Abstract:
A series of pegylated cis-A2B2- or A3B-type ZnPcs, substituted on the α-positions with
tri(ethylene glycol) and hydroxyl groups, were synthesized from a new bis-phthalonitrile. A
clamshell-type bis-phthalocyanine was also obtained as a byproduct. The hydroxyl group of one
ZnPc was alkylated with 3-dimethylaminopropyl chloride to afford a pegylated ZnPc
functionalized with an amine group. All mononuclear ZnPcs were soluble in polar organic
solvents, showed intense Q absorptions in DMF, and had fluorescence quantum yields in the range
0.10–0.23. The clamshell-type bis-phthalocyanine adopts mainly open shell conformations in
DMF, and closed clamshell conformations in chloroform. All ZnPcs were highly phototoxic to
human carcinoma HEp2 cells, particularly the amino-ZnPc mainly protonated under physiological
conditions, which showed the highest phototoxicity (IC50 = 0.5 μM at 1.5 J/cm2
) and dark
cytotoxicity (IC50 = 22 μM), in part due to its high cellular uptake. The ZnPcs localized in
multiple organelles, including mitochondria, lysosomes, Golgi and ER.
