| Hybrid inorganic-organic materials represent an important new direction in the field of materials chemistry, combining the structural diversity of organic molecules with the diverse optical, magnetic, electronic, and catalytic properties found throughout the periodic table. Of the 13,000 such materials characterized to date, the vast majority are coordination polymers in which isolated metal atoms or clusters bridged by organic molecules into multidimensional networks. Hybrid metal oxides, inorganic-organic materials with infinite metal-oxygen-metal networks, are far less common, but offer distinct advantages over coordination polymers in terms of thermal stability and magnetic and electronic properties. Unfortunately, no general strategies for rationally synthesizing new examples have been described.; In this work, we show that reactions using hydrothermal synthesis and organic ligands with significant flexibility are most likely to generate new examples of hybrid metal oxides. Hydrothermal reaction conditions favor structures with fewer water molecules coordinated to metal centers, resulting in increased sharing of ligand binding sites between metal centers to maintain ideal coordination geometry. Secondly, infinite M-O-M networks require coordinating atoms (typically oxygen or nitrogen atoms) at very specific points. A high degree of positional flexibility on the part of the organic ligand is therefore necessary in order to ensure that such atoms are available. Although these principles do not guarantee hybrid metal oxide formation, the number of new hybrid metal oxides described in this dissertation demonstrate that they improve the odds considerably. |
