Supramolecular assemblies based on polyoxometalates and pillar[n]arenes

In this project we propose the design of novel inorganic/organic hybrid systems based on the supramolecular recognition involving noncovalent interactions. These systems will consist of archetypal polyoxometalate (POM) clusters such as the Lindqvist, Anderson, Keggin and Dawson polyanions and a family of macrocyclic organic compounds known as pillar[n]arenes(n=5-8). A bottom-up approach will be followed to investigate the nature of interactions between the organic and inorganic building units. Several characterization techniques will be employed to assess these systems including multinuclear 1D and 2D Nuclear Magnetic Resonance (NMR), Electrospray Ionization Mass Spectrometry (ESI-MS) and Isothermal Titration Calorimetry (ITC) in solution. Single-crystal/Powder X-Ray diffraction (XRD), Elemental Analysis (EA), Thermogravimetric Analysis (TGA) and Infrared Spectroscopy (IR) will be used to characterize resulting materials in the solid state. Depending on the size, shape and functional groups present on both moieties, different types of host-guest complexes are anticipated. The interactions between POMs and pillararenes can be tuned by changing the reaction parameters, nature of the POM counter-cations, or by functionalising the rims of the pillararenes with polar or cationic groups. Furthermore, different hybrid POMs with covalently grafted organic groups will be prepared as they are expected to exhibit favourable interactions with pillararenes through hydrophobic interactions