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Ethers on Si(001): A Prime Example for the Common Ground between Surface Science and Molecular Organic Chemistry
Author(s) -
Pecher Lisa,
Laref Slimane,
Raupach Marc,
Tonner Ralf
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201707428
Subject(s) - chemistry , nucleophile , lewis acids and bases , ether , bond cleavage , ether cleavage , molecule , computational chemistry , reactivity (psychology) , physical organic chemistry , williamson ether synthesis , adsorption , cleavage (geology) , photochemistry , catalysis , organic chemistry , materials science , medicine , alternative medicine , pathology , fracture (geology) , composite material
By using computational chemistry it has been shown that the adsorption of ether molecules on Si(001) under ultrahigh vacuum conditions can be understood with classical concepts of organic chemistry. Detailed analysis of the two‐step reaction mechanism—1) formation of a dative bond between the ether oxygen atom and a Lewis acidic surface atom and 2) nucleophilic attack of a nearby Lewis basic surface atom—shows that it mirrors acid‐catalyzed ether cleavage in solution. The O−Si dative bond is the strongest of its kind, and the reactivity in step 2 defies the Bell–Evans–Polanyi principle. Electron rearrangement during C−O bond cleavage has been visualized with a newly developed method for analyzing bonding, which shows that the mechanism of nucleophilic substitutions on semiconductor surfaces is identical to molecular S N 2 reactions. Our findings illustrate how surface science and molecular chemistry can mutually benefit from each other and unexpected insight can be gained.