1.
J Phys Chem A
; 117(51): 13976-87, 2013 Dec 27.
Artigo
em Inglês
| MEDLINE
| ID: mdl-24299203
RESUMO
We show computational evidence that ground-state moderately strong hydroxyarenes (Ar-OH, pKa â¼ 0) dissociate by forming an ion-pair intermediate that lives for 3-5 ps. The concentration of this intermediate is approximately 2 times smaller than that of the un-ionized acid at pH â¼ 0.6 and is characterized by average C-O bond lengths (1.30 Å) that are intermediate between those of un-ionized (1.29 Å) and fully dissociated (1.34 Å) species. During the lifetime of the ion-pair intermediate the excess proton fluctuates between the oxygen atom of the phenolic moiety and those of water molecules in the first and second solvation shells on a subpicosecond time scale (â¼100-300 fs).