ИСТИНА

Planar binuclear phthalocyanines are macroheterocycles of porphyrazine family consisting of two phthalocyanine rings directly annulated with common aromatic spacer, thus forming new extended system of π-conjugation. Binuclear phthalocyanines sharing benzene, naphthalene or pyrazine linkers are well known. Their main absorption maxima is red-shifted, and singlet oxygen quantum yields are significantly higher, comparing to analogous mononuclear complexes, making them promising compounds for oxidative coupling catalysis and photodynamic cancer therapy. Herein we report the synthetic route to novel binuclear phthalocyanines sharing a common carbazole spacer. Initial compound - carbazole tetranitrile 1 was obtained throughout 6 step synthesis starting from ethyl acetoacetate. To increase yields of target complexes, it was then transformed to the bis-diiminoisoindoline form, which is more reactive in statistical condensation reaction. Binuclear complexes 3-5 demonstrate an intense absorption up to 721 nm hypsochromically shifted in comparison with the earlier described planar binuclear complexes sharing common benzene and naphthalene rings. At the next stage the benzyl group protection was successfully removed from 9H-carbazole moiety. Thus, complex 6 prospective for further structural modification via nucleophilic substitution, Ullmann or Buchwald-Hartwig coupling reactions was obtained.