Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9756932 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2005 | 8 Pages |
Abstract
Monomeric acetic acid MA and propionic acid MP were isolated in argon matrices at 10 K by using a pulse deposition technique. The dimerization of the monomers was induced by warming the matrices from 10 to 40 K. Under these conditions the diffusion of small trapped molecules is rapid and the dimerization could be monitored directly by IR spectroscopy. Both carboxylic acids form the symmetrical dimers B with two strong COâ¯HO hydrogen bridges as the thermodynamically most stable dimers. With acetic acid a less stable dimer AA could be obtained if high concentrations of acetic acid in argon were used during the deposition of the matrix. On annealing this dimer rearranges to the more stable BA. In contrast, propionic acid does not form a corresponding less stable dimer under any experimental condition. These observations are rationalized on the basis of DFT and ab initio calculations.
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Authors
Wolfram Sander, Marcus Gantenberg,