Spin Chemistry of Guest@Host Systems

This thesis describes the nuclear and electronic spin chemistry of incarcerated guest molecules to form a guest@host complex in conjunction with the utility of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy. The first chapter describes the background and motivation of our scientific pursuit. Chapters 2-4 describe the nuclear spin chemistry of the two allotropes of elemental hydrogen, para-H2 and ortho-H2, incarcerated in C60, open-C60 and C70 fullerenes to form endofullerene guest@host complex, symbolized as pH2@fullerene and oH2@fullerene, respectively. Chapter 2 presents experimental results of the temperature dependence of the equilibrium of the interconversion of oH2@fullerene and pH2@fullerene and the use of different paramagnetic spin catalysts for this interconversion. Chapters 3 and 4 presents the spin-lattice relaxation (T1) and the paramagnet- enhanced relaxation, relaxivity (Rx) of o1,2H2@fullerene (1,2H2 = 1H-NMR-active H2 and HD) as well as the introduction of a new system for magnetic exploration: H2O@fullerene. Chapter 5 describes the electron spin chemistry of a paramagnetic nitroxide molecule incarcerated inside a capsule (nitroxide@octa acid) and presents supramolecular effects on paramagnetic interaction between the nitroxide incarcerated inside the capsuleplex with the nitroxide in bulk aqueous media studied by electron paramagnetic resonance (EPR) spectroscopy.