TY - JOUR
T1 - Tautomerism in porphycenes
T2 - Analysis of rate-affecting factors
AU - Ciąćka, Piotr
AU - Fita, Piotr
AU - Listkowski, Arkadiusz
AU - Kijak, Michał
AU - Nonell, Santi
AU - Kuzuhara, Daiki
AU - Yamada, Hiroko
AU - Radzewicz, Czesław
AU - Waluk, Jacek
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2015/2/12
Y1 - 2015/2/12
N2 - Double hydrogen transfer occurring in both ground and the lowest electronically excited singlet states was studied for a series of 19 differently substituted porphycenes. The rates of tautomerization have been determined using femtosecond pump-probe spectroscopy with polarized light. The values vary by over 3 orders of magnitude, suggesting the importance of tunneling. Good correlation exists between the values of the rates and the parameters characterizing the strength of two intramolecular hydrogen bonds: proton NMR shift, distance between the hydrogen-bonded nitrogen atoms, and the NH stretching frequency. While hydrogen-bond strength is the main factor determining the rate of double hydrogen transfer, other factors, such as static and dynamic symmetry breaking and the population of low-frequency vibrations also have to be taken into account.
AB - Double hydrogen transfer occurring in both ground and the lowest electronically excited singlet states was studied for a series of 19 differently substituted porphycenes. The rates of tautomerization have been determined using femtosecond pump-probe spectroscopy with polarized light. The values vary by over 3 orders of magnitude, suggesting the importance of tunneling. Good correlation exists between the values of the rates and the parameters characterizing the strength of two intramolecular hydrogen bonds: proton NMR shift, distance between the hydrogen-bonded nitrogen atoms, and the NH stretching frequency. While hydrogen-bond strength is the main factor determining the rate of double hydrogen transfer, other factors, such as static and dynamic symmetry breaking and the population of low-frequency vibrations also have to be taken into account.
UR - http://www.scopus.com/inward/record.url?scp=84922818874&partnerID=8YFLogxK
U2 - 10.1021/jp506150r
DO - 10.1021/jp506150r
M3 - Article
AN - SCOPUS:84922818874
SN - 1520-6106
VL - 119
SP - 2292
EP - 2301
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 6
ER -