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

• Published in: Science (American Association for the Advancement of Science) Vol. 340; no. 6139; pp. 1434 - 1437
• Main Authors: de Oteyza, Dimas G., Gorman, Patrick, Chen, Yen-Chia, Wickenburg, Sebastian, Riss, Alexander, Mowbray, Duncan J., Etkin, Grisha, Pedramrazi, Zahra, Tsai, Hsin-Zon, Rubio, Angel, Crommie, Michael F., Fischer, Felix R.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 21.06.2013; The American Association for the Advancement of Science
• Subjects: Annealing; Atomic force microscopes; Atomic force microscopy; Atoms; Chemical bonding; Chemical reactions; Chemistry; Cobalt; Covalent bonds; Enediynes; Exact sciences and technology; Imaging; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Medical imaging; Molecular structure; Molecules; Online; Organic Chemistry; Physics; Reactants; Scanning probe microscopes, components and techniques; Atomic force microscopy; Cyclization; Reaction mechanism; Diynic compound; Imagery; Ethylenic compound; Covalent bonds
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1238187

Observing the intricate chemical transformation of an individual molecule as it undergoes a complex reaction is a long-standing 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. We used noncontact atomic force microscopy to investigate reaction-induced changes in the detailed internal bond structure of individual oligo-(phenylene-1, 2-ethynylenes) on a (100) oriented silver surface as they underwent a series of cyclization processes. Our images reveal the complex surface reaction mechanisms underlying thermally induced cyclization cascades of enediynes. Calculations using ab initio density functional theory provide additional support for the proposed reaction pathways.