Investigation of paramagnetic supramolecular systems
(host-guest) in aqueous and organic solutions. To this aim were
developed:
1) Different methods and radical probes (guest) to use EPR
(spectroscopy of paramagnetic electronic resonance) to investigate
the properties of host systems such as cyclodextrins,
cucurbiturils, calyxarenes, micelles and gold nanoparticles. In
particular were determined the stability constants and the
association and dissociation rate constants of supramolecular
complexes, that hold together by weak interactions, include
hydrogen bonding, van der Waals and hydrophobic forces, not easily
accessible by using other techniques.
2) Different synthetic strategy for the preparation of
auto-assembled systems, in which the radical guest is mechanical
interlocked inside the host molecule. We are interested to prepare
a relatively new class of molecular architectures denominated
Rotaxanes, in which a cyclic component (bead) is threaded by a
linear chain (thread) trapped by bulky groups (stoppers) at one
([1]rotaxane) or at both ([2]rotaxane) termini of the thread. In
particular we use stoppers like paramagnetic TEMPO derivatives. The
prepared structures were characterized by using 1D and 2D NMR,
ESI-MS, and EPR.