Water-soluble fullerenes using solubilizing agents, and their applications

Host–guest and supramolecular chemistry can produce water-solubilization of fullerenes such as C60, C70, and C60/70 derivatives by hydrophobic interactions, CH–π interactions, and/or π–π 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.