Porphyrin Sponges: Structural Systematics of the Host Lattice

Analysis of the crystal structures of over 100 tetraarylporphyrin-based lattice clathrates reveals the extent to which van der Waals interactions between host molecules govern the crystal packing. In all these materials, corrugated sheets of tightly packed porphyrin molecules stack to form arrays of parallel channels in which a remarkable variety of guest species are accommodated. Conservation of the host structure in the absence of any covalent or hydrogen-bonding connection between host molecules suggests an engineering strategy for the designed construction of molecular solids. This strategy is based on the use of rigid molecular building blocks with self-complementary shapes. Identification of the features of the molecular structure responsible for the versatility of tetraarylporphyrin-based clathrates lays the groundwork for the development of new microporous materials. X-ray structural data are provided for 34 new materials.