Yongjun Li    Yuliang Li    DaobenZhu

           We investigated the aggregation behavior of a new zinc porphyrin derivative in which two zinc porphyrins were attached to the 4,4’-position of the 2,2’-bipyridyl group, and the 2,2’-bipyridine (bpy) was complexed with palladium dichloride. The precursor bpy–ZnP, has one typical structural feature: two porphyrin units can rotate freely around the central bipyridine bond, the relative position of two porphyrins can be controlled by the addition/elimination equilibrium of metal ions. This system is a typic amphiphile because the bipyridine–PdCl₂ units exhibit hydrophilic properties and the porphyrin units show hydrophobic interactions under specific solvent environments. SEM and TEM imagines confirmed that this molecule was able to self-assemble into vesicles with a diameter of 200 nm in CHCl₃/CH₃OH, which could turn into hollow capsules in formation of V-like configuration and the condition of heat-treatment. This approach provides a rational way for the construction of vesicles and corresponding hollow capsules, which own promising applications in optoelectronic nanodevices.

Angew. Chem. Int. Ed.  (2006, Vol. 45, 3639－3643.) 

SEM and TEM imagines of vesicles and corresponding hollow capsules.