Water-soluble fullerenes using solubilizing agents, and their applications

Host-guest and supramolecular chemistry can produce water-solubilization of fullerenes such as C-60, C-70, and C-60/70 derivatives by hydrophobic interactions, CH-pi interactions, and/or pi-pi interactions. For materials and biomedical applications, these water-soluble host-fullerene complexes must have the following important properties: (i) high solubility, (ii) high stability, and (iii) functionalization of the host-fullerene complex. These objectives can be achieved by selection of appropriate host molecules, development of novel solubilizing methods, and synthesis of functionalized host molecules. This review describes the introduction of a variety of host molecules that can solubilize fullerenes in water. In addition, we describe applications of host-fullerene complexes, in particular using photoinduced energy- and electron-transfer processes in water.