PHOTOINDUCED DOUBLE PROTON-TRANSFER IN A MODEL HYDROGEN-BONDED BASE PAIR - THEORETICAL-STUDY

A theoretical study of the 7-azaindole dimer confirms the photoinduced biprotonic transfer mechanism in the first (π, π*) excited singlet state. Emission is forbidden from the first excited singlet state (Ag) of the normal form and it is allowed from the same state (Bu) of a tautomeric form. Proton transfer depends very strongly on the distance between the two monomer molecules, and extension of this mechanism to explain U.V. induced mutation in DNA is conditioned to the possibility of its basis attaining the optimal separation. © 1979.