Repozytorium
Wyszukaj
Kolekcje
Inne
Hydrogen detachment driven by a repulsive 1πσ* state - an electron localization function study of 3-amino-1,2,4-triazole.
Autorzy
Rok wydania
2018
Czasopismo
Physical Chemistry Chemical Physics
Numer woluminu
20
Strony
5210-5216
DOI
10.1039/c7cp06744e
Kolekcja
Język
Angielski
Typ publikacji
Artykuł
Electron localization function analysis reveals the details of a charge induced hydrogen detachment
mechanism of 3-amino-1,2,4-triazole, identified recently to be responsible for phototautomerization of
the molecule. In this process vertical excitation to the 1ps* state is followed by the barrier-less migration
of a H atom along the N–H bond toward the conical intersection with the S0 ground state. The most
striking feature revealed for the 1ps* state is partial ejection of s* electrons outside the molecule, even
beyond the NH group, at the Franck–Condon point. Further gradual spatial localization of the electron
around the proton moving along the N–H stretching coordinate gives a plausible explanation for the
repulsive character of the 1ps* potential energy surface with the proton wading through the region of
space where some negative charge is accumulated (‘a virtual acceptor’), dragging some electron density.
This mechanism resembles the one postulated for the hydrogen transfer from a donor molecule (D–H)
to an acceptor one (A) in a class of vertically excited molecules with a preexisting inter- or intramolecular
D–H A motif, even though the acceptor molecule is absent. The present analysis demonstrates
also that the bond evolution and changes in the electron density along the excited state reaction
path can be effectively studied with the use of an electron localization function.
Adres publiczny
http://dx.doi.org/10.1039/c7cp06744e