Photophysical Properties of Novel Phthalocyanines: Multi Emission by Excited at Short Wavelength

Abstract

Two novel phthalocyanines: tetra-azobenzene substituted zinc

phthalocyanine ZnPc.(Oazo)₄ and polymeric ytterbium phthalocyanine

carboxyl (YbPPc.COOH) have been synthesized and their electronic

adsorption and emission spectra have been investigated by spectrometric

method. Both of the synthesized compounds can emit two fluorescent

peaks when excited at short wavelength (below 400 nm) and one peak

when excited at long wavelength (higher than 600 nm) as well. For

YbPPc.COOH, in pH 7.4 buffer solution, when excited at 330 nm, beside

normal fluorescent peak at 720 nm, a second emission peak appeared at

455 nm. The fluorescence quantum yield of two emission was 0.35

(720 nm em, 635 nm ex) and 0.33 (455 nm em, 330 nm ex), respectively.

This equivalent multi-emission phenomenon by different excited wavelength

indicates good applied potential in photodynamic diagnose and

fluorescence imagination.