Preparation and characterization of novel double-decker rare-earth phthalocyanines substituted with 5-bromo-2-thienyl groups

Abstract

Abstract Background A series of rare-earth bisphthalocyanines of praseodymium, samarium and gadolinium bearing 5-bromo-2-thienyl substituents were prepared for the first time. Results Three bis[octakis(5-bromo-2-thienyl)] rare-earth metal(III) bisphthalocyanine complexes (Pr, Sm, Gd) were synthesized for the first time. The new compounds were characterized by UV–vis, NIR, FT-IR, mass spectroscopy and thermogravimetry as well as elementary analysis and electrochemistry. Production of singlet oxygen was also estimated using 9,10-dimethylanthracene method. Conclusions The bromine substituent causes significant changes in molecule paramagnetism, singlet oxygen production, HOMO position and spectral characteristics. The compounds in solutions exist in two forms (neutral and/or reduced) depending on the solvent and rare-earth metal. Moreover, the compounds exhibit much increased stability under acid conditions compared with non-brominated derivatives. Graphical abstract Prepared compounds for the study of their chemical and other properties.

Keywords

• Rare-earth bisphthalocyanines
• UV–vis spectroscopy
• NIR spectroscopy
• Singlet oxygen production
• Reduction
• Cyclic voltammetry