Photophysical properties of a newly synthesized unsymmetrically substituted zinc phthalocyanine

Abstract

A novel unsymmetrically substituted zinc phthalocyanine (ZnPc) containing six hexylthio units and a morpholinoethoxy group was synthesized and characterized. Statistical condensation reaction of two different phthalonitriles was used for the preparation of unsymmetrical ZnPc. The novel compound was purified using chromatographic methods with the help of high solubility differences of phthalonitrile derivatives. Characterization of the compound was achieved by using NMR, FT-IR, UV-Vis, and mass spectroscopic methods. The photophysical measurements were made in tetrahydrofuran (THF). Fluorescent quantum yield (ΦF) and fluorescence lifetime (τF) of unsymmetrical ZnPc were determined. Fluorescent quenching experiments were done by adding benzoquinone (BQ) in THF, and Stern-Volmer constant (Ksv) and quenching constant (kq) values were calculated.

Phthalocyanines prepared from 4,5-dihexylthiophthalonitrile, a popular building block

“…ZnPc(SHex)6-M is substituted by a morpholine moiety [ 46 ] that is known to potentiate the photodynamic activity of phthalocyanine [ 47 – 49 ]. It offers also the possibility of further quaternization, which is very useful for antibacterial photodynamic therapy.…”