Iron and Porphyrin Metal-Organic Frameworks: Insight into Structural Diversity, Stability, and Porosity

Reaction of iron(IIII)chloride with the free base tetrakis(4-carboxyphenyl)porphyrin (H2TCPP) in the presence of different bases leads to the formation of a series of iron/porphyrin metal-organic frameworks. Such a crystal engineering approach led to the obtaining of four structures presenting three different topologies and inorganic secondary building units. Depending on the synthesis conditions, isolated Fe-III octahedra, diiron(II) paddle wheel dimers, or extended [Fe-III(OH)O-4](n) chains could be obtained in a controlled manner. The influence of the synthetic conditions on the final structure and the oxidation state of iron is discussed. Stability of the porous solids towards air and water is studied, and their intrinsic porosity is assessed.