| Summary: | 碩士 === 國立成功大學 === 化學系碩博士班 === 94 === Vanadium plays important roles in biology and medicine. For instance, vanadium containing nitrogenase (V-nitrogenase) catalyzes the reduction of dinitrogen to ammonia. Some vanadium compounds such as VIVO-bis(maltolato), VIVO-bis(acetylacetonato) and VV-dipicolinato were found to replace insulin for treating type II diabetes.
The mechanism of vanadium nitrogenase catalyzes nitrogen fixation is still obscure. How vanadium compounds can treat diabetes is also not well understood. According to the spectroscopic studies, vanadium site in V-nitrogenase has a S-rich coordination environment. It has been reported that the mechanism of vanadium insulin mimics might be related to the interaction of vanadium compound with the cystein residue of protein tyrosine phosphatase (PTP). Thus, it is very important to have a fully understanding for the chemistry of vanadium compounds, particularly, in sulfur-rich ligation environment. In this research, we use polythiolate ligands, and [PS3]H3 (P(C6H4-2-SH)3), [PS3’]H3 (P(C6H3-5-Me-2-SH)3), and[PS3”]H3 (P(C6H3-3-SiMe3-2-SH)3) as a title ligand for reacting with VIII species. We obtained [(C3H7)4N][VIII(PS3)N3] (1), [PPh4][VIV(PS3”)(PS3”SH)] (2) and [VIV(PS3”)(PS3”S-C-S)] (3). Compound 1 is the first example of V(III) species binding to an N3- ion, an alternate substrate of nitrogenase. In addition, the catalytic reactivity of the reduction of azide by [VIII(PS3”)Cl]- was also investigated. [PPh4][VIV(PS3”)(PS3”SH)] (2) and [VIV(PS3”)(PS3”S-C-S)] (3) represent rare examples of seven-coordinate nonoxovanadium(IV) compounds. In this dissertation, we will detail the syntheses, structural characterization, reactivities, spectroscopies of these compounds.
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