Femtosecond emission study of H-atom transfer reaction dynamics in a new system with an internal H-bond

We present ultrafast emission studies of a new molecule, which undergoes a photoinduced H-atom transfer reaction in solution. We discuss the nature of the observed elementary fluorescence dynamics having time constant of 40-100 fs, ∼600 fs and 20 ps. These times due to in-plane and out-of-plane motions of the formed keto-type (K) phototautomer, strongly decrease its emission intensity having a lifetime of 20 ps. Fs-anisotropy emission decay supports the assignments.