Synthesis and Reactivity of Metallaradicals

无机化学、生物无机化学和金属有机化学项目的重点是制备含有未配对电子的新型有机金属化合物。预计新化合物中将包括一些可用作有机分子氧化催化剂的化合物。通过阳离子烷基前驱体去质子化制备三价铬(III)亚烷基化合物。在将其应用于官能化烯烃的开环歧化聚合的同时，还将对它们的反应活性进行充分的表征和阐明。还将尝试制备铬(II)和铬(IV)的烷基，以及顺磁性氢化铬，并将探索这些新化合物对将小的不饱和分子插入碳-铬键的反应性。以前在钴(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构型。例如，将探索通过与五甲基环戊二烯配体配位来稳定这些高氧化态。另一项扩展将旨在制备四面体钴氧配合物，用于有机底物的氧化。三(吡唑基)硼酸盐配体将被用来稳定高价钴，以开发利用氧气的氧化催化剂。

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.