Unique supramolecular assemblies are constructed based on a saddle-distorted non-planar porphyrin, dodecaphenylporphyrin (H2DPP), and its metal complexes. The saddle distortion facilitates protonation of pyrrole nitrogens to afford a stable diprotonated porphyrin, which can act as an electron acceptor. A diprotonated hydrochloride salt of a saddle-distorted dodecaphenylporphyrin ([H4DPP]Cl2) forms a nano-sized channel structure called a "porphyrin nanochannel". Electron-donating molecules such as hydroquinones are included as guest molecules in the porphyrin nanochannel. Photoinduced electron transfer from the guest molecules to the singlet state of H4DPP2+ occurs, producing H 4DPP+• and cation radicals of the guest molecules. The saddle distortion also results in higher Lewis acidity at a metal center to maintain axial coordination of ligands, due to poor overlap of the lone-pair orbitals with the d orbitals of the metal center. By taking advantage of saddle distortion of both H4DPP2+ and zinc phthalocyanine, 1,4,8,11,15,18,22,25-octaphenylphthalocyanine (ZnOPPc), a discrete supramolecular assembly composed of H4DPP2+ and ZnOPPc, is obtained using 4-pyridinecarboxylate (4-PyCOO-) that connects the two components by hydrogen bonding and coordination bonding, respectively. Photoexcitation of the assembly results in efficient electron transfer from ZnOPPc to H4DPP2+ in the supramolecular complex.
- Photoinduced electron transfer
- Saddle-distorted phthalocyanine
- Saddle-distorted porphyrin
- Supramolecular assembly