Ultrafast deactivation processes in aminopyridine clusters: excitation energy dependence and isotope effects.
Fast excited-state relaxation in H-bonded aminopyridine clusters occurs via hydrogen transfer in the excited state. We used femtosecond pump-probe spectroscopy to characterize the excited-state reaction coordinate. Considerable isotope effects for partially deuterated clusters indicate that H-transfer is the rate-limiting step and validate ab initio calculations in the literature. A nonmonotonous dependence on the excitation energy, however, disagrees with the picture of a simple barrier along the reaction coordinate. An aminopyridine dimer serves as a model for Watson-Crick base pairs, where similar reactions have been predicted by theory.
Samoylova
E
E
Contribution from the Max Born Institute, Max-Born-Str. 2A, D-12489, Berlin-Adlershof, Germany.
Smith
V R
VR
Ritze
H-H
HH
Radloff
W
W
Kabelac
M
M
Schultz
T
T
D000631:Aminopyridines / Q000737:chemistry*; D020029:Base Pairing; D003903:Deuterium / Q000737:chemistry*; D019281:Dimerization; D006859:Hydrogen / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D013053:Spectrophotometry; D013816:Thermodynamics
D000631:Aminopyridines; D006859:Hydrogen; D003903:Deuterium