CRAFTING POROUS CRYSTALLINE NETWORKS IN MOLECULAR BASED SOLIDS. Israel Goldberg, School of Chemistry, Tel-Aviv University, 69978 Ramat-Aviv, Israel

The versatility of porphyrin-based metallomacrocycles as crystalline hosts appears to be unequaled due to the large size, high symmetry, rigidity and thermal stability of the molecular framework. It is feasible to tailor their shape and functionality features by organic synthesis, and thus affect the microstructure of the resulting assembly. In this study we demonstrate that a suitable functionalization of the metallomacrocyclic framework with polarized aryl groups can be used to develop simple chemical models of self-assembly via weak intermolecular forces, and to control the spontaneous built-up of the porphyrin lattice by molecular recognition properties of the respective sensor groups. The strength and multiplicity of the noncovalent interactions are expected to act in concert to reinforce directional preferences and dominate the crystal field. In the resulting crystalline materials the molecular building blocks are incorporated into pseudo-rigid polymeric arrangements with a porous architecture.

Our preparative efforts focused on the design of several new classes of hollow crystalline networks in which the metallomacrocyclic units are linked into multi-dimensional polymeric architectures via metal-ligand coordination, hydrogen-bonding, dipolar association, halogen-halogen interaction, [[pi]]-[[pi]] stacking and C-H..[[pi]].contacts. The size and shape characteristics of the pore structure in these networks are determined by the nature of the particular supramolecular synthon involved in steering the intermolecular self-assembly. Most of the porphyrin-based solids have a strong tendency to incorporate molecular guest components of complementary shape into the lattice, and thus provide novel types of potential solid state receptors for isolation, separation, transport, exchange and controlled release of molecular entities. The structural and inclusion features of the various motifs will be discussed in some detail.