Excited State Proton Transfer of Pyranine in different solvent

Abstract

Excited-state proton transfer (ESPT) often occurs in aromatic alcohols. When these molecules are electronically stimulated, a proton can be transferred to a suitable acceptor unit. Due to this photoinduced activity, their acidity rises by several orders of magnitude. In this dissertation, the ESPT behaviour of pyranine, one of the most prevalent photoacids, is examined in several organic solvents, which either enhance or hinder proton transfers. Pyranine is examined using steady-state and timeresolved spectroscopy to establish its identity as photoacid capable of ESPT. We confirm that alcohols' poor proton transfer efficiency hinders ESPT, while water enables it. The efficiency of ESPT is primarily determined by solvent characteristics and hydrogen bonding capacities.