Bond selectivity in electron-induced reaction due to directed recoil on an anisotropic substrate

• Published in: Nature communications Vol. 7; no. 1; p. 13690
• Main Authors: Anggara, Kelvin, Huang, Kai, Leung, Lydie, Chatterjee, Avisek, Cheng, Fang, Polanyi, John C.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.12.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 639/638/440/950; 639/638/542/968; Adsorption; Catalysis; Humanities and Social Sciences; multidisciplinary; Reagents; Science; Science (multidisciplinary); Singapore
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms13690

Bond-selective reaction is central to heterogeneous catalysis. In heterogeneous catalysis, selectivity is found to depend on the chemical nature and morphology of the substrate. Here, however, we show a high degree of bond selectivity dependent only on adsorbate bond alignment. The system studied is the electron-induced reaction of meta-diiodobenzene physisorbed on Cu(110). Of the adsorbate’s C-I bonds, C-I aligned ‘Along’ the copper row dissociates in 99.3% of the cases giving surface reaction, whereas C-I bond aligned ‘Across’ the rows dissociates in only 0.7% of the cases. A two-electronic-state molecular dynamics model attributes reaction to an initial transition to a repulsive state of an Along C-I, followed by directed recoil of C towards a Cu atom of the same row, forming C-Cu. A similar impulse on an Across C-I gives directed C that, moving across rows, does not encounter a Cu atom and hence exhibits markedly less reaction. The ability to selectively break a chemical bond in a molecule is indispensable to chemical synthesis. Here, the authors show that a hundred-fold bond selectivity can be obtained in electron-induced surface reaction due simply to different bond alignments at the surface.