Near-infrared absorbing ligand-oxidized dinuclear phthalocyanines.

Ligand-oxidized annulated dinuclear phthalocyanine zinc(II) and lithium(I) complexes absorbing in the NIR region (lambda=1000-2200 nm) with high extinction coefficients are described. Analogous mononuclear Pc complexes were used for comparison. The oxidized Pcs were characterized in solution by electronic absorption, EPR and NMR spectra. The NIR transitions were explained by using MO diagrams calculated semiempirically. The reversible oxidation behavior of the phthalocyanine complexes was also estimated by cyclic voltammetry. These new extremely long wavelength absorbing phthalocyanines are interesting as materials with new electronic properties.