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

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. [Figure: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13065-017-0260-x) contains supplementary material, which is available to authorized users.