Diaryl-Substituted Perylene Bis(imides): Synthesis, Separation, Characterization and Comparison of Electrochemical and Optical Properties of 1,7-and 1,6-Regioisomer

A series of diaryl-substituted perylene bis(imides) (PBIs) containing electron-donating and -withdrawing aryl groups in the bay region (1-, 6-, 7- and/or 12-positions of the perylene core) were synthesized by Suzuki coupling reaction. The corresponding regioisomers, namely, 1,7- and 1,6-regioisomer, were separated from the mixture by conventional column chromatography without any need of recrystallization. All the individual regioisomers were fully characterized by 1H NMR and HRMS spectroscopy. The compounds were studied by optical spectroscopy and electrochemical techniques. The optical and electrochemical properties of 1,7-regioisomer are slightly different from the 1,6-regioisomer of the respective diaryl-PBI. Significant redshift and broadening of the absorption and emission maxima were observed in all synthesized PBIs depending upon the electronic nature of the attached aryl group. This is very first time such large series of 1,6-diarylperylenetetracarboxydiimides with their corresponding 1,7-regioisomers were synthesized, separated, characterized and studied in detail.