Formation of Submicron Scale Particles of Narrow Size Distribution from a Water-Soluble Dendrimer with Links to Porphyrins and a Fullerene

A water-soluble l-lysine dendrimer (6) with links to porphyrins and a fullerene was synthesized, in which the dendrimer surface was modified with carboxylate groups. The aqueous solution of 6 showed the Soret band characteristic of the aggregated porphyrins in the UV−vis spectra; however, this aggregate was dissociated by the addition of 2-hydroxypropyl-β-cyclodextrin (10 wt % in H2O). TEM and AFM showed the formation of submicron-scale particles of 6. TEM showed the spherical particles of 6 with almost uniform size (100−110 nm) in the presence of the cyclodextrin. AFM showed the oval particles of 6 in the absence of the cyclodextrin. DLS measurement indicated that cyclodextrin dissociated the aggregated structure of 6 in H2O. Thus, a large number of porphyrins and fullerenes were successfully accumulated with a narrow size distribution via the particle formation of the amphiphilic dendrimer.