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Gas Phase Structures of Peroxides: Experiments and Computational Problems
Author(s) -
Oberhammer Heinz
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402700
Subject(s) - dihedral angle , bond length , chemistry , gas phase , molecular geometry , crystallography , phase (matter) , quantum chemistry , computational chemistry , rotational spectroscopy , diffraction , molecule , hydrogen bond , physics , organic chemistry , crystal structure , optics , supramolecular chemistry
Gas‐phase structures of several organic and inorganic peroxides X‐O‐O‐X and X‐O‐O‐X′, which have been determined experimentally by gas electron diffraction and/or microwave spectroscopy, are discussed. The OO bond length in these peroxides varies from 1.481(8) Å in Me 3 SiOOSiMe 3 to 1.214(2) Å in FOOF and the dihedral angle ϕ (XO‐OX) between 0° in HC(O)O‐OH and near 180° in Bu t O‐OBu t . Some of the peroxides cause problems for quantum chemistry, since several computational methods fail to reproduce the experimental structures. Extreme examples are MeO‐OMe and FO‐OF. In the case of MeO‐OMe only about half of the more than 100 computational methods reported in the literature reproduce the experimentally determined double‐minimum shape of the torsional potential around the OO bond correctly. For FO‐OF only a small number of close to 200 computational methods reproduce the OO and OF bond lengths better than ±0.02 Å.