Acidity of Benzoic Acids Bearing the (CO)(5)Cr = CN(CH3)(2) Group

Benzoic acids 2a and 2b, bearing the (CO)(5)Cr=CN(CH3)(2) group in the p- and m-position, and the corresponding benzoic acids 2c and 2d, in which the rotation of the aminocarbene moiety was blocked by the presence of a methyl group, were prepared together with the corresponding N,N-dimethylamido aci...

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Bibliographic Details
Published inOrganometallics Vol. 29; no. 18; pp. 4135 - 4138
Main Authors Parik, Patrik, Kulhanek, Jiri, Ludwig, Miroslav, Wagner, Roman, Rotrekl, Ivan, Drahonovsky, Dusan, Meca, Ludek, Smidkova, Marketa, Tobrman, Tomas, Dvorak, Dalimil
Format Journal Article
LanguageEnglish
Published WASHINGTON Amer Chemical Soc 27.09.2010
Subjects
Chemistry
Chemistry, Inorganic & Nuclear
Chemistry, Organic
Physical Sciences
Science & Technology
HYDROGEN
DISSOCIATION
AMINOCARBENE COMPLEXES
CARBON-ATOM
WEAK ACIDS
ACETONITRILE
PROTON-TRANSFER
CHROMIUM
SOLVENT
METAL-CARBENE COMPLEXES
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Summary:Benzoic acids 2a and 2b, bearing the (CO)(5)Cr=CN(CH3)(2) group in the p- and m-position, and the corresponding benzoic acids 2c and 2d, in which the rotation of the aminocarbene moiety was blocked by the presence of a methyl group, were prepared together with the corresponding N,N-dimethylamido acids 3a-d. The measurement of pK(a) values in EtOH and DMF revealed that the (CO)(5)Cr = CN(CH3)(2) group is a very weak electron acceptor (sigma(p) = 0; sigma(m) = 0.14). The restriction of the rotation of the aminocarbene moiety did not significantly influence its electronic properties. The obtained results are in accordance with earlier findings that the relatively strong acidity of carbene complexes bearing hydrogens at the alpha-position to the carbene atom is due to the resonance stabilization of the anion.
ISSN:0276-7333
DOI:10.1021/om100608x