Physicochemical properties of <i>meso</i>-benzoporphycenes with various substituents introduced into the benzene moiety fused to the porphycene framework

Benzo[[Formula: see text]]porphycenes with two substituents introduced into a benzene moiety fused to one of the ethylene bridges at the meso-positions of the porphycene framework (mMB(X) 2 Pc, X [Formula: see text] CF 3 , Cl, H, CH 3 , OCH[Formula: see text] were prepared, and the electronic effects of the substituents on the properties of porphycenes were investigated. These porphycene derivatives were fully characterized by mass spectrometry, 1 H NMR and [Formula: see text]C NMR spectroscopy. The lowest-energy absorption bands of mMB(CF[Formula: see text]Pc and mMB(Cl) 2 Pc are blue-shifted compared to the analogous bands of mMB(H) 2 Pc, while those of mMB(CH[Formula: see text]Pc and mMB(OCH[Formula: see text]Pc are red-shifted. Theoretical studies indicate that the LUMO and HOMO energy levels are stabilized when electron-withdrawing substituents are bound to the fused benzene moiety, and these findings support the features of the Q-band spectra of the presented porphycenes. In addition, electrochemical measurements are found to be influenced by a series of the substituents. Therefore, the substituents attached to the fused benzene moiety are found to contribute to the porphycene [Formula: see text]-conjugate system and modification of the meso-positions of the framework exerts a strong influence on the physicochemical properties of the porphycene.