Functional organic/inorganic hybrids and triphenylene-based dendritic materials

New charge-transfer hybrids containing ferrocene as the electron donor and polyoxometalates (POMs) as the electron acceptor have been synthesized using organically-functionalized POM clusters as building blocks. The structures of these hybrids have been confirmed by 1H NMR spectroscopy, ESI-MS spectrometry, and X-ray crystal diffraction measurements. Direct charge-transfer transitions from the ferrocenyl unit to the POM cluster are observed in their UV-visible absorption spectra.; Using a similar building block approach, unprecedented organometallic POM hybrids containing a transition metal complex covalently linked with a POM cluster have also been successfully prepared. The synthesis involves the anchoring a terpyridine ligand onto the surface of a POM cluster through the Sonogashira coupling reaction of an iodofunctionalized cluster with an ethynyl terpyridine, followed by the coordination of a metal ion. The resulting organometallic POM hybrid shows both metal-to-ligand charge transfer transition (MLCT) associated with the transition metal complex portion and the ligand-to-metal charge transfer (LMCT) transition associated with the imido-POM cluster. Electrochemical characterization yields redox processes consistent with its structure.; The third thrust of this thesis involves the development of new triphenylene-based dendrimers. An efficient and versatile synthetic approach leading to AB2 functionalized triphenylenes---necessary building blocks for triphenylene-based dendrimers---has been demonstrated. The synthesis of the first generation triphenylene-based dendron was completed, validating the synthetic approach. The structure of the dendron has been confirmed by 1H NMR and MALDI-TOF MS spectroscopic measurements. Photophysical and thermal property studies indicate that the various triphenylene derivatives exhibit different aggregation behaviors.