Synthesis, spectral properties, cation-induced dimerization and photochemical stability of tetra-(15-crown-5)-phthalocyaninato indium(III)

The novel 2,3,9,10,16,17,23,24-tetra-(15-crown-5)phthalocyaninato indium(III) hydroxide [(15 C 5)₄ Pc ] In ( OH )(I) was obtained by direct interaction of tetra-(15-crown-5)-phthalocyanine with indium acetylacetonate with 90% yield. The set of UV-vis, ¹ H NMR and MALDI-TOF spectroscopy data allowed the unambiguous interpretation of complex structure. It was shown that the developed synthetic approach can be also used for synthesis of indium(III) 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine [( BuO )₈ Pc ] In ( OH )(II). Photophysical characteristics (fluorescence and singlet oxygen quantum yields) of I were established. The photochemical stability of I was compared with tetra-(15-crown-5)-phthalocyanine H ₂[(15 C 5)₄ Pc ] and aluminum(III) complex [(15 C 5)₄ Pc ] Al ( OH ). It was found that cation-induced formation of cofacial dimers [2I × 4MX] ( M = K ⁺, Rb ⁺, X = CO ₃^2-, OPic ^-, OPiv ^-, SO ₄^2-, ClO ₄^-, Br ^-) resulted in significant enhancement of complex photostability.