Synthesis and Reactivity of Metallaradicals

本项目在无机、生物无机和有机金属化学专业的重点是制备含有不成对电子的新型有机金属化合物。这些新化合物有望包括一些作为有机分子氧化催化剂有用的化合物。将阳离子烷基前驱体脱质子制得铬（III）烷基烯。在研究它们在功能化烯烃开环复分解聚合中的应用的同时，还将对它们的反应性进行全面的表征和阐明。还将尝试制备铬（II）和铬（IV）的烷基，以及顺磁性铬氢化物，并探索这些新化合物对小不饱和分子插入碳-铬键的反应性。先前在钴（IV）和钴(V)烷基领域的工作将扩展到新的烷基和新的配位几何。例如，通过与五甲基环戊二烯配体的配位来稳定这些高氧化态将被探索。另一个扩展将旨在制备四面体钴氧配合物，这将用于氧化有机底物。三（吡唑基）硼酸盐配体将用于稳定高价钴，试图开发利用二氧的氧化催化剂。

The focus of this project in the Inorganic, Bioinorganic and Organometallic Chemistry Program is the preparation of new organometallic compounds which contain unpaired electrons. The new compounds are expected to include some which are useful as catalysts for the oxidation of organic molecules. Chromium(III) alkylidenes will be prepared by deprotonation of cationic alkyl precursors. Full characterization and elucidation of their reactivity will be pursued in parallel to their application in ring opening metathesis polymerization of functionalized olefins. The preparation of alkyls of chromium(II) and chromium(IV), and of paramagnetic chromium hydrides, will be attempted also, and the reactivities of these new compounds toward insertion of small unsaturated molecules into the carbon-chromium bond will be explored. Previous work in the area of cobalt(IV) and cobalt(V) alkyls will be extended to new alkyl groups and new coordination geometries. For example, stabilization of these high oxidation states by coordination to the pentamethylcyclopentadienyl ligand will be explored. Another extension will aim at the preparation of tetrahedral cobalt oxo complexes, which would be used in oxidations of organic substrates. Tris(pyrazolyl)borate ligands will be utilized to stabilize high-valent cobalt in an attempt to develop oxygenation catalysts which utilize dioxygen.