The effect of amphiphilic polymers on the association, morphology and photophysical properties of hypocrellin coordination polymer/fullerene assemblies.

The yttrium coordination polymer of pyrene modified hypocrellin A (Y(3+)-PyrHA) is synthesized and characterized. The methoxydiglycol malonate modified fullerene can be included in the cavity of Y(3+)-PyrHA in organic solution and buffer solution containing amphiphilic polymers, such as polyvinyl pyrrolidone (PVP), pluronic F127 and P123. The interaction between an amphiphilic polymer and Y(3+)-PyrHA plays an important role in controlling the size and morphology of Y(3+)-PyrHA/fullerene. TEM images of Y(3+)-PyrHA/fullerene in 1% F127 and P123 show nanoparticles in the size range 10-60 nm, while TEM images of Y(3+)-PyrHA/fullerene in 1% PVP display large-scale aggregation. Singlet oxygen is generated by irradiation of the polymer solution of Y(3+)-PyrHA/fullerene in the presence of oxygen. The electron paramagnetic resonance (EPR) spin trapping and 9,10-dimethoxyanthracene-2-sulfonic acid sodium salt (MAS) photooxidation results suggest that in 1% P123 solution Y(3+)-PyrHA/fullerene exhibits a higher singlet oxygen quantum yield than Y(3+)-PyrHA and the corresponding fullerene.