Establishing Supramolecular Control over Solid-State Architectures: A Simple Mix and Match Strategy

With the help of robust principles of crystal engineering, it is possible to construct co-crystals where two or more different molecular entities coexist in the same crystalline lattice; the supramolecular assembly is driven by noncovalent interactions, most commonly by hydrogen bonds. We have synthesized two ditopic amide based ligands (<i>N</i>-(4-pyridin-2-yl)isonicotinamide) and (<i>N</i>-(3-pyridin-2-yl)nicotinamide) and systematically established their binding preferences when faced with aliphatic dicarboxylic acids with an odd and even number of carbon atoms. Each ligand was co-crystallized with four odd and four even-chain dicarboxylic acids, and 13/16 reactions produced crystals suitable for single-crystal structure determination. On the basis of these results, it is clear that carefully selected systems can be manipulated to produce assemblies in the solid state with very precise control over topology and dimensionality. These ligands can be made to produce either 0-D or 1-D architectures simply by fine-tuning the choice of co-crystallizing agent in the supramolecular synthesis. This mix-and-match strategy allows us to mimic the reliability and versatility of covalent synthesis, in terms of successfully preparing a target with predetermined connectivity and metrics