J-type aggregation and thermochromic behavior of a schiff base in solution: Role of keto-enol tautomerization.

In present work, we have been investigated the thermochromism, keto-enol tautomerization, J-type aggregation and aggregation induced enhanced fluorescence (AIEF) in a single schiff base molecule (HNBzP) along with excited state intramolecular proton transfer (ESIPT) process. It is observed that keto-enol tautomerization plays an important role on thermochromism, J-type aggregation and aggregation induced enhanced fluorescence (AIEF) process in solution. From UV-Vis and fluorescence studies, J-type aggregation is observed and shows the aggregation induce enhanced fluorescence (AIEF) behaviour in solusion. The excited state intramolecular proton transfer (ESIPT) process is investigated in different solvents. Optimized geometry and electronic properties are calculated by DFT method for better understanding at molecular level.