Photoisomerization of 1,2-Di(4-pyridyl)ethylene According to NMR and UV Spectroscopy Data and Density Functional Modeling.

Photoisomerization of 1,2-di(4-pyridyl)ethylene under UV irradiation was studied by NMR and UV spectroscopy in solutions of acetone, acetonitrile and chloroform. It has been established that in the studied solutions under irradiation, geometric photoisomerization occurs: the trans-isomer transforms into the cis-isomer and then cyclization occurs. DFT modeling of the listed processes, states and UV absorption spectra of the sample in an acetonitrile solution was performed.