Investigation of Photochromic Fluorescence Features and Synthesis of Diarylethene Type Naphthalimide Compounds

The aim of the study was to synthesise novel photo-exchangeable photochromic fluorescence compounds. Starting from N-butyl-4-bromo-3-iodo-1,8-naphthalimide new compounds: 3,4-Bis(3,5-dimethyl-4-pyrazolyl)-N-butyl-1,8-Naphthalimide 6 and 3,4-Bis (1,3,5-trimethyl-4-pyrazolyl)-N-butyl-1,8-Naphthalimide 7 were prepared via two step Suzuki coupling reaction of pyrazolyl boronic acid esters, and characterized by 1 H-NMR, 13 C-NMR, MS and FTIR. Their photochromic fluorescence properties were investigated. Additionally, a solvent effect on the fluorescence properties of 6 and 7 was investigated. Increase of organic solvent polarity results in a red shift (to longer wavelengths) of the fluorescence emissions.