Synthesis, spectral and electrochemical characterization of non-aggregating α-substituted vanadium(IV)-oxo phthalocyanines

Two α-substituted vanadium-oxo phthalocyanines, [( OC 6 H 3(t- Bu )2)4Pc] VO and [( OC 8 H 17)4Pc] VO , where OC 6 H 3(t- Bu )2 is 2,4-di-tert-butylphenoxy and OC 8 H 17 is 2,2,4-tri-methyl-3-pentoxy, were synthesized and characterized by elemental analysis, mass spectrometry, UV-visible, IR, ESR spectroscopy and electrochemistry. Both complexes have good solubility and do not aggregate in polar or non-polar solvents. Three reductions and two oxidations can be observed in DMF containing 0.2 M TBAP. A HOMO-LUMO gap of ~1.4 V is seen for both complexes. The first two one-electron reductions and first oxidation are reversible diffusion controlled electrode processes under the given experimental conditions. The effects of solvent and phthalocyanine macrocycle substituents on the Q bands of the electronic absorption spectra are discussed.