10.1021/ja045936c.s001
Massimo Boiocchi
Massimo
Boiocchi
Laura Del Boca
Laura
Del Boca
David Esteban Gómez
David Esteban
Gómez
Luigi Fabbrizzi
Luigi
Fabbrizzi
Maurizio Licchelli
Maurizio
Licchelli
Enrico Monzani
Enrico
Monzani
Nature of Urea−Fluoride Interaction: Incipient and Definitive
Proton Transfer
American Chemical Society
2004
Bu
urea deprotonation
tetrabutylammonium salt
CH 3 COO
H 2 PO 4
stability decreases
C 6 H 5 COO
formation
HF 2
HSO 4
HCO
MeCN solution
2004-12-22 00:00:00
Dataset
https://acs.figshare.com/articles/dataset/Nature_of_Urea_Fluoride_Interaction_Incipient_and_Definitive_Proton_Transfer/3311230
1,3-bis(4-nitrophenyl)urea (<b>1</b>) interacts through hydrogen bonding with a variety of oxoanions in
an MeCN solution to give bright yellow 1:1 complexes, whose stability decreases with the decreasing basicity
of the anion (CH<sub>3</sub>COO<sup>-</sup> > C<sub>6</sub>H<sub>5</sub>COO<sup>-</sup> > H<sub>2</sub>PO<sub>4</sub><sup>-</sup> > NO<sub>2</sub><sup>-</sup> > HSO<sub>4</sub><sup>-</sup> > NO<sub>3</sub><sup>-</sup>). The [Bu<sub>4</sub>N][<b>1</b>·CH<sub>3</sub>COO]
complex salt has been isolated as a crystalline solid and its molecular structure determined, showing the
formation of a discrete adduct held together by two N−H···O hydrogen bonds of moderate strength. On
the other hand, the F<sup>-</sup> ion first establishes a hydrogen-bonding interaction with <b>1</b> to give the most stable
1:1 complex, and then on addition of a second equivalent, induces urea deprotonation, due to the formation
of HF<sub>2</sub><sup>-</sup>. The orange-red deprotonated urea solution uptakes carbon dioxide from air to give the
tetrabutylammonium salt of the hydrogencarbonate H-bond complex, [Bu<sub>4</sub>N][<b>1</b>·HCO<sub>3</sub>], whose crystal and
molecular structures have been determined.