%0 Generic %A Boiocchi, Massimo %A Del Boca, Laura %A Gómez, David Esteban %A Fabbrizzi, Luigi %A Licchelli, Maurizio %A Monzani, Enrico %D 2004 %T Nature of Urea−Fluoride Interaction:  Incipient and Definitive Proton Transfer %U https://acs.figshare.com/articles/dataset/Nature_of_Urea_Fluoride_Interaction_Incipient_and_Definitive_Proton_Transfer/3311230 %R 10.1021/ja045936c.s001 %2 https://acs.figshare.com/ndownloader/files/5149963 %K Bu %K urea deprotonation %K tetrabutylammonium salt %K CH 3 COO %K H 2 PO 4 %K stability decreases %K C 6 H 5 COO %K formation %K HF 2 %K HSO 4 %K HCO %K MeCN solution %X 1,3-bis(4-nitrophenyl)urea (1) 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 (CH3COO- > C6H5COO- > H2PO4- > NO2- > HSO4- > NO3-). The [Bu4N][1·CH3COO] 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- ion first establishes a hydrogen-bonding interaction with 1 to give the most stable 1:1 complex, and then on addition of a second equivalent, induces urea deprotonation, due to the formation of HF2-. The orange-red deprotonated urea solution uptakes carbon dioxide from air to give the tetrabutylammonium salt of the hydrogencarbonate H-bond complex, [Bu4N][1·HCO3], whose crystal and molecular structures have been determined. %I ACS Publications