The novel double-decker lanthanide metal phthalocyanines substituted with 1-[3,5-bis (trifluoromethyl)phenyl] propoxyl: Synthesis, characterization, electrochemistry, spectroelectrochemistry, and electrochromism

Novel 1-[3,5-bis(trifluoromethyl)phenyl]propoxyl substituted double-decker phthalocyanine (Pc) complexes GdPc2 (2), LuPc2 (3) and NdPc2 (4) were synthesized by the reaction of 1-[3,5-bis(trifluoromethyl)phenyl]propoxy phthalonitrile with convenient rare earth metal acetates in n-amyl alcohol under the 1,8-diazabicyclo [5.4.0]undec-7-ene catalysis at 300 degrees C. The new precursor for the syntheses of complexes was obtained from 1[3,5-bis(trifluoromethyl)phenyl]propanol and 4-nitrophthalonitrile in acetonitrile at reflux temperature in the presence of potassium carbonate as catalyst. All the complexes were characterized using UV-Vis, fluorescence, FT-IR, and MALDI-TOF mass spectroscopies. Moreover, FT-IR, 1H-NMR, and 1H-1H COSY NMR methods were used to characterize the starting compound 1. The sandwich structure of the complexes was also confirmed by their electrochemical and spectroelectrochemical measurements. The characteristic first reduction process of the radical Pc ring was observed at 0.03 V for GdPc2 (2), 0.24 V for LuPc2 (3), and 0.19 V for NdPc2 (4). In accordance with their double-decker structure, the complexes showed ring-based electron transfer processes with distinct spectral and color changes in the electrolyte medium. With highly reversible redox processes and net spectral changes, the LuPc2 (3) displayed a better electrochromic response than the others. The electrochromic film measurements suggested that the LuPc2 (3) is a promising candidate for electrochromic devices.