Effect of axial ligands on the photophysical properties of new silicon(IV) phthalocyanines

Abstract

A series of axial di-substituted silicon(IV) phthalocyanines with electron-donating and electron-withdrawing properties were synthesized. The compounds were characterized by elemental analysis, ¹H NMR, IR, and ESI-MS. The effect of axial ligands on the photophysical properties of silicon phthalocyanines was studied by UV/Vis, steady-state and time-resolved fluorescence spectroscopic analyses. Compared with silicon phthalocyanines with electron-donating properties, silicon phthalocyanines with electron-withdrawing properties could expand the π-conjugation in the dyes, resulting in a redshift of Q bands, lower fluorescence emission intensity and fluorescence quantum yields, but increasing fluorescence lifetimes. These results strongly suggest that the molecular design of phthalocyanines is essential for construction of photoactive materials.

Keywords:

• Silicon(IV) phthalocyanine
• Photophysical property
• Electron-donating and electron-withdrawing groups

Acknowledgements

This research was supported by the National Natural Science Foundation of China (21274021, 61335011, and 81471703), and the college students’ innovative and entrepreneurial training program of Fujian Province (hxhg-21).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 21274021], [grant number 61335011], and [grant number 81471703].