Control of supramolecular porphyrin assemblies in the gel phases by metalation and axial coordination

To construct various unique porphyrin assemblies, urea groups bearing-porphyrin gelators 1-H ₂, 1-Cu and 1-Zn were newly synthesized. It was revealed by SEM and UV-vis spectra that introduce of Cu(II) into the porphyrin nuclei changes the stacking mode in the gel phases. 2-H ₂ and 2-Cu having triethoxysilyl groups at their periphery successfully give organic/inorganic hybrids composed of porphyrin superstructures after sol-gel reaction. On the other hand, 1-Zn is found to gelatinize benzene only in the presence of piperazine. SEM images of the gels showed that increasing the stoichometry of piperazine to 1-Zn varies the morphology of 1-Zn · piperazine complex aggregates: that is, spherical structure(0 eq.), 1-D fibillar structure(0.5 eq.), 2-D sheet structure(1.0 eq.). In addtion, we have studied the viscoelasticity of 1-Zn · piperazine complex gel.