Design, synthesis and characterization of novel building blocks for supramolecular assemblies.

The study of supramolecular systems, held together by non-covalent interactions, started with the design of novel building blocks. The target donors were then prepared by means of organic synthesis and characterized by analytical tools. Pyridyl-based ligands have been designed with various shapes, rigidity, lengths and number of donor atoms. The project was carried over by reacting the organic linkers with various complementary building blocks. When metal ions and unsaturated metal complexes were used, discrete or polymeric assemblies were obtained. Structural characterization of the products by means of Single-Crystal X-ray Diffraction (SC-XRD) was coupled with several analytical tools to investigate the properties of the final materials. In some cases, the luminescence properties of the building blocks were preserved in the final networks. In addition to the use of transition metal ions as complementary building blocks, we studied the possibility to employ carboxylic acids for the preparation of supramolecular assemblies, thus forming organic co-crystals. In order to explore the versatility of the polypyridyl organic linkers in supramolecular chemistry, we decided to investigate their reactivity towards three-coordinated boron species. Cyclic-borasiloxane derivatives were reacted towards pyridyl linkers producing the first example of luminescent chiral helices prepared by B–N bond formation. Polypyridyl derivatives are also known to interact with halogens via halogen bond. Our contribute in this field was aimed to the formation of halogen-bonded supramolecular assemblies. A wide variety of products was isolated including: halogen-bonded 1D polymers, T-shaped adducts, CT adducts and organic salts featuring the presence of unprecedented polyhalides networks. Concurrently to our studies on pyridyl derivatives, we decided to design a new class of charged building blocks represented by co-facial bifluorene derivatives. A butterfly-shaped synthon belonging to these class of linkers was designed featuring four carboxylic acid functionalities. The reactivity towards metal ions is presented herein along with the structurally characterized products. The results presented in this thesis clearly promote co-facial bifluorenes as promising candidate for future supramolecular assemblies for sensing applications.