Supramolecular Crystal Chemistry with Porphyrin Tinkertoys. Hydrogen-Bonding and Coordination Networks with the “Chair” and “Table” Conformers of Tetra(3-carboxyphenyl)porphyrin

Abstract

This study explores further the supramolecular reactivity of the meso-tetra(3-carboxyphenyl)porphyrin (T3CPP) building block in the context of crystal engineering. T3CPP has coordination as well as hydrogen bonding tetradentate functionalities, and exhibits orientational versatility of the 3-carboxylic substituents with respect to the porphyrin core; chair- and table-like conformers have been expressed in this study. In the “chair” variant of T3CPP, two adjacent carboxylic functions are oriented upward and the other two downward, while in the “table” isomer all four carboxylic arms are oriented in the same direction. Solvothermal reactions of the T3CPP with cadmium and zinc ions afforded metalation of the porphyrin core and hybrid coordination compounds with uniquely interesting and novel architectures. This includes a discrete 4:2 Cd/Zn:porphyrin assembly (4), where the four metal ions link (as mononuclear connectors) between the two metalloporphyrins (present in a “table” conformation) into a molecular-...