Towards tailoring of metal-containing bending crystals

The paucity of reliable and robust strategies for assembling molecular building blocks in a predictive way is one of the main challenges that stand in the way of targeting materials with desired properties. This is especially true for metal-organic systems that employ building units of lower dimensionality, whereas the organic solid-state has delivered numerous synthons that provide effective avenues for supramolecular synthesis. Recently we established a protocol for supramolecular synthesis of 1-D chains comprising 0-D metal-containing building units that are linked via predictable hydrogen bonds. To make this approach more general and applicable to a variety of metal-based building blocks equipped with functionalities capable of forming different types of non-covalent interactions, we opted for assemblies based on 1-D metal- containing building units. We focused on cadmium(II) halides as those tend to produce 1-D coordination polymers with predefined metal-metal spacing. This central structural spine was further equipped with ligands bearing functionalities that are known to form well-defined synthons in molecular solids. To rationalize the outcome of the synthetic and structural work, molecular electrostatic potential surfaces (MEPs) were calculated. Once the supramolecular synthetic strategy was established, we probed our needle-like crystals for potential bending behaviour. The pronounced mechanically induced elastic bending of selected crystals will be discussed in details.