Covalent Bond Structure in Single-Molecule Chemical Reactions

ROM 2013-10
Author: Corresponding Author: Michael F. Crommie1,4, //
Institute: (1) Department of Physics, University of California at Berkeley, Berkeley, USA. (2) Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, San Sebastián, Spain. (3) Department of Chemistry, University of California at Berkeley, Berkeley, USA. (4) Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, USA. (5) Donostia International Physics Center (DIPC), San Sebastián, Spain. (6) Nano-Bio Spectroscopy Group and ETSF Scientific Develoment Center, Dpto. de Física de Materiales, Universidad del País Vasco UPV/EHU, San Sebastián, Spain.
Publication: Science 2013, 340, 1434-1437 /
Instrument: LT STM

Observing the intricate chemical transformation of an individual molecule as it undergoes a complex reaction is a longstanding challenge in molecular imaging. Advances in scanning probe microscopy now provide the tools to visualize not only the frontier orbitals of chemical reaction partners and products, but their internal covalent bond configurations as well. Here we demonstrate the use of noncontact atomic force microscopy to investigate reaction-induced changes in the detailed internal bond structure of individual oligo-(phenylene-1,2-ethynylenes) on Ag(100) as they undergo a series of cyclization processes. Our images reveal the complex surface reaction mechanisms underlying thermally induced cyclization cascades of enediynes. Additional evidence for the proposed reaction pathways is obtained using ab initio density functional theory.

• Authors
Dimas G. de Oteyza1,2, Patrick Gorman3, Yen-Chia Chen1,4, Sebastian Wickenburg1,4, Alexander Riss1, Duncan J. Mowbray5,6, Grisha Etkin3, Zahra Pedramrazi1,Hsin-Zon Tsai1, Angel Rubio2,5,6, Michael F. Crommie1,4, Felix R. Fischer3,4