Synthesis of ytterbium bisphthalocyanines: Photophysicochemical properties and nonlinear absorption behavior

•The nonlinear absorption parameters of tetrapyridin-2-yloxy or tetrapyridin-4-yloxy phthalocyaninato ytterbium are reported.•Both complexes exhibit low fluorescence and singlet oxygen quantum yields and high triplet quantum yields.•Very low limiting intensity values were obtained.

Herein we report on the syntheses, photophysico-chemical properties and nonlinear absorption parameters of bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-2-yloxy phthalocyaninato)} ytterbium (III) (3) and bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III) (4). The fluorescence and singlet oxygen quantum yields obtained for complexes 3 and 4 are low. The triplet quantum yield obtained for complex 3 is high at ΦT = 0.89 whereas for complex 4ΦT = 0.48. The third order optical susceptibility values are of the order: 10−11 esu (for complex 3), and 10−13 esu (for complex 4) while the hyperpolarizability values are of the order: 10−28 esu (for complex 3) and 10−31 esu (for complex 4). Complexes 3 and 4 show two-photon absorption coefficients of the order of 10−46 cm4 s/photon and 10−48 cm4 s/photon, and threshold intensities as low as 0.3 J cm−2 and 0.0045 J cm−2, respectively.

Graphical abstractNonlinear absorption parameters are larger for bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-2-yloxy phthalocyaninato)} ytterbium (III) compared to bis-{1(4), 8(11), 15(18), 22(25)-(tetrapyridin-4-yloxy phthalocyaninato)} ytterbium (III), showing the effects of low symmetry in the latter.Figure optionsDownload full-size imageDownload high-quality image (60 K)Download as PowerPoint slide