THE ELECTROCHROMIC BEHAVIOUR OF LANTHANIDE BISPHTHALOCYANINES: THE ANOMALOUS NATURE OF THE GREEN LUTETIUM SPECIES

Abstract
Double integration of the electron paramagnetic resonance signal associated with the green form of lutetium bisphthalocyanine in dimethylformamide solution indicates it is a minor species. Magnetic circular dichroism spectroscopy strongly suggests the chromophore is not a radical. These findings are in keeping with the recently resurrected hypothesis [Daniels et al., J. Coord. Chem. (1993) 28, 23–31] that the “electrochromic” color changes observed in lanthanide bisphthalocyanine chemistry are acid-base in nature and not due to oxidation-reduction processes involving the phthalocyanine rings.