Synthesis of water-soluble highly two-photon responsive [60]fullerene-diphenylaminofluorene chromophore dyads

We have synthesized an amphiphilic donor-acceptor type [60] fullerene-diphenylaminofluorene (DPAF) containing oligo( ethylene glycol) moieties, denoted C-60-DPAF-EG(n). The hydrophobic C-60-DPAF moiety consisting of an electron-donating diphenylaminofluorene unit and an electron-accepting C-60 cage shows large cross-sections of two-photon absorptivity (2PA) in the nanosecond region. The attachment of two hydrophilic oligo( ethylene glycol) segments on DPAF mainly increases water-solubility of the corresponding chromophoric macromolecules that enhances their potential application in biomedical treatments. Here, we present the synthesis and self-assembly study of these amphiphilic materials in aqueous solution. New C-60-DPAF-EGn compounds were structurally characterized by various spectroscopic methods including, H-1-NMR, C-13-NMR, FT-IR, and UV spectroscopies. In the vesicle formation investigation, UV-visible absorption spectra, dynamic light scattering measurements, and transmission electron microscopy were used as primary methods for morphology characterization of molecular self-assembly behavior of these amphiphilic [60]fullerene-diphenylaminofluorene chromophore dyads.