New Multicomponent Porous Architecture of Self-Assembled Porphyrins/Calixarenes Driven by Nickel Ions

A new multicomponent material with nanoporous structure has been synthesized by co-crystallization of a mixture of cationic <i>meso</i>-tetrakis­(4-<i>N</i>-methylpyridyl)­porphyrin (H₂T₄) and <i>meso</i>-tri­(4-<i>N</i>-methylpyridyl)­porphyrin (H₂T₃py) with polyanionic 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis­(hydroxylcarbonylmethoxy)­calix[4]­arene (C₄TsTc) in the presence of Ni²⁺ ions. The structural analysis indicates that the overall architecture is assembled by interpenetrated two-dimensional (2D) meshes where the nodes are built up by a central tetracationic H₂T₄ porphyrin with arms hosted in sulphonated rims of four cavitands. The approximately 2D square network is formed by Ni²⁺ ions bridging the calixarene carboxylate rims in a tail-to-tail fashion. The central H₂T₄ stacks with two external H₂T₃py molecules having the neutral pyridine arm <i>N</i>-coordinated to Ni²⁺ ions. These metal centers interconnect the orthogonal 2D meshes by further coordination of calixarene–carboxylate groups. Self-organization of the new multicomponent material, featuring large channels (60% of volume accessible to solvent molecules) and potential readily accessible metal active sites, has been driven by both supramolecular host–guest recognition and coordinative assembly. The thermal behavior of native and nickel-containing crystals was studied by hot stage microscopy and differential scanning calorimetry. The decomposition temperatures of the multicomponent materials, 465–470 °C, are about 100 °C higher than those of the single building blocks