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A. Riss, A. Pérez Paz, S. Wickenburg, H. Tsai, D. De Oteyza, A. Bradley, M. Ugeda, P. Gorman, H. Jung, M. Crommie, A. Rubio, F. Fischer:
"Imaging single-molecule reaction intermediates stabilized by surface dissipation and entropy";
Nature Chemistry, 8 (2016), 678 - 683.

Chemical transformations at the interface between solid/liquid or solid/gaseous phases of matter lie at the heart of key
industrial-scale manufacturing processes. A comprehensive study of the molecular energetics and conformational
dynamics that underlie these transformations is often limited to ensemble-averaging analytical techniques. Here we report
the detailed investigation of a surface-catalysed cross-coupling and sequential cyclization cascade of 1,2-bis(2-ethynyl
phenyl)ethyne on Ag(100). Using non-contact atomic force microscopy, we imaged the single-bond-resolved chemical
structure of transient metastable intermediates. Theoretical simulations indicate that the kinetic stabilization of
experimentally observable intermediates is determined not only by the potential-energy landscape, but also by selective
energy dissipation to the substrate and entropic changes associated with key transformations along the reaction pathway.
The microscopic insights gained here pave the way for the rational design and control of complex organic reactions at the
surface of heterogeneous catalysts.