Importantly, as shown in Figure , the proton transfer is highly dynamic and different event of back-and forward-transfer may be observed. However, and also considering the involved time-scale the tautomerization happens largely on the singlet manifold, and no direct correlation with ISC efficiency can be pointed out. This observation also represents a striking difference with the isolated system, for which the direct tautomerization was one of the driving forces leading to the triplet population. .