Design, Synthesis, Crystal Structures, Magnetic And Spectral Studies Of Nitronyl Nitroxides And Their Coordination Complexes

Nitronyl nitroxide, both as the spin carriers and basic building unit of metal-nitronyl nitroxide radical complexes molecular-based magnets, has received a lot of attention in the field of molecular-based magnetic materials. Moreover, nitroxide was able to quench the excited states of fluorophores, and the imidazole unit of nitronyl nitroxide can function as an electron donor. The thesis is focused on synthesis, crystal structures, magnetic and spectral properties of nitronyl nitroxides and metal-nitronyl nitroxides. The main results are summarized as follows:1. A new compound containing two nitronyl nitroxide units bridged by tetra-(ethyleneoxy) was designed and synthesized for sensing metal ions, by taking the features of nitronyl nitroxides: a chromophore showing absorption in the visible range, reversible oxidation/reduction and coordination to metal ions. This new nitronyl nitroxide derivative was found to be able to sense metal ions both spectroscopically and electrochemically.2. Taking advantage of the fluorescence quenching ability of nitronyl nitroxides and reversible boronate formation between boronic acids and diols, new saccharides sensor based on the ensemble of one compound with a boronic group and the other compound with two phenolic -OH groups were developed3. Three new nitronyl nitroxides L₁/L₂ with amide units and L₃ with 1, 2, 3-triazole were synthesized and characterized by X-ray crystal structural analysis and magnetic characterization. Reactions of L₁/L₂ with M(hfac)2 (hfac = hexafluoroacetylatonate, M= Co(II), Ni(II), Mn(II)) afforded five hetero-spin complexes M L₁/L₂. The magnetic data were analyzed with theoretical models. Reactions of L3 with Cu(F₃CCO₂)₂ afforded bi- and tetranuclear hetero-spin complexes (Cu)₂(L₃)₂ and (Cu)₄(L₃)₂.4. A series of exploration research work was performed on other aspects of nitronyl nitroxides.