TY - JOUR
T1 - Chemistry
T2 - Sequential proton transfer through water bridges in acid-base reactions
AU - Mohammed, Omar F.
AU - Pines, Dina
AU - Dreyer, Jens
AU - Pines, Ehud
AU - Nibbering, Erik T.J.
PY - 2005/10/7
Y1 - 2005/10/7
N2 - The proton transfer mechanism between aqueous Brønsted acids and bases, forming an encounter pair, has been studied in real time with ultrafast infrared spectroscopy. The transient intermediacy of a hydrated proton, formed by ultrafast dissociation from an optically triggered photoacid proton donor ROH, is implicated by the appearance of an infrared absorption marker band before protonation of the base, B-. Thus, proton exchange between an acid and a base in aqueous solution is shown to proceed by a sequential, von Grotthuss-type, proton-hopping mechanism through water bridges. The spectra suggest a hydronium cation H3O+ structure for the intermediate, stabilized in the Eigen configuration in the ionic complex RO -⋯H3O+⋯B-.
AB - The proton transfer mechanism between aqueous Brønsted acids and bases, forming an encounter pair, has been studied in real time with ultrafast infrared spectroscopy. The transient intermediacy of a hydrated proton, formed by ultrafast dissociation from an optically triggered photoacid proton donor ROH, is implicated by the appearance of an infrared absorption marker band before protonation of the base, B-. Thus, proton exchange between an acid and a base in aqueous solution is shown to proceed by a sequential, von Grotthuss-type, proton-hopping mechanism through water bridges. The spectra suggest a hydronium cation H3O+ structure for the intermediate, stabilized in the Eigen configuration in the ionic complex RO -⋯H3O+⋯B-.
UR - http://www.scopus.com/inward/record.url?scp=26444519205&partnerID=8YFLogxK
U2 - 10.1126/science.1117756
DO - 10.1126/science.1117756
M3 - Article
C2 - 16210532
AN - SCOPUS:26444519205
SN - 0036-8075
VL - 310
SP - 83
EP - 86
JO - Science
JF - Science
IS - 5745
ER -