Accumulated proton-donating ability of solvent molecules in proton transfer.
Solvent-inventory experiments on the excited-state proton transfer of a 7-hydroxyquinoline molecule complexed cyclically with two alcohol molecules in the host medium of n-alkane have been carried out with various combinations of alcohols having different proton-donating abilities. Alcohol molecules participating in the hydrogen-bonded chain of the cyclic complex accelerate proton transfer in a concerted fashion by accumulating their proton-donating abilities. The rate-determining deprotonation of the alcohol molecule hydrogen-bonded directly to the imino group of 7-hydroxyquinoline is stimulated by the push-ahead effect of the next alcohol molecule in the hydrogen-bonded chain. Our results provide a clue at the level of molecules on the fundamental mechanistic elucidation of proton transport occurring through a proton wire consisting of diverse amino acids.
Park
Sun-Young
SY
School of Chemistry, Seoul National University, NS60, Seoul 151-742, Korea.
Jang
Du-Jeon
DJ
D000438:Alcohols / Q000737:chemistry; D006860:Hydrogen Bonding; D007700:Kinetics; D011522:Protons; D011804:Quinolines / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*
D000438:Alcohols; D011522:Protons; D011804:Quinolines; D012997:Solvents; C037219:quinoline