Synthesis of Porphyrin Derivatives Bearing Six Carboxylic Acids for the Formation of Three-Dimensional Hydrogen-Bonded Network Structures

we synthesized a series of porphyrin derivatives with six carboxylic acid groups to explore their potential in forming hydrogen-bonded networks (YSHs). By systematically varying the position and structure of these carboxylic acid groups, we observed distinct types of hydrogen-bonded frameworks, including two- and three-dimensional networks. Using single-crystal X-ray crystallography, we confirmed that these derivatives form YSHs with unique structural properties influenced by carboxylic acid positioning and pi-pi interactions. The 1Zn derivative forms a robust 3D hydrogen-bonded network stabilized by pi-pi stacking interactions, while the 2Ni derivative, with no such stacking, exhibits reduced stability and collapses upon solvent removal. Structural variations like the terphenylene and biphenyl linkers in 3Zn and 4Zn lead to flexible frameworks, while the 5Zn dimer forms two distinct structures depending on the solvent environment. Our findings reveal that careful control over carboxylic acid orientation and linker structure enables the design of diverse hydrogen-bonded networks with tunable stability and dimensionality. These insights advance our understanding of supramolecular assembly principles in porphyrin-based materials and offer new pathways for developing high-performance frameworks for applications in catalysis, sensing, and materials science.