Tetrakis-phthalocyanines bearing electron-withdrawing fluoro functionality: Synthesis, spectroscopy, and electrochemistry

Abstract

In this study, 2,9,16,23-tetrakis-4'-(2,3,5,6-tetrafluoro)-phenoxy- phthalocyaninatometalfree and metal(II) complexes, (H2PcBzF 16, ZnPcOBzF 16, CuPcOBzF 16, and CoPcOBzF 16) (Bz: Benzene) (2H, Zn, Cu, and Co), have been prepared directly from the corresponding 4'-(2,3,5,6-fluorophenylthio)-phthalonitrile compounds in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in high boiling quinoline solvent. Tetrafluoro atoms on 2,3,5,6-position of benzene at the peripheral sites of phthalocyanines (Pcs) give rise interesting solubility to tetrakismetallophthalocyanines. Although all complexes were soluble in DCM, CHCl3, THF, DMF, and DMSO with increasing order, complexes synthesized, particularly H2PcBzF16, CuPcOBzF 16, have very limited solubility in DMF and DMSO. The complexes have been characterized by elemental analysis, FTIR, 1H NMR, UV-vis, and MALDI-TOF mass spectral data. The cyclic voltammetry and differential pulsed voltammetry of the complexes show that while H2PcBzF16, CuPcOBzF 16, and ZnPcOBzF 16 give ligand-based reduction and oxidation processes, CoPcOBzF16 gives both ligand and metal-based redox processes, in harmony with the common metallophthalocyanine complexes. Redox processes due to both aggregated and disaggregated species were simultaneously observed during the first reduction process. The nature of the metal-based redox processes was confirmed using spectroelectrochemical measurements. © 2009 Wiley Periodicals, Inc.